响应曲面法优化2-(4-羟基苯氧基)丙酸甲酯结晶工艺

Optimization of Crystallization Process of Methyl-2-(4-Hydroxyphenoxy) Propionate Based on Responsive Surface Methodology

现有的 2-(4-羟基苯氧基)丙酸甲酯产品质量与后续工艺需求有一定差距,如产品粒度小、粒度分布不均匀等。本文利用工厂提供的原料,采用响应曲面中的CCD(Central Composite Design)设计实验,分析了搅拌速率、降温速率、晶种质量、陈化时间等因素对结晶产品的影响,研究了工艺参数之间的交互影响,确定了多因素下最优工艺操作条件,对优化产品进行了分析,结果表明产品可满足工艺需求。

Methyl-2-(4-hydroxyphenoxy) propionate is an important intermediate for the synthesis of aryloxyphenoxy propionate (APP), a high efficiency herbicides. There is a certain gap between the existing products and the ideal one, such as the particle size and the size distribution. Central composite design (CCD), a kind of responsive surface methodology, was used to explore the effects of stirring rate, cooling rate, seeding quantity and aging time on the particle size and the coefficient of variation (C.V.) of methyl-2-(4-hydroxyphenoxy) propionate. On the basis of regression analysis, regression equations related to responsive values and factors were developed, respectively. For control of crystal size, the most important parameters were aging time, seeding quantity, stirring rate and cooling rate, respectively. For control of crystal size distribution, the most important parameters were stirring rate, seeding quantity, aging time and cooling rate, respectively. The interactions between stirring rate and seeding quantity, stirring rate and aging time, were important as well. The crystallization process was optimized using the following parameters: Stirring rate of 400 r/min, cooling rate of 5 °C/h, seeding quantity of 2.5 g, and aging time of 20 min. In the above conditions, methyl-2-(4-hydroxyphenoxy) propionate were prepared, with a purity of above 98%, an average particle size of 1 054.27 μm in narrow size distribution, and 0.891 3 in C.V. The predicted values well fit the experimental values, which thereby demonstrates that the established models were accurate and reliable for the analysis and prediction of the reactive crystallization process.