3.6 Dehydration

Heterogeneous catalysts are more effective from an economical point of view for biodiesel production. Sometimes transesterification can be a beneficial alternative to hydrolysis as it does not involve formation of water, and moreover, it brings out

Etherification refers to the synthesis of ethers from alcohol and acid. Ethers are an indispensable part of the fuel industry as, like the properties of alcohol, ether also enhances the octane value of fuel when added in appropriate proportion. Several model reactions via RD such as MTBE, ETBE, and TAME have been studied since last two decades. These fuel oxygenates are formed by reaction of isobutylene with alcohol to give ether and water. However, another alternative is to react tert-amyl alcohol (TAA) with corresponding lower alcohol such as methanol or ethanol.

> Alcohol þ Isobutylene➔Ether Ex : for MTBE : CH3OH þ ð Þ CH3 2CCH2➔CH3OC CH ð Þ3 3 For ETBE : CH3CH2CH3 þ C2H5OH➔ð Þ CH3 3OC2H5

Transfer of alkyl group from one molecule to another is known as alkylation. Cumene and ethyl benzene are some examples which are synthesized using alkylation process. In this process alkanes, which are a part of paraffin compounds, are reacted with an aromatic compound which results in production of a high-quality fuel substitutes like cumene. These compounds are added to gasoline as a blend to improve its octane number, reduce the engine problems like gum deposits on oxidation, etc. High aviation fuel blends are produced using an alkylation process whose octane number is denoted by a performance number having a value of greater than 100. The catalytic alkylation method uses aluminum chloride and hydrochloric acid as catalyst to initiate the reaction between benzene and

In an aldol condensation, an enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone, followed by a dehydration to give a conjugated enone. By using reactive distillation (RD), one can improve the selectivity toward the intermediate or final product depending on the type of catalyst used and by continuously removing the desired product from the reaction zone.

the value added through formation of another ester.

Distillation - Modelling, Simulation and Optimization

3.3 Etherification

3.4 Alkylation

propylene.

94

3.5 Aldol condensation

Dehydration reaction simply means removal of water. This process is employed generally for glycerol to obtain acetol. This reaction is usually carried into the presence of various metallic catalysts like alumina, magnesium, ruthenium, nickel, platinum, palladium, copper, Raney nickel, etc. Single-stage and two-stage reactive distillation techniques are being employed, and special care is being taken to regenerate these catalysts as they are classified as precious and non-precious catalysts.


**Author details**

Shahin Kharaji FAPKCO Industrial Company, Shiraz, Iran

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*4.4. Plant Materials, Growth Conditions and Stress Treatments*

Seeds of *Arabidopsis thaliana* ecotype Columbia (Col-0) were used in this research. The seeds were surface sterilized with bleach and washed extensively with sterilized water for three times, and then incubated in a growth chamber after cold treatment for two days. After growth for one week, the seedlings were exposed to various stress conditions in plates containing 150 mM NaCl and 10 µM ABA, respectively. For cold and heat treatment, 7-day-old plants were placed at 4 ◦C or 42 ◦C incubator with normal illumination. Samples from leaves, buds, flowers and siliques were collected from well-growing plants at the same time. All the plant materials were harvested by liquid nitrogen cooling before stored at −80 ◦C.