碱和盐对十二烷基硫酸钠/正戊醇-环己烷-水拟三元体系相图影响

摘要

An important application of psudo ternary phase diagrams is to obtain microemulsion for nano material preparation.Therefore, psudo ternary phase diagrams of sodium dodecyl sulfate(SDS)/n-C5H11OH-cyclohexane-water at 45 ℃ and its conductivity were studied.Pseudo ternary phase diagrams agree well with conductivity measurement.Then psudo ternary phase diagrams of SDS/n-C5H11OH-cyclohexane-water, SDS/n-C5H11OH-cyclohexane-Zn(NO3)2, SDS/n-C5H11OH-cyclohexane-NaOH at 45 ℃ and 65 ℃ were measured and compared.The influence of alkali NaOH and salt Zn(NO3)2 on peudo ternary phase diagrams was discussed.The result shows that oil-in-water(O/W) and water-in-oil(W/O) microemulsion areas are smaller after (Zn(NO3)2) or (NaOH) was added into SDS/n-C5H11OH-cyclohexane-water system.The O/W microemulsion areas disappeared in SDS/n-C5H11OH-cyclohexane-NaOH peudo ternary phase diagrams at 45 ℃.There are still 5 areas in psudo ternary phase diagrams and smaller O/W and W/O microemulsion areas after NaOH or Zn(NO3)2 was added in SDS/cyclohexane-water system at 65 ℃.These study results were applied in the preparation nano ZnO particle in microemulsion system.Tansimission electron microscopy and X-ray diffraction studies show that the sample preparaed by the guidance of psudo ternary phase diagrams is nano ZnO particle.%拟三元相图的研究可为获得制备纳米材料的微乳液提供理论依据. 本文首先通过实验绘制了45 ℃下十二烷基硫酸钠(SDS)/正戊醇-环己烷-水溶液体系的拟三元相图,并用电导法进行了验证,说明电导的测定结果与相图吻合的很好. 其次,绘制了45 ℃及65 ℃下,SDS/正戊醇-环己烷-水、SDS/正戊醇-环己烷-硝酸锌水溶液和SDS/正戊醇-环己烷-氢氧化钠水溶液体系的拟三元相图并对6个相图进行了比较,研究了碱(NaOH)和盐(Zn(NO3)2)对SDS/正戊醇-环己烷-水拟三元体系相图影响. 结果表明,硝酸锌及碱的加入使SDS/正戊醇-环己烷-水拟三元相图水包油(O/W)和油包水(W/O)区域明显的缩小. 45 ℃时,SDS/正戊醇-环己烷-氢氧化钠水溶液体系的拟三元相图中的O/W区域甚至消失;65 ℃时, O/W和W/O区域均存在,且3个相图的W/O和O/W区域有重叠区. 在此基础上,确定了制备纳米ZnO的微乳液的条件,即SDS/正戊醇-环己烷-硝酸锌水溶液和SDS/正戊醇-环己烷-氢氧化钠水溶液体系的拟三元相图中W/O区域的重叠区(各相图中的Ⅱ区). 制备的纳米氧化锌为多晶结构,平均粒径为80 nm.