Hydrocarbon conversion catalyst composition

Abstract

A hydrocarbon conversion catalyst composition which comprises ZSM-48 and/or EU-2 zeolite particles and refractory oxide binder essentially free of alumina in which the average aluminium concentration of the ZSM-48 and/or EU-2 zeolite particles is at least 1.3 times the aluminium concentration at the surface of the particles, processes for preparing such catalyst compositions and processes for converting hydrocarbon feedstock with the help of such compositions.

That which is claimed: 
     
         1 . A process for preparing a hydrocarbon conversion catalyst composition, wherein said process comprises:
 preparing an extrudable mass, comprising a silica binder essentially free of alumina and ZSM-48 and/or EU-2 zeolite particles having a bulk silica-to-alumina molar ratio (SAR) of at least 150 and at most 210 and present in an amount to provide a zeolite content of said hydrocarbon conversion catalyst composition of at least 20 wt % and at most 70 wt %;   extruding said extrudable mass into extrudates;   drying and calcining said extrudates to provide calcined extrudates;   dealuminating said calcined extrudates by contacting said calcined extrudates with a solution of a fluor containing salt to provide a dealuminated extrudate; and   incorporating into said dealuminated extrudate a catalytic metal selected from the group consisting of platinum, palladium, and nickel.   
     
     
         2 . A process as recited in  claim 1 , wherein said silica binder further includes both silica sol and silica powder containing silica particles having a mean diameter between 10 μm and 200 μm. 
     
     
         3 . A process as recite in  claim 2 , wherein the average aluminum concentration of said ZSM-48 and/or EU-2 zeolite particles is at least 1.1 times the aluminum concentration at the surface of the particles. 
     
     
         4 . A process as recited in  claim 3 , wherein said drying of said extrudates is conducted at a temperature in the range of from 60° C. to 250° C. for a time sufficient to dry said extrudate, and said calcining of said extrudates is conducted in air or another inert gas at a temperature in the range of from 250° C. to 850° C. for a time in the range of from 1 to 48 hours or more. 
     
     
         5 . A process as recited in  claim 4 , further comprising:
 drying and calcining said dealuminated extrudate before said step of incorporating said catalytic metal into said dealuminated extrudate.   
     
     
         6 . A process as recited in  claim 5 , wherein said drying of said dealuminated extrudate is conducted at a temperature in the range of from 80 to 200° C. for a time in the range of from 0.5 to 10 hours and said calcining of said dealuminated extrudate is conducted at a temperature in the range of from 200 to 650° C. 
     
     
         7 . A process as recited in  claim 6 , wherein said solution is an aqueous solution comprising a fluorosilicate salt, wherein the fluorosilicate salt is represented by the formula: (A) 2/b ,SiF 6 , wherein ‘A’ is a metallic or non-metallic cation other than H+ having the valence ‘b’. 
     
     
         8 . A process as recited in  claim 7 , wherein said solution has a concentration of salt of at least 0.005 mole of salt/l. 
     
     
         9 . A process as recited in  claim 8 , wherein said solution has a pH between 2 and 8. 
     
     
         10 . A process as recited in  claim 9 , wherein the zeolite content of said hydrocarbon conversion catalyst composition, on a dry basis, is in the range of from 25 to 65 wt %, as calculated on the total finished catalyst composition. 
     
     
         11 . A process as recited in  claim 10 , wherein the average aluminium concentration of said ZSM-48 and/or EU-2 zeolite particles is at least 1.2 times the aluminium concentration at the surface of the particle. 
     
     
         12 . A process as recited in  claim 11 , wherein the zeolite content, on a dry basis, is of from 30 to 60 wt % as calculated on the total hydrocarbon catalyst composition. 
     
     
         13 . A process as recited in  claim 12 , further comprising zeolite ZSM-12, wherein the zeolite ZSM-12 content in said hydrocarbon conversion catalyst composition is an amount of at most 50% wt based on said ZSM-48 and/or EU-2 zeolite present in the hydrocarbon conversion catalyst composition, and wherein the average aluminum concentration of said ZSM-48 and/or EU-2 zeolite particles is at least 1.5 times the aluminium concentration at the surface of the particle. 
     
     
         14 . A process as recited in  claim 13 , wherein the average aluminium concentration of said ZSM-48 and/or EU-2 zeolite particles is at least 2 times the aluminium concentration at the surface of the particle.