Pseudocumene

Structural formula
General
Surname	Pseudocumene
other names	1,2,4-trimethylbenzene; asym. trimethylbenzene;
Molecular formula	C 9 H 12
Brief description	colorless liquid with an oily aromatic odor
External identifiers / databases
EC number	202-436-9
ECHA InfoCard	100.002.216
PubChem	7247
Wikidata	Q376994
properties
Molar mass	120.19 g mol −1
Physical state	liquid
density	0.88 g cm −3
Melting point	−44 ° C
boiling point	169 ° C
Vapor pressure	2.8 hPa (25 ° C); 6 hPa (37.7 ° C); 15 hPa (50 ° C);
solubility	practically insoluble in water (0.06 g l −1 at 20 ° C)
Refractive index	1.5048
safety instructions
H and P phrases	H: 226-304-332-319-335-315-411
	P: 261-273-301 + 310-305 + 351 + 338-331
Toxicological data	5000 mg kg −1 ( LD 50 , rat , oral )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Pseudocumene ( 1,2,4-trimethylbenzene ) is a benzene substituted with three methyl groups and thus an alkylbenzene and an aromatic hydrocarbon . With its isomers hemellitol (1,2,3-trimethylbenzene) and mesitylene (1,3,5-trimethylbenzene) it belongs to the group of trimethylbenzenes and also to the group of C ₃ -benzenes .

Occurrence

Pseudocumene occurs in coal tar . It has also been identified as a flavoring in coffee .

Extraction and presentation

Pseudocumene can be obtained by disproportionation of xylene in the presence of aluminum chloride.

properties

Pseudocumene is an oily, less volatile, colorless liquid with an aromatic odor, which is practically insoluble in water.

The compound forms flammable vapor-air mixtures. The compound has a flash point of 50 ° C. The explosion range is between 0.8% by volume (42 g / m ³ ) as the lower explosion limit (LEL) and 7.0% by volume (350 g / m ³ ) as the upper explosion limit (UEL).) The ignition temperature is 485 ° C. The substance therefore falls into temperature class T1.

use

Pseudocumene is an intermediate in the manufacture of drugs and dyes . The pseudocumene produced in the petrochemical industry is converted into trimellitic acid by catalytic oxidation of the methyl groups .

It is used as a scintillator for the detection of charged particles .

safety instructions

Pseudocumene can cause acute or chronic health hazards. Acute there is a weak irritant effect on the mucous membranes and the skin. A depressive effect on the central nervous system can occur, which can lead to chronic disorders of this.

Web links

Commons : Pseudocumene - collection of images, videos and audio files

Entry on pseudocumene . In: P. J. Linstrom, W. G. Mallard (Eds.): NIST Chemistry WebBook, NIST Standard Reference Database Number 69 . National Institute of Standards and Technology , Gaithersburg MD, accessed December 12, 2018.
EPA: fact sheet

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Entry on 1,2,4-trimethylbenzene in the GESTIS substance database of the IFA , accessed on December 19, 2018(JavaScript required) .
^ Karl Griesbaum, Arno Behr, Dieter Biedenkapp, Heinz-Werner Voges, Dorothea Garbe, Christian Paetz, Gerd Collin, Dieter Mayer, Hartmut Höke: Hydrocarbons . In: Ullmann's Encyclopedia of Industrial Chemistry . Wiley-VCH Verlag GmbH & Co. KGaA, 2000, ISBN 978-3-527-30673-2 , doi : 10.1002 / 14356007.a13_227 .
↑ Entry on 1,2,4-trimethylbenzene in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ ^a ^b Entry on pseudocumene in the Hazardous Substances Data Bank , accessed June 19, 2013.
^ M. Stoll, M. Winter, F. Gautschi, I. Flament, B. Willhalm: Recherches sur les arômes 13 ^e communication Sur l′arôme de café. I . In: Helvetica Chimica Acta . tape 50 , no. 2 , 1967, p. 628-694 , doi : 10.1002 / hlca.19670500229 .
↑ ^a ^b E. Brandes, W. Möller: Safety-related parameters. Volume 1: Flammable Liquids and Gases. Wirtschaftsverlag NW - Verlag für neue Wissenschaft, Bremerhaven 2003.
↑ Air oxidation of pseudocumene: Patent EP0513835 : Process for the production of trimellitic acid. Registered on May 15, 1992 , published on August 9, 1995 , applicant: Lonza , inventors: Carlo Fumagalli, Lorenzo Capitanio, Giancarlo Stefani. ‌
↑ Brigitte Röthlein: Everywhere - and hard to believe. Researchers at TUM hunt for neutrinos deep underground. In: Fascination Research: https://portal.mytum.de/pressestelle/faszination-forschung/ . Technical University of Munich, 2008, p. 65 , accessed on January 9, 2020 .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Entry on 1,2,4-trimethylbenzene in the GESTIS substance database of the IFA , accessed on December 19, 2018(JavaScript required) .

[ullmann-2] Karl Griesbaum, Arno Behr, Dieter Biedenkapp, Heinz-Werner Voges, Dorothea Garbe, Christian Paetz, Gerd Collin, Dieter Mayer, Hartmut Höke: Hydrocarbons . In: Ullmann's Encyclopedia of Industrial Chemistry . Wiley-VCH Verlag GmbH & Co. KGaA, 2000, ISBN 978-3-527-30673-2 , doi : 10.1002 / 14356007.a13_227 .

[CLP_100.002.216-3] Entry on 1,2,4-trimethylbenzene in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[HSDB-4] Entry on pseudocumene in the Hazardous Substances Data Bank , accessed June 19, 2013.

[DOI10.1002/hlca.19670500229-5] M. Stoll, M. Winter, F. Gautschi, I. Flament, B. Willhalm: Recherches sur les arômes 13 ^e communication Sur l′arôme de café. I . In: Helvetica Chimica Acta . tape 50 , no. 2 , 1967, p. 628-694 , doi : 10.1002 / hlca.19670500229 .

[Brandes-6] E. Brandes, W. Möller: Safety-related parameters. Volume 1: Flammable Liquids and Gases. Wirtschaftsverlag NW - Verlag für neue Wissenschaft, Bremerhaven 2003.

[7] Air oxidation of pseudocumene: Patent EP0513835 : Process for the production of trimellitic acid. Registered on May 15, 1992 , published on August 9, 1995 , applicant: Lonza , inventors: Carlo Fumagalli, Lorenzo Capitanio, Giancarlo Stefani. ‌

[8] Brigitte Röthlein: Everywhere - and hard to believe. Researchers at TUM hunt for neutrinos deep underground. In: Fascination Research: https://portal.mytum.de/pressestelle/faszination-forschung/ . Technical University of Munich, 2008, p. 65 , accessed on January 9, 2020 .