Noble metal supported on a base metal catalyst

Abstract

The present invention provides an electroless process for making a catalyst in a liquid or gaseous medium comprising contacting a base metal with a chemical cleaning agent and simultaneously or sequentially treating said base metal under reducing conditions with a noble metal-containing material, the catalyst prepared using the process, and a method of using the catalyst.

What is claimed is: 
     
       1. An electroless process for making a catalyst having a noble metal deposited on a base metal which process comprises in a liquid or gaseous medium; (1) contacting a base metal with a cleaning agent selected from the group consisting of a chlorosilane, .Iadd.and .Iaddend.an alkoxysilane . .and a non-oxidizing acid.!., and   (2) treating said base metal under reducing conditions with a noble metal containing material.   
     
     
       2. The process of claim 1 wherein the contacting and treating steps are carried out sequentially. 
     
     
       3. The process of claim 1 wherein the contacting and treating steps are carried out simultaneously. 
     
     
       4. The process of claim 1 wherein the base metal is selected from the group consisting of titanium, vanadium, chromium, manganese, molybdenum, tungsten, iron, cobalt, nickel, copper, zinc, and alloys thereof. 
     
     
       5. The process of claim 4 wherein the base metal is selected from the group consisting of iron, nickel, chromium, and alloys thereof. 
     
     
       6. The process of claim 4 wherein the noble metal-containing material contains at least one noble metal selected from the group consisting of platinum, iridium, ruthenium, rhodium and palladium. 
     
     
       7. The process of claim 4 wherein said noble metal-containing material is a homogeneous noble metal solution. 
     
     
       8. The process of claim 7 wherein the homogeneous noble metal solution contains (i) at least one noble metal halide, noble metal-containing complex or a salt of a noble metal halide and (ii) a solvent therefor. 
     
     
       9. The process of claim 7 wherein the homogeneous noble metal solution comprises: (i) a platinum halide, a salt of a platinum halide or a mixture thereof, and   (ii) a solvent selected from the group consisting of water, cyclic and linear ethers, alcohols and mixtures thereof, and wherein the base metal is selected from the group consisting of iron, nickel, and alloys thereof.   
     
     
       10. The process of claim 9 wherein the platinum halide or salt thereof is selected from the group consisting of H 2  PtCl 6 , Na 2  PtCl 6 , Na 2  PtCl 4  and mixtures thereof, and the solvent is selected from the group consisting of tetrahydrofuran, 2-propanol, ethanol, 1,2-dimethoxyethane and mixtures thereof. 
     
     
       11. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) at least one platinum complex and (ii) a solvent selected from the group consisting of aromatic hydrocarbons, chlorinated aliphatic and aromatic hydrocarbons and mixtures thereof; and wherein the base metal is selected from the group consisting of iron, nickel, and alloys thereof. 
     
     
       12. The process of claim 11 wherein the platinum complex is selected from the group consisting of Pt(2,4-pentanedioate) 2 , PtCl 2  (triphenylphosphine) 2  and mixtures thereof, and the solvent is selected from the group consisting of methylene chloride, toluene, o-dichlorobenzene and mixtures thereof. 
     
     
       13. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) a palladium halide, a salt of a palladium halide or a mixture thereof; and (ii) a solvent selected from the group consisting of water and an aliphatic alcohol having 1 to 3 carbon atoms, and mixtures thereof; and wherein the base metal is selected from the group consisting of titanium, iron, nickel, copper, and alloys thereof. 
     
     
       14. The process of claim 13 wherein the palladium halide or salt thereof is selected from the group consisting of PdCl 2 , Na 2  PdCl 4 , Na 2  PdCl 2  and mixtures thereof, and the solvent is selected from the group consisting of water, methanol, and mixtures thereof. 
     
     
       15. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) at lease one palladium complex and (ii) a solvent selected from the group consisting of chlorinated hydrocarbons having 1 to 6 carbon atoms, linear and cyclic ethers having 4 to 6 carbon atoms and mixtures thereof. 
     
     
       16. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) a ruthenium halide or salt thereof and (ii) a solvent selected from the group consisting of water, a linear and branched aliphatic alcohol having 1 to 3 carbon atoms, linear and cyclic ethers having 4 to 6 carbon atoms and mixtures thereof; and wherein the base metal is selected from the group consisting of iron, cobalt, nickel, copper, and alloys thereof. 
     
     
       17. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) at least one ruthenium complex and wherein the base metal is selected from the group consisting of iron, cobalt, nickel, copper, and alloys thereof. 
     
     
       18. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) a rhodium halide or thereof and (ii) a solvent selected from the group consisting of water, linear and branched aliphatic alcohols having 1 to 3 carbon atoms, linear and cyclic ethers having 4 to 6 carbon atoms, and wherein the base metals are selected from the group consisting of titanium, manganese, iron, cobalt, nickel, and alloys thereof. 
     
     
       19. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) at least one rhodium complex and wherein the base metal is selected from the group consisting of titanium, manganese, iron, cobalt, nickel, and alloys thereof. 
     
     
       20. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) an iridium halide or salt thereof and (ii) a solvent selected from the group consisting of water, linear and branched aliphatic alcohols having 1 to 3 carbon atoms, linear and cyclic ethers and mixtures thereof and wherein the base metal is selected from the group consisting of titanium, iron, nickel, and alloys thereof. 
     
     
       21. The process of claim 7 wherein the homogeneous noble metal solution comprises (i) at least one iridium complex and wherein the base metal is selected from the group consisting of titanium, iron, nickel, and alloys thereof. 
     
     
       22. The process of claim 8 wherein the amount of the noble metal halide or salt thereof, or of the noble metal complex ranges from about 0.02 to 2.0 weight percent, based upon the amount of base metal. 
     
     
       23. The process of claim 1 wherein reducing conditions are provided by a chemical reducing agent selected from the group consisting of. (i) a silane having the formula:   (R).sub.y Si(H).sub.x        wherein x and y are each individually at least 1, x+y=4, and R is the same or different and is selected from the group consisting of a halogen, an alkoxy group having 1 to 5 carbon atoms, an alkyl group having 1 to 6 carbon atoms, and a haloalkyl group having 1 to 4 carbon atoms,   (ii) formaldehyde, and   (iii) a base metal having a reduction potential higher than that of the noble metal.   
     
     
       24. The catalyst produced by the process of claim 1. .Iadd. 
     
     
       25.  The process of claim 1 wherein the cleaning agent is a chlorosilane. .Iaddend..Iadd.26. The process of claim 1 wherein the cleaning agent is an alkoxysilane. .Iaddend.