US 3,959,374 A · Process for the preparation of mixed isomeric methylene-bridged polycyclohexylpolyamines

Abstract

A process is described for the preparation of mixed isomeric methylene-bridged polycyclohexylpolyamines wherein a mixed isomeric methylene-bridged polyphenyl polyamine mixture having a functionality of from about 2.0 to about 3.3 is pretreated by contacting the mixture and hydrogen with a nickel-containing hydrogenation catalyst at a temperature of from about 25.degree.C. to about 250.degree.C. under a pressure of about 500 to about 15,000 psig. The pretreated isomeric polyamine is then hydrogenated in the presence of ammonia under conventional hydrogenation conditions employing a ruthenium-containing hydrogenation catalyst. The pretreatment step allows the utilization of mixed isomeric methylene-bridged polyphenyl polyamine feed mixtures for the production of isomeric methylene-bridged polycyclohexylpolyamines in high yields without attendant deactivation of the ruthenium hydrogenation catalyst heretofore observed. The process is particularly applicable to continuous operation.

Claims17

Dependent claims

In a process for the preparation of mixed isomeric methylene-bridged polycyclohexylpolyamines comprising hydrogenating a mixed isomeric methylene-bridged polyphenyl polyamine mixture at a temperature within the range of about 150.degree. to about 250.degree.C under a pressure of about 500 to about 15,000 psig in the presence of ammonia and a ruthenium-containing hydrogenation catalyst, the improvement comprising:

initially intimately contacting, in the presence of hydrogen, the mixed isomeric methylene-bridged polyphenyl polyamine mixture with a nickel-containing hydrogenation catalyst at a temperature of between about 25.degree. to about 250.degree.C under a pressure of about 500 to about 15,000 psig and for a time effective in preventing the rapid deactivation of said ruthenium-containing hydrogenation catalyst in said hydrogenating step;
and then
hydrogenating said mixed isomeric methylene-bridged polyphenyl polyamine mixture in the presence of said ammonia and said ruthenium-containing hydrogenation catalyst.

A continuous process for preparing isomeric methylene-bridged polycyclohexylpolyamines in high yields from mixed isomeric methylene-bridged polyphenyl polyamine mixtures containing ruthenium-containing hydrogenation catalyst poisons, said continuous process comprising:

injecting flowing streams of a mixed isomeric methylene-bridged polyphenyl polyamine mixture and hydrogen into a first zone having a temperature of from about 25.degree.C to about 250.degree.C, a pressure of between about 500 to about 15,000 psig and containing a nickel-containing hydrogenation catalyst, said flowing streams being injected at respective flow rates sufficient to form a flowing mixture stream having at least 100% molar excess hydrogen based upon said polyamine mixture;
passing said flowing mixture stream through said first zone containing said nickel-containing hydrogenation catalyst to provide intimate contacting of said flowing mixture stream with said catalyst for a time effective in substantially inactivating said ruthenium-containing hydrogenation catalyst poisons;
passing the effluent flowing from the first zone and ammonia through a second zone having a temperature of about 150.degree. to about 250.degree.C, a pressure of between about 500 to about 15,000 psig and containing a ruthenium-containing hydrogenation catalyst, said ammonia being passed at a rate sufficient to provide a molar ratio of about 3 to about 30 moles ammonia per mole of polyamine mixture;
and
recovering the isomeric methylene-bridged polycyclohexylpolyamines from the effluent flowing from said second zone.

2 more elements

Dependencies are inferred from the claim text.

Process for the preparation of mixed isomeric methylene-bridged polycyclohexylpolyamines

Life of this patent

Process for the preparation of mixed isomeric methylene-bridged polycyclohexylpolyamines

Life of this patent

Abstract

Claims17