不同链长烷基季铵离子在蒙脱石层间域内排列方式的对比

COMPARATIVE STUDY ON THE AGGREGATION OF DIFFERENT LONG-CHAIN ALKYLAMMONIA IN MONTMORILLONTTE

选用含不同烷基长链的三种季铵盐——十二烷基三甲基溴化铵(DDTMAB)、十四烷基三甲基溴化铵(TDTMAB)、十六烷基三甲基溴化铵(HUTMAB),对河北钠交换蒙脱石进行了有机柱撑实验,以X射线衍射分析方法对实验产物进行了对比研究。结果表明,由于烷基链中所含的碳原子数目不同,三种长链季铵离子对蒙脱石的柱撑效果不同,DUTMA^+在蒙脱石层间域内可形成平卧单层、平卧双层和假三层三种不同排列方式;TDTMA^+与DDTMA^+在低浓度条件下形成的前两种排列方式相同,而第三种则不同,为倾斜单层排列;HUTMA^+有机柱撑产物中除了具有前两者的排列方式外,还具有倾斜双层排列方式。不同排列方式的复合产物可以多相共存。此外,随着柱撑剂浓度的增加,三种长链烷基季铵离子在蒙脱石层间域内的排列方式及其演化是不同的。

The orientation of quaternary ammonium cation in the interlayer of organic pillared montmorillonite prepared at different concentrations of DDTMAB, TDTMAB, HDTMAB has been studied using X-ray powder diffraction (XRD). The arrangement model and transmutation of DDTMA+ , TDTMA+ and HDTMA+ in the interlayer of montmorillonite were different. The arrangement model of DDTMA+ in the interlayer of montmorillonite changes in the order of lateral-monolayer →lateral-bilayer→pseudotrilayer; TDTMA+ changes in the order of lateral-monolayer →lateral-bilayer → paraffin-type monolayer→random stacking + lateral-bilayer, and HDTMA+ changes in the order of lateral-monolayer→lateral-bilayer →paraffin-type monolayer →pseudotrilayer →paraffin-type-bilayer. These differences are mainly due to the difference in length of alky chain.