**6. Conclusions**

pCDs have many advantages, including a sustainable source of raw materials, low cost, multiple synthetic methods, and a simple synthesis procedure. They not only have the characteristics of cyclodextrin molecules, such as an internal hydrophobic-external hydrophilic cavity structure and hand-shaped features, but they also have the excellent mechanical strength, hardness, and good thermal stability of polymers.

This article introduced the research progress of pCDs, including their synthesis and applications in analytical separation science, materials science, and biomedicine. The field of analysis and separation science mainly uses the cavity structure and hand shape characteristics of pCDs to realize separation and detection. In the field of materials science, CDs have been incorporated into various materials. Compared with traditional materials, pCDs have the characteristics of a high flux and solubility, resulting in practical materials with superior properties. In the field of biomedicine, compared with traditional materials, pCDs have the advantages of specific identification, non-toxicity, and good biocompatibility. In short, pCDs have been increasingly applied in the fields of analysis and separation science, material science, and biomedicine because of their unique characteristics.

While emphasizing the multi-field applications of pCDs, this article focused on its scientific and technological innovation as drug delivery vehicles, using the latest research as examples to illustrate their potential for cancer treatment and the elimination of fungi. A summary of the development trend in pCDs from multiple fields and perspectives illustrates the large growth in the amount of pCD research and the large potential for development, and this work provides direction for future research.

**Author Contributions:** Literature search, Y.L. and T.L.; figures, Q.W., Y.L. and S.L.; study design, C.C. and X.H.; data collection, C.L. and Q.W.; data analysis, X.H. and C.L.; data interpretation, T.L. and S.L.; writing, C.C. and Y.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by National Natural Science Foundation of China (81901896); and Scientific Research Foundation of Fuzhou University (GXRC-19025).

**Data Availability Statement:** Data are available in a publicly accessible repository.

**Conflicts of Interest:** The authors declare no conflict of interest.


*Article* **"The Unbearable Green Demon": A Critical Analysis of Press Representation around the Extermination of Monk Parakeets in Madrid**

**Laura Fernández \*, Jose A. Moreno and Alejandro Suárez-Domínguez**

Department of Communication, Pompeu Fabra University, 08002 Barcelona, Spain<EMAIL_ADDRESS>(J.A.M<EMAIL_ADDRESS>(A.S.-D.)

**\*** Correspondence<EMAIL_ADDRESS>
**Abstract:** We examine the press representation of monk parakeets (*Myiopsitta monachus*) and their population management in Madrid city. To do this, we analyze mentions of this species in six Spanish newspapers for the case of Madrid. We apply a mixed methodology composed of framing, text analysis, and sentiment analysis. This multi-method approach allows us to further examine the framing and word choice of the newspapers, concluding that the press representation of monk parakeets has been biased and non-ethically led. We discuss this outcome by proposing a media representation guided by non-speciesist ethical framings and avoiding the objectification of nonhuman animals.

**Keywords:** monk parakeet; Madrid; press representation; invasive species; conservationism; control methods; speciesism; framing analysis; text analysis; sentiment analysis

#### **1. Introduction**

The monk parakeet (*Myiopsitta monachus*) is an avian species of parrot originally from South America (Ministerio de Agricultura, Alimentación y Medio Ambiente 2013). Due to the international pet trade, individuals of this species were captured from the wild and introduced into Europe, with the first record of their presence in Spain in 1975 (Edelaar et al. 2015) and in Madrid in January 1985, with monk parakeet nests and offspring first spotted in 1989 in a eucalyptus (*Eucalyptus*) at Canillejas (Carrasco Núñez 2014).

Since this species' introduction, records have shown exponential growth in Mediterranean countries (Postigo et al. 2019) and in Madrid city in particular (Martín Pajares 2006). The scientific evidence on monk population size and distribution indicates that "Spain alone hosts 84% of the EU monk parakeet population" (Postigo et al. 2019, p. 919), with 6702 estimated monk parakeets in Madrid and around 5000 in Barcelona in 2019 (around 50% of those in the EU in both municipalities) (Postigo et al. 2019, p. 919).

The first monk parakeet census in Madrid was taken in 1998 (p. 123). The estimated population in 2000 was around 1000 (De Ayala 2002). Nowadays, the number is not clear, with estimates from 6702 (Postigo et al. 2019, p. 919) to more than 10,000, as argued by the Madrid City Council (EFE 2020a).

Years after its introduction, this species of parrots has been able to adapt and survive in urban environments after its deliberate or accidental liberation and escape (Souviron-Priego et al. 2018). The monk parakeet species (*Myiopsitta monachus*) was included in the Spanish Catalog of Invasive Exotic Species in 2013 in Royal Decree 630/2013 (Carrasco Núñez 2014). The Madrid City Council, encouraged and supported by the Spanish Ornithological Society SEO/Birdlife, has determined that the monk parakeet population needs to be controlled due to the potential damage this species causes to ecosystems, human economies, and health. The main damages presumably caused by parakeets are the noise, the potential damage if their nests fall on people, agricultural damages (Senar et al. 2016), potential disease

**Citation:** Fernández, Laura, Jose A. Moreno, and Alejandro Suárez-Domínguez. 2022. "The Unbearable Green Demon": A Critical Analysis of Press Representation around the Extermination of Monk Parakeets in Madrid. *Journalism and Media* 3: 382–404. https://doi.org/10.3390/ journalmedia3030027

Academic Editors: Carrie P. Freeman and Núria Almiron

Received: 29 October 2021 Accepted: 16 June 2022 Published: 21 June 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

95

transmission, and, most importantly, alleged environmental competition with native birds (SEO Birdlife 2017) (hereinafter, the "problem/s"). As a response to these problems, the Madrid City Council approved services using lethal methods that involve slaying the parrots, as per the guidelines proposed by the Spanish Ministry for the Ecological Transition and the Demographic Challenge, or MITECO (Ministerio para la Transición Ecológica y el Reto Demográfico), for exotic invasive species (Orueta 2007).

Previous literature on human responses to introduced species and the control strategies adopted for their populations underlines the importance of analyzing social perceptions and attitudes toward these nonhuman animals before planning an intervention (Berthier et al. 2017; Ribeiro et al. 2021; Perry and Perry 2008). Scientists and political authorities need to consider the existence of previous social manifestations of ethical concerns regarding eradication plans, as is the case with activist campaigns and public dissent against the slaying of monk parakeets that has already taken place in other parts of the world (Seymour 2013; Crowley et al. 2019). Media professionals have the ethical duty of amplifying the voices of affected stakeholders, including nonhuman animals, in situations in which they are primarily affected (Freeman and Merskin 2016; Animals and Media 2016; UPF-CAE 2016).

Is well known that the media has a great influence on shaping human views, attitudes, and relations with other nonhuman animals (Molloy 2011; Almiron et al. 2016). This potential impact must therefore be handled with professionality and moral responsibility to include nonhuman animals with whom humans share the environment. Ethical guidelines on journalism and nonhuman animals point out the need to (a) provide continuous coverage of situations that affect nonhuman individuals, as well as the work of animal advocacy organizations; (b) avoid anthropocentric perspectives and speciesist bias when covering nonhuman animal issues; and (c) select appropriate terminology to avoid the denigration, devaluation, and misrepresentation of other animals (Freeman and Merskin 2016; Animals and Media 2016; UPF-CAE 2016). Although nonhuman animals do not literally have a voice in terms of human language, they do communicate and have specific needs and interests of their own (Freeman et al. 2011). Ethical journalism needs to listen, and responsibly represent these nonhuman animal voices and perspectives, particularly in a speciesist, human-dominated world (Freeman et al. 2011; Almiron and Tafalla 2019).

Accordingly, we are interested in examining how this problem is presented by Spanish newspapers and how this representation is related to the material lives of these birds and the social attitudes towards them. This is important because the presence of monk parakeets in Madrid city urban areas have been framed as a problem on the grounds of the conservation biology field. However, we suspect that this evidence, if not ethically framed, can help to promote a view where monk parakeets' lives and interests are overlooked.

We conducted research to examine how monk parakeets were represented in six Spanish newspapers for a six-year period (2015–2021) when the Madrid City Council decided on population management. Our main research objectives were to examine (1) whether and how the press represented the "problem" with the monk parakeet (*Myiopsitta monachus*) population in Madrid and its origin, (2) which political organizations and institutions were presented as responsible for managing this "problem", (3) the management solutions that were suggested for solving this "problem", (4) who the media gave voice to and whether it was for or against the killing, and (5) which keywords and sentiments were associated with the news covering monk parakeets in the examined Spanish newspapers. For this goal, we used the framing, keyword, and sentiment analysis methodologies. This paper aims to contribute to the existent literature on critical animal and media studies, journalism studies, and press representation by covering an under-studied case: the representation of monk parakeet population management in the city of Madrid.

This paper is structured as follows: Firstly, we present a literature review organized into three main sections: (1) "The Monk Parakeet", with basic information about these birds, their introduction into Spain, and their current status; (2) "Exotic, Invasive, Pest", where we explore the categorization of monk parakeets and question their status as an exotic invasive species or pests from a non-anthropocentric and anti-speciesist ethical view; and (3) "Press

Representation of Nonhuman Animals", where we explore previous literature on this topic, with special attention to liminal nonhuman animals considered invasive or pests. Secondly, we present the methodologies of our research, namely, framing, keyword, and sentiment analysis. Lastly, we provide our main results, and we discuss them in conversation with existing literature on the topic.

