Noble metal containing hydrogenation catalyst for selective hydrogenation of 1, 4 butynediol to 1, 4 butenediol, and a process for the preparation thereof

Abstract

A hydrogenation catalyst of the general formula AB(y)C(z) wherein A is a support comprising of a salt of a Group II A metal or zeolite, B is a noble metal selected from Pt or Pd, y=0.2 to 10%, C is nickel and z=0 to 15.0%, with the proviso that when B is Pt, z=0.

1 . A hydrogenation catalyst of the general formula AB(y)C(z) wherein A is a support comprising of a salt of a Group II A metal or zeolite, B is a noble metal selected from Pt or Pd, y=0.2 to 10%, C is nickel and z=0 to 15.0%, with the proviso that when B is Pt, z=0.  
   
   
       2 . A process for the preparation of a hydrogenation catalyst of the general formula AB(y)C(z) wherein A is a support comprising of a salt of a Group II A metal or zeolite, B is a noble metal selected from Pd or Pt, y=0.2 to 10%, C is nickel and z=0 to 15.0%, with the proviso that when B is Pt, z=0, said process comprising: 
 i. dissolving a noble metal precursor in a mineral acid by stirring at a temperature in the range between 60° C. to 120° C.;    ii. diluting the above solution by adding water;    iii. adjusting the pH of the solution to the range of 8-12 by adding a base;    iv. adding a support to the above solution;    v. heating the mixture to a temperature in the range of 60° C. to 120° C.;    vi. reducing the above mixture using a conventional reducing agent;    vii. separating the catalyst formed by any conventional method;    viii. washing and drying the product to obtain the catalyst.    
   
   
       3 . A process as claimed in  claim 2  wherein the catalyst obtained at the end of step viii is mixed with a solution of nickel in a basic medium having a pH in the range of 8-12; stirred for about 1 hour; the catalyst formed is separated by any conventional method; dried at about 150° C. up to 10 hours in static air; reduced at a temperature in the range of between 390-420° C. for a time period in the range of between 5-12 hours in a flow of hydrogen; the product being separated, washed and dried to obtain the catalyst.  
   
   
       4 . A process as claimed in  claim 2  wherein the noble metal source is a salt of a noble metal selected from the group consisting of acetate, bromide, and chloride of and the source of nickel is a salt of nickel selected from the group consisting of acetate, carbonate, chloride and nitrate.  
   
   
       5 . A process as claimed in  claim 2  wherein the support is a salt of a Group II A metal selected from the group consisting of acetates, nitrates, chlorides and carbonates of magnesium, calcium and barium and the source of zeolite is NH 4 -ZSM5.  
   
   
       6 . A process as claimed in  claim 2  wherein the base used is selected from the group consisting of sodium carbonate, potassium carbonate, potassium hydroxide, and sodium hydroxide.  
   
   
       7 . A process as claimed in  claim 2  wherein the reducing agent used is selected from the group consisting of hydrazine hydrate, hydrogen containing gas, and formaldehyde.  
   
   
       8 . A process as claimed in  claim 2  wherein A is a support comprising of a salt of a Group II A metal, B is platinum and y=0.2 to 10%, said process comprising: 
 i. dissolving a platinum precursor in a mineral acid by stirring at a temperature in the range between 60° C. to 120° C.;    ii. diluting the above solution by adding water;    iii. adjusting the pH of the solution to the range of 8-12 by adding a base;    iv. adding a support to the above solution;    v. heating the mixture to a temperature in the range of 60° C. to 120° C.;    vi. reducing the above mixture using a conventional reducing agent;    vii. separating the catalyst formed by any conventional method;    viii. washing and drying the product to obtain the desired catalyst.    
   
   
       9 . A process for the preparation of 1,4 butenediol from 1,4 butynediol said process comprising subjecting the 1,4 butynediol to hydrogenation by any conventional method characterised in that the catalyst used for the hydrogenation is of the general formula AB(y)C(z) wherein A is a support comprising of a salt of a Group II A metal, B is a noble metal selected from Pd and Pt, y=0.2 to 10%, C is nickel and z=0 to 15.0% with the proviso that when B is Pt, z=0.  
   
   
       10 . A process as claimed in  claim 8  wherein the selectivity of the process at milder process conditions is 100%.  
   
   
       11 . Use of a novel hydrogenation catalyst of the general formula AB(y)C(z) wherein A is a support comprising of a salt of a Group II A metal or zeolite, B is a noble metal selected from Pd and Pt, y=0.2 to 10%, C is nickel and z=0 to 15.0% with the proviso that when B is Pt, z=0, for the preparation of 1,4 butenediol from 1,4 butynediol.