Preparation of secondary amines

Inactive Publication Date: 2004-01-22
HUNTSMAN PETROCHEMICAL LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Palladium has been known previously as a reductive amination catalyst; however, in the known cases this catalyst was only found useful for making tertiary amines using ketones, as the alkylation according to prior art methods would not cease at the secondary amine stage, but would proceed uncontrollably to a tertiary amine product.

Method used

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  • Preparation of secondary amines
  • Preparation of secondary amines

Examples

Experimental program
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example 2

[0020] Preparation of N-isopropyl-N',N'-dimethyl-1,3-propylenediamine

[0021] The procedure of Example 1 was repeated, with the exception that the nickel catalyst used previously was replaced by a 1% palladium on carbon catalyst (Engelhard) and the reaction temperature was reduced to 120.degree. C. The effluent was analyzed and gave about 97% yield of N-isopropyl-N',N'-dimethyl-1,3-propylenediamine. No significant amounts of di-isopropyl DMAPA or coupling products were detected. The effluent was distilled to give 99.5% pure N-isopropyl-N',N'-dimethyl-1,3-propylene-diamine.

example 3

[0022] Preparation of N,N'-Diisopropylisophorone Diamine

[0023] About 300 g per hour of isophorone diamine and 450 g per hour of acetone were fed upflow into a 600 cc packed-bed reactor filled with a nickel catalyst as described in example 1 above. Hydrogen was fed at about 100% in excess. The reaction was conducted at 2000 psig and 140.degree. C. Lights were stripped out of the reactor effluent under reduce pressure. The resulting product was analyzed to contain 8.78 meq / g of total amine and 3.557 meq / g of primary amine. This result indicates that a significant amount (40.5%) of primary amine group was not alkylated. Also, GC analysis showed about 2.00% of "heavies" were present. In other words, amine coupling had occurred.

example 4

[0024] Preparation of N,N'-Diisopropylisophorone Diamine

[0025] A 200 cc DOWTHERM.RTM. heated stainless steel tubular upflow reactor which has an inside diameter of 0.815" and a thermostat fabricated from 0.25" OD tubing extend upwardly into the reactor was used. The reactor was filled with a 1.0% palladium on carbon catalyst (Engelhard). About 100 g per hour of isophorone diamine and 135 g per hour of acetone was fed into the tubular reactor, simultaneously, along with hydrogen at about 100% in excess. The reaction was conducted at 2000 psig and 150.degree. C. Lights were stripped out of the reactor effluent under reduce pressure. The resulting product was analyzed to contain 7.89 meq / g of total amine, 0.07 meq / g of primary amine, and 0.04 meq / g of tertiary amine. GC analysis also showed no evidence of coupling. This result indicates, with Pd / C