Preparation of molecular sieves involving spray drying

Abstract

Molecular sieves are prepared by forming a reaction mixture slurry, spray drying the reaction mixture slurry to form particles, and heating the spray dried reaction mixture at a temperature and pressure sufficient to cause crystallization of the molecular sieve. The reaction mixture contains an organic templating agent capable of forming the molecular sieve. The template may be added to the reaction mixture either by adding all of the template prior to spray drying, or by adding a portion of the template prior to spray drying with the remainder being added after spray drying.

1 . A method of preparing a crystalline molecular sieve comprising: 
 a. forming an aqueous slurry comprising an active source of silicon oxide and an organic templating agent capable of forming the molecular sieve;    b. spray drying the aqueous slurry to form particles;    c. heating the spray dried particles at a temperature and pressure sufficient to cause crystallization of the molecular sieve.    
     
     
         2 . The method of  claim 1  wherein step c is conducted in the absence of added water.  
     
     
         3 . The method of  claim 1  wherein the aqueous slurry further comprises an active source of an alkali metal oxide.  
     
     
         4 . The method of  claim 1  wherein the aqueous slurry further comprises an active source of the oxides of aluminum, boron, iron, gallium, indium, titanium, or mixtures thereof.  
     
     
         5 . The method of  claim 4  wherein the oxide is aluminum oxide.  
     
     
         6 . The method of  claim 1  wherein the aqueous slurry further comprises seed crystals of the molecular sieve.  
     
     
         7 . The method of  claim 1  wherein the molecular sieve is the zeolite ZSM-5.  
     
     
         8 . The method of  claim 1  wherein the molecular sieve is zeolite beta.  
     
     
         9 . The method of  claim 4  wherein the mole ratio of silicon oxide to the oxides of aluminum, boron, iron, gallium, indium, titanium, or mixtures thereof is greater than 12.  
     
     
         10 . A method of preparing a crystalline molecular sieve comprising: 
 a. forming an aqueous slurry comprising an active source of silicon oxide and an organic templating agent capable of forming the molecular sieve;    b. spray drying the aqueous slurry to form particles;    c. adding additional organic templating agent to the spray dried particles to form a slurry; and    d. heating the slurry from step c at a temperature and pressure sufficient to cause crystallization of the molecular sieve.    
     
     
         11 . The method of  claim 10  wherein the aqueous slurry further comprises an active source of an alkali metal oxide.  
     
     
         12 . The method of  claim 10  wherein the aqueous slurry further comprises an active source of the oxides of aluminum, boron, iron, gallium, indium, titanium, or mixtures thereof.  
     
     
         13 . The method of  claim 12  wherein the oxide is aluminum oxide.  
     
     
         14 . The method of  claim 10  wherein the aqueous slurry further comprises seed crystals of the molecular sieve.  
     
     
         15 . The method of  claim 10  wherein the molecular sieve is the zeolite ZSM-5.  
     
     
         16 . The method of  claim 10  wherein the molecular sieve is zeolite beta.  
     
     
         17 . The method of  claim 12  wherein the mole ratio of silicon oxide to the oxides of aluminum, boron, iron, gallium, indium, titanium, or mixtures thereof is greater than 12.