Preparation Of Indoline By Catalytic Hydrogenation

Indoline is an important chemical and pharmaceutical intermediates which is widely used in dyes, medical and other fields for the synthesis of indoline derivatives. Recently, the Institute of China Sinopec Nanhua Group has made progress in indole producing technology, which made the development of indole downstream products industry chain become the next focus of their study. Therefore, searching industrial method for the preparation of indoline is of great significance.This paper made laboratory study of indoline producing technology through catalytic hydrogenation method to obtain the basic conditions of the reaction and the reaction factors. Combined with Aspen plus-a process simulation software, the reaction product of the separation process was simulated and optimized, and the results can provide guidance for the design of indoline industrialization. The main results are as follows.(1) Through the screening work of catalysts, solvents, and additives as well as single factor experiment, orthogonal experiment, a green, efficient indoline synthetic route which is suitable for industrial producing was developed. The resulting optimized experimental method is as follow:using indole as raw material,10% Pd/C as catalyst, water as solvent, though catalytic hydrogenation procedure, indoline was performed. The best reaction conditions were:the amount of catalyst is 3%(wt), the reaction pressure is 3 MPa, p-TSA dosage is 1.3 eq and the reaction temperature is 75℃. Under these conditions, the average yield of indoline is 93.14%. Economic estimate result shows that the process has good economic benefits potential.(2) Through Aspen plus, an annual output of 40 tons of indoline product process was established to design and simulate the separation process for indoline crude product system. Through flash module, distillation simple design and strict design as well as sensitivity analysis, the separation process parameters of each module were obtained, such as flash temperature, distillation reflux ratio, number of stages, feed location, sensitive stage location, etc., which finally met the high-purity requirements of indoline products.