The Destruction of Polychlorinated Biphenyls

terconversion of branched alkyl (a) and linear acyl ( f ) species, which is consistent with the observations made above. Thus by modifying the microstructure of the liquid assembly, through the addition of surface active agents and the polarity of the organic solvent, it is possible to effect high selectivities to total aldehydes. Other features which make this system attractive are that high normaliso ratios can be achieved at relatively low phosphine concentrations (less than 1/10 of that of the conventional triphenylphosphine-rhodium system). Minimal losses of phosphine, surfactant and rhodium occur, and the phosphine and surfactant are not degraded under the reaction conditions. A related water soluble system has been developed by Rhdne Poulenc and Ruhr Chemie (5). This system utilises sulphonated triphenylphosphine as a water solubilising ligand and operates at higher temperatures and pressures than the truly homogeneous rhodium-phosphine. A comparison of the sulphonated and carboxylated phosphine systems is given in Table VII. The trisulphonated triphenylphosphinerhodium catalyst is operated commercially by Ruhr Chemie for the hydroformylation of propylene and the complexity of these reaction systems suggests that the design of an industrial plant for the hydroformylation of high molecular weight alkenes will not be trivial. However, the mild operating conditions which result from the use of the 4-diphenylphosphinobenzoate-rhodium catalyst, together with the high selectivities attained, mean that this system has considerable potential for the manufacture of aldehydes in the fine organic chemicals markets.