系列烷基芳基磺酸盐在水溶液中胶束化的焓-熵补偿现象.pdf

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1、物理化学学报(Wul／HuaxueXuebao)638ActaPhys．一Ch／m．S／n．，2010，26(3)：638一．642March[Article】www．whxb．pku．edu．cn系列烷基芳基磺酸盐在水溶液中胶束化的焓．熵补偿现象于涛李钟丁伟，罗石琼栾和鑫童维曲广淼李安军z程杰成z(大庆石油学院化学化工学院，黑龙江大庆163318；大庆油田有限责任公司，黑龙江大庆163453)摘要：以表面张力法研究了系列烷基芳基磺酸盐在水溶液中胶束化的热力学性质，并考察了温度与分子结构对胶束化的影响．结果表明，烷基芳基磺酸盐在水溶液中胶束化是一个自发过程，主要来自

2、熵驱动；随着温度升高，先有利于胶束化而后又不利于胶束化，且熵变对吉布斯自由能变的贡献有下降趋势，而焓变的贡献有增大趋势；胶束化存在焓一熵补偿现象，补偿温度均在(306_+2)K，基本不随烷基芳基磺酸盐的分子结构的改变而变化；随着芳环上短烷基链或长烷基链碳数的增加，胶束化能力和胶束的稳定性均提高，而随着芳环向长烷基链中间位置移动，胶束化能力和胶束的稳定性均下降．关键词：烷基芳基磺酸盐；胶束化；热力学；熵驱动；焓熵补偿中图分类号：0648；0645Enthalpy．-EntropyCompensationofMicellizationofAlkylarylSulfona

3、tesinAqueousSolutionsYUTao，LIZhongDINGWei’LUOShi．-QiongLUANHuo-XinTONGWeiQUGuang-MiaoLIAn-JunCHENGJie-Cheng(ChemistryandChemicalEngineeningCollege,DaqingPetroleumInstitute．Daqing163318，HeilongjiiangProvince,PR．China；2DaqingOilFieldCompanyLimited，Daqing163453，HeilongaiiangProvince．P．尺．C

4、hina)，Abstract：Weusedasurfacetensionmc【hodtoj．nvestigatethethermodynamicpropertiesofmicellizationinaqueoussolutionforseveralalkylarv1sulfo,natestNLatweresynthesizedinourlaboratory,．T"hejtnfluenceoftemperatureandmolecularstructureonthemicelliz~ationiLsdiscussed．Resuitsshowthatthemicelli

5、zationofalkylarylsulfonatesjinaqueoussolutionsisspontaneousandentropy-driven,．Asthetemperaturerises，themicellizationiseasyinitiallybutthenbecomesmoredifficult．ThecontributionofentropychangetothechangeinGibbsfreeenergytendstodecreasebutthecontributionofenthalpychangetothechange’inGibbsf

6、reeenergytendstoincrease．rI'hemicellizationjsenthalpy-entropycompensated．Thecompensationtemperature()isfoundtobe(306_+2)K，whichisindependentofthemolecularstructureofthealkylary1subfonates．Theformationabilityandthestabilitlyofthemicellesincreasewhenthecarbpqonatomsoftheshortor’Longalkyl

7、chainsonthearomaticrings’increase,．butdecreaseasthearomaticringsshiftfromtheedgetothemiddleofthelongcarbonicchains．KeyWords：Alkylarylsulfonate；Micellization；Thermodynamics；Entropy-driven；Enthalpy．-entropycompensationReceived：O}ctober14．2009；Revised：D~qecember7，2009；PutblishedonWeb：Fe