toluene toluene toluene (/ˈtɒl.juiːn/), also known as toluol (/ˈtɒl.ju.ɒl, -ɔːl, -oʊl/), is a substituted aromatic hydrocarbon. it is a colorless, water-insoluble liquid with the smell associated with paint thinners. it is a mono-substituted benzene derivative, consisting of a methyl group (ch3) attached to a phenyl group. as such, its systematic iupac name is methylbenzene. toluene is predominantly used as an industrial feedstock and a solvent. toluene names preferred iupac name toluene systematic iupac name methylbenzene other names methyl benzenebenzylenephenylmethanetoluolanisen identifiers cas number 108-88-3 y 3d model (jsmol) interactive image abbreviations phmemephbnhtol chebi chebi:17578 n chembl chembl9113 y chemspider 1108 y drugbank db01900 n echa infocard 100.003.297 iuphar/bps 5481 kegg c01455 y pubchem cid 1140 rtecs number xs5250000 unii 3fpu23bg52 y comptox dashboard (epa) dtxsid7021360 inchi inchi=1s/c7h8/c1-7-5-3-2-4-6-7/h2-6h,1h3 ykey: yxfvvabegxronw-uhfffaoysa-n yinchi=1/c7h8/c1-7-5-3-2-4-6-7/h2-6h,1h3key: yxfvvabegxronw-uhfffaoyat smiles cc1ccccc1 properties chemical formula c7h8 molar mass 92.141 g·mol−1 appearance colorless liquid odor sweet, pungent, benzene-like density 0.8623 g/ml (25 °c) melting point −95.0 °c (−139.0 °f; 178.2 k) boiling point 110.60 °c (231.08 °f; 383.75 k) solubility in water 0.54 g/l (5 °c)0.519 g/l (25 °c)0.63 g/l (45 °c)1.2 g/l (90 °c) log p 2.73 vapor pressure 2.8 kpa (20 °c) magnetic susceptibility (χ) −66.1·10−6 cm3/mol thermal conductivity 0.1310 w/(m·k) (25 °c) refractive index (nd) 1.4941 (25 °c) viscosity 0.560 mpa·s (25 °c) structure dipole moment 0.375 d thermochemistry heat capacity (c) 157.3 j/(mol·k) std enthalpy offormation (δfh⦵298) 12.4 kj/mol std enthalpy ofcombustion (δch⦵298) 3.910 mj/mol hazards occupational safety and health (ohs/osh): main hazards highly flammable ghs labelling: pictograms signal word danger hazard statements h225, h304, h315, h336, h361d, h373 precautionary statements p210, p240, p301+p310, p302+p352, p308+p313, p314, p403+p233 nfpa 704 (fire diamond) 2 3 0 flash point 4 °c (39 °f; 277 k) autoignitiontemperature 480 °c (896 °f; 753 k) explosive limits 1.1–7.1% threshold limit value (tlv) 50 ml/m3, 190 mg/m3 lethal dose or concentration (ld, lc): lc50 (median concentration) >26700 ppm (rat, 1 h)400 ppm (mouse, 24 h) lclo (lowest published) 55,000 ppm (rabbit, 40 min) niosh (us health exposure limits): pel (permissible) twa 200 ppm c 300 ppm 500 ppm (10-minute maximum peak) rel (recommended) twa 100 ppm (375 mg/m3) st 150 ppm (560 mg/m3) idlh (immediate danger) 500 ppm safety data sheet (sds) siri.org related compounds related aromatic hydrocarbons benzenexylenenaphthalene related compounds methylcyclohexane supplementary data page toluene (data page) except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). n verify (what is yn ?) infobox references as the solvent in some types of paint thinner, permanent markers, contact cement and certain types of glue, toluene is sometimes used as a recreational inhalant and has the potential of causing severe neurological harm. history the compound was first isolated in 1837 through a distillation of pine oil by pierre joseph pelletier and filip neriusz walter, who named it rétinnaphte. in 1841, henri étienne sainte-claire deville isolated a hydrocarbon from balsam of tolu (an aromatic extract from the tropical colombian tree myroxylon balsamum), which deville recognized as similar to walter's rétinnaphte and to benzene; hence he called the new hydrocarbon benzoène. in 1843, jöns jacob berzelius recommended the name toluin. in 1850, french chemist auguste cahours isolated from a distillate of wood a hydrocarbon which he recognized as similar to deville's benzoène and which cahours named toluène. chemical properties the distance between carbon atoms in the toluene ring is 0.1399 nm. the c-ch3 bond is longer at 0.1524 nm, while the average c-h bond length is 0.111 nm. toluene reacts as a normal aromatic hydrocarbon in electrophilic aromatic substitution. because the methyl group has greater electron-releasing properties than a hydrogen atom in the same position, toluene is more reactive than benzene toward electrophiles. it undergoes sulfonation to give p-toluenesulfonic acid, and chlorination by cl2 in the presence of fecl3 to give ortho and para isomers of chlorotoluene. importantly, the methyl side chain in toluene is susceptible to oxidation. toluene reacts with potassium permanganate to yield benzoic acid, and with chromyl chloride to yield benzaldehyde (étard reaction). the c-h bonds of the methyl group in toluene are benzylic, which means that they are weaker than c-h bonds in simpler alkanes. reflecting this weakness, the methyl group in toluene undergoes halogenation under free radical conditions. for example, when heated with n-bromosuccinimide (nbs) in the presence of aibn, toluene converts to benzyl bromide. the same conversion can be effected with elemental bromine in the presence of uv light or even sunlight. toluene may also be brominated by treating it with hbr and h2o2 in the presence of light. c6h5ch3 + br2 → c6h5ch2br + hbr c6h5ch2br + br2 → c6h5chbr2 + hbr the methyl group in toluene undergoes deprotonation only with very strong bases; its pka is estimated to be approximately 41. complete hydrogenation of toluene gives methylcyclohexane. the reaction requires a high pressure of hydrogen and a catalyst. miscibility toluene is miscible (soluble in all proportions) with ethanol, benzene, diethyl ether, acetone, chloroform, glacial acetic acid and carbon disulfide, but immiscible with water. production toluene occurs naturally at low levels in crude oil and is a byproduct in the production of gasoline by a catalytic reformer or ethylene cracker. it is also a byproduct of the production of