Patent / 1972
Palladium-active carbon hydrogenation catalyst
A Pd/C catalyst was made by redn. of Pd chloride in aq. suspension of active C with H-coal gas mixts. at 50.degree. and used for the redn. of .beta.-naphthoyl chloride to .beta.-naphthaldehyde or for the simultaneous dehalogenation and selective redn. of exocyclic methylene double bonds in pregnatriene, pregnadiene, and tetracycline derivs. Thus, 5 g Pd chloride in H2O was added to a suspension of 54 g active carbon in 100 ml H2O and a 96% H-4% coal gas mixt. passed through the suspension 2 hr at 50.degree. to give a 5% Pd/C catalyst. 9.alpha.-Bromo-11.beta.,17.alpha.-dihydroxy-16-methylenepregna-1,4-diene-3,20-dione was hydrogenated in AcOH in the presence of this catalyst at 20-30.degree. and 1000 mbar to give 93.4% 16.beta.-methyl-11.beta.,17.alpha.-dihydroxypregna-1,4-diene-3,20-dione of high cortisone activity.