Tetramethylbenzenes

from Wikipedia, the free encyclopedia
Tetramethylbenzenes
Surname Prehnitol Isodurol Durol
other names 1,2,3,4-tetramethylbenzene 1,2,3,5-tetramethylbenzene 1,2,4,5-tetramethylbenzene
Structural formula Structure of prehnitol Structure of Isodurol Structure of Durol
CAS number 488-23-3 527-53-7 95-93-2
PubChem 10263 10695 7269
ECHA InfoCard 100.006.976 100.007.653 100.002.242
Molecular formula C 10 H 14
Molar mass 134.22 g mol −1
Physical state liquid firmly
Melting point −6.3 ° C −20 ° C 79.2 ° C
boiling point 205 ° C 197.9 ° C 196.8 ° C
solubility insoluble in water,
good in ethers, alcohols, benzene , acetone
GHS
labeling
no classification available
07 - Warning
Caution
02 - Highly / extremely flammable
danger
H and P phrases see above 319 228-413
see above no EUH phrases no EUH phrases
see above 305 + 351 + 338 210

In chemistry, tetramethylbenzenes form a group of substances whose structure consists of a benzene ring with four methyl groups  (–CH 3 ) as substituents . Their different arrangement results in three constitutional isomers with the empirical formula C 10 H 14 . They are mainly known by their common names Prehnitol (1,2,3,4-tetramethylbenzene), Isodurol (1,2,3,5-tetramethylbenzene) and Durol (1,2,4,5-tetramethylbenzene). They also belong to the group of C 4 benzenes .

history

The durol was discovered in 1870 ( Rudolph Fittig , Paul Jannasch ). The discoverers report that it is the first hydrocarbon in the benzene series that is solid at room temperature. The name was therefore chosen after the Latin durus (= hard).

The prehnitol was discovered in 1886. It can be converted into prehnitic acid by oxidation . This acid crystallizes in a similar way to the mineral prehnite occurring in South Africa and was therefore named after it. The name giver for the Prehnitol was Adolf von Baeyer . The mineral, in turn, was named after a colonel von Prehn .

properties

The boiling points of the three isomers are close to one another, while their melting points differ more clearly. Due to its symmetry, Durol has the highest melting point of 79.2 ° C; in contrast to the other two isomers, it is a solid.

literature

Web links

Commons : Tetramethylbenzenes  - Collection of images, videos, and audio files

Individual evidence

  1. ↑ a b CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
  2. ↑ a b Entry on Isodurol in the GESTIS substance database of the IFA , accessed on December 26, 2019(JavaScript required) .
  3. ↑ a b c Entry on Durol in the GESTIS substance database of the IFA , accessed on December 26, 2019(JavaScript required) .
  4. ↑ Data isodurene at Sigma-Aldrich , accessed on 26 December 2019 ( PDF ).
  5. ^ A b Christian Wiegand: “Origin and interpretation of important organic trivial names. I. Hydrocarbons of the Benzene Series ”, in: Angewandte Chemie , 1948 , 60  (4), pp. 109–111 ( doi : 10.1002 / anie.19480600407 ).