#### **2. Literature Review**

#### *2.1. The Monk Parakeet (Myiopsitta monachus)*

Monk parakeets are sentient and intelligent individuals that belong to an avian species of the family *Psittacidae* and are originally from South America (Martín Pajares 2006). Monk parakeets can be recognized by their green color, greyish chest, and bluish remiges (Muñoz Gallego 2019) (Figure 1). They are medium size, 28−29 cm long, weigh between 90 and 140 g (Muñoz Gallego 2019), and do not have sexual dimorphism (Muñoz Gallego 2019). In Spanish urban areas, monk parakeets usually live in urban parks or gardens (Carrasco Núñez 2014), and in the case of Madrid, most of their nests are found in cedars (*Cedrus* spp.) and Oriental planes (*Platanus* × *acerifolia* (*Aiton*) *Willd*) (Martín Pajares 2006).

**Figure 1.** Three monk parakeets on the grass in Rome, Italy. Source: Vito Giaccari/Pexels.

They are generally monogamous, "so quite a few monk parakeets stay together in a pair but some change, often after their pair mate had disappeared—dead or dispersed" (Dawson-Pell 2021). Monk parakeets are highly social birds (Muñoz and Real 2006) that have a sedentary lifestyle, a broad diet (Appelt et al. 2016), and gregarious behavior (Di Santo et al. 2013).

A unique characteristic of the monk parakeet is that it is the only species in its family to build its own nest with twigs, sometimes using existing cavities (Hernández-Brito et al. 2021). Its preferred place to build its nests is at the top of trees, 12.3 m high on average (Carrasco Núñez 2014). They generally prefer to stay on tree perches to reduce predation risks, prevent overheating due to high summer temperatures during the day, and be able to rest (Di Santo et al. 2013). However, larger clusters can be observed on the ground, especially for feeding purposes (Di Santo et al. 2013). Di Santo et al. (2013) also argued that they come together on the ground, where they are more vulnerable, probably to reduce the risks of predation or potential attacks (p. 280), which speaks to the social nature of monk parakeet behavior.

Another piece of evidence of their social behavior, even beyond their species, is that they live in communal nests, and each nest has a variable number of brooding chambers that are used year-round (Carrasco Núñez 2014). During the breeding season, each chamber is inhabited by a pair of breeding adults, and in non-breeding periods each chamber can accommodate three or four individuals (Fresia Martín 1989). Their clutch has four to eight eggs (Carrasco Núñez 2014) that are deposited every two days (Aramburú 1991). Some studies detected cohabitation in the same monk parakeets' nests by different species of birds, such as the Italian sparrow (*Passer italiae*) (Moltoni 1945) and the Spanish sparrow (*Passer hispaniolensis*) (Lorenzo Gutiérrez 1993). Monk parakeets' nests' chambers are therefore frequently used by other avian species to avoid predators (Wagner 2012), and these nests provide a substrate for breeding, offering a thermoregulated environment that determines avian reproductive success (Hernández-Brito et al. 2021). Monk parakeets' facilitation of other species' development through their nests has made them earn the qualification of "ecosystem engineers", meaning that monk parakeets create a "nest web" that provides a resource to several birds who nest in secondary cavities (Hernández-Brito et al. 2021).

Even FCC, the company in charge of the monk parakeet slaying in Madrid, recognized in their report about the same situation in Zaragoza that monk parakeets cohabit and share nests with white storks (*Ciconia ciconia*), western jackdaws (*Coloeus monedula*), rock doves (*Columba livia*), common wood pigeons (*Columba palumbus*), Eurasian collared doves (*Streptopelia decaocto*), and house sparrows (*Passer domesticus*), and that co-feeding is also peaceful between monk parakeets and several avian urban species (Esteban 2016).

Regarding their global distribution, this species can adapt to different urban and nonurban environments both in its original habitat and where it has been introduced (Martín Pajares 2006), being among the most successfully introduced and established parrots worldwide (Appelt et al. 2016). Most monk parakeets have been caught from the wild and moved from South America to pet shops and homes in different countries around the globe (Edelaar et al. 2015). According to CITES records, 84.20% of individuals were traded for commercial purposes and unreported purposes in 14.62% of cases (Calzada Preston et al. 2021, p. 704). Spain is among the top three countries importing monk parakeets (along with Mexico and the US) (Calzada Preston et al. 2021, pp. 705–6); however, since 2005 the imports have been reduced, after the European Union passed the Wild Bird Declaration and prohibited the export of wild-caught birds (Grupo de Aves Exóticas, SEO/Birdlife 2012 in Calzada Preston et al. (2021, pp. 706–9).

Monk parakeets were therefore brought to Spain because of legal and illegal wildlife and pet trade, and they were able to adapt to urban ecosystems after release or escape (Martín Pajares 2006; Edelaar et al. 2015; Abellán et al. 2016; Souviron-Priego et al. 2018; Calzada Preston et al. 2021). The dimension of the global problem of human export of nonhuman animals is huge, and the case of monk parakeets is good evidence of it. Nowadays, there are records of these birds being established and/or bred on five continents and in multiple countries, including Europe (Austria, Belgium, Czech Republic, Denmark, France, Germany, Italy, the Netherlands, Portugal, Slovakia, Spain, and the United Kingdom), America (Brazil, Canada, Caiman Islands, Chile, Dominican Republic, Guadeloupe, Mexico, Puerto Rico, Venezuela, and the US—including the Virgin Islands), Asia (Israel and Japan), Africa (Kenya), and Oceania (Australia) (Calzada Preston et al. 2021, pp. 706–9).

#### *2.2. Exotic, Invasive, Pest*

Special attention has been paid to the language used to talk about nonhuman animals, their characteristics and activities, and how certain terminology reproduces speciesism and helps normalize violence towards them (Dunayer 2001; Stibbe 2012; Freeman and Merskin 2016; Animals and Media 2016; UPF-CAE 2016). We present in this section an explanation of several terms used to describe and label monk parakeets and their implications from an ethical point of view1.

When an animal or plant species is described as exotic, it refers to "any species, including its larvae, seeds, eggs, spores, or other biological material capable of propagating the species, which is not native to that ecosystem (Beck et al. 2008). An exotic species does not necessarily cause economic or environmental harm to an ecosystem" (Barros 2016, pp. 311–12). In the case of terrestrial vertebrate nonhuman animals, most of those established in Europe were introduced as commodities by animal exploitation industries such as the pet trade, the live food trade, or the fur industry (Keller et al. 2011). Even if not all species moved beyond their native range can establish at a certain territory, research shows that their presence implies global biodiversity loss and damage to human economies and health (Keller et al. 2011).

A non-native species is termed an "introduced" species when it "enters" a new environment or geographic location, intentionally or accidentally by several "introduction pathways" (the various processes and mechanisms of entrance) (Jeschke et al. 2021). Nonhuman animals can spread naturally from a neighboring region where the species is not autochthonous (Jeschke et al. 2021) or be displaced by direct or indirect human intervention and transportation (Keller et al. 2011). This introduction can be deliberate (for instance, for fishing or hunting purposes) or accidental (in the case of escapes of nonhuman animals kept as pets). The introduced species has been considered a "casual" species if it cannot self-sustain but is found beyond human breeding or cultivation, or an "invasive" species when "it spreads widely and causes measurable environmental, economic, or human health impacts" (Keller et al. 2011, p. 2). The Spanish Official State Gazette considers that the term "invasion" describes the negative impact a species has upon its non-native ecosystem due to its rapid spreading and population growth (Boletín Oficial del Estado 2011).

The invasive nature of a species is frequently debatable among the scientific community because many factors that are not necessarily predictable when it is introduced are at stake (Álvarez Halcón 2014). The success of a certain species to becoming established in a given area depends on multiple factors—the similarity with its original environment; the size of the initial population (propagule) and how often it is introduced; the presence of predators, parasites, diseases, food resources, and/or potential competitors; the species' own biological characteristics; the type and complexity of the new ecosystem; and the size of the new area, among other unpredictable environmental factors (Álvarez Romero et al. 2008). In the case of exotic birds in Spain and Portugal, most introductions were the result of accidental escapes of traded birds around the world, of which a large proportion escaped from public zoological parks (Abellán et al. 2016). Approximately 8% of introduced bird species successfully establish breeding populations in the wild, which is aligned with the tens rule2 (Abellán et al. 2016, p. 269). Wild-caught birds are more able to survive in new environments, which contributes to their establishment success (Abellán et al. 2017, p. 9388). In the spread stage, "success seems to be mainly influenced by the extent to which climatic conditions in this region resemble those from the species' native range" (Abellán et al. 2017, p. 9388). In Spain, the organism responsible for the inclusion or exclusion of a given species on the Spanish Catalog of Invasive Exotic Species is the Ministry for the Ecological Transition and the Demographic Challenge (Herrero Puncernau et al. 2012). This catalog includes species "susceptible of becoming a serious threat by competing with native wild species and altering their genetic purity or ecological balance, as well as potentially invasive exotic species" (Herrero Puncernau et al. 2012, pp. 12–133). The monk parakeet (*Myiopsitta monachus*) was cataloged as an invasive exotic species in Spain in 2013.

Monk parakeets have also been associated with the terms "pest" and "plague", which are also used for introduced species that can potentially damage ecosystems. However, there are no objective criteria to define a particular species as a pest, which is a completely anthropic concept that human animals apply to any species they regard as unpleasant (Alguazas Martínez 2017). This sense of being unpleasant is generally motivated by its perception as existing in huge and growing populations. In the case of the urban cohabitation with nonhuman animals labeled as pests, this perception is also related to the separation humans socially create between the city and nature (Borsellino 2015).

