2,3-dimethylbutadiene

Structural formula
General
Surname	2,3-dimethylbutadiene
other names	2,3-dimethylbutadiene Dimethylbutadiene (ambiguous) Methylisoprene
Molecular formula	C 6 H 10
Brief description	highly flammable, volatile, liquid
External identifiers / databases
CAS number 513-81-5 EC number 208-172-0 ECHA InfoCard 100.007.430 PubChem 10566 Wikidata Q3597985
properties
Molar mass	82.15 g mol −1
Physical state	liquid
density	0.73 g cm −3
Melting point	−76 ° C
boiling point	68 ° C
Vapor pressure	358.6 hPa (37.7 ° C)
solubility	very sparingly soluble in water (0.129 g l −1 at 25 ° C) miscible with chloroform
Refractive index	1.438 (20 ° C)
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 225 P: 210
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

2,3-Dimethylbutadiene (more precisely 2,3-dimethyl-1,3-butadiene ) is a chemical compound from the group of aliphatic , unsaturated hydrocarbons and dienes .

Extraction and presentation

2,3-Dimethyl-1,3-butadiene can easily be obtained from pinacol by an acid-catalyzed dehydration reaction .

${\displaystyle {\ce {3 C6H14O2 -> C6H10 + 2 C6H12O + 4 H2O}}}$

properties

2,3-Dimethyl-1,3-butadiene is a highly flammable, volatile liquid that is very sparingly soluble in water.

use

2,3-Dimethyl-1,3-butadiene is used to produce other chemical compounds (for example 1,3,6-triene derivatives) by Diels-Alder cycloaddition reactions and polymerization reactions (for example to methyl rubber ). She is also involved in the manufacture of synthetic rubber .

Diels-Alder reaction using 2,3-dimethyl-1,3-butadiene and N -ethyl maleimide

safety instructions

The vapors of 2,3-dimethyl-1,3-butadiene can form an explosive mixture with air ( flash point −1 ° C).

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on 2,3-dimethyl-1,3-butadiene in the GESTIS substance database of the IFA , accessed on March 4, 2018(JavaScript required) .
2. ↑ ^{a b} data sheet 2,3-dimethyl-1,3-butadiene, 98%, stab. with 100ppm BHT at AlfaAesar, accessed on March 4, 2018 ( PDF )(JavaScript required) .
3. ↑ ^{a b} Data sheet 2,3-Dimethyl-1,3-butadiene, 98%, contains 100 ppm BHT as stabilizer from Sigma-Aldrich , accessed on March 4, 2018 ( PDF ).
4. ↑ CFH Allen, Alan Bell, LW Newton, and ER Coburn: 2,3-Dimethyl-1,3-butadiene In: Organic Syntheses . 22, 1942, p. 39, doi : 10.15227 / orgsyn.022.0039 ; Coll. Vol. 3, 1955, p. 312 ( PDF ).