十六烷基三甲基溴化铵在N,N-二甲基乙酰胺/长链醇体系中临界胶束浓度和热力学函数的微量量热法研究  

Studies on the CMC and Thermodynamic Functions of Cetyltrimethyl-ammonium Bromide in the N,N-dimethylacetamide/Long-chain Alcohol Systems using Microcalorimetric Method

作　　者：朱跃[1] 张可[1] 侯婷婷[1] 刘海莹[1] 崔茂金[1] 张洪林[1] 李干佐[2] 于丽[2] 

机构地区：[1]曲阜师范大学化学科学学院,曲阜273165 [2]山东大学胶体与界面化学教育部重点实验室,济南250100

出　　处：《化学学报》2009年第20期2309-2314,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(No.30370945);山东省自然科学基金(No.Y2006B13)资助项目

摘　　要：用微量量热法测定了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)在非水溶剂N,N-二甲基乙酰胺(DMA)中,分别加入长链醇(正庚醇、正辛醇、正壬醇、正癸醇)体系的热功率-时间曲线,由测得的曲线上的数据得到了临界胶束浓度(CMC)和形成热(ΔHm).根据热力学理论,计算了热力学函数(ΔGm,ΔSm),讨论了温度、醇中的碳原子数、醇的浓度与临界胶束浓度(CMC)和热力学函数之间的关系.结果表明:十六烷基三甲基溴化铵(CTAB)的DMA溶液,在含有相同浓度的各种醇的体系中,CMC,ΔHm和ΔSm的值随着温度的升高而增加;而ΔGm的值随着温度的升高而略有降低.在相同温度及相同浓度的醇体系中,CMC,ΔHm,ΔGm和ΔSm的值都随着醇中碳原子数的增加而降低.在相同温度及相同醇的体系中,CMC和ΔGm的值随着醇的浓度的增加而增加;而ΔHm和ΔSm的值随着醇的浓度的增加而减少.The power-time curves of cation surfactant cetyltrimethylammonium bromide （CTAB） in the N,N-dimethyl acetamide （DMA）/long-chain alcohol （heptanol, octanol, nonanol and decanol） systems were determined using a titration microcalorimetric method. From the curves, the critical micelle concentrations （CMC） and formation heat （AHme） were obtained. According to thermodynamic theory, the △Gm^- and △Sm^- were calculated. The relationships among the alcohol carbon number, concentration of alcohols, temperature, CMC and thermodynamic functions have been discussed. It can be concluded as follows： for N,N-dimethylacetamide solution of cetyltrimethylammonium bromide, under the condition of identical concentration of alcohols, the values of CMC, △Hm^- and ASme increase with the increment of the temperature, otherwise the values of △Gm^- decrease with the increment of the temperature. Under the condition of identical temperature and alcohol concentration, the values of CMC, △Hm^-, △Gm^- and ASme decrease with the increment of the alcohol carbon number. Under the condition of identical temperature and identical alcohol, the values of CMC and △Gm^- increase with the increment of the alcohol concentration, and the values of △Hm^- and △Sm^- decrease with the increment of alcohol concentration.

关 键 词：十六烷基三甲基溴化铵(CTAB) N N-二甲基乙酰胺(DMA) 长链醇(庚醇 辛醇 壬醇 癸醇) 临界胶束浓度 (CMC) 热力学函数(△Hm^- △Gm^- △Sm^-) 微量量热法 

分 类 号：O648.12[理学—物理化学]