When referring to so-called exotic or invasive nonhuman animals, xenophobic references and war metaphors—similar to those used for human migrants and refugees—are abundant (Subramaniam 2001; Khazaal and Almiron 2021). This language provokes a sense of otherness and negative emotions such as fear and revulsion that easily legitimize their persecution and eradication (Inglis 2020, pp. 300–2). In Meera Iona Inglis' words:

"Animals which have been labelled 'invasive species' are the great villains of the wildlife conservation world. They are represented, both by the popular media and within academic discourse, as marauders, aliens, killers and monsters (Strayer and Waldman 2013). As a result, the public is encouraged to perceive these animals, not as valuable members of the biotic community, but as a threat that needs to be met with deadly force" (Inglis 2020, p. 299).

Although there is evidence of the potential damage certain nonhuman animals can cause to ecosystems and human economies or health, this categorization is not neutral (Subramaniam 2001) and its use faces the problem of promoting wrongful species discrimination (Abbate and Fischer 2019) and devaluing the lives of nonhuman animals, which cannot be ethically justified (Inglis 2020, p. 300). On the one hand, a more nuanced understanding of the interaction of different species is needed, particularly in the context of fast environmental transformations and the climate emergency (Pearce 2015). On the other hand, Inglis' proposal (2020) is to avoid these simplistic and demonizing terms, using "potential problem species" instead (Inglis 2020, p. 309). Inglis is convinced that changing the way we describe, speak about, and appreciate nonhuman animals can influence public policy and how the problems associated with them are managed (Inglis 2020, p. 300). Other alternative terms we collect and suggest would be, simply, "introduced nonhuman animals", "allochthonous species", "displaced nonhuman animals", or "nonhuman animal migrants" (Khazaal and Almiron 2021).

Furthermore, the construction of nonhuman animals as invaders or pests hides a human supremacist, speciesist, and anthropocentric worldview. In this case, the slaying of monk parakeets has been justified with the hypothetical greater good of maintaining habitat balances rather than individual lives, while focusing much less on the human responsibility in monk parakeets' transportation for business purposes (Almiron and Tafalla 2019). It is important to bear in mind that eradication plans and management of exotic species "are situated within complex social and political contexts that certainly cannot be understood by focusing solely on the amount of damage done to the physical environment; if that were the case, farmed animals would be the first to be targeted" (Reis 2014, p. 304). In fact, under this environmental logic and considering Earth's history, humans are one of the most invasive species of all (Inglis 2020, p. 311). However, the culling of human animals will, of course, never be ethically justified for environmental or ecosystemic reasons, which confirms the centrality of humans in comparison to "second-class sentient beings toward whom compassion and cruelty are applied differently" (Almiron and Tafalla 2019, p. 8).

Because monk parakeets are labeled as an exotic invasive species by law, their management is depicted as a must. Various methods of monitoring, controlling, and eradicating the parrots are applied in different contexts. The Spanish ministry guidelines suggest the following methods for the slaying of monk parakeets: nest destruction, the use of traps, shooting, the use of toxic products, biological control, intimidation, and live capture, with the latter being the most recommended method (Orueta 2007). More recent research argues for shooting as the most effective and cost-efficient method to eradicate the monk parakeet population (Senar et al. 2021, p. 471).

The scientific literature does not generally emphasize monk parakeets as sentient, valuable individuals that deserve moral consideration (Subramaniam 2001; Abbate and Fischer 2019; Inglis 2020). In addition, human ethical responsibility for the problems created by displaced species is overlooked when discussing the proposed methods of the control or

eradication of certain species (Almiron and Tafalla 2019). What is worse, the main source of the problem (the global transportation and trade of exotic birds) remains active and not well controlled, therefore giving room to potential release, escape, and settlement of other introduced birds in the future (Souviron-Priego et al. 2018; Eurogroup for Animals 2020).

#### *2.3. Press Representation of Nonhuman Animals*

Studying the press discourse around nonhuman animals "can provide insight into social attitudes toward other species" (Herzog and Galvin 1992, p. 77). Moreover, the press can play a relevant role in turning the public's attention to particular issues and frames (Freeman 2009) through the agenda-setting effect (McCombs and Shaw 1972). The press is not only helpful in understanding social attitudes toward certain nonhuman animals, but also crucial in building them. This process is related to a social constructionist view that Freeman (2009) addresses by referring to Hall's (1997) idea: "the meanings humans associate with anything are not derived from nature; they are social constructions created through human language" (Freeman 2009, p. 83).

In this regard, framing this type of nonhuman animals as a plague, pest, or similar metaphor can contribute to undermining their moral status, so their welfare seems unimportant (van Gerwen et al. 2020). As argued in the previous section, "words such as 'invaders', 'foreigners' and 'aliens' are frequently used to create a sense of otherness, making the persecution of non-native animals seem justifiable" (Inglis 2020, p. 301). Furthermore, the liminal status4 of the parakeets must be considered, as the discussions about animal treatment, welfare, and rights do not usually concern these types of nonhuman animals or human obligations toward them (Donaldson and Kymlicka 2011; van Gerwen et al. 2020). On top of that, the speciesist mainstream perspective in the press discourse does not include nonhuman animals' voices, as Freeman understands them: "a description of the animals' response to their situation or through allowing humans to speak on behalf of the nonhumans' interests" (Freeman 2009, p. 85).

By analyzing the media representation of the Asian carp (an invasive species in the United States), Mando and Stack observed a rhetorical methodology that combines strategies "such as the invocation of proximization, spectacle, and anti-immigration rhetoric to achieve a specific negative response" (Mando and Stack 2018, p. 1). Proximization is a "discourse strategy of presenting physically and temporally distant events and states of affairs (including 'distant' adversarial ideologies) as increasingly and negatively consequential to the speaker and her addressee" (Cap 2014, p. 190). Cap's proximization theory is, to him, "arguably the most viable model to capture the us vs. them opposition and conflict" (Cap 2018, p. 382). These strategies are used when representing invasive species to create a sense of threat and fear through this kind of proximization discourse (Mando and Stack 2018).

A study on the representation of seagulls in the British press underlines the alarmist, sensationalist, and inaccurate coverage of seagulls and their relations with human animals in urban areas (Carr and Reyes-Galindo 2017). The authors found two main frames to depict seagulls: "pest-as-annoyance" and "pestilence-as-harmful" (Carr and Reyes-Galindo 2017, p. 156). Both frames denote that the seagulls are seen as unpleasant, dirty, and problematic beings that do not belong in the city and should therefore be culled. Events related to seagull attacks were given continuity, creating a sense of repetition that presented the problem as a constant (p. 165). The relations between seagulls and humans were very much mediated by the problematic sharing of a space, where human urban coexistence with liminal seagulls underlined human supremacist notions of belonging (Carr and Reyes-Galindo 2017, p. 154). Carr and Reyes-Galindo argued that "When animals transgress the cultural boundaries of what is perceived as 'appropriate' living spaces, the relevance of cultural stereotyping in the definition of a 'pest' comes to the fore even more clearly" (Carr and Reyes-Galindo 2017, p. 156). Seagull–human proximity was presented as a cause for fear, disgust, and danger, with the potential to shape people's attitudes toward these birds

and public policies that involve the extermination of the pests (Carr and Reyes-Galindo 2017, p. 148).

Previously, Stewart and Cole (2016) examined the press representation of urban foxes in the UK before and after a fox attacked two nine-year-old twins in 2010. Stewart and Cole argue that the depiction of foxes changed after the incident, as urban foxes started gaining attention in the media. The way foxes were portrayed shifted from "loveable characters", "totems of nature", and "pseudo-'pets'" to "vermin" and "transgressive, unclean and mysterious killers" (Stewart and Cole 2016). Press representation of foxes' transgressions reshaped the relations between human and nonhuman animals, justifying violence toward foxes and revealing "the precariousness of the benevolent toleration on non-human others in human-defined urban milieu, with lethal consequences" (Stewart and Cole 2016, p. 136).

Press representation of possums in New Zealand reveals similar mechanisms, including speciesist and patriotic references and war metaphors. In 2009, Potts detected two predominant portrayals of possums in the press: "foreign threat narrative" and "revenge narrative". These frames are devised by a polarization of kiwis (perceived as the national symbol and a beloved animal) against possums (alien invaders). Both portrayals perpetuate speciesism by demonizing and blaming possums, conveying the idea that they intentionally and maliciously attack, destroy, or invade New Zealand, and ignoring human responsibility in their past releases and the fact that "they are as much victims of human colonization and exploitation as the native animals of Aotearoa" (Potts 2009, pp. 17–18). McCrow-Young et al. (2015) identified three main themes in their later analysis: "the techniques and updates on the War on Possums", "possum killing as sport/a game", and "victims versus enemies", with kiwis again being framed as the possums' victims. In this case, too, press representation helps portray the possum as an invader, pest, and national threat, fabricating a discourse that legitimizes its extermination and obscures the sentient, living creature behind this construction.

Possums are often presented as "cute, but ... lethal". Potts highlights that "This rhetoric is employed when trying to combat sentimentalism that may arise from the obvious aesthetic appeal of the possum" (2009, p. 3). Similarly, monk parakeets are socially regarded as beautiful, charismatic birds (Berthier et al. 2017; Ribeiro et al. 2021). The positive perception of monk parakeets implies that population management tactics may find opposition and resistance (Seymour 2013; Crowley et al. 2019; Ribeiro et al. 2021).

