【摘要】 工业上2,4-甲苯二异氰酸酯的生产主要通过结晶方法来实现,过冷度和相平衡图对结晶工艺和设备的设计起到重要作用。以工业生产的甲苯二异氰酸酯为原料制备了不同2,4-甲苯二异氰酸酯含量的熔融液,采用冷却曲线法测定了过冷度并绘制了相图。结果表明:降温速率越快时,过冷度越小,但当降温速度小于4℃·h^-1时,过冷度变化不大;搅拌速率越大时过冷度越大,但当搅拌速度大于400 r·min^-1时过冷度不再变化。分别采用Wilson方程、NRTL模型及UNIFAC基团法对相平衡实验数据进行回归。相比其它方法,UNIFAC基团法对相平衡计算具有更高的精度。更多还原

【Abstract】 In the industrial process, the production of 2, 4-tolylene diisocyanate is mainly performed with crystallization method. Undercooling degree and phase diagram play an important role in the design of crystallization process and equipment. The melting solution of different 2, 4-tolylene diisocyanate contents was prepared from industrial diisocyanate. The undercooling degree of toluene diisocyanate with different isomer ratio was measured by cooling curve method and the phase diagram was drawn. The faster the cooling rate, the smaller the undercooling degree was. When cooling speed was less than 4 ℃·h^-1, undercooling degree changed little. The higher the stirring rate, the higher the undercooling degree was. The undercooling degree was change when the stirring speed was more than 400 r·min^-1. The experimental data were regressed by Wilson, NRTL and UNIFAC equations. Compared with other methods, UNIFAC equation had higher accuracy in phase equilibrium calculation.更多还原