Английская Википедия:Dimethylbutadiene
Dimethylbutadiene, formally referred to as 2,3-dimethyl-1,3-butadiene, is an organic compound with the formula (CH3)2C4H4. It is colorless liquid which served an important role in the early history of synthetic rubber. It is now a specialty reagent.
Synthesis
Dimethylbutadiene is readily prepared by an acid catalyzed dehydration reaction of pinacol:[1]
The current industrial route involves dimerization of propene followed by dehydrogenation.[2]
Applications
In 1909, Fritz Hofmann and a team working at Bayer succeeded in polymerizing dimethylbutadiene. It was then called methyl isoprene because it has one more methyl group than isoprene. Their polymer was the first synthetic rubber.[3] The polymer had a number of deficiencies relative to natural rubber.[4] The Bayer synthesis of dimethylbutadiene involved the dehydration of pinacol, as described above.[2]
Reactions
Dimethylbutadiene readily undergoes Diels-Alder reactions and reacts faster than 1,3-butadiene. Its effectiveness in this reaction is attributed to the stabilization of the cis-conformation owing to the influence of the methyl groups on the C2 and C3 positions.
References
- ↑ Шаблон:OrgSynth
- ↑ 2,0 2,1 Шаблон:Citation.
- ↑ The Moving Powers of Rubber, Leverkusen, Germany: LANXESS AG: 20.
- ↑ Шаблон:Cite web
