Surface Properties and Catalytic Activity of Fibrillar Aluminas

Alumina FE (fibrous powder containing no sodium) and alumina FF (fibrous fine particles with small bulk density) were synthesized, and their surfaces and catalytic properties were studied. Both fibrillar aluminas were found to have high acid strengths and large amounts of oxidizing and reducing sites compared with gibbsite aluminas.For the isomerization of 1-butene, only Al2O3 FF showed no decrease in activity, and the selectivity (the ratio of cis-2-butene to trans-2-butene) was 1.6. In the reaction of propylene oxide, Al2O3 FE produced a larger amount of propion aldehyde compared with a gibbsite. On the other hand, Al2O3 FE predominantly formed ketone in the reaction of 1-methylcyclohexene oxide, while Al2O3 FF formed allyl alcohol predominantly. For the alkylation of phenol with methanol, Al2O3 FF was more active than Al2O3 FE, and it formed a larger amount of anisole than an activated alumina. For the hydrocracking of thiophene, MoO3 CoO mounted on a fibrillar Al2O3 was much more active than the same catalyst mounted on Al2O3 prepared by homogeneous precipitation.