氯化钾与磷酸复分解反应的动力学研究

Research on double decomposition reaction kinetics of potassium chloride and phosphoric acid

研究了以氯化钾和热法磷酸为原料,采用复分解法制备磷酸二氢钾的方法。考察了反应时间、反应温度、原料配比对氯化钾转化率的影响。在反应温度为373～413 K和反应时间为1～4 h的条件下,研究氯化钾与热法磷酸的宏观反应过程,自阻化作用对该反应过程的反应速率影响较大,阻缓系数β随反应温度升高而增大。应用德罗兹多夫方程拟合实验数据,确定了动力学方程:1/t ln[1/(1-X)]-βX/t=exp(-65 840/RT)+2.215,并求得了反应的表观活化能Ea=65.84 kJ/mol,经验证表明模型可靠。该研究旨在揭示氯化钾和热法磷酸制备磷酸二氢钾的宏观反应过程的相关规律,为设计反应器和优化工艺条件提供一定的理论依据。

Abstract： Using potassium chloride and thermal phosphoric acid as raw materials, the double decomposition reaction process to prepare potassium dihydrogen phosphate was studied.Influences of reaction time ,reaction temperature,and mix ratio of materials on the conversion rate of potassium chloride were investigated.Under the conditions of the reaction temperature at 373~413 K and the reaction time at 1~4 h, the macroreaction process of potassium chloride and thermal phosphoric acid was studied.Self-impeding effect played an important role on the reaction rate ,and its coefficient （/3） increased with the increasing temperature.Drozdov equation was selected to simulate the reaction data and the dynamic equation was confirmed：1/t ln[1/（1-X）]-βX/t=exp（-65 840/RT）＋2.215.Apparent activation energy （Ea） was 65.84 kJ/mol,and the mode was reliable.Study was expected to reveal the related mechanism of the preparation for potassium dihydrogen phosphate with potassium chloride and thermal phosphoric acid, so as to provide a necessary theoretical basis for the design of reactor and for optimization of pro- eessing conditions.