Development and design of crystallization process strongly depend on accurate solid-liquid equilibrium data. In this paper, the solubility of 3-chlorophthalic anhydride and 4-chlorophthalic anhydride in methyl acetate + cyclohexane binary solvent mixtures was determined from T = (283.15 to 328.15) K by gravimetric method under atmospheric pressure. The results show that the solubility of 3-chlorophthalic anhydride and 4-chlorophthalic anhydride increases with the increasing of temperature at constant solvent composition. At fixed temperature, the solubility of 3-chlorophthalic anhydride increases with mole fraction of methyl acetate increasing. Nevertheless, the solubility of 4-chlorophthalic anhydride displays a maximum with the solvent composition changing. To extend the applicability range of the solubility data, experimental solubility data in binary solvent mixtures was correlated by the modified Apelblat equation, the CNIBS/R-K equation and the Jouyban-Acree equation. It is found that the correlated data is in good agreement with the experimental data. The metastable zone width (MSZW) of 3-chlorophthalic anhydride and 4-chlorophthalic anhydride were also determined by the polythermal method at three different cooling rates. Finally, the cooling crystallization process of 3-chlorophthalic anhydride was designed to separate and purify 3-chlorophthalic anhydride according to its solubility and MSZW data.

结晶过程的开发和设计在很大程度上取决于准确的固液平衡数据。本文通过T测定了3-氯邻苯二甲酸酐和4-氯邻苯二甲酸酐在乙酸甲酯+环己烷二元溶剂混合物中的溶解度 在大气压下通过重量分析法测定（K = 283.15至328.15）K。结果表明，在恒定溶剂组成下，3-氯邻苯二甲酸酐和4-氯邻苯二甲酸酐的溶解度随温度的升高而增加。在固定温度下，3-氯邻苯二甲酸酐的溶解度随乙酸甲酯的摩尔分数的增加而增加。然而，4-氯邻苯二甲酸酐的溶解度随着溶剂组成的变化而显示出最大值。为了扩展溶解度数据的适用范围，通过改进的Apelblat方程，CNIBS / RK方程和Jouyban-Acree方程将二元溶剂混合物中的实验溶解度数据进行关联。发现相关数据与实验数据吻合良好。还通过多热法在三种不同的冷却速率下测定了3-氯邻苯二甲酸酐和4-氯邻苯二甲酸酐的亚稳区宽度（MSZW）。最后，根据3-氯邻苯二甲酸酐的溶解度和MSZW数据设计了3-氯邻苯二甲酸酐的冷却结晶工艺，以分离纯化3-氯邻苯二甲酸酐。