GB1247015A - Improvements relating to catalysts - Google Patents

Abstract

1,247,015. Zeolitic hydrocarbon conversion catalysts. TEXACO DEVELOPMENT CORP. 15 Aug., 1968, No. 38966/68. Heading B1E. [Also in Division C5] A zeolitic catalyst containing a water-insoluble multivalent heavy metal compound dispersed in the unit crystallographic cells of the zeolite is prepared by a process which comprises subjecting an alkali metal or ammonium zeolite having a pore size of from 7 to 13 Angstroms to ion exchange by contact with an aqueous solution of a water-soluble salt having a multivalent heavy metal cation thereby to introduce a multivalent heavy metal ion into a cation position in the zeolite, and thereafter subjecting the multivalent heavy metal cation substituted zeolite to ion exchange by contact with an aqueous solution of a water-soluble compound having a metal-containing anion and a cation selected from alkali metal ions and ammonium ions (including quaternary ammonium ions) thereby to form a precipitated water-insoluble compound of the multivalent heavy metal cation and the metal-containing anion, the molecules of the precipitated compound being dispersed within the unit cells of the zeolite. The zeolite may be faujasite, mordenite, clinoptilolite, zeolite X or zeolite Y. The metal of the multivalent heavy metal cation is a metal selected from Groups I, II, VI, VII and VIII, for example copper, silver, zinc, cadmium, chromium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, rhodium, palladium, osmium, iridium or palladium. The metal-containing anion may comprise titanium, vanaduim, chromium, molybdenum, tungsten or manganese and may be a vanadate, chromate, molybdate, tungstate or sulphur analogue thereof. The precipitated compound may be a simple salt, for example cobalt tungstate, cobalt thiotungstate, nickel tungstate or nickel thiotungstate; a complex salt, for example silver hydroxylamine tungstate; a compound comprising a dehydrated form of the anion, for example copper metatungstate or zinc paratungstate; or a compound comprising a polymeric form of the anion, for example ferric di-, tri-, tetra- or penta-tungstate. The zeolite containing the precipitated compound may be subjected to -further ion exchange by contact with an aqueous solution of a rare earth metal compound thereby to form a rare earth metalsubstituted zeolite containing molecules of the precipitated compound dispersed within the unit cells of the zeolite; reference also is made to such further ion exchange by contact with an aqueous solution of a water-soluble compound of magnesium, calcium, zinc, manganese, cobalt or nickel. Alternatively and when the water-soluble compound has an alkali metal cation, the zeolite containing the precipitated compound may be subjected to further ion exchange by contact either with acid thereby to form hydrogen zeolite containing molecules of the precipitated compound dispersed with the unit cells of the zeolite or with an ammonium compound thereby to form ammonium zeolite which may be heated to form hydrogen zeolite containing molecules of the precipitated compound dispersed within the unit cells of the zeolite; the hydrogen zeolite so formed may be calcined. The multivalent heavy metal substituted zeolite may be contacted, simultaneously with the aqueous solution of the water-soluble compound, with an aqueous solution of a water-soluble hydroxide or a water-soluble salt of a week acid, for example a carbonate or oxalate, having a cation selected from alkali metal ions and ammonium ions thereby to form a further precipitated compound of the multivalent heavy metal cation and hydroxide ion or the anion of the salt of the week acid, the molecules of the further precipitated compound being dispersed, together with the molecules of the precipitated compound, within the unit cells of the zeolite; the further precipitated compound may be converted by suitable treatment to oxide, sulphide or elemental metal form. In the preparation of the catalyst, water washing may be employed after at least one of the treatment steps. Details are given of the preparation of zeolite Y shaving cobalt tungstate dispersed therein and being essentially in the hydrogen form but apparently also containing some residual cobalt in a lattice position. Reference has been directed by the Comptroller to Specification 1,175,294.