The reactive precipitation process of procaine benzylpenicillin is reviewed, while such secondary pro-cesses as ageing, agglomeration, breakage, and the effects of operation parameters on crystal size are emphasized. In the reactive precipitation the ageing of particles has a little effect on the process, while the greater effect comes from the agglomeration and breakage of particles, furthermore, the mixing has also notable influence on the product size. All of these provide the bases for further study on reactive precipitation.

A general expression for the relationship between induction period and supersaturation was developed based on polynuclear approach. Different mechanism of primary nucleation in solution can be illustrated by the expression. The results of induction period determined by laser scattering method shows that the crystallization of ciprofloxacin hydrochloride monohydrate in water/ethanol or aqueous solution is by the mechanism of primary nucleation followed by one-dimensional diffusion growth, and then one-dimensional continuous or "birth and spread" growth on crystal face. The growth mechanism on the crystal face is affected by temperature and solvent.

1-环丙基-7-氯-6-(1-哌嗪基0-4-氧-1,4-二氢-3-喹啉闳酸盐酸盐为环丙沙星合成中主要的杂质之一，研究基物化性质对于改善环丙沙星的结晶分离提纯具有重要意义。本文研究了1-环丙基-7-氯-6-（1-哌嗪基）-4-氧-1，4-二氢-3-喹啉羧酸盐酸盐的熔化、分解特性，溶解度与离子强度，温度和PH值的关系，并测定了该物质的离解常数，估算了该物质在水溶液中的活度积。

运用分岔理论，对同时发生初级成核和二次成核的等温连续混合悬浮混合排料（CMSMPR）结晶的定态特性进行了分析，推导了系统存在多定态及发生持续振荡的参数条件。以结晶过程的物性参数、动力学参数以及操作参数为基础，应用非线性方程组的延拓方法分别求解极限点条件方程及Hopf分岔点条件方程组，确定了系统存在多定态及发生持续振荡的参数边界。

The bench-scale cooling crystallization for ternary solution of L-ascorbic acid (Vitamin C) was studied. The solid-liquid phase diagram of Vitamin C-water-ethanol system was obtained on the basis of differential scanning calorimeter (DSC) curves. The heat of crystallization of Vitamin C was calculated with the aid of quantitative analysis. According to the population balance equation under unsteady state, the rates of nucleation and growth were determined. The parameters of crystallization kinetics equations were estimated by regression of experimental data. Crystal morphology and size were determined with x-ray diffraction and TAII Coulter Counter.