两步法合成二甲基二烯丙基氯化铵的工艺改进

以二甲胺与烯丙基氯为原料在高压釜中合成中间产物二甲基烯丙基胺(DMAA),将它与水相分离后用片状NaOH干燥,再与等摩尔烯丙基氯在丙酮混合溶剂中回流合成二甲基二烯丙基氯化铵(DMDAAC);水相蒸发浓缩一半体积后,用干燥油相的NaOH中和,使二甲胺和DMAA再生,进入下一轮反应。结果表明,当叔胺化反应温度为60℃,n(二甲胺)∶n(烯丙基氯)=(2.05~2.10)∶1,时间为3.5 h时,DMAA的收率达96.5%,比传统两步法工艺提高了27.1%,废液体积减少了1.12 mL/(mLDMAA);当V(DMAA)∶V(烯丙基氯)∶V(混合溶剂)=1∶1∶3,季铵化温度为45℃,反应时间为10 h时,DMDAAC的收率为92.3%,比传统两步法工艺提高了20.3%;w(DMDAAC)=99.87%。采用元素分析、FTIR和1HNMR对产物的结构进行了表征。该研究已完成10 L规模扩试。

Process Improvement of the Two-Step Method for the Synthesis of Dimethyldiallylammonium Chloride

The in-process product dimethylallylamine(DMAA) was synthesized using dimethylamine and allyl chloride as materials in autoclave.After separation,the oil phase of DMAA was dried by flake sodium hydroxide and then reacted with equimolar allyl chloride to synthesize dimethyldiallylammonium chloride(DMDAAC) by refluxing in combined acetone solvent.The water phase produced in the synthetic process of DMAA was concentrated to half its original volume and neutralized using the sodium hydroxide for the oil phase drying to regenerate the dimethylamine and DMAA which were used again.With n(dimethylamine)∶n(allyl chloride)=(2.05～2.10)∶1,reacting in autoclave at 60 ℃ for 3.5 h,the yield of DMAA is up to 96.5% which is 27.1% higher than that in the traditional two-step method and the volume of waste liquid decreases by 1.12 mL/(mL DMAA).When V(DMAA)∶V(allyl chloride)∶V(combined solvent)=1∶1∶3,quaternarization temperature is 45 ℃ and time is 10 h,the yield of DMDAAC is 92.3% which is 20.3% higher than that in the traditional two-step method.The mass fraction of DMDAAC is up to 99.87%.Structure of the product was characterized by elementary analysis,FTIR and ~1HNMR.The 10 L bench-scale research for this technology have been done.