US 6,723,880 B2 · Preparation of secondary amines from primary amines

Abstract

A process for producing secondary amines of the formula R1R2N—A—NH—A—NR1R2, where R1 and R2 are linear or branched C1-20-alkyl radicals, optionally substituted with from 1 to 5 phenyl groups; or cyclohexyl radicals; or together with the nitrogen atom to which they are bound, form a 3 to 7 membered saturated ring, optionally containing further hetero atoms selected from the group consisting of N, O and S, and optionally substituted with from 1 to 5 C1-2-alkyl groups. The group A is a linear or branched C2-20-alkylene group, optionally containing from 1 to 5 phenylene groups; or a radical of the formula —CH(R3)—[CH2]k—X—[CH(R3)—[CH2]k—X]m—CH(R3)—[CH2]k—, where R3 is H or CH3, X is O, S or NR4, R4 is H or a linear or branched C1-4-alkyl group, k is 1 or 2, and m is an integer from 0 to 4; or a group of the formula where n, o, p, and q are, independently, integers from 1 to 4. In this process, primary amines of the formula R1R2N—A—NH2 are reacted in the presence of hydrogen and a catalyst comprising at least one element or compound of an element of groups VIII and IB of the Periodic Table, preferably group IB, and in particular, Cu. Through this process, a high selectivity of the desired amines can be achieved.

Claims26

Dependent claims

A process for preparing a secondary amine of the formula

where
R1, R2 may be identical or different and are each, independently of one another, a linear or branched alkyl radical having from 1 to 20 carbon atoms which may bear from 1 to 5 phenyl groups as substituents or a cyclohexyl radical or together with the N atom to which they are bound form a 3- to 7-membered saturated ring which may contain further heteroatoms selected from the group consisting of N, O and S and may be substituted by from 1 to 5 alkyl groups having 1 or 2 carbon atoms,
A is a linear or branched alkylene group having from 2 to 20 carbon atoms which may have from 1 to 5 phenylene groups in its chain, or a radical of the formula
where R3=H or CH3, X=O or S or an NR4 group in which R4 is H or a linear or branched alkyl group having from 1 to 4 carbon atoms, k is 1 or 2 and m is an integer from 0 to 4, or a group of the formula
where n, o and p, q are each, independently of one another, integers from 1 to 4,
by reaction of primary amines of the formula
R1R2N—A—NH2 (II),
where R1, R2 and A are as defined for formula (I),
in the presence of hydrogen and a chromium-free catalyst comprising at least one element or compound of an element of groups VIII and IB of the Periodic Table of the Elements.

6 more elements

Dependencies are inferred from the claim text.

Preparation of secondary amines from primary amines

Life of this patent

Preparation of secondary amines from primary amines

Life of this patent

Abstract

Claims26