季铵盐(Aliquat 336)萃取对氨基苯磺酸的特性研究

利用季铵盐(Aliquat 336)为反应剂,在较宽的pH值条件下,研究了对氨基苯磺酸稀溶液的萃取相平衡特性;测定了反应剂浓度、稀释剂种类、盐的存在以及溶液pH值对反应萃取平衡分配系数的影响;提出了反应剂与对氨基苯磺酸负离子的阴离子交换反应机理,建立了平衡分配系数D值的表达式。结果表明,极性稀释剂不利于对氨基苯磺酸的萃取,惰性稀释剂能提供较大的萃取平衡分配系数,其顺序为:苯>四氯化碳>氯仿>正辛醇;盐的存在会降低Aliquat 336的萃取效率;与三烷基胺(Alamine 336)相比,Aliquat 336具有更宽的pH值适用范围。

Extraction p-Aminobenzene Sulfonic Acid from Dilute Solution by Chemical Complexation with Aliquat 336

Based on systematic investigation and analysis of literature, p-aminobenzene sulfonic acid is selected as a typical amphoteric organics to be separated from dilute solution. A chlorinated quaternary ammonium salt, Aliquat 336, is used as complexing agent. Since the pH of aqueous solution is an important factor in chemical complexation extraction of the solutes, its effect on extraction equilibrium is especially studied in the experiments. The effects of type of diluents, concentration of complexing agent and salt on distribution ratio D are also investigated. By using Mass Action Law, an expression of equilibrium distribution ratio for p-aminobenzene sulfonic acid/ Aliquat 336/ diluent system is proposed. The results show that the precision of the model parameters fitting are quite satisfactory. Distribution ratio D is higher in inert diluent and the sequence is benzene > tetrachloromethane > chloroform > n-octanol. The existence of salt can reduce D rapidly. Meanwhile, the extraction behavior by Aliquat 336 was compared with that by Alamine 336, and there was a wider efficient pH region for Aliquat 336.