초록

A catalyst and process for purifying crude terephthalic acid wherein the catalyst is prepared by contacting a carbonaceous support with an aqueous solution of sodium tetranitropalladate.

대표청구항 ▼

A process for purifying crude terephthalic acid containing up to 10,000 ppm of 4-carboxybenzaldehyde wherein 4-carboxybenzaldehyde content is reduced to a level of less than 100 parts per million in a standard laboratory test wherein said process comprises hydrogenating said crude acid in liquid pha

A process for purifying crude terephthalic acid containing up to 10,000 ppm of 4-carboxybenzaldehyde wherein 4-carboxybenzaldehyde content is reduced to a level of less than 100 parts per million in a standard laboratory test wherein said process comprises hydrogenating said crude acid in liquid phase at a temperature of from about 100°C. to about 300°C. and a pressure of from about 200 to about 1500 psi with hydrogen in the presence of water and of a catalyst composition which comprises crystallites of catalytically active palladium upon the surface of a porous activated carbon support material having a surface area of at least 600 m2/g wherein said crystallites are predominantly less than 35 Åin longitudinal measurement, and wherein said catalyst composition is prepared by contacting said support with an aqueous solution of a nitritopalladate salt.