CATALYTIC COMPOSITION, METHOD FOR MANUFACTURING THEREOF AND METHOD FOR THE PURIFICATION OF TEREPHTHALIC ACID.

摘要

The invention relates to catalytic compositions from metals of group VIII, used for purification of terephthalic acid, to methods of preparing such compositions and to a process of purification of terephthalic acid. The invention allows for creating stable and selective catalysts used in the process of purification of terephthalic acid. The catalytic composition comprises crystalline particles of palladium or catalytically active palladium and of at least one metal of group VIII of the periodic table, whereby said elements are deposited on the surface of a carbonated matter. The carbonated matter represents a mesoporous graphitelike material, whereby the size of pores thereof is comprised between 40 and 400 Aring;, the proportion of pores in the total volume is at least 0.5 and the degree of similarity thereof to graphite is at least 20 %. The crystalline particles of the metals are distributed across the volume of the granules of said carbonated matter such that the maxima of distribution of the active components of the granule are separated from the external surface of the granule by a distance equal to 130 % of the radius of the granules. The inventive catalytic composition comprises crystalline particles of palladium and rhodium or of palladium and ruthenium or else of palladium and platinum, whereby the total metal content may vary between 0.1 and 3.0 wt.%, and the ratio of palladium to other metals may vary between 0.1 and 10.0.