Toluene

Toluene
	;
General
Chem. formula	C₇h₈
Physical properties
Molar mass	92.14 g / mol
Density	0.86694 g / cm³
Thermal properties
T. melt.	−95 ℃
T. bale.	110,6 ℃
Cr. point	320 ° C (593 K), 4,299 kPa
Specific Heat of Evaporation	364 kJ / kg
Chemical properties
Solubility in water	14 mg / 100 ml
Classification
CAS Number
PubChem
ChemSpider
EINECS Number	203-625-9
RTECS	XS5250000
Chebi	17578
Drugbank
Smiles
	CC1 = CC = CC = C1
Inchi
	1S / C7H8 / c1-7-5-3-2-4-6-7 / h2-6H, 1H3
Security
NFPA 704	3 2 0
	Data is provided for standard conditions (25 ℃, 100 kPa) , unless otherwise indicated.

Toluene (from Spanish Tolu , tolu balsam ) - methylbenzene, PhMe - a colorless liquid with a characteristic odor, refers to arenas .

Toluene was first obtained by P. Pelletier in 1835 by distillation of pine resin . In 1838, A. Deville was isolated from a balsam brought from the city of Tolu in Colombia , in whose honor he received his name ^[1] .

Content

1 General characteristics
2 Chemical properties
3 Receiving and purification
4 Application
5 Danger and handling
6 Toluene Substance Abuse
7 See also
8 Notes
9 References

General characteristics

Colorless mobile volatile liquid with a pungent odor, exhibits a weak narcotic effect. It mixes in unlimited quantities with hydrocarbons, many alcohols , simple and complex esters , does not mix with water. The refractive index of light is 1.4969 at 20 ° C. Combustible, burns with a smoky flame.

Chemical Properties

Toluene is characterized by electrophilic substitution in the aromatic ring and substitution in the methyl group by a radical mechanism.

The electrophilic substitution in the aromatic ring occurs mainly in the ortho and para positions relative to the methyl group .

In addition to substitution reactions, toluene enters into the reactions of addition ( hydrogenation ), ozonolysis. Some oxidizing agents (alkaline solution of potassium permanganate , diluted nitric acid ) oxidize the methyl group to carboxyl . Auto-ignition temperature 535 ° C. Flash point 4 ° C.

The interaction of toluene with strong oxidizing agents produces benzoic acid :

Interaction with potassium permanganate in an acidic environment:

{\mathsf {5C_{6}H_{5}CH_{3}+6KMnO_{4}+9H_{2}SO_{4}\rightarrow }}

{\ displaystyle {\ mathsf {5C_ {6} H_ {5} CH_ {3} + 6KMnO_ {4} + 9H_ {2} SO_ {4} \ rightarrow}}}

{\mathsf {\rightarrow 5C_{6}H_{5}COOH+6MnSO_{4}+3K_{2}SO_{4}+14H_{2}O}}.

{\ displaystyle {\ mathsf {\ rightarrow 5C_ {6} H_ {5} COOH + 6MnSO_ {4} + 3K_ {2} SO_ {4} + 14H_ {2} O}}.}

Interaction with potassium permanganate in a neutral environment

{\mathsf {C_{6}H_{5}CH_{3}+2KMnO_{4}\rightarrow C_{6}H_{5}COOK+2MnO_{2}+KOH+H_{2}O}}

{\ displaystyle {\ mathsf {C_ {6} H_ {5} CH_ {3} + 2KMnO_ {4} \ rightarrow C_ {6} H_ {5} COOK + 2MnO_ {2} + KOH + H_ {2} O}} }

Interaction with halogens in the light

{\mathsf {C_{6}H_{5}CH_{3}+X_{2}{\xrightarrow[{}]{h\nu }}C_{6}H_{5}CH_{2}X+HX}}

{\ displaystyle {\ mathsf {C_ {6} H_ {5} CH_ {3} + X_ {2} {\ xrightarrow [{}] {h \ nu}} C_ {6} H_ {5} CH_ {2} X + HX}}}

Receiving and cleaning

The product of catalytic reforming of gasoline fractions of oil . It is distinguished by selective extraction and subsequent distillation . Also, good yields are achieved by catalytic dehydrogenation of heptane through methylcyclohexane .

