摘要本文研究了二甲基二烯丙基氯化铵（DMDAAC）单体溶液中杂质甲醛的形成条件，根据文献和基本原理对甲醛形成机理作了推测并进行了实验验证。以乙酰丙酮为衍生试剂，建立了DMDAAC 单体溶液中甲醛杂质含量测定的分光光度法，对单体合成用原料、不同条件（pH、反应温度、反应时间）下单体分解破坏、常规和极端条件下单体合成工艺过程中的甲醛进行分析检测。 结果表明， 该分析方法在0.5～8mg/L范围内呈线性相关，相关系数 R2为 0.9995，精密度为 0.975%～8.862%，加标回收率为 92.06%～115.1%。DMDAAC 单体用原料分析方面，原料特别是二甲胺溶液不会引入甲醛杂质。DMDAAC单体破坏分解方面，随着体系 pH、反应时间、反应温度的增加，甲醛的形成量逐渐变大，当pH=13、T=90℃、t=6h 时DMDAAC 单体中甲醛高达 30.098mg/L，当 pH=7、T=35℃、t=1～6h 时 DMDAAC 单体中甲醛含量在检测限 0.2mg/L 左右。DMDAAC 单体合成工艺过程方面，反应体系在高温等极端条件的甲醛生成量高于常规条件下的甲醛生成量。甲醛的形成是由于季铵盐 DMDAAC 在碱性条件下形成季铵碱，进一步分解生成甲醇，甲醇在反应体系被氧化所致。在工业生产中，为避免甲醛的形成，应控制 DMDAAC 合成反应体系始终保持低pH、低温的状态。 30267
毕业论文关键词 二甲基二烯丙基氯化铵 甲醛 杂质 机理
Title Preliminary research on the formation mechanism of formaldehyde impurity in dimethyldiallylammonium chloride
Abstract The conditions for the formation of formaldehyde in dimethyldiallylammonium chloride (DMDAAC) were researched and the formation mechanism was discussed in this paper. With acetyl acetone as a derivating agent, the spectrophotometric method for determination of formaldehyde was established. The formaldehyde in raw materials, decomposition at different conditions(pH, reaction temperature, reaction time) and synthesis with conventional and extreme conditions were detected. The results showed that, the linear detection range was 0.5～8mg/L with correlation coefficient of 0.9995 while the recovery rate was 92.06%～115.1%. In DMDAAC decomposition, the amounts of formaldehyde became larger with the increase of pH, reaction time and reaction temperature, and the amount was as high as 30.098mg/L when pH=13, 90℃ and 6h while the amounts were near the detection limit when pH=7, 35℃ and 1～6h. In DMDAAC synthesis, the amount of formaldehyde under extreme conditions was larger than that of normal conditions. As for the mechanism, the formaldehyde formation might be due to the decomposition of quaternary ammonium alkali coming from quaternary ammonium alkaline conditions, and formed methanol in reaction system would be oxidized to generate formaldehyde. In industrial production, low pH and low temperature should be maintained in order to avoid the formation of formaldehyde.
Keywords Dimethyldiallylammonium chloride Formaldehyde Impurity Mechanism
目次
1引言..1
1.1DMDAAC的性质与应用.1
1.1.1DMDAAC的结构与性质..1
1.1.2DMDAAC的应用..1
1.2DMDAAC的合成.1
1.2.1DMDAAC的合成反应历程1
1.2.2DMDAAC的一步法合成..2
1.2.3DMDAAC的两步法合成..3
1.3季铵盐/季铵碱的分解4
1.4存在问题..4
1.5本文研究目标和工作内容5
1.5.1研究目标5
1.5.2工作内容5
2实验原理.6
2.1分光光度法原理..6
2.2季铵碱分解机理..6
2.3气相色谱-质谱联用原理.7
3实验部分.8
3.1实验仪器与试剂..8
3.1.1实验仪器8
3.1.2实验试剂8
3.2实验方案设计.8
3.3实验结果与分析.10
3.3.1甲醛分析方法的建立.10
3.3.2DMDAAC单体合成用原料分析.13 二甲基二烯丙基氯化铵中杂质甲醛形成机理初探:http://www.youerw.com/huaxue/lunwen_25902.html