作者:李爱军 徐朝洁 张志伟
来源:《河北科技大学学报》2016年第04期
周洋感谢门
陆军学员方队
摘要:为满足市场需求,对2,3-二氯吡啶的合成工艺进行了研究。以2-氯烟酸为起始原料,经酰胺化、霍夫曼(Hofmann)酰胺降解、重氮化和Sandmeyer 4步反应,得到2,3-二氯吡啶,对影响产率的因素(如PCl3用量、NaOH浓度、反应温度、催化剂用量)进行了优化。结果表明:酰胺化中,n(2-氯烟酸)∶n(PCl3)=1∶0.45;霍夫曼降解反应中,NaOH质量分数为18%,反应温度为75~80 ℃;Sandmeyer反应中,n(2-氯-3-氨基吡啶)∶n(氧化铜)=1∶0.3。在此优化条件下,反应总收率为70.33%(以2-氯烟酸计),纯度达98.5%,通过1H-NMR进行了结构表征。此法产品纯度高,操作简便,原料易得。 输液管 关键词:农药工程;2,3-二氯吡啶;2-氯烟酸;Hofmann降解;重氮化;Sandmeyer反应
频率补偿电路
中图分类号:TQ453.2文献标志码:A 文章编号:1008-1542(2016)04-0364-04
文件管理系统 Abstract:In order to meet the market demand, the synthetic process of 2,3-dichl全身长指甲
oropyridine is studied. 2,3-dichloropyridine is synthesized from 2-chloronicotinic acid via amidation, Hofmann degradation, diazotization and Sandmeyer reaction. The factors influencing the yield (for example the amount of PCl3, the concentration of NaOH, the reaction temperature and the amount of catalyst) are optimized. The results show that the optimum conditions are as following: In amidation reaction, n(2-chloronicotinic acid)∶n(PCl3)=1∶0.45, in Hofmann degradation, the concentration of NaOH is 18%, the reaction temperture is at 75~80 ℃, and in Sandmeyer reaction, n(2-chloro-3-amino pyridine)∶n(CuO)=1∶0.3. Under the optimized conditions, the yield of the products is 70.33%(counted based on 2-chloronicotinic acid), the purity is 98.5%. The structure is characterized by 1H-NMR, which shows that the synthetic process has the advantages of high purity, simple operation and easily obtained raw material.