#### **3. Materials and Methods**

#### *3.1. Aim and Sample*

This research aimed to examine the representation of monk parakeets in Spanish newspapers, specifically regarding the execution campaign started by the City Council of Madrid. To do that, we selected three of the major printed newspapers in terms of audience (AIMC 2021) with regional or local sections in Madrid: *El País*, *El Mundo*, and *ABC*. These newspapers represent the mainstream press in Spain. In general terms, whereas *El País* has an editorial line closer to social democracy, *El Mundo* is more associated with economic liberalism, and *ABC* with conservatism. To enrich the sample, we added online newspapers—*elDiario.es* and *Público*—that, albeit not the most read or influential, have proven interesting for the study of critical animal standpoints in previous research (Moreno and Almiron 2021). We also added *El Español*, the leader in digital audiences, to provide a similar online-only newspaper with a more liberal editorial line than its two online-only counterparts (El Español 2021).

To gather the sample of texts we used the Factiva database for *El País*, *El Mundo*, and *ABC*, and the newspapers' advanced search engines for *elDiario.es*, *Público*, and *El Español*. We looked for texts containing the keywords *"cotorras"* (monk parakeets) and "Madrid" between 1 January 2015, and 31 May 2021. The Spanish term *cotorras* could refer to either monk parakeets or rose-ringed parakeets (*Psittacula krameri*). Since in Madrid there is an inferior population of rose-ringed parakeets than monk parakeets, these species are related

to very different effects on the environment, and since population management in Madrid city is more directed towards monk parakeets, we decided to focus only on this species for our analysis and assumed that the *cotorras* mentioned during this period in the press were monk parakeets unless the contrary was specified. We discarded wrong mentions or texts that did not address the situation of parrots in Madrid. This resulted in a sample of 64 texts.

#### *3.2. Framing Analysis*

To frame is to define a problem or situation based on a part of reality, i.e., to explain a complex issue from a particular point of view (Entman 1993). In communication studies, it allows the researcher to identify how a certain issue is portrayed by the media, and which definitions, solutions, or interpretations are discussed to comprehend reality's nuances. Framing has been largely used in communication research, including research within the field of critical animal and media studies (i.e., Freeman 2014; Khazaal and Almiron 2014; Moreno and Almiron 2021; Fernández 2021).

We took framing as a tool to qualitatively detect descriptions, responsibilities, and solutions concerning the problem. Specifically, to answer objectives 1 (problem and origin) and 4 (critical discourses), we conducted a qualitative analysis of these frames after reading all the texts. For objectives 2 (responsibilities) and 3 (solutions), we opted for quantitative analysis of the texts. The frames of analysis of objective 2 were inductively elaborated, coding the entities referred to as responsible for the problem and grouping them. For the frame analysis of objective 3, we inductively coded the following pre-established categories from the review of press articles: (1) extermination, (2) reproductive control, (3) nest destruction, and (4) other solutions. We searched the sample for these frames, counting "yes" or "no" for each one of them in all the texts.

#### *3.3. Keyword and Sentiment Analysis in R*

Computational techniques for text analysis are a promising methodology in communication studies, despite their hard implementation in academic routines due to the steep learning curve of these tools (Arcila-Calderón et al. 2016). This paper includes two computational analyses that complement the abovementioned framing analysis.

On the one hand, we analyzed the most frequent keywords using R. To do that, we collected a sample of mentions by taking the paragraphs mentioning parakeets (if the text was not centered on them) or the whole text (if that was the theme of the piece). Then, we processed this sample in R: We converted the text into token words to be analyzed, excluded useless stop words in Spanish, counted the words, and represented the result in plots with the graphic package *ggplot2*. Later, we reviewed the word sample manually to delete ambiguous terms or connectors and translated the most frequent words into English. This basic analysis provided us with an overview of the most common words the press is using to talk about monk parakeets.

On the other hand, we conducted a sentiment analysis, a text-analysis technique that compares the words used with their associated sentiments gathered in a dictionary. For this analysis, we used the translation of the {*tidytext*} dictionaries and instructions provided by Fradejas Rueda (2020). The sentiment analysis was conducted with two dictionaries: *ncr*, which includes a wide variety of emotions (Negative, Positive, Fear, Trust, Anger, Sadness, Disgust, Premonition, Joy, and Astonishment), and *bing*, which only includes Positive and Negative emotions. The same sample of token words used for the word counting in the previous step was used here.

#### **4. Results**

#### *4.1. Monk Parakeets' Presence: Framing the "Problem"*

The press portrays the presence of monk parakeets in Madrid as a problem, as shown in the qualitative assessment that follows. The problems caused by monk parakeets that the media emphasize include those related to their invasive status, such as the biodiversity threat and the species extinction (Aunión 2016). They are presented as competing with local species, particularly house sparrows (*Passer domesticus*) (Domingo 2021), and damaging certain trees, such as cedars (*Cedrus* spp.), by eating their sprouts and affecting trees and the whole ecosystem (Domingo 2021; Tena 2020). Monk parakeets are very frequently described as plagues or pests (Rivas 2018; Lantigua 2018; Gallello 2020; Domingo 2020c; Barcala 2021; Domingo 2021): "the worst invasive plague of the city" (Rivas 2018) whose presence has "serious consequences" (Pinedo 2015). The problem is centrally related to the number of them (Planelles 2015), their aggressiveness (Merino 2015; Tena 2020), that they "invade Spain" (El País 2016a), and that they bother citizens and neighbors with their "deafening noise" (Barcala 2021) or "strident trills" (Gallello 2020). Probably the most blatant example of the rhetoric analyzed here is the one that gives a title to this paper. *El Español* refers to the monk parakeet in the title of a news piece as "Monk Parakeet: the unbearable green demon spreading out of control in Madrid" (Fava and Barreno 2018).

Their nests are presented as a risk in the city because of potential falls onto people (Rivas 2018; EFE 2020b). They are also considered vectors of diseases such as salmonellosis, psittacosis, or avian influenza (EFE 2017; Domingo 2019; Domingo 2020b). To a lesser extent, monk parakeet presence is said to be degrading urban furniture (Barcala 2021; Reyero 2018). Monk parakeets are also presented as being in ecological competition with other avian species such as the house sparrow, as stated by Borja Carabante, a local delegate for Environment and Mobility:

"We need to understand that not all the environment is the same and that there are good and evil. Those who come from elsewhere aggressively, unfortunately, must not be here—they do not have the same ecological right to life as we all have. They are where they should not be and they are hurting us" (El Español 2019).

Most texts do not mention the origin of the overpopulation of monk parakeets in urban areas (the legal and illegal trade of bird species for human purposes). However, some press articles point out that "this species came to Spain because people bought parrots as pets" and that monk parakeets have been "victims of commercialization" (Pérez Mendoza 2020) and victims of "human negligence" who "now pay the consequences in their own flesh" (Ferrero 2019).

#### *4.2. Political Organizations' and Institutions' Responsibility in the Management*

Given that the presence of monk parakeets in Madrid urban areas is considered a problem that needs to be managed, we explored to whom the analyzed newspapers attributed the responsibility of the control/eradication campaign. In 23 articles, no political personalities or institutions are presented as responsible for managing this problem. In 22 cases, the responsibility is attributed to the Madrid City Council, and in one case it is attributed specifically to the Getafe City Council, in an article where the management of parakeets in that municipality was specifically being discussed (Público 2019). In nine articles, the political powers of the autonomous community of Madrid are considered responsible, and in nine cases the responsibility is attributed to local administrations in general. The Spanish ministries are mentioned in three cases (particularly, the Ministry of Agriculture, Fisheries, and Food in two cases and the Ministry for the Ecological Transition and the Demographic Challenge in one case). Natural scientists and scientific organizations are explicitly considered in three cases, in one case the author explicitly mentions the Spanish Ornithological Society SEO/Birdlife (Rivas 2018), and finally, animal protection organizations are only mentioned in one case, namely, the FEPA (Spanish Federation of Animal Protection), composed of nine animal protection entities in coordination (González 2018) (see Figure 2 for an extension of the attribution of responsibility by the newspaper).

News articles often refer to the legal framework when framing which institutions have the responsibility of addressing the situation. An example that reflects this argument is the following:

"This need to remove invasive exotic birds is regulated by a Royal Decree from 2013. The removal is the regional government's competence. However, according to sources from the Madrid Regional Ministry of the Environment it is up to the local council to locate the problem and get the regional government's authorization to eliminate them. Madrid City Council claims to have the authorization to remove the nests from the municipality. When these are located in private areas, it is the landlord who must request authorization" (El País 2016b).

In an article from *El Español*, explicit coordination of the political powers is recommended: "There should be a coordination of the three levels of administration, starting with the Ministry of Agriculture, Fisheries, Food and Environment with a National Plan because the parrots do not understand territorial limits" (Fava and Barreno 2018).

**Figure 2.** Attributed responsibility for population management of monk parakeets in the analyzed articles. Source: Own elaboration from texts from *El País*, *El Mundo*, *ABC*, *elDiario.es*, *Público*, and *El Español*.

#### *4.3. Proposed Methods for Monk Parakeet Population Management*

We codified four main frames of solutions offered by the press to manage monk parakeet populations in Madrid: (1) extermination, (2) reproductive control, (3) nest destruction, and (4) other solutions; however, extermination results in the most present frame.

