Research On The Continuous Synthesis Process For Mthpa

Synthesis of crude MTHPA was the key reaction for MTHPA curing agent. This reaction is a liquid-liquid phases reaction, in which a mixed C5or piperylene solution, maleic anhydride were used as raw materials, and hydroquinone was used as inhibitor. At present, MTHPA was usually produced in batch reactors. For this synthesis process, there were many shortcomings as low production capacity, unstable quality of product, high consumption of mixed C5and high intensity of operation etc., so it is necessary to develop a new continuous synthesis process to solve these problems.In order to develop the continuous synthesis process for MTHPA, the following three aspects were studied in this paper.Firstly, the effects of concentration ratio, reaction temperature and solvents on the Diels-Alder reaction of pentadiene with maleic anhydride were studied, and the kinetic data were determined in a0.5L flask. According to the basic principles of Diels-Alder reaction, the reaction kinetics model was established as following: Using of numerical methods for regression analysis of experimental data, the activation energys and pre-exponential factors of the model were obtained for different solvents of MTHPA, toluene and acetone. The activation energys were7.90×104J·mol-1、7.02×104J·mol-1、4.26×104J·mol-1, and the pre-exponential factors were43×1012L·(mol·min)-1、2.69×1010L·(mol·min)-1、3.24×105L·(mol·min)-1, respectively.The results showed that the reaction was agreeed with the second-order reaction. The different solvents had little effect on activation energy, but large effect on pre-exponential factor.Secondly, the property data of the materials in the reaction system were calculated by using Aspen plus under different operating conditions. Respectively, the liquid-liquid homogeneous reaction in the CSTR and PFR, and gas-liquid heterogeneous reaction in the countercurrent packed tower reactor were simulated. The results showed that the gas-liquid countercurrent packed tower reactor is superior to the homogeneous CSTR and PFR.The effect of gas-liquid mass transfer on the reaction of pentadiene gas with maleic anhydride liquid was investigated with the different gas-liquid transfer methods. It showed that the gas-liquid mass transfer had significant influence on the gas-liquid reaction. The apparent reaction rate could be significantly improved by the enhancement of gas-liquid mass transfer.Lastly, some preliminary experiments were carried out in the pilot packed tower which was buil by simulation design. This packed tower reactor can be divided into three sections:gas-liquid reaction section, gas-liquid reaction section with liquid phase transition and homogeneous reaction section with liquid phase transition. The different theoretical models were established for three sections.