592-48-3Relevant articles and documents
Dissociation of 1,3-Hexadiene and the Resonance Energy of the Pentadienyl Radical
Trenwith, Antony B.
, p. 266 - 271 (1980)
Measurements of the rate at which methane is formed in the pyrolysis of 1,3-hexadiene at temperatures over the range 694-759 K and pressures between 25 and 200 Torr show that the dissociation reaction CH3CH2CH=CHCH=CH2 -> CH3.+ .CH2CH=CHCH=CH2 is a homogeneous, first-order reaction under these conditions and the rate expression is log(k1/s-1) = (15.92 +/- 0.17)-(66390 +/- 840)/θ where θ = 2.303RT/cal mol-1 (1 cal = 4.18 J).The experimental activation energy yields for the pentadienyl radical, ΔH = 45.9 +/- 1.0 kcal mol-1 at 298 K and a resonance energy of 18.5 +/- 1.5 kcal mol-1, assuming a value of 98.2 kcal mol-1 for the primary C-H bond dissociation energy in alkenes.
Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction
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, (2019/05/08)
The invention provides a method for synthesizing diene compounds based on an aldehyde-ketone condensation reaction. The method comprises the following steps: firstly, under the action of a condensation catalyst, performing a condensation reaction on ketone compounds and aldehyde compounds to obtain condensation products; then, under the action of a reduction catalyst, performing a reduction reaction on the condensation products obtained in the previous step to obtain reduction products; under the action of a catalyst, performing a dehydration reaction on the reduction products obtained in theprevious step to obtain the diene compounds. According to the method, ketone, aldehyde as well as homologues of ketone and aldehyde which are cheap and easy to obtain can be used as raw materials forsynthesizing the diene compounds such as butadiene, piperylene as well as homologues of butadiene and piperylene, experimental conditions are mild, the operation is simple, and a large-scale synthesisprospect is achieved.
Tetrabutylphosphonium Bromide Catalyzed Dehydration of Diols to Dienes and Its Application in the Biobased Production of Butadiene
Stalpaert, Maxime,Cirujano, Francisco G.,De Vos, Dirk E.
, p. 5802 - 5809 (2017/09/15)
We report the use of the ionic liquid tetrabutylphosphonium bromide as a solvent and catalyst for dehydration of diols to conjugated dienes. This system combines stability, high reaction rates, and easy product separation. A reaction mechanism for the model compound 1,2-hexanediol is proposed and experimentally corroborated. This particular mechanism allows for the selective formation of conjugated dienes, in contrast with purely acidic catalysis. Next, the reaction is also performed on various other diols. As a first application, we assessed the biobased production of 1,3-butadiene. With 1,4-butanediol as the starting material, a 94% yield of butadiene was reached at 100% conversion.
