EFFECT OF PRECIPITATION MEDIUM ON SURFACE-ACIDITY AND CATALYTIC PERFORMANCE OF CHROMIUM ORTHOPHOSPHATES IN CYCLOHEXENE SKELETAL ISOMERIZATION AND CUMENE CONVERSION
Fm. Bautista et al., EFFECT OF PRECIPITATION MEDIUM ON SURFACE-ACIDITY AND CATALYTIC PERFORMANCE OF CHROMIUM ORTHOPHOSPHATES IN CYCLOHEXENE SKELETAL ISOMERIZATION AND CUMENE CONVERSION, Journal of materials chemistry, 3(9), 1993, pp. 975-978
The influence of the precipitation medium and thermal treatment of CrP
O4 (Cr: P= 1) catalysts on their surface acidity (number and strength
distribution) was studied by means of the gas-phase chemisorption of p
yridine (PY) and 2,6-dimethylpyridine (DMPY) at 573 and 673 K. In addi
tion, cyclohexene skeletal isomerization (CSI) and cumene conversion (
CC), were selected as dynamic methods for surface acid characterizatio
n. Catalysts obtained in propylene oxide-aqueous ammonia exhibited a h
igher number and strength of acid sites and, hence, greater activity i
n CSI and CC processes, than catalysts obtained in propylene oxide or
aqueous ammonia exclusively. Moreover, cumene dehydrogenation (to alph
a-methylstyrene) always predominated over cumene dealkylation (to prop
ylene and benzene) and accounted for 100% selectivity of CrP-A and CrP
-P catalysts. Furthermore, a correlation between surface acidity and c
atalytic activity was found.