coke from coal. final separation and purification is done by any of the distillation or solvent extraction processes used for btx aromatics (benzene, toluene, and xylene isomers). other preparative routes toluene can be prepared by a variety of methods. for example, benzene reacts with methanol in presence of a solid acid to give toluene: c 6 h 6 + ch 3 oh → t o c 6 h 5 ch 3 + h 2 o uses precursor to benzene and xylene toluene is mainly used as a precursor to benzene via hydrodealkylation: c6h5ch3 + h2 → c6h6 + ch4 the second ranked application involves its disproportionation to a mixture of benzene and xylene. nitration nitration of toluene gives mono-, di-, and trinitrotoluene, all of which are widely used. dinitrotoluene is the precursor to toluene diisocyanate, which used in the manufacture of polyurethane foam. trinitrotoluene is the explosive typically abbreviated tnt. oxidation benzoic acid and benzaldehyde are produced commercially by partial oxidation of toluene with oxygen. typical catalysts include cobalt or manganese naphthenates. solvent toluene is a common solvent, e.g. for paints, paint thinners, silicone sealants, many chemical reactants, rubber, printing ink, adhesives (glues), lacquers, leather tanners, and disinfectants. fuel toluene can be used as an octane booster in gasoline fuels for internal combustion engines as well as jet fuel. toluene at 86% by volume fuelled all the turbocharged engines in formula one during the 1980s, first pioneered by the honda team. the remaining 14% was a "filler" of n-heptane, to reduce the octane rating to meet formula one fuel restrictions. toluene at 100% can be used as a fuel for both two-stroke and four-stroke engines; however, due to the density of the fuel and other factors, the fuel does not vaporize easily unless preheated to 70 °c (158 °f). honda solved this problem in their formula one cars by routing the fuel lines through a heat exchanger, drawing energy from the water in the cooling system to heat the fuel. in australia in 2003, toluene was found to have been illegally combined with petrol in fuel outlets for sale as standard vehicular fuel. toluene incurs no fuel excise tax, while other fuels are taxed at more than 40%, providing a greater profit margin for fuel suppliers. the extent of toluene substitution has not been determined. niche applications in the laboratory, toluene is used as a solvent for carbon nanomaterials, including nanotubes and fullerenes, and it can also be used as a fullerene indicator. the color of the toluene solution of c60 is bright purple. toluene is used as a cement for fine polystyrene kits (by dissolving and then fusing surfaces) as it can be applied very precisely by brush and contains none of the bulk of an adhesive. toluene can be used to break open red blood cells in order to extract hemoglobin in biochemistry experiments. toluene has also been used as a coolant for its good heat transfer capabilities in sodium cold traps used in nuclear reactor system loops. toluene had also been used in the process of removing the cocaine from coca leaves in the production of coca-cola syrup. toxicology and metabolism main article: toluene (toxicology) the environmental and toxicological effects of toluene have been extensively studied. inhalation of toluene in low to moderate levels can cause tiredness, confusion, weakness, drunken-type actions, memory loss, nausea, loss of appetite, hearing loss, and colour vision loss. some of these symptoms usually disappear when exposure is stopped. inhaling high levels of toluene in a short time may cause light-headedness, nausea, or sleepiness, unconsciousness, and even death. toluene is, however, much less toxic than benzene, and as a consequence, largely replaced it as an aromatic solvent in chemical preparation. the us environmental protection agency (epa) states that the carcinogenic potential of toluene cannot be evaluated due to insufficient information. in 2013, worldwide sales of toluene amounted to about 24.5 billion us-dollars. similar to many other solvents such as 1,1,1-trichloroethane and some alkylbenzenes, toluene has been shown to act as a non-competitive nmda receptor antagonist and gabaa receptor positive allosteric modulator. additionally, toluene has been shown to display antidepressant-like effects in rodents in the forced swim test (fst) and the tail suspension test (tst), likely due to its nmda antagonist properties. toluene is sometimes used as a recreational inhalant ("glue sniffing"), likely on account of its euphoric and dissociative effects. toluene inhibits excitatory ion channels such as the nmda receptor, nicotinic acetylcholine receptor, and the serotonin 5-ht3 receptor. it also potentiates the function of inhibitory ion channels, such as the gabaa and glycine receptors. in addition, toluene disrupts voltage-gated calcium channels and atp-gated ion channels. recreational use toluene is used as an intoxicative inhalant in a manner unintended by manufacturers. people inhale toluene-containing products (e.g., paint thinner, contact cement, correction pens, model glue, etc.) for its intoxicating effect. the possession and use of toluene and products containing it are regulated in many jurisdictions, for the supposed reason of preventing minors from obtaining these products for recreational drug purposes. as of 2007, 24 u.s. states had laws penalizing use, possession with intent to use, and/or distribution of such inhalants. in 2005 the european union banned the general sale of products consisting of greater than 0.5% toluene. bioremediation several types of fungi including cladophialophora, exophiala, leptodontidium (syn. leptodontium), pseudeurotium zonatum, and cladosporium sphaerospermum, and certain species of bacteria can degrade toluene using it as a source of carbon and energy.