Rhodium on carbon catalyst.

摘要

A particulate catalyst composition suitable for purification of terephthalic acid under reducing condi­tions and a method of preparation of such catalyst are disclosed. The catalyst composition includes catalyti­cally active rhodium on a porous, granular, carbonaceous support material having a surface area of at least about 600 cm²/gram. Rhodium is present in an amount of about 0.01 to about 2 weight percent, based on the total weight of dry catalyst composition and calculated as elemental metal. In the presence of hydrogen, this catalyst exhi­bits a reduced terephthalic acid decomposition rate that is comparable to that for a palladium-on-carbon catalyst having the same catalyst metal loading. The catalyst is prepared by contacting a carbonaceous support material having a surface area of at least 600m²/gm and a pH value in its aqueous suspension of 9-11 with an aqueous rhodium salt solution having a pH of 1-4.