909. ------. [GWYNN, M. H.] (Allied Chemical & Dye Corp.). Cleaning Metal Catalysts With Alcoholic Caustic Solution. United States Patent 2,473,880, June 21, 1949; appl. filed Aug. 11, 1942, Serial No. 454,429; 3 claims (Cl. 252-414). Chem. Abs., vol

Patent Abstracts

909. ------. [GWYNN, M. H.] (Allied Chemical & Dye Corp.). Cleaning Metal Catalysts With Alcoholic Caustic Solution. United States Patent 2,473,880, June 21, 1949; appl. filed Aug. 11, 1942, Serial No. 454,429; 3 claims (Cl. 252-414). Chem. Abs., vol. 43, 1949, p. 6763.

Deposits of resinous materials are removed from hydrogenation catalysts such as Ni, Cu, Co, Pt, and Pd catalysts of supported or unsupported, stationary or powdered type by treatment with a solution of caustic alkali in an aliphatic alcohol or ketol. The temperature range is 150º-300º C., and the preferred alcoholic solvent is ethylene glycol. Alcohols or ketols boiling below 150º C. may be used when the solution is maintained under superatmospheric pressure high enough to prevent undue volatilization of the solvent at the temperatures used for treating the catalyst. After treatment with the caustic alkali solution, the catalyst is washed with H₂O to remove the resinous material, which has been made H₂O-soluble but not removed by the solution. The catalyst may be used without further treatment or may be subjected to reactivation, for example, by immersion in a solution of nitrate of the catalytic metal followed by decomposition of the nitrate. In a train of converters connected in series, it may be necessary to remove resin only from the catalyst near the reaction zone; the remainder of the catalyst may be shifted toward the inlet end and fresh catalyst introduced at the outlet end of the zone. 4 literature refs., 3 foreign patents, and 11 United States patents cited.