To prepare ultra-fine particles and offer correlative applications such as the micronization of drugs with rapid expansion of supercritical solution (RESS), the first work in measuring the solubility of risocaine has been carried out at different operation conditions in this paper. The trend of solubility due to changes in specific operational parameters has been examined. The results of pressure (9-30 MPa) and temperature (308-328K) effecting on solubility show that the solubility increases mainly along with the increasing density. With applying different models to correlate the solubility data, we found Chrastil models had better correlation effects than the Peng Robinson EOS model, Mendez-Santiago and Teja equation model, with providing a nearly perfect average absolute relative deviation (AARD) of 0.0596. In the second part of work, RESS was applied to prepare risocaine particles at five different process conditions, including extraction temperature (308-328K), extraction pressure (9-30MPa), nozzle temperature (100-120°C), nozzle diameter (0.1-0.4nm) and spray distance (2-4cm).The size and morphology were determined by scanning electron microscopy (SEM). On the basis of the different experimental operation conditions, granular, filmily and threadlike particles with diameter (1-100nm) were obtained, it was also demonstrated that a successful size reduction of risocaine particles.

The activated carbon-containing catalysts (Pd/C and Pt/C) have been prepared by surface modification of the activated carbon with palladium chloride and chloroplatinic acid solution, respectively. The Pt/C catalyst is characterized by XRD pattern. The glyphosate is prepared from catalytic oxidation N-phosphonomethyl iminodiacetic acid. Effect of different catalysts and amount of the catalyst in catalytic oxidation are investigated. Compared with Pt/C catalyst, Pd/C catalyst is more active. Optimum amount of Pd/C catalyst is 45 mol/m3 PMIDA.