Studies On Key Chemical Engineering Problems In The Synthesis Of Tetraphenylporphyrin Manganese(Ⅲ) Chloride

In the recent decades, metalloporphyrins are widely used as oxidation catalyst in catalytic oxidation of hydrocarbon. The behavior of this kind of metalloporphyrins catalyzing the activity dioxygen under mild conditions, just the same as that of cytochrome P-450 monooxygenase in biological phenomena. Based on that, the metalloporphyrins present high catalytic activities and high selectivities in the catalytic oxidation of hydrocarbons without co-reducing reagents. At present, the method proposed by Adler is frequently used to synthesis 5, 10, 15, 20-tetraphenylporphyrin（TPPH₂）. During the synthesis process, the solvent is propionic acid, the raw material is pyrrole and benzaldehyde, and the main product is TPPH₂. The method of synthesis5,10,15,20-tetraphenylporphyrin manganese（Ⅲ） chloride（TPPMnCl） is also proposed by Adler.During the synthesis process, the solvent is N,N-dimethylformamide（DMF）, the raw material is5,10,15,20-tetraphenylporphyrin and manganese（II） chloride, and the main product is TPPMnCl.This paper takes the industrial scale synthesis of TPPMnCl as the research background, and the key chemical engineering technology in the synthesis of TPPMnCl as the research object. To better understand the mechanism and kinetics in the synthesis reaction of TPPH₂ and TPPMnCl, the phase equilibrium data and the reaction kinetics data are extremely essential in reasonably set of reaction conditions, recovery of solvent conditions, product separation and purification conditions. The main works of this paper including the following three aspects:1. Solid-liquid equilibrium in the synthesis of TPPMnClThe experimental apparatus and the correspondent analysis method were built. The solid-liquid equilibrium（SLE） data for the ternary systems（water + propionic acid + TPPH₂, water + ethanol +TPPH₂, water + DMF + TPPH₂, water + DMF + TPPMnCl, water + ethanol + TPPMnCl, and water+ DMF + MnCl₂） were measured at atmospheric pressure. The modified Apelblat equation was used to correlate the experiment data, and the parameters of Apelblat model were obtained for each ternary system. The average absolute-relative-deviation（AARD） values were between 0.82 % and2.08 %, which means that the solubilities calculated by the modified Apelblat equation were in good agreement with experimental data. To better understand the dissolution process of solute in each ternary system, the thermodynamic parameters of solution such as Gibbs free energy, dissolution enthalpy, dissolution entropy, and isobaric heat capacity were obtained from the experiment solubilities by using the Clark-Glew equation.2. Reaction mechanism and kinetics for the synthesis of TPPH₂The research of this part was based on the synthesis method of Adler, considering the special analytical system, we established a suitable analysis method. Gas phase chromatography（GC） wasused to analyze benzaldehyde and pyrrole, ultraviolet-visible spectrophotometer was used to analyze TPPH₂, the reproducibility and regularity of experimental data was very well. The effects of reactant concentration, reaction temperature, reactant ratio, and initial water content on the reaction process were systematic studied, the optimum reaction conditions were also determined. The experimental results shown that, under the condition that of the benzaldehyde and pyrrole were added at reflux temperature, the initial water content is 0 %, the concentration of benzaldehyde and pyrrole concentration was 0.35 mol/kg PA, and the reaction temperature was 409.15 K, the yield of TPPH₂ was highest. Based on the experimental data and literatures, we put forward the mechanism of TPPH₂ synthesis, the dynamic model was established, and the model parameters were regressed. The proposed dynamic model can reflect the concentration of benzaldehyde and pyrrole with the changing time, and the concentration values calculated by the model were in good agreement with experimental data.3. The synthesis technology conditions of the synthesis of TPPMnClThe research of this part was based on the synthesis method proposed by Adler, a suitable analysis method was established. Both the concentration of TPPH₂ and TPPMnCl was determined by ultraviolet-visible spectrophotometer, the reproducibility and regularity of experimental data was very well. The effects of reactant concentration, reaction temperature, reactant ratio, and initial water content on the reaction process were systematic studied, the optimum reaction conditions were also determined. The experimental results show that, the higher the concentration of the reactants and molar ratio of MnCl₂ to TPPH₂, the higher yield of TPPMnCl. However, the effect of reaction temperature and initial water content on reaction rate was specially, the reaction rate was the fastest when the temperature is 415.15 K or the initial content of water is 2.0 %. Based on the experimental data and literatures, we put forward the mechanism of the synthesis of TPPMnCl. Another independent experiment verified the synthetic reaction of TPPMnCl is a reversible reaction, and the reaction mechanism proposed can explain the experimental phenomenon reasonably.