Processes for regenerating dispersions of ligand-stabilized, palladium(ii) halide complexes used in carbonylation catalysts

Claim 1

A process for regenerating spent palladium carbonylation catalysts consisting of dispersions of ligand-stabilized palladium(II) halide catalyst complexes in quaternary ammonium, phosphonium, and arsonium salts of trihalostannate(II) and trihalogermanate(II), the spent catalyst being obtained from the carbonylation of olefins, said ligand-stabilixed catalysts being selected from the group consisting of: [(C 2 H 5 ) 4 N][SnCl 3 ]-PdCl 2 [P(C 6 H 5 ) 3 ] 2 [(c 2 h 5 ) 4 n][snCl 3 ]-PdCl 2 [P(p-CH 3 .C 6 H 4 ) 3 ] 2 [clCH 2 ( 6 H 5 ) 3 P][SnCl 3 ]-PdCl 2 [P(C 6 H 5 ) 3 ] 2 [(n-C 4 H 9 ) 4 N][SnCl 3 ]-PdCl 2 [P(C 6 H 5 ) 3 ] 2 (c 6 h 5 ) 4 as][SnCl 3 ]-PdCl 2 [P(C 6 H 5 ) 3 ] 2 [(c 2 h 5 ) 4 n][geCl 3 ]-PdCl 2 [P(C 6 H 5 ) 3 ] 2 [(c 2 h 5 ) 4 n][snCl 3 ]-PdCl 2 [P(p-CH 3 O.C 6 H 4 ) 3 ] 2 , and [(C 7 H 15 ) 4 N][GeCl 3 ]-PdCl 2 [As(C 6 H 5 ) 3 ] 2 , by the steps of: (a) Contacting said spent catalyst with an aqueous solution of hydrogen peroxide at 20° to 150° C in the mole ratio of 1-10 4 mole of peroxide per gram atom of palladium present in said catalyst. (b) Adding additional stabilizing ligand to the solid catalyst in the mole ratio of 1-10 mole of ligand per gram atom of palladium present, said stabilizing ligand being selected from the group consisting of triphenylphosphine, triphenylarsine, tri-p-tolylphosphine and tri-p-methoxyphenylphosphine, until the spent palladium carbonylation catalyst is regenerated.