Process for recovering homogenous metal hydrate catalysts

Abstract

The present invention relates to a process for recovery of homogeneous metal hydride catalyst from a reactor stream as catalyst suitable for recycle to a reactor comprising the steps of: removing a stream from a reactor, said stream comprising the homogeneous metal hydride catalyst; contacting the stream with a solid acidic absorbent under process conditions which allow at least some of the metal to become bound to the absorbent; subjecting the metal bound to the absorbent, under process conditions which allow desorption of the metal, to a fluid stripping medium comprising hydrogen and solvent; and recovering the active metal hydride catalyst.

1 . A process for recovery of homogeneous Group VIII noble metal hydride catalyst from a reactor stream as catalyst suitable for recycle to a reactor comprising the steps of: 
 (a) removing a stream from a reactor, said stream comprising the homogeneous Group VIII noble metal hydride catalyst;    (b) contacting the stream with a solid acidic absorbent under process conditions which allow at least some of the metal to become bound to the absorbent;    (c) subjecting the metal bound to the absorbent, under process conditions which allow desorption of the metal, to a fluid stripping medium comprising hydrogen and solvent; and    (d) recovering the active Group VIII noble metal hydride catalyst.    
     
     
         2 . A process according to  claim 1  wherein the fluid stripping medium is a single fluid phase.  
     
     
         3 . A process according to  claim 2  wherein the single fluid phase is a supercritical phase.  
     
     
         4 . A process according to  claim 1  wherein the fluid stripping medium comprises two fluid phases.  
     
     
         5 . A process according to any one of  claims 1  to  4  wherein the Group VIII noble metal hydride catalyst is a platinum, palladium, iridium or rhodium hydride catalyst.  
     
     
         6 . A process according to  claim 5  wherein the catalyst is HRh(CO)(PPh 3 ) 3 .  
     
     
         7 . A process according to any one of  claims 1  to  6  wherein the reactor stream is from a hydroformylation reactor.  
     
     
         8 . A process according to  claim 7  wherein the reactor stream contains non-volatile by-products of the reaction.  
     
     
         9 . A process according to any one of  claims 1  to  8  wherein the reactor stream having been contacted with the solid acidic absorbent is removed.  
     
     
         10 . A process according to any one of  claims 1  to  9  wherein the acidic absorbent is an ion-exchange resin.  
     
     
         11 . A process according to any one of  claims 1  to  10  wherein the acidic absorbent is a styrene divinyl copolymer containing sulphonic acid groups or carboxylic acid groups.  
     
     
         12 . A process according to any one of  claims 1  to  11  wherein the acidic absorbent has a silica-containing backbone and an acidic functional group attached to the silica.  
     
     
         13 . A process according to  claim 12  wherein the acidic functional group is an aromatic carboxylic acid, an aliphatic carboxylic acid, an aromatic sulphonic acid or an aliphatic sulphonic acid.  
     
     
         14 . A process according to any one of  claims 1  to  13  wherein the acidic-absorbent is Amberlyst™ 15 or Amberlyst™ DPT-1.  
     
     
         15 . A process according to any one of  claims 1  to  14  wherein step (b) is carried out at a temperature of from about 20° C. to about 100° C.  
     
     
         16 . A process according to  claim 15  wherein the temperature is in the region of about 50° C. to about 95° C.  
     
     
         17 . A process according to any one of  claims 1  to  16  wherein the reactor stream is concentrated prior to contact with the acidic absorbent.  
     
     
         18 . A process according to any one of  claims 1  to  17  wherein the reactor stream is diluted with a solvent compatible with the absorbent before it is contacted with the absorbent.  
     
     
         19 . A process according to any one of  claims 1  to  18  wherein the reactor stream is subjected to oxidation to break clustered catalyst prior to being contacted with the acidic absorbent.  
     
     
         20 . A process according to  claim 19  wherein the stream having been subjected to oxidation is treated to hydrocarbonylation.  
     
     
         21 . A process according to any one of  claims 1  to  20  wherein the gaseous phase of the stripping medium additionally includes carbon monoxide.