高纯度二甲基二烯丙基氯化铵的制备

以二甲胺和烯丙基氯为原料,制备高纯度二甲基二烯丙基氯化铵(DMDAAC).将第一阶段(叔胺化反应)分两步投料:第一步是二甲胺与烯丙基氯按物质的量的比为1∶0.5投料；第二步是继续滴加烯丙基氯和氢氧化钠,投料比为n(二甲胺)∶n(烯丙基氯)∶n(氢氧化钠)=1∶0.5∶1.采用气相色谱和pH酸度计监控传统一步法与该合成方法,并以聚合产物聚二甲基二烯丙基氯化铵(PDMDAAC)的特征粘度衡量DMDAAC聚合性能.结果表明,第一阶段体系维持pH≤l1,该合成方法所得DMDAAC中各杂质的含量均下降了60％ ～ 70％,季胺化反应控制在6h为宜,PDMDAAC特征粘度稳定在1.6 ～2.2 dL/g,DMDAAC聚合性能较好.

Synthesis of dimethyldiallyl ammonium chloride with high purifty

Dimethyldiallyl ammonium chloride(DMDAAC) with high purity is synthesized with dimethylamine and allyl chloride.The feature of this method is that the stage 1(tertiary amination) of the process is divided into two steps.At first,allyl chloride is dropped in dimethylamine when the molar ratio of dimethylamine to allyl chloride is 1∶0.5.Subsequently,the mixture of allyl chloride and sodium hydroxide(1∶0.5∶1 molar ratio of dimethylamine:allyl chloride:sodium hydroxide) is added.Gas chromatography and pH-meter are applied to monitor the traditional method and the method used in this study.The intrinsic viscosity of resultant polydiallyldimethylammonium chloride(PDMDAAC) is used to measure the polymerization performance of DMDAAC.The results show that the mass of impurities of DMDAAC decreases by 60%～70% with pH≤11 in the stage 1 and 6 h of reaction time of quaternization.The intrinsic viscosity of PDMDAAC is stable in the range of 1.6～2.2 dL/g,which indicates that DMDAAC has good polymerization performance.