Process for the preparation of trichloroethylene

Abstract

In the process, a copper/rhodium catalyst impregnated with 0.1 to 10.0% by weight, based on the total weight of active charcoal catalyst support and active components, of a water-soluble phosphonium halide is employed for the preparation of trichloroelethylene from perchloroethylene and hydrogen.

We claim: 
     
       1. A process for the preparation of trichloroethylene comprising reacting perchlorethylene and hydrogen in the presence of a supported catalyst at a temperature of .[.150°-200°.]. .Iadd.150° to 250°.Iaddend. C. and a hydrogen pressure 1 to 10 bar absolute, said catalyst consisting of a support of active charcoal having a BET surface area of more than 500 m 2  /g, impregnated with 0.5 to 20% by weight of copper in elemental or chemically bonded form, 0.01 to 1.0% by weight of rhodium or palladium in elemental or chemically bonded form and 0.1 to 10.0% by weight of a water-soluble phosphonium halide, said weight based on the total weight of catalyst support and active components. 
     
     
       2. The process of claim 1, wherein the water-soluble phosphonium compound is selected from compounds of the formula (Ph 3  PR)X, in which Ph represents a phenyl radical; R is selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl radical and a substituted or unsubstituted aryl radical; and X is selected from the group consisting of chloride, bromide and iodide. 
     
     
       3. The process of claim 2, wherein R is a methyl or ethyl radical. 
     
     
       4. The process of claim 1 wherein the water-soluble phosphonium halide is selected from the group consisting of methyltriphenylphosphonium chloride, methyltriphenylphosphonium bromide, ethyltriphenylphosphonium chloride and ethyltriphenylphosphonium bromide. 
     
     
       5. The process of claim 1 wherein the amount of the water-soluble phosphonium halide compound is from 3.0 to 7.0% by weight. 
     
     
       6. The process of claim 1 wherein the support of active charcoal has a particle size of from 2 to 10 mm. 
     
     
       7. The process of claim 1 wherein the copper is present as a water-soluble copper compound. 
     
     
       8. The process of claim 7 wherein the water-soluble copper compound is copper (II) chloride. 
     
     
       9. The process of claim 1 wherein the amount of copper is from 50 to 150% by weight in elemental of chemically bonded form. 
     
     
       10. The process of claim 1 wherein the rhodium or palladium is present as a water-soluble rhodium or palladium compound. 
     
     
       11. The process of claim 10 wherein the rhodium and palladium water-soluble compound is selected from the group consisting of rhodium (II) chloride and palladium (II) chloride. 
     
     
       12. The process of claim 1 wherein the amount of the rhodium or palladium is from 0.02 to 0.2 percent by weight.