Colloidal rhodium catalysts in water were prepared by the reaction of rhodium chloride and sodium borohydride in the presence of Celite, White Carbon and Avisel. Hydrogenation of paraquat by the catalysts afforded 1, 1'-dimethyl-4, 4'-bipiperidine in good yields. The reactions using the catalysts supported with Celite or White Carbon were superior to the reaction of nonsupported catalysts.

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