二烯丙基甲基烷基溴化铵的结构与性质的关系

对4种二烯丙基甲基烷基(n=12,14,16,18)溴化铵(标记为C12,C14,C16,C18)的性质与性能进行了研究。 通过测定其热稳定性、表面活性和絮凝性能,考察产物结构对其性质与性能的影响规律。 结果表明,季铵盐C12~C18的主要分解温度分别为170~300 ℃、172~303 ℃、170~293 ℃和170~310 ℃,对应失重率分别为92.8%、92.6%、96.4%和87.4%;临界胶束浓度(cmc)和临界胶束浓度下的表面张力(γ_cmc)分别为5.2、3.5、1.4、1.1 mmol/L和26.6、25.2、33.8、35.8 mN/m,显示出较高的表面活性;季铵盐C16的发泡与稳泡性能最好,C12的Krafft点<0 ℃,C14、C16和C18的Krafft点分别为1、8和19 ℃; C12和C14分别对膨润土和高岭土的絮凝能力最强,表明单体的絮凝性能具有结构选择性。

Relationships Between Structures and Properties of Diallylmethylalkylammonium Bromide

The properties and performances of four kinds of quaternary ammonium salt monomers were researched. The relationships between structures and properties or performances for the four kinds of diallylmethylalkyl(n=12,14,16,18) ammonium bromides(marked C12,C14,C16,C18) were discussed on the basis of the determination of the thermal stability, surfactivity and flocculation ability. Quaternary ammonium salts C12~C18 decompose within 170~300 ℃,172~303 ℃,170~293 ℃ and 170~310 ℃, their mass loss rates are 92.8%, 92.6%, 96.4% and 87.4%, respectively. Their critical micelle concentration(cmc) and the corresponding surface tension(γ_cmc) are 2.0, 3.5, 1.4, 1.1 mmol/L and 26.6, 25.2, 33.8, 35.8 mN/m, respectively. All monomers show excellent surfactivity. The quaternary ammonium salt C16 possesses the best foaming power and foam stability. C12 Krafft point is <0 ℃. Krafft points of C14, C16 and C18 are 1 ℃, 8 ℃ and 19 ℃, respectively. The C12 and C14 appear the strongest flocculation ability to bentonite and kaolin suspansion, indicating that the flocculation performance of monomers are of certain selectivity to structures.