知识与财富的链接
研究了以2,4-二氟苯甲醛为起始原料,以水为溶剂经硼氢化钾还原,带水剂的作用下进行氯化和氰化反应一锅法合成2,4-二氟苯乙腈。考察了不同还原剂和带水剂对反应收率及产品质量的影响。结果表明,适宜的工艺条件为:2,4-二氟苯甲醛∶硼氢化钾∶氯化亚砜∶氰化钠=1∶0.36∶1.26∶1.35,用甲苯作为带水剂及氯化反应和氰化反应的溶剂,氰化反应的温度为90℃,反应时间3 h,总收率可达62.1%。该过程具有操作简单、适合工业化生产的特点。
2,4-Difluorophenylacetonitrile was synthesized from 2,4-difluorobenzaldehyde by reduction with KBH4 in water,followed by chlorination and cyanation in the water-carrying agent in one-pot.The effect of the different types of the reductant and water-carrying agent on the yield was investigated.The experimental result showed that the optimal condition was as follows:the molar ratio of 2,4-difluorobenzaldehyde,potassium borohydride,thionyl chloride and sodium cyanide was 1 ∶0.36 ∶1.26 ∶1.35,toluene was used as the water-carrying agent and the solvent of chlorination and cyanation,temperature of cyanation was 90 ℃,time was 3 h,the total yield was 62.1%.The improved synthetic process is practical and easy to be scaled up.
