4,4-Diaminodiphenylmethane → 4,4'-Diaminodicyclohexylmethane

Beteiligte Stoffe

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Due to these disadvantages and others, the utilization of catalysts containing metallic ruthenium has become preferred in the art in such hydrogenation processes as described in U.S. Pat. Nos. 2,606,924; 2,606,925; 2,494,563; 3,347,917; 3,676,495; and others. U.S. Pat. No. 2,606,924 to Whitman (1952) and U.S. Pat. No. 2,494,563 to Kirk, et al. (1950) describe processes for the preparation of certain stereoisomeric bis (4-aminocyclohexyl)methanes by the hydrogenation of bis(4-aminophenyl)methane with a ruthenium metal catalyst in the presence or absence of volatile organic solvent. More particularly, Whitman (2,606,924) discloses that steroisomeric bis(4-aminocyclohexyl)methane mixtures liquid at normal temperatures can be produced by the hydrogenation of bis(4-aminophenyl)methane at a temperature of 75°-125°C. and a pressure of between 100-15,000 psi in the presence of a ruthenium catalyst. Kirk, et al. (2,494,563) teach that the hydrogenation of bis(4-aminophenyl)methane in the presence of a ruthenium catalyst at temperatures between 140°-250°C. and pressures above 500 psi, e.g., 1,500-3,500 psi, results in a reaction product which, upon distillation and redistillation in vacuo, provides stereoisomeric bis (4-aminocyclohexyl)methane mixtures having a freezing point above 40°C.

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