The proposed solutions for managing the problem of the monk parakeet population focus on exterminating them (as suggested in 42.19% of the texts). Solutions such as the reproductive control of this species appear in 28.13% of the texts, and destroying the nests is a suggestion included in 17.19% of the texts. Other solutions are present in 23.44% of the texts. Some of these include creating a census to assess the magnitude of the alleged problem, to ban the commerce of this species, to move them to other areas, to capture them, to avoid releasing them when they are held as pets, to extract them from natural areas, to ethically control their spread; or to ethically design a plan for them (see Figure 3 for the frequency of each frame in the examined sample).

The unwillingness to seek non-lethal alternatives is palpable in the press, as *El País* argues when an interviewee states that the nests being removed will only make parakeets go elsewhere and keep breeding: "slaying them is the only way to get rid of them" (Ramos Aísa 2019). An *ABC* article also holds that "From SEO/Birdlife they remind that the national legislation establishes the complete elimination" (Domingo 2021). This portrayal of the extermination is accompanied by information on the economic cost of the extermination, as can be read in *El Mundo*: "PSOE5 council member Alfredo González described as 'absurd' an operation that costs 260 euros per specimen to be exterminated" (Roces 2020). Solutions along the lines of reproductive control are usually mentioned together or as a complement to extermination: "adult specimens will be hunted using different methods such as cage traps, nets, or compressed air carbines. At the same time, the egg clutches will be sterilized and controlled. The nests shall also be removed" (Domingo 2020a).

**Figure 3.** Proportion of each frame within the analyzed texts. Source: Own elaboration from texts from *El País*, *El Mundo*, *ABC*, *elDiario.es*, *Público*, and *El Español*.

#### *4.4. Representation of Animal Advocacy Discourses Critical to the Slaying*

The representation of alternative discourses in opposition to the extermination of monk parakeets is anecdotical in comparison with those supporting the slaying, mostly based on biological conservation arguments but also presumed urban co-habitation risks and conflicts with the parrots.

News articles mostly omit citizen sensitivities against extermination and animal advocacy positions in search of ethical management strategies or solutions. These discourses are sometimes framed as well intentioned, but they are delegitimized because of the unfeasibility of alternative control and eradication methods. For instance, in *ABC* the extermination is said to be "hard and painful" (Domingo 2017), but the text underlines that there are no other options. In an article from *El Español*, the pressure of animal advocacy organizations to stop the shooting of parakeets in Seville is presented, only to later argue that cruelty-free

measures are unviable (Fava and Barreno 2018). The search for ethical possibilities for monk parakeet population management is considered a concern of sensitive people. For example, Emilia Landaluce wrote in *El Mundo*: "It is evident that monk parakeets should be eliminated. The challenge is to do it without hurting citizen sentimentality" (Landaluce 2019). This argument reflects an anthropocentric view in which the interests of the nonhuman animal are neglected, and only the human interests matter. A headline from an *ABC* article presents the animal advocacy organizations as "the opposition": "The City Council estimates the existing invasive birds at 13,000 and wants to reduce them to 10% while the opposition calls for a new census after the snowfall" (Barcala 2021).

The solutions found in the texts for the most part do not take into account moral determinants or the parrots' interests. Only a few texts do consider it, especially those on the animalist blog *El Caballo de Nietzsche* ("*Nietzsche's Horse*"), on *elDiario.es*. For example, this blog covers the creation of the Spanish Federation for Animal Protection (Federación Española de Protección Animal, FEPA), which is working on ethical management alternatives for parakeets (González 2018), and an interview with Sergio Barbero, a veterinarian expert in exotic nonhuman animals who talks about how unethical and inefficient the current control methods are (Asamblea Antiespecista de Madrid 2021). The later article (Asamblea Antiespecista de Madrid 2021) is also the only one in which the "Son Nuestras Vecinas" ("They Are Our Neighbors") campaign against the extermination is mentioned. This campaign includes street protests, demonstrations, organized calls, emails to the business in charge of the slaying, sticking posters on the streets, and sharing among neighbors the online petition for more ethical management of monk parakeet populations in Madrid.<sup>6</sup> The campaign represents parakeets as community members and as part of a marginalized population, as documented in previous campaigns against the slaying of monk parakeets in New York City (Seymour 2013).

#### *4.5. Terminology Used to Describe Monk Parakeets and Sentiments Evoked by the News*

Our keyword analysis using R showed an insightful list of top words. Among the most common words in the press, *nidos* (nests) stands out, which points out the importance of these structures, often criticized by their weight and size. *Ejemplares* ("specimens") is a frequently used word, whose implicit meaning leads to the reification of these individuals in terms of numbers. *Problema/s* ("problem/s") is also common, which implies a negative portrayal of the parakeets' existence. It is important to highlight that *invasora/s* ("invader/s") is also present on this list, which portrays this species as a threat to other local species and ecosystems. This image is emphasized with words such as *plaga* ("plague"), with a harder pejorative meaning. In addition, *enfermedades* ("diseases") is present on this list, as parakeets are alleged suspects of carrying and potentially transmitting diseases to human animals (Figure 4). The presence of the word *Kramer* in this sample is also highlighted, referring to rose-ringed parakeets, since that species is a minority in Madrid compared to monk parakeets. This happens because of the unclear language used by the press to broadly refer to both species (monk parakeet and rose-ringed parakeet).

The sentiment analysis using the *ncr* dictionary showed that the words used in the mentions for parakeets were categorized mainly as negative words (Figure 5). In addition, other emotions, such as fear, anger, and sadness, have a certain presence in the texts, whereas joy is not as present. Further analysis with the *bing* dictionary confirmed that negative words are almost six times more used than positive words in this sample (Figure 6).

**Figure 4.** The 50 most frequent words. Source: Own elaboration from texts from *El País*, *El Mundo*, *ABC*, *elDiario.es*, *Público*, and *El Español*.

**Figure 5.** Sentiment analysis using the *ncr* dictionary. Source: Own elaboration from texts from *El País*, *El Mundo*, *ABC*, *elDiario.es*, *Público*, and *El Español*.

**Figure 6.** Sentiment analysis using the *bing* dictionary. Source: Own elaboration from texts from *El País*, *El Mundo*, *ABC*, *elDiario.es*, *Público*, and *El Español*.

#### **5. Discussion and Conclusions**

Our analysis revealed that the representation in the Spanish press regarding the situation of monk parakeets in Madrid has been biased and has not taken ethical aspects into account. The issue has been described without much emphasis on the human origin of the problem, namely, the legal and illegal international trade of nonhuman animals. The presence of monk parakeet (*Myiopsitta monachus*) populations in Madrid is presented as problematic. This could be mainly due to the invasive status of the species, the noise they create with their tweets, or the potential risk of nest falls and disease transmission. In addition to the alarmist and disgust-driven tone of these alleged risks, important information on the sentience, social life, history, and characteristics of these individuals is omitted. The political responsibility for the management of the problem is not clear and not always presented: In most of the cases, any institutions are presented as responsible for managing the monk parakeet population (23 articles), and in the articles accounting for the responsibility it is mostly attributed to the Madrid City Council (22 cases). This demonstrates the lack of clarity in communicating to the public which institutions and organizations have taken part in the process of deciding this policy, which does not facilitate

the democratic exercise of political participation in decisions involving coexistence with nonhuman animals.

Among the frames used to suggest solutions for the problem of displaced allochthonous monk parakeets, the press highlights the extermination of these parrots, and this is aggravated by the poor representation of the critical discourses on the slaying proposed by animal advocacy organizations. These discourses are almost absent, and when present, they are mainly framed in a way that ridiculed or delegitimized the ethical concerns (with few but important exceptions, such as those articles from the section *El Caballo de Nietzsche* at *elDiario.es*). The most present words in the texts reflect a speciesist use of language and objectification of the individuals of this species. Finally, the sentiment analysis showed a very negative emotional charge in the chosen words. This, together with a lack of discussion on moral dilemmas and potential non-lethal paths to solve this ethically controversial situation, makes the role of the press in reporting the situation of the parakeets in Madrid poor and ethically weak.

Our results show that most of the analyzed texts (42.19%) include a frame of extermination as a management tactic to eradicate the monk parakeet population in Madrid, and non-lethal population management tactics are much less represented. Although various non-lethal methods such as audio, chemical, and visual deterrents have been tested and proven ineffective (Avery and Lindsay 2016), contraception with chemical DiazaConTM "is a promising contraceptive tool for monk parakeets and is associated with no ill health effects at a dose less than 50 mg kg–1" (Yoder et al. 2007, p. 12). The effects are reversible, and its efficacy has been proven by a reduction of 68.4% relative to the sites not exposed to DiazaConTM in field studies in the US (Avery et al. 2008, p. 1450). This contraceptive has not been recommended as an effective population management strategy due to its possible effect on non-target native species (Senar et al. 2021). However, its refinement through the presentation of permanent bait sites for parakeets to be fed with DiazaConTM-treated bait will minimize potential exposure to non-target species and will broaden its usefulness (Avery et al. 2008, p. 1451). This contraception has been shown to be an effective non-lethal method for reducing monk parakeet reproduction, and safe for non-target species (Yoder 2011; Avery and Shiels 2018, p. 341). Other long-term measures to prevent potential problems related to allochthonous species is to plan interventions to prevent and regulate the possession and trade of displaced nonhuman animals as pets. As environmental and animal defense organizations argue, the creation of a positive list would be more effective than the current negative list (CITES 2021), because it would only include species whose sale and trade are legal, making possession of all other species illegal (Eurogroup for Animals 2020). Although this measure is not enough to stop the whole pet trade, it would be an important step in reducing both the exploitation of nonhuman animals and the potential damages derived from the escape or release of displaced nonhuman animals. Importantly, global wild animal trade regulation and abolition is a constructive common ground goal for both conservation biologists' and animal rights groups' efforts (Perry and Perry 2008).

