Research On The Oxidation Kinetics For Glyphosate Catalyzed By Activated Carbon

IDA is currently the world's most advanced glyphosate synthesis process, more than 75% of the glyphosate production companies are using this technology in the world. IDA method iminodiacetic acid as raw materials, in the role of a catalyst, the oxidation of double glyphosate (PMIDA). The raw materials of the method easy to get good quality products, high yield, good economic returns, suitable for industrial production.PMIDA oxidation is the final step in this process, is a critical step. Activated carbon catalytic oxidation PMIDA, optimization of process conditions at home and abroad have been many reports.Using activated carbon catalyst in PMIDA oxidation is simple, high selective, simple post-processing and has high purity products. At present, activated carbon catalysts have different sources, different specific surface area and difference performance. For industrial reactor amplification and optimization of the reaction conditions, the dynamics of the research has important significance. 1.The main reaction is: (HO)2POCH2N(CH:COOH)2+1/2O2?(HO)2:POCH2NHCH2COOH+HCHO+CO2 The main secondary reaction is: (HO)2 POCH2NHCH2COOH+1/2O2?(HO)2 POCH2NH2+CO2+HCOH According to the reaction mechanism proposed the main kinetics2. In a 200mL autoclave, with activated carbon as a catalyst, the influences of the catalytic oxidation of reaction temperature, reaction pressure and other process conditions were explored. According to the reaction mechanism proposed the main equation, the kinetics parameters were obtained by estimating nonlinear regression. For the first activated carbon, pre-exponential factor of the main reaction rate constants is 4.83 × 104mo·L-1·h-1 and the main reaction activation energy is 5.57 × 10J·mol-1 Pre-exponential factor of the adsorption equilibrium constant of PMIDA is 4.83 X 104 L · mol-1 and adsorption heat is 2.09 × 10J·mol-1. For the second activated carbon, pre-exponential factor of the main reaction rate constants is 2.45 × 1010mol·L-1·h-1 and the main reaction activation energy is 5.64 × 104J·mol-1. Pre-exponential factor of the adsorption equilibrium constant of PMIDA is 1.19 × 1010 L·mol-1 and adsorption heat is 5.42×104J·mol-1.3.With glyphosate as reactant, activated carbon as the catalyst, side reactions glyphosate solution is oxidized with oxygen, and explore the influences of the catalytic oxidation of reaction temperature, reaction pressure and other process conditions were explored in the PMIDA oxidation process. According to the reaction mechanism proposed the secondary equation, the kinetics parameters were obtained by estimating nonlinear regression. For the first activated carbon, pre-exponential factor of the secondary reaction rate constants is 3.01 × 108mol·L-1·h-1 and the secondary reaction activation energy is 5.96 × 104J · mol-1. Pre-exponential factor of the adsorption equilibrium constant of PMG is 1.49 × 104 L·mol-1 and adsorption heat is 3.69 × 104J· mol-1. For the second activated carbon, pre-exponential factor of the secondary reaction rate constants is 3.89 × 108mol·L-1·h-1 and the secondary reaction activation energy is 6.02 × 104J · mol-1. Pre-exponential factor of the adsorption equilibrium constant of PMG is 7.61 × 107L·mol-1 and adsorption heat is 5.98 × 104J·mol-1.3. By testing aperture, entrance, and specific surface area of the two different fresh and deactivation catalysts, the causes of catalyst deactivation can be analyzed. The results show that compared with the fresh catalyst, the deactivated catalyst has lower surface area, smaller pore volume, smaller specific surface area and smaller hole diameter. The results can match with the nitrogen adsorption isotherm characterization results.4. By establishing a mathematical model for simulating the dynamical model of two kinds of catalysts, the kinetics models are reliable. And the performance of the two kinds of catalysts were analyzed. It is found that adsorption rate constant of the two catalysts are very different, and the surface reaction rate constant is similar. Analysis of two kinds of specific surface area and pore size of catalysts, we can know that specific surface area and pore size of catalyst 2 are larger than catalyst 1. So catalyst 2 has more active sites and more pores, which is conducive to the spread of the material.