Toluene is purified similarly to benzene , only if concentrated sulfuric acid is used, it should be taken into account that toluene is sulfonated more easily than benzene, which means that it is necessary to maintain a lower temperature of the reaction mixture (practically less than 30 ° C ).

Toluene also forms an azeotropic mixture with water ^[2] ^[3] .

Toluene can be obtained from benzene by the Friedel-Crafts reaction using iron tribromide as a catalyst:

{\mathsf {C_{6}H_{6}+CH_{3}Br{\xrightarrow[{}]{FeBr_{3}}}C_{6}H_{5}CH_{3}+HBr}}

{\ displaystyle {\ mathsf {C_ {6} H_ {6} + CH_ {3} Br {\ xrightarrow [{}] {FeBr_ {3}}} C_ {6} H_ {5} CH_ {3} + HBr} }}

Application

Raw materials for the production of benzene , benzoic acid , nitrotoluene (including trinitrotoluene ), toluene diisocyanates (via dinitrotoluene and toluene diamine) benzyl chloride and other organic substances.

It is a solvent for many polymers , is part of various commodity solvents for varnishes and paints . It is a part of solvents: R-40, R-4, 645, 646 , 647 , 648. It is used as a solvent in chemical synthesis.

Danger and handling

Toluene vapors can penetrate through intact skin and respiratory organs, cause damage to the nervous system (inhibition, disturbances in the functioning of the vestibular apparatus), including irreversible. Therefore, it is necessary to work with toluene and the solvents of which it is a part in durable rubber gloves in a well-ventilated room or using exhaust ventilation.

Fire hazard, flammable liquid. The concentration limits of the explosiveness of the vapor-air mixture of 1.3 - 6.7%. It has a weak narcotic effect.

According to other sources (SANPIN, precautions when working with volatile organic solvents), toluene is a highly toxic poison that affects the blood formation function of the body, similar to benzene. Hematopoiesis is manifested in cyanosis and hypoxia . There is also toluene substance abuse.

In general, toluene, like other benzene homologs, is very toxic, its prolonged exposure can lead to irreversible damage to the central nervous system , blood-forming organs and create the prerequisites for the occurrence of encephalopathy .

Experiments in rats did not reveal the risks of increasing the number of tumors with long-term exposure to toluene. However, data on human exposure are currently not available, and the US Environmental Protection Agency classifies toluene as a group D carcinogen (“insufficient data to classify”) ^[4] . but according to observations of toxicomania of any cancers caused by toluene, it was not noticed, but with regular inhalation of toluene-containing substances, a number of other diseases can be obtained. A gas mask can serve as an optimal protection against toluene vapor.

Toluene Substance Abuse

Toluene and mixtures containing it, for example, P-646 are hallucinogenic substances . To combat substance abuse , Henkel removed toluene from Moment glue, replacing it with acetone .

Notes

↑ Henri-Étienne Sainte-Claire Deville - biography of Henri-Etienne Deville on the NNDB website
↑ Toluene
↑ Gordon A., Ford R. Sputnik chemist. Translation into Russian by Rosenberg E.L., Koppel S.I.M.: Mir , 1976 .-- 544 p.
↑ Toluene: Health Information Summary (Neopr.) (2005). Date of treatment January 5, 2015.

Links

Toxicological Profile for Toluene (ver. September 2000) // ATSDR
GOST 14710-78 Petroleum Toluene. Technical conditions (neopr.) . Date of appeal May 31, 2013.

[nndb-deville-1] Henri-Étienne Sainte-Claire Deville - biography of Henri-Etienne Deville on the NNDB website

[2] Toluene

[3] Gordon A., Ford R. Sputnik chemist. Translation into Russian by Rosenberg E.L., Koppel S.I.M.: Mir , 1976 .-- 544 p.

[4] Toluene: Health Information Summary (Neopr.) (2005). Date of treatment January 5, 2015.