This framing of the issue, where monk parakeets have attributed responsibility and are portrayed as purposely destroying ecosystems or damaging human economies and health, is also unfair and misleading to the fact that monk parakeets are themselves victims and survivors of the global wildlife trade. The focus on monk parakeet demonization (e.g., by being described as aggressive birds (Merino 2015; Tena 2020)) silences the human origin of this alleged problem and overlooks our collective responsibility to find ethical solutions to address it while not damaging these sentient and intelligent birds. It also reveals the tremendous anthropocentric, speciesist, and profit-oriented character of these management tactics. The same policy is not applied to introduced nonhuman animals if humans can benefit from their exploitation—e.g., despite its invasive status, the rainbow trout's release is permitted by the Spanish Congress, so fishermen can kill them for sport or business (Rejón 2018). Other than framing, language also makes the role of newspapers in representing the issue around parakeets crucial, as noted by critical animal-studies researchers and nonhuman animals-inclusive journalism ethical guidelines in order to avoid denigration, devaluation, and misrepresentation of nonhuman individuals (Dunayer 2001; Stibbe 2012; Freeman and Merskin 2016; Animals and Media 2016; UPF-CAE 2016). Thus, we have observed that word choice contributes to setting the framing described above. It is important to analyze the language used by the press because it contributes to limiting the debate on the management methods used. This results in only contemplating measures that are simpler to implement or economically more convenient, but that do not usually coincide with the most ethical methods.

The language used by the press has proven to be a challenge for this analysis. In this sense, the term *cotorra* is sometimes used ambivalently for monk parakeets and rose-ringed parakeets. We have taken this imprecision into account in the framing analysis by analyzing these framings and considering the solutions and liabilities for the Madrid case regardless of whether the rose-ringed parakeet (*cotorra de Kramer*) is mentioned. In the quantitative analysis of keywords, this word was not excluded in order to understand to what extent it appears in the texts. Thus, we discovered that the problems attributed to the rose-ringed parakeet, which is present in other parts of Spain, are sometimes mixed with the problems attributed to the monk parakeet in Madrid. This results in an argument that lumps both species together to argue for the unethical solutions identified (despite the Madrid problem involving primarily monk parakeets).

Furthermore, speciesist concepts such as *ejemplares* ("specimens") are used to refer to nonhuman sentient individuals. This objectifies them and omits the referent of the flesh-and-blood individuals (Animals and Media 2016; UPF-CAE 2016). We also see at play the "cute, but. . . lethal" rhetoric (Potts 2009), which counteracts and punishes the compassionate human feelings and positive social attitudes toward monk parakeets. The language used to refer to monk parakeets includes terms such as "exotic", "invaders", "pests", "demons", "aggressive birds", or "threats", provoking emotions like the fear that helps legitimize the idea of an enemy or threat that has to be fought (Subramaniam 2001; Inglis 2020). At the same time, as we observed in the sentiment analysis, the word choice in the press coverage is clearly related to negative emotions. In addition, the *ncr* dictionary showed that fear, along with anger, is the most present emotion. This type of language is based on "us versus them" rhetoric, as described by Cap (2018). "Exotic" alludes to an outsider that is not local. These kinds of dichotomies and binary concepts are also seen in anti-migration speeches, as observed by Mando and Stack (2018) regarding Asian carp in the United States. This discourse also shares characteristics with the one used to criminalize human migrants and perpetuate a "good and evil" and "us vs them" xenophobic rhetoric (Subramaniam 2001; McCrow-Young et al. 2015; Inglis 2020; Khazaal and Almiron 2021). The nationalist and patriotic rhetoric featuring "competition between species" (introduced species vs. native) used in the representation of possums and kiwis in New Zealand (Potts 2009) is also present—although less frequently and intense—in the interactions between monk parakeets ("alien invaders", "threat") and house sparrows ("small", "lovely", "local species").

Our research has certain limitations. For instance, we could have selected a broader sample and included other important Spanish newspapers, or even examined other media like television or social media. We could also have improved our differentiation of monk parakeets and rose-ringed parakeets in our analysis and broader developed the problems of the local authorities, control management services, and the press mixing both cases and species altogether. In addition, we could have included a visual analysis of press photographs of the analyzed articles, given that "visual messages often make a deeper impression on the collective imaginary than the written word" (Fernández 2021, p. 344) and influence the readers' interpretation of the written text. Future studies in this line of research could also be aimed at analyzing activist discourses and how campaigns and solutions proposed by animal advocacy movements are articulated. Likewise, the conservationist rhetoric used to justify the extermination of species considered invasive and limit the exploration of non-lethal paths to population management and the search for common ground among conservation biologists and animal advocates (Perry and

Perry 2008) (e.g., the monk parakeet case or others) can be an interesting object of study, especially for traditions such as critical discourse analysis and cultural studies. Extending the focus to other geographical contexts for comparative studies would also be relevant. Finally, computational analysis of the lexicon used and sentiment analysis could be equally extended to other species and situations as well as to other contexts, as these quantitative methods have great potential in the communication field.

Despite our limitations, this research covered a gap of knowledge regarding press representation of liminal, introduced nonhuman animals, an under-studied, controversial, and highly relevant topic in our climate deadlock context (Almiron and Tafalla 2019). Our results are aligned with previous research on the press representation of nonhuman animals that points to the need for an ethical improvement in the press coverage of nonhuman animal-related issues (e.g., Freeman 2009; Khazaal and Almiron 2014; Moreno and Almiron 2021). This research thus joins the contributions of critical animal studies, a newly created and growing field of study that addresses human-nonhuman animal relations from an interdisciplinary, ethically engaged, non-speciesist, and critical perspective on interconnected systems of oppression (Best et al. 2007).

Spanish newspapers have mainly contributed through their coverage and biased representation to advocating for the extermination of monk parakeets in Madrid, ignoring their voices (Freeman et al. 2011), omitting the human- and profit-driven cause of the monk parakeets' presence in Madrid urban areas and reproducing anthropocentric and speciesist arguments to justify their extermination, therefore slowing down the social efforts to find other possible, and more ethical, solutions. For us, on a hopeful note, this can only be a good starting point to take up the challenge of bringing about a radical, more inclusive, and compassionate change in the media representation of monk parakeets and other nonhuman animals and their complex realities.

**Author Contributions:** Conceptualization, L.F., J.A.M. and A.S.-D.; methodology, L.F., J.A.M. and A.S.-D.; software, J.A.M.; validation, L.F., J.A.M. and A.S.-D.; formal analysis, L.F., J.A.M., and A.S.- D.; investigation, L.F., J.A.M. and A.S.-D.; resources, L.F., J.A.M. and A.S.-D.; data curation, L.F., J.A.M. and A.S.-D.; writing—original draft preparation, L.F., J.A.M. and A.S.-D.; writing—review and editing, L.F. and J.A.M.; visualization, L.F., J.A.M. and A.S.-D.; supervision, L.F. and J.A.M.; project administration, L.F.; funding acquisition, L.F. and J.A.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Spanish Ministry of Science, Innovation and Universities, grant number FPU18/04207 and the Generalitat de Catalunya (Department of Universities and Research) and the European Social Fund, grant number 2018FI\_B\_00094.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available in this paper. Further information on the sample and datasets are available on request from the corresponding author.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Notes**

#### **References**

El País. 2016a. Las cotorras 'invaden' España. *El País*, July 13.

El País. 2016b. 'Si hablas con personas mayores, te dicen que hay menos pájaros', señala Juan . . . . *El País*, September 18.

Entman, Robert M. 1993. Framing: Toward Clarification of a Fractured Paradigm. *Journal of Communication* 43: 51–58. [CrossRef]

Ferrero, Berta. 2019. El exceso de determinadas especies de animales no es nuevo en Madrid. *El País*, December 15.

Fradejas Rueda, José Manuel. 2020. Estilometría y análisis de texto con R para filólogos. *Cuentapalabras*. December 26. Available online: http://www.aic.uva.es/cuentapalabras/ (accessed on 15 June 2022).

Freeman, Carrie P. 2009. This Little Piggy Went to Press: The American News Media's Construction of Animals in Agriculture. *The Communication Review* 12: 78–103. [CrossRef]

Freeman, Carrie P. 2014. *Framing Farming: Communication Strategies for Animal Rights*. Amsterdam: Brill Rodopi.

Lantigua, Isabel F. 2018. ¿De qué se quejan los madrileños? *El Mundo*, June 9.

Lorenzo Gutiérrez, Juan Antonio. 1993. Nidificación del Gorrión moruno (*Passer hispaniolensis*) en nidos de Cotorra gris (*Myiopsitta monachus*) en Tenerife (*Islas canarias*). *Butlletí del Grup Català d'Anellament* 10: 75–77.

