Recent advances in R and D of commercial catalysts for acrylonitrile synthesis, styrene production and toluene disproportionation processes

This paper reports the progresses in R and D and commercial application of the industrial catalysts, developed and produced by SRIPT for acrylonitrile , styrene and toluene disproportionation processes. The research works of developing a unique method of catalyst preparation, a dding proper amount of sodium ions to the Mo-Bi oxides system to improve ca talytic activity and attrition resistance, and adding bromine ions to incre ase acrylonitrile selectivity have been conducted. The new catalyst for acr ylonitrile production, MB-96, has been successfully used in a plant of 25 0 00 t/a with an acrylonitrile yield of 82 mol%. In the development of the catalysts for ethylbenzene dehydrogenation, the s tudies on the structure of active phase and the effects of potassium and ce rium as promoters show that under reaction conditions potassium mainly prom otes the electronic exchange between Fe2+ and Fe3+ ions, while cerium impro ves the stability of Fe-K phase. The new catalyst, GS-05, has been successf ully used in an ethylbenzene dehydrogenation plant of 60 000 t/a with an et hylbenzene conversion of 65-66 wt% and a styrene selectivity higher than 96 wt%. In the development of the catalysts for toluene disproportionation and tran salkylation, the studies on improving the synthesis of mordenite, coke form ation behavior of catalyst and modifying surface acidity have been done. Th e new catalyst HAT-095 has been successfully used in a plant of 1 007 000 t /a with a reaction temperature of only 634 K under a high space velocity of 1.44 h(-1) and a high conversion of 45 mol%, showing high activity and hig h stability. (C) 1999 Elsevier Science B.V. All rights reserved.