电导滴定法测定离子型表面活性剂的临界胶束浓度的研究  

STUDY ON DETERMINATION OF CRITICAL MICELLE CONCENTRATION OF IONIC SURFACTANT BY CONDUCTANCE TITRATION

作　　者：马磊 郭蓉蓉 周骏宏[1,2] 郭雪 杨懿 张内雪 罗辉 MA Lei;GUO Rongrong;ZHOU Junhong;GUO Xue;YANG Yi;ZHANG Neixue;LUO Hui(Qiannan Normal University for Nationalities,Duyun 558000,China;Guizhou Sunward Fuquan Chemicals Co.,Ltd.,Fuquan 550400,China)

机构地区：[1]黔南民族师范学院磷化工实验室,贵州都匀558000 [2]贵州胜威福全化工有限公司,贵州福泉550400

出　　处：《离子交换与吸附》2022年第5期437-443,共7页Ion Exchange and Adsorption

基　　金：贵州省科技计划项目(黔科合支撑[2021]一般307);贵州省教育厅自然科学研究项目(黔教技[2022]007);贵州高校乡村振兴研究中心项目

摘　　要：测定离子型表面活性剂的临界胶束浓度(CMC)常采用电导法,但常规电导法测定过程操作环节多、易积累实验误差,导致测量精度不高。为了提高电导法的精准度及适用性,本文对现有电导测定方法进行改进,采用对同一份初始溶液连续滴加高浓度表面活性剂,同步测定电导的连续电导滴定法测定,由于减少了溶液配制及稀释、溶液切换、电极清洗等环节,最大限度降低测量误差,收到了良好效果。采用本法对常见的离子型表面活性剂进行测定,获得准确的结果,并研究了烷基三甲基氯化铵的不同烷基链长、温度等对CMC测定的影响,结果表明,随着长碳链烷基季铵盐碳链上碳原子个数的增多,阳离子表面活性剂的CMC呈减小趋势,二者呈良好的线性关系,线性方程式为logCMC=-0.32486×烷基数+5.31198;十二烷基硫酸钠在40℃、50℃和60℃时CMC分别为5.03mmol/L、5.36mmol/L和7.82mmol/L,即CMC随温度的升高呈增大趋势。Conductivity method is often used to determine the critical micelle concentration(CMC)of ionic surfactants.However,the conventional conductivity method has many operation steps and is easy to accumulate experimental errors,resulting in low measurement accuracy.In order to improve the accuracy and applicability of the conductivity method,this paper improves the existing conductivity determination method,and adopts the continuous conductivity titration method for simultaneous determination of conductivity by continuously adding high concentration surfactant to the same initial solution.Due to the reduction of solution preparation and dilution,solution switching,electrode cleaning and other links,the measurement error is minimized and good results are obtained.The common ionic surfactants were determined by this method,and the accurate results were obtained.The effects of different alkyl chain length and temperature of alkyl trimethyl ammonium chloride on the determination of CMC were studied.The results showed that the CMC of cationic surfactants decreased with the increase of the number of carbon atoms on the carbon chain of long carbon chain alkyl quaternary ammonium,and there is a good linear relationship between them.The linear equation is logCMC=-0.32486×alkyl number+5.31198;the CMC of sodium dodecyl sulfate at 40℃,50℃and 60℃are 5.03mmol/L,5.36mmol/L and 7.82mmol/L,respectively.That is CMC increased with increasing temperature.

关 键 词：离子型表面活性剂 临界胶束浓度(CMC) 连续滴定法 烷基数 依数性 

分 类 号：TQ423.1[化学工程] O655.2[理学—分析化学]