| 摘要 |
Yields >50% with selectivities >90% wt are obtained by the adiabatic catalytic dehydrogenation of ethylbenzene and siopropylbenzene (to styrene and alpha-methyl-styrene respectively) by using an improved system of 2 different catalysts:- (1) being more selective in the upper part of the reaction apparatus with a volume corresponding to 20-25% wt yield at initial-temp. 600-620 degrees C. from alpha-methylstyrene and 620-650 degrees C for styrene and composed of 65-70% wt Fe2O3, 2-3% wt, Cr2O3, 30-35% wt. K2O; specific surface 10m2/g, pore diameter 1000-75000 A; (2) being more active in the lower part with a volume corresponding to 20-25 to 50-55% wt. yield; and composed of 85-90% wt. Fe2O3, 5-8% wt. K2O 2-5% wt Cr2O3; specific surface >10 m2/g., macroscopic structure with mean pore radius 300-1000 A. The same catalyst can be used in 2 layers of which the upper is diluted with inert material. |
