Chemical Properties
clear colourless to brown liquid
Uses
Crotonyl chloride is used in agrochemical, pharmaceutical and dyestuff field. Crotonoyl chloride was used in the synthesis of α,β-unsaturated ester.
Synthesis
Preparation of Raw Materials; 1-1 :(Preparation of Crotonyl chloride) Firstly, 1kg of crotonic acid was added to a 5L three-necked reaction flask fitted with a condenser and gas absorption device. Under slow stirring, 1650 mL (1.5 mol) of thionyl chloride was slowly added through a constant pressure dropping funnel, and a large amount of hydrogen chloride gas was released during the reaction. Stirring was continued at room temperature until the gas release slowed down significantly. Subsequently, the reaction mixture was slowly heated to reflux. Upon completion of the reaction, the unit was changed to a distillation unit for atmospheric pressure distillation and the 116-124 °C fraction was collected to give 871 g of crotonyl chloride in 72% yield.
Purification Methods
If the IR of a film has no OH bands, then fractionally distil it, taking the middle fraction and redistilling it. If OH bands are present, then add excess of oxalyl chloride, reflux for 3hours, then distil off the reagent and fractionally distil the crotonoyl chloride as before. Stabilise the distillate with 160ppm of hydroquinone. The amide forms needles m 158o from aqueous ammonia, and the anilide also forms needles but with m 115-118o from H2O. [Beilstein 2 H 411, 2 I 188, 2 II 392, 2 III 1265, 2 IV 1506.]
References
[1] Journal of Organometallic Chemistry, 1987, vol. 322, p. 131 - 140
[2] Journal of Organic Chemistry, 2009, vol. 74, # 22, p. 8739 - 8753
[3] Patent: US2012/165532, 2012, A1. Location in patent: Page/Page column 3
[4] Helvetica Chimica Acta, 1985, vol. 68, p. 1406 - 1426
[5] Journal of Organic Chemistry USSR (English Translation), 1981, vol. 17, # 11, p. 2072 - 2075
