5-Chloro-1-pentene

821-09-0

928-50-7

General procedure for the synthesis of 5-chloro-1-pentene from 4-penten-1-ol: In a 2000 mL four-necked flask equipped with a mechanical stirrer, a dropping funnel, a reflux condenser tube, and a thermometer, 200 g (2.33 mol) of 4-penten-1-ol, 2 g of bismuth trioxide, and 700 g of pyridine were added sequentially. Stirring was turned on and the temperature of the reaction system was lowered to 0 °C using an ice-salt bath. Subsequently, 238 g (2 mol) of thionyl chloride was slowly added dropwise through a dropping funnel, with the rate of dropwise acceleration being controlled to maintain the reaction temperature at no more than 5 °C. After the dropwise addition, the ice-salt bath was withdrawn and the reaction system was allowed to warm up naturally to 10-30 °C and stirred continuously for 72 h in this temperature range. If the reaction temperature exceeds 30°C, it needs to be cooled down to below 30°C with an ice-salt bath. Upon completion of the reaction, the reaction mixture was filtered through a Brinell funnel and the filter cake (containing catalyst and pyridine hydrochloride) was collected. The filter cake was washed twice with 200 mL of acetone, the filtrate and washings were combined and poured into 1500 mL of distilled water, and the lower organic phase was separated after standing and layering. The organic phase was washed with water to neutral, followed by distillation under reduced pressure. Fractions with boiling points of 88-95 °C were collected under vacuum at 255 mmHg to give 1.99 g of colorless liquid product in 95.22% yield. The purity of the product was 98.27% by gas chromatography.