MDPI St. Alban-Anlage 66 4052 Basel Switzerland Tel. +41 61 683 77 34 Fax +41 61 302 89 18 www.mdpi.com

*Journalism and Media* Editorial Office E-mail<EMAIL_ADDRESS>www.mdpi.com/journal/journalmedia

MDPI St. Alban-Anlage 66 4052 Basel Switzerland Tel: +41 61 683 77 34

www.mdpi.com

ISBN 978-3-0365-5618-5


**1. Introduction**

Bioethanol is a renewable, biodegradable, non-toxic raw material nowadays produced in an ever-larger amount as the base for a possible green transition to energy production. Its global production is expected to grow up to 41.4 billion liters by 2025, with a progressive reduction in price [1]. It is well known that bioethanol can selectively be dehydrogenated to ethyl acetate under mild conditions, using copper-based catalysts [2–11].

$$\text{\textbullet 2C}\_2\text{H}\_5\text{OH} \rightleftharpoons \text{CH}\_3\text{COOC}\_2\text{H}\_5 + 2\text{H}\_2\tag{1}$$

Pure hydrogen exempt from CO and directly usable in fuel cells can be obtained from ethanol through this route. Moreover, the reaction is reversible and ethyl acetate can then be hydrogenated to ethanol closing the chemical cycle. On this basis, in the present work we suggest the possibility to use ethanol or derivatives as hydrogen vectors (LOHC, Liquid Organic Hydrogen Carrier) operating in a new original way. As known, hydrogen is a powerful vector of energy, but it is difficult to transport [12]. In fact, its volumetric energy density is very low due to its very scarce density under standard temperature and pressure conditions (0.0824 kg/m3 under ideal gas conditions). This low density causes a very low

**Citation:** Santacesaria, E.; Tesser, R.; Fulignati, S.; Raspolli Galletti, A.M. The Perspective of Using the System Ethanol-Ethyl Acetate in a Liquid Organic Hydrogen Carrier (LOHC) Cycle. *Processes* **2023**, *11*, 785. https://doi.org/10.3390/pr11030785

Academic Editor: Davide Dionisi

Received: 1 February 2023 Revised: 1 March 2023 Accepted: 3 March 2023 Published: 7 March 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

volumetric energy content of hydrogen, i.e., 0.01 MJ/L H2 for the gas at ambient conditions and 8.5 MJ/L H2 for liquefied H2. One possible solution is to store hydrogen inside a liquid molecule that can easily be transported and that can release it when needed. In this regard, many different LOHCs have been proposed in the literature such as methylcyclohexane, decaline, dodecahydro-N-ethyl carbazole, and other molecules containing aromatic rings. A more detailed list of possible LOHC molecules is reported in some recently published reviews [13–15]. All these LOHCs have the advantage of a high hydrogen density but also many disadvantages such as: (*i*) aromatic molecules are harmful, not renewable, and not biodegradable; (*ii*) their dehydrogenation occurs at relatively high temperatures with high consumption of heat; (*iii*) catalysts promoting the reaction are normally based on precious noble metals (Pt, Pd) susceptible to deactivation or poisoning. Another proposed approach is the use of methanol, ethanol, and hydrocarbons to produce hydrogen by steam reforming but in this case, CO and CO2 are obtained as by-products. CO2 must be separated, and CO contaminates the produced hydrogen. Moreover, the process is irreversible and consumes the reactants causing CO2 emissions [16]. On the other hand, several researchers have described the ethanol dehydrogenation to ethyl acetate by using different catalysts [2–11] and some patents have also been published on this reaction describing the employment of different catalysts and related operative conditions [17–19]. Moreover, an industrial process has been developed and patented by Davy Process Technology, a Johnson and Matthey company [20–22]. More recently, Eurochem Engineering developed and patented in 2011 an industrial process for ethanol dehydrogenation to ethyl acetate carried out in a packed bed tubular reactor containing a more efficient copper-copper chromite commercial catalyst [23]. Under the best conditions, an ethanol conversion of 50–60 mol% and selectivity to ethyl acetate higher than 97% were obtained. The reaction was conducted in a temperature range of 473–493 K and 20–25 atm of pressure with an ethanol contact time of about 90–100 g·h/mol. In that process, 1 mole of pure hydrogen was obtained as a co-product for each mole of converted ethanol. The obtained hydrogen can easily be separated by condensing ethanol and ethyl acetate. All the aspects of this process have been studied in a detailed way and the results have been already reported in some different publications [24–27]. The kinetics of the reaction has been accurately studied by performing many experimental runs in different operative conditions, in the perspective of a suitable scale-up towards the industrial plant and a dedicated paper has been published [28]. The dehydrogenation reaction is reversible, and this is the reason for the limited ethanol conversion obtainable in a single step. The reverse reaction is therefore feasible and different works have studied the hydrogenation of ethyl acetate to ethanol by using different copper-based catalysts [29–33]. All these works, respectively devoted to ethanol dehydrogenation and ethyl acetate hydrogenation, demonstrate the feasibility of the use of ethanol as a LOHC because it is possible to close the chemical cycle of dehydrogenation of ethanol and hydrogenation of ethyl acetate. However, until now no-one has suggested the use of ethanol as a LOHC except for the proposal reported in a work recently published by Tran et al. [34] and in the more recent one by Mevawala et al. [35]. Tran et al. proposed the use of ethanol as a LOHC considering the cycle dehydrogenation-hydrogenation promoted by a ruthenium complex in homogeneous phase. Although the homogeneous catalytic approach is not convenient with respect to the heterogeneous one, the work is important because it is a further demonstration of the feasibility of the idea to use ethanol as a hydrogen carrier. On the other hand, the paper of Mevawala et al. [35] studied the thermodynamic and environmental aspects of the ethanol–ethyl acetate cycle for hydrogen storage applications, without an in-depth analysis of the catalytic systems. Their modeling of the overall cycle determined an energy efficiency up to 88%, a significantly high value with respect to those of other LOHCs, mainly addressed to the very low endothermicity of the reaction. Moreover, a preliminary eco-balance evidenced that the use of ethanol was more sustainable from a carbon emission perspective when compared with fossil LOHCs. Therefore, starting from the existing literature and considering, as a reference, the performance of the already wellknown copper-copper chromite catalyst in promoting ethanol dehydrogenation we would

like to define the best operative conditions for both ethanol dehydrogenation and ethyl acetate hydrogenation, also with the aim to find alternative catalysts exempt of chromium with similar or superior performances. In the perspective of the scale-up, the kinetics of both the dehydrogenation and hydrogenation reactions in conventional reactors will be defined for a preliminary determination of the techno-economic aspects of a structured process with the aim to optimize the characteristics of three different application areas: energy-storage, energy-transport, and mobility application.

#### **2. Methodology of Ethanol Dehydrogenation**

#### *2.1. Thermodynamics of the Occurring Reactions*

The conversion of ethanol to ethyl acetate occurs according to the following stoichiometry:

$$2\text{C}\_2\text{H}\_5\text{OH} \rightleftharpoons \text{CH}\_3\text{COOC}\_2\text{H}\_5 + 2\text{H}\_2\tag{2}$$

ΔH◦ 500 K = 33.64 kJ/mol; ΔG◦ 500 K = −6.44 kJ/mol

From experimental observation, this reaction is the addition of two consecutive reactions that are:

$$(1)\ \text{C}\_2\text{H}\_5\text{OH} \rightleftharpoons \text{CH}\_3\text{CHO} + \text{H}\_2\tag{3}$$

ΔH◦ 500 K = 71.30 kJ/mol; ΔG◦ 500 K = 10.59 kJ/mol

$$(2)\ \text{CH}\_3\text{CHO} + \text{CH}\_3\text{CH}\_2\text{OH} \rightleftharpoons \text{CH}\_3\text{COOCH}\_2\text{CH}\_3 + \text{H}\_2\tag{4}$$

ΔH◦ 500 K = −37.66 kJ/mol; ΔG◦ 500 K = −17.03 kJ/mol

It is opportune to observe that the overall reaction (2) is moderately endothermic, while reaction (3) is endothermic, and the successive reaction (4) is on the contrary exothermic. The equilibrium constants of the three reactions, at 500 K, are respectively:

$$\text{K}\_{\text{p2-500 K}} = 4.69; \text{ K}\_{\text{p3-500 K}} = 0.080; \text{ K}\_{\text{p4-500 K}} = 58.94$$

The equilibrium of reaction (3) is shifted to the left but as acetaldehyde is consumed by reaction (4) it proceeds to the right and the equilibrium of the overall reaction is moderately shifted to the right at 500 K. The overall reaction (2) is more favored at 600 K with the equilibrium constant being about 17. Thermodynamic calculations have been made on data reported by Stull et al. [36]. The choice of 500 K, as reference temperature, is a compromise between the thermodynamic and kinetic properties of the involved reactions, because higher temperatures favor the occurrence of undesired side reactions.

## *2.2. Catalysts Normally Employed for Promoting the Ethanol Dehydrogenation*

Many different catalysts have been used for promoting ethanol dehydrogenation [2–11,17–28]. It is possible to distinguish two different classes of copper catalysts respectively containing copper/copper chromite, and copper metal supported and/or promoted by different oxides such as Al2O3, Cr2O3, ZnO, ZrO2, and SiO2. The presence of oxide compounds has the scope to improve the dispersion of Cu thus, as consequence, slowing down the catalyst deactivation due to the metal sintering. Some other catalysts containing Ni or Pd have also been tested with lower performances. Interesting is the use of ruthenium complexes acting in a homogeneous phase, at very low temperatures, and promoting both ethanol dehydrogenation and ethyl acetate hydrogenation. Many papers and reviews have been published on the subject and nowadays some conclusions can be drawn [37–39]. According to Finger et al. [37], the dehydrogenation of ethanol to acetaldehyde occurs on the Cu surface, while the coupling of acetaldehyde with ethanol occurs mainly at the interface Cu-metal oxide (ZnO, ZrO2) where ethanol is adsorbed as alkoxide. According to Pang et al. [38], acetaldehyde is generated preferably on an unreduced Cu+ site while H2 is liberated on Cu0. The ratio Cu+/Cu0 would be therefore important for the selectivity, and a high presence of Cu+ favors the formation of acetaldehyde, while the contrary favors the formation of ethyl acetate. As previously reported, the

Cu dispersion is of paramount importance, the activity being normally proportional to the specific surface area of Cu. In this regard, the support has a great influence on catalyst activity, selectivity and stability. For example, a high acidity of the support is detrimental, favoring the dehydration path instead of the dehydrogenation one; thus, the oxides, being weak acids or basic, favor dehydrogenation. Oxides trapping the Cu particles favor stability, hindering the deactivation due to sintering. It seems that stability can be induced also by alloying Cu with a moderate quantity of Ni. The operative conditions are also very important, considering that the formation of acetaldehyde is favored by low pressure (<1 atm) and high temperature (>573 K), whilst the selectivity to ethyl acetate increases at a relatively high pressure (10–30 atm) and low temperature (<523 K). The optimal operative conditions will be chosen through a compromise that allows the achievement of the maximum ethyl acetate yield. Phung [12] recently published a review on copper-based catalysts for ethanol dehydrogenation examining, on the basis of the previous literature, the respective roles of: Cu loading, Cu dispersion, the particle size, the Cu support and related acidity or basicity and contact time.

#### *2.3. A Reference Catalyst, Reaction Mechanism and Related Kinetic Model*

In this work, the behavior of a copper-copper chromite catalyst could be used as a reference starting point for comparing kinetic data obtained by employing other catalysts because the kinetics of that catalyst are well known from different sources [28,40]. Different kinetic models have been proposed in the literature. For example, Tu et al. [40] considered the main overall reaction to be of the pseudo-first order; thus, the model suggested by these authors was oversimplified. Moreover, the tested copper chromium catalysts were deactivated with time and a deactivation kinetic law was proposed by the same authors. More recently, a kinetic model based on reliable reaction mechanisms has been published by Carotenuto et al. [28]. The model proposed by these authors considered the following reaction scheme:

$$\text{CH}\_3\text{CH}\_2\text{OH} \rightleftharpoons \text{CH}\_3\text{CHO} + \text{H}\_2\tag{5}$$

$$\text{CH}\_3\text{CHO} + \text{CH}\_3\text{CH}\_2\text{OH} \rightleftharpoons \text{CH}\_3\text{COOCH}\_2\text{CH}\_3 + \text{H}\_2\tag{6}$$

$$\text{2CH}\_3\text{CHO} \to \text{Other products} \tag{7}$$

Probably occurring according to the following reaction mechanisms:

C2H5OH + σ0 σ*EtOH* (8)

$$
\sigma\_{\rm EOH} + \sigma\_0 \to \sigma\_{\rm Ach} + \sigma\_{\rm H2} \text{ rate determining step} \tag{9}
$$

$$
\sigma\_{AcH} \rightleftharpoons \sigma\_0 + \text{CH}\_3\text{CHO} \tag{10}
$$

$$
\sigma\_{\rm H2} \to \sigma\_0 + \rm H\_2 \tag{11}
$$

σ0 is the fraction of free active sites on the catalytic surface, while σi is the fraction of active sites occupied by adsorbed "i" molecules. The "rate determining step" should be the surface reaction between chemisorbed ethanol and a catalyst void site to form adsorbed acetaldehyde. For the second reaction the following mechanism was suggested:

C2H5OH + σ0 σ*EtOH* (12)

CH3CHO + σ0 σ*AcH* (13)

$$
\sigma\_{EOH} + \sigma\_{AcH} \rightleftharpoons \sigma\_{EA} + \sigma\_{\text{H2}}\text{ rate determining step}\tag{14}
$$

$$
\sigma\_{EA} \rightleftharpoons \sigma\_0 + \text{CH}\_3\text{COOCH}\_2\text{CH}\_3 \tag{15}
$$

$$
\mathfrak{o}\_{\text{H2}} \rightleftharpoons \mathfrak{o}\_{\text{0}} + \text{H}\_{\text{2}} \tag{16}
$$

In this case, the rate determining step would be the reaction between adsorbed ethanol and adsorbed acetaldehyde. Based on the postulated reaction mechanisms, it is possible to write the following kinetic law expressions:

R

$$r\_1 = \frac{k\_1 P\_{EtOH} \left(1 - \frac{1}{Kc\_1} \frac{P\_{AcH} P\_{H\_2}}{P\_{EtOH}}\right)}{\left(1 + b\_{EOH} P\_{EtOH} + b\_{AcH} P\_{AcH} + b\_H P\_H + b\_{EA} P\_{EA}\right)^2} \tag{17}$$

R

R

R

R

$$r\_2 = \frac{k\_2 P\_{EtOH} P\_{AcH} \left(1 - \frac{1}{\mathcal{K}c\_2} \frac{P\_{EA} P\_{H\_2}}{P\_{EOH} P\_{AcH}}\right)}{\left(1 + b\_{EtOH} P\_{EtOH} + b\_{AcH} P\_{AcH} + b\_H P\_H + b\_{EA} P\_{EA}\right)^2} \tag{18}$$

$$r\_3 = k\_3 P^2\_{AcH} \tag{19}$$

The reactions of acetaldehyde to other undesired products are normally reactions of acetaldehyde condensation as deeply investigated by Inui et al. [7] and Colley et al. [8]; many different undesired products could be obtained in the worst operative conditions as in the following scheme (Scheme 1):

**Scheme 1.** Pathways of by-products formation from acetaldehyde condensation.

To avoid the formation of acetaldehyde condensation by-products it is clearly imperative to keep the acetaldehyde concentration in the system low and to achieve this result the catalyst selectivity becomes of paramount importance. In contrasty, no-one observed an acetaldehyde decomposition reaction to CO by using copper-copper chromite catalysts.

In the kinetic approach followed by Carotenuto et al. [28], the reaction of acetaldehyde to other undesired side products was simplified to a pseudo-second-order reaction because it was characterized by a very low conversion. The best fitting parameters obtained by interpreting all the experimental runs performed are summarized in Table 1. The kinetic parameters reported in Table 1 seem reliable because the activation energies and the adsorption constants are reasonable values compatible with the postulated reaction mechanism. The very low value of k3 and the negligible value of the corresponding activation energy is justified by: (*i*) the approximation introduced by arbitrarily assuming a pseudo-second order rate law; (*ii*) the fact that reaction (7) is not a single reaction but is an assembly of different reactions exclusively consuming acetaldehyde; (*iii*) the very low amount of by-products that determines high analytical errors.

**Table 1.** Optimized kinetic parameters obtained for a commercial copper-copper chromite catalyst, from [28], reported with the permission of Elsevier.

This reaction system is singular because, looking at the reaction scheme, we can observe that ethanol transformation to ethyl acetate passes through the formation of acetaldehyde, an endothermic reaction (ΔH ≈ 71 kJ/mol), while the successive reaction is moderately exothermic (ΔH ≈ −40 kJ/mol). This means that using a tubular reactor it is opportune to separate it in different stages (at least 2) differently heated if the system should be maintained approximately isotherm. In the first part it is necessary to furnish heat, whilst in the second one the cooling of the reactor is required. On the other hand, if a unique adiabatic reactor is adopted and a hot reagents stream (e.g., 508 K) is fed, it is possible to observe initially a decrease in the temperature followed by a progressive moderate increase. For an isothermal tubular reactor, the following system of differential equations must be simultaneously solved:

$$\frac{dF\_{\text{EtOH}}}{dZ} = -\mathcal{W}\_{\text{cat}}(r\_1 + r\_2) \tag{20}$$

$$\frac{dF\_{\rm{AcH}}}{dZ} = W\_{\rm{cat}}(r\_1 - r\_2 - 2r\_3) \tag{21}$$

$$\frac{dF\_{AcOEt}}{dZ} = \mathcal{W}\_{cat}r\_2\tag{22}$$

$$\frac{dF\_{H2}}{dZ} = W\_{cat}(r\_1 + r\_2) \tag{23}$$

where *Fi* is the molar flow rate of component i, *Z* = L/Lbed is the dimensionless reactor length, *Wcat* is the loaded catalyst weight and *rj* are the rates of the j-reactions referred to the unit of catalyst weight. Figure 1 shows the conversion of ethanol and selectivities to respectively ethyl acetate and acetaldehyde as a function of the contact time W/F (g·h/mol), at 493 K and 20 atm, calculated with the described kinetic model and related parameters.

A similar kinetic approach has been published by Men'shchikov et al. [41], who interpreted runs performed on a catalyst composed of copper-zinc-chromium supported on alumina (CuO-ZnO-Cr2O3-Al2O3) in the temperature range 503–563 K and pressure of 10–20 atm. The runs were carried out in a continuous fixed-bed reactor and interpreted with a Langmuir–Hinshelwood kinetic model. The conversion to ethyl acetate changed with the temperature from 10 to 47%, acetaldehyde was produced in a small amount from 0.7 to 3%, while increasing the temperature greatly increased the presence of other by-products from 0.3% to 7%. Optimal kinetic parameters of the model were determined and interpreted for all the kinetic runs showing an error of ±20%. Starting from similar results, it would be possible to do a scale-up and formulate the best arrangement of the plant equipped with a conventional reactor for producing hydrogen and ethyl acetate.

**Figure 1.** Kinetic behavior of copper-copper-chromite catalyst. Ethanol conversion and selectivities to respectively ethyl acetate and acetaldehyde, for different contact times at 493 K and 20 atm. Curves have been obtained by solving the system of differential Equations (10)–(13) with the parameters of Table 1.