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, adding proper amount of sodium ions to the Mo-Bi oxides system to improve catalytic activity and attrition resistance, and adding bromine ions to increase acrylonitrile selectivity have been conducted. The new catalyst for acrylonitrile production, MB-96, has been successfully used in a plant of 25 000 t/a with an acrylonitrile yield of 82 mol%. In the development of the catalysts for ethylbenzene dehydrogenation, the studies on the structure of active phase and the effects of potassium and cerium as promoters show that under reaction conditions potassium mainly promotes the electronic exchange between Fe2+ and Fe3+ ions, while cerium improves the stability of Fe-K phase. The new catalyst, GS-05, has been successfully used in an ethylbenzene dehydrogenation plant of 60 000 t/a with an ethylbenzene conversion of 65-66 wt% and a styrene selectivity higher than 96 wt%. In the development of the catalysts for toluene disproportionation and transalkylation, the studies on improving the synthesis of mordenite, coke formation behavior of catalyst and modifying surface acidity have been done. The 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 high stability. (C) 1999 Elsevier Science B.V. All rights reserved.