加料顺序对两种盐溶解性的影响

Effect of feeding sequence on solubility of two salts

盐的溶解及盐效应的研究对化工技术开发具有重要意义。采用平衡法,常压下,测得了对苯二甲酸二钠在不同温度下于水中的溶解度。在常压和298.15 K下,考察了对苯二甲酸二钠等7种有机盐和无水硫酸钠等3种无机盐在水中的两两溶解过程,发现加料顺序会影响两种盐的溶解性。得到如下结果:先溶解难电离的盐再溶解易电离的盐,则后者的溶解速度变化不明显;而先溶解易电离的盐再溶解难电离的盐,则后者的溶解速度会显著降低且溶解度变小。将其中一种盐的量固定后,在一定时间内另一种盐所能溶解的量定义为准溶解度。测定了对苯二甲酸二钠在不同浓度的柠檬酸三钠水溶液中的准溶解度,为相关化工行业的产品分离纯化提供依据。

Study on salt dissolution and salt effect is important for development of chemical technology. The solubility of terephthalic acid disodium in water at different temperatures was measured by using equilibrium method at atmospheric pressure. For seven organic salts and three inorganic salts, the dissolving process of two salts in water was examined under the normal pressure and 298.15 K. It is found that the feeding sequence affects the dissolution of two salts. When difficult ionized salt is dissolved first and easily ionized salt is dissolved later, the dissolution rate of the latter does not change obviously; when easily ionized salt is dissolved first, the dissolution rate of difficult ionized salt is significantly reduced and the solubility decreases. Fixing the amount of one salt, the amount of another salt dissolved in a period of time is defined as the quasi-solubility. The determination of quasi-solubility of terephthalic acid disodium in different concentrations of sodium citrate solution provides the basis for purification of chemical products.