MNO_3(M=Na,K,Rb,Cs)在多元醇水混合溶剂中的溶解度、溶液密度和折光率比较研究

A Comparative Study on Salt Solubility,Densities and Refractive Indices in Ternary Systems Composed of Alkali Metal(Na,K,Rb,and Cs) Nitrate,Alcohol,and Water

本文对多羟基醇质量分数为0～100%全浓度范围内碱金属硝酸盐的溶解度、饱和溶液的密度和折光率等进行对比研究。溶液为多羟基醇-碱金属硝酸盐-水三元体系,其中,多羟基醇包括乙二醇、1,2-丙二醇和丙三醇,碱金属硝酸盐包括硝酸钠、硝酸钾、硝酸铷和硝酸铯。从羟基及碳链的角度对碱金属硝酸盐的溶解度、饱和溶液的密度和折光率进行了比较。结果发现,随着羟基数目增加,碱金属硝酸盐的溶解度和溶液的密度增大;羟基数目相同时,碳链越长,溶解度和密度越小;而对于折光率来说,羟基数目的增加使折光率变大,但碳链对折光率几乎无影响,表现出乙二醇和1,2-丙二醇体系的折光率曲线几乎重合;对于盐析率来说,温度对盐析率影响不大,醇溶剂的影响结果为1,2-丙二醇〉乙二醇〉丙三醇,即多羟基醇中羟基数目增加,盐析效应减小。

This paper reports the changes of salt solubility,solution density and the solution refractive index（RI）with changes of the alcohol concentration（mass fraction covering a wide range of 0~100%）in ternary solution systems composed of alkali metal（Na,K,Rb,or Cs,respectively）nitrate,alcohol（ethylene glycol,1,2-propanediol or glycerol,respectively）and water at different temperatures.Experimental results from the saturated systems showed that the salt solubility and solution density generally decreased with the increase of alcohol content in a system while the changing trend of RI with alcohol was just the opposite.Moreover,alcohols containing more hydroxyl groups usually resulted in higher salt solubility,solution density and solution RI than those containing less of this group.In addition,temperature tested in a range from 288 to 318Khad little impact on these parameters of the ternary systems.This report provides the basic experimental data on the primary physicochemical properties of alkali metal salts-alcohol-water ternary systems,which are important for industrial applications of alkali metal salts separation and purification among others.