GB1044983A - Improvements in and relating to zeolites - Google Patents

Abstract

A process for the preparation of crystalline Type Y zeolite having the following molar ratio of constituents in its dehydrated form 0.9\sB0.2 Na2O: Al2O3: XSiO2 where X has a value from 3 to 7, comprises preparing an aqueous reaction mixture containing Na2O, SiO2 and Al2O3, the molar ratios of the constituents being within the following ranges. <TABS:1044983/C1/1> and heating the reaction mixture to a crystallization temperature of 180 DEG to 250 DEG F. for at least 24 hours and recovering the crystallized Type Y zeolite product. The reactants may be mixed at ambient temperature and then the reaction mixture may be maintained at 50-140 DEG F. for 1-15 hours prior to heating to the crystallization temperature. The product crystals, after separation from the mother liquor and thorough washing, may be activated by heating to 300-450 DEG C. to remove water of hydration to give an anhydrous product suitable for use as an adsorbent. The zeolites may be subjected to ion-exchange with metal cations of Groups I to VIII and the rare earth metals to give products suitable for use as catalysts. The ion-exchanged zeolites may be further modified by impregnation with noble metals, e.g. Pd, Pt, Rh, Mo, Cr, V, Co, Ni, Cu, Ag or Mn.ALSO:Crystalline Type Y zeolite having the following molar ratio of constituents in its dehydrated form 0.9 \sB 0.2 Na2O : Al2O3 : XSiO2 where X has a value from 3 to 7 is prepared by preparing an aqueous reaction mixture containing Na2O1 SiO2 and Al2O3, the molar ratio of constituents being within the following range: .SiO2/Al2O3.3.0 - 9.5 .Na2O/SiO2.0.20 - 0.27 .H2O/SiO2.3 - 10 and heating the reaction mixture to a crystallization temperature of 180 DEG -250 DEG F. for at least 24 hours and recovering the crystallized Type Y zeolite product. The zeolite may be subjected to ion exchange with a metal cation e.g. of Group I to VIII and the rare earth metals or a hydrogen containing cation e.g. ammonium to reduce the Na content (Na2O) to less than 10% by wt. based on the weight of zeolite crystals to give products useful as catalysts for hydrocarbon conversion processes. The ion-exchanged zeolites can be further modified for certain applications e.g. hydrocracking by impregnation with a suitable metal e.g. Pd, Pt, Rh, Mo, Cr, V, Co, Ni, Cu, Ag or Mn. Preferably the zeolite are first decationized by base exchange with NH14 or H ions and then heated with the appropriate metal salt or ammonium complex of the metal e.g. ammonium chloroplatinate and palladium chloride and the catalyst will generally contain 0.01 to 5.0 wt per cent of the metal.