双子阳离子表面活性剂胶束催化羧酸酯水解  

Hydrolysis of Carboxylic Acid Esters Catalyzed by Cationic Gemini Surfactant Micelle

作　　者：胡伟[1] 谢家庆[2] 杜鹃[1] 孟祥光[1] 寇兴明[1] 胡常伟[1] 曾宪诚[1] 

机构地区：[1]四川大学化学学院教育部绿色化学与技术重点实验室,四川成都610064 [2]四川理工学院化学系,四川自贡643000

出　　处：《四川大学学报（自然科学版）》2005年第5期1017-1021,共5页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(20173038;29873031;20107004)

摘　　要：在pH7.0～9.0和25℃下,用分光光度法研究了双子阳离子表面活性剂(16-2-16,2Br-)胶束及其相应的普通阳离子表面活性剂CTAB胶束对羧酸酯(对-硝基苯基α-吡啶甲酸酯(PNPP)和对-硝基苯基乙酸酯(PNPA))水解的催化作用.用胶束催化的相分离模型处理实验数据,得到了相关常数Ks和km.结果表明:(1)用胶束催化相分离模型处理双子阳离子表面活性剂胶束催化反应是合理的;(2)在相同的反应条件下,双子阳离子表面活性剂(16-2-16,2Br-)胶束比CTAB胶束能更有效的催化羧酸酯水解反应;(3)PNPP和PNPA水解反应的表观速率常数kobsd及其在胶束相中的反应速率常数km均随反应体系pH增大而增加,水解剪切反应为酸-碱催化反应过程.In this paper, hydrolyses of p-nitrophenyl picolinate （PNPP） and p-nitrophengl acetate （PNPA） catalyzed by two types of cationic surfactant micelles （Gemini dimethylene-1,2-bis（cetyltrimethylammonium bromide （16-2-16, 2Br^-） and cetyltrimethylammonium bromide （CTAB）） were studied spectrophotometrically in the pH range of 7.0-9.0 and 25℃. Based on the phase-separation model of micellar catalysis , the experimental data were treated to afford the relative parameters Ks and km. The results indicated that , firstly, the reaction catalyzed by Gemini surfactant micelles treated by the phase-separation model of micellar catalysis is reasonable; secondly, Gemini sarfactant （16-2-16,2Br^-） micellar system effectively catalyzes the hydrolyses of carboxylic acid esters compared with CTAB micellar system under same reaction conditions; thirdly, kobsd and km of PNPP and PNPA hydrolyses increase with the increasing in pH of reaction system, hydrolytic shearing reactions of PNPP and PNPA are acid-base catalytic processes.

关 键 词：双子阳离子表面活性剂 胶束催化 羟酸酯 水解 反应动力学 

分 类 号：O643[理学—物理化学] O647.11[理学—化学]