JPS5814365B

A catalyst carrier comprising gamma alumina wherein the apparent bulk density is in the range of from 0.65 g/cc to 0.71 g/cc, the total pore volume is in the range of from 0.55 cc/g to 0.65 cc/g, the content of pores having a diameter in the range of from 60A to 110A occupies at least 75% of the total pore volume, the surface area is in the range of from 210 m2/g to 250 m2/g and the attrition loss is less than 0.5 wt. %. This sort of catalyst carrier can be namufactured through a series of steps of: (a) preparing a first alumina hydrosol having an aluminum concentration in the range of from 9.8 wt. % to 14.4 wt. % and a weight ratio of aluminum to chloride in the range of from 0.95 to 1.20, (b) preparing a second alumina hydrosol having an aluminum concentration in the range of from 9.5 wt. % to 13.0 wt. % and a weight ratio of aluminum to chloride in the range of from 0.85 to 0.95 by adding hydrochloric acid to said first hydrosol, (c) preparing an alumina precursor having an aluminum concentration in the range of from 6.0 wt. % to 7.0 wt. % by commingling said second hydrosol with a suitable gelling agent in an amount of from 1.65 to 1.85 times the chemical equivalent necessary to neutralize the chloride contained in the second hydrosol and (d) dispersing this precursor as droplets in a suspending medium thereby forming hydrogel particles, ageing the thus obtained hydrogel particles in said suspending medium and then in an aqueous ammonia, washing the aged particles in water, drying and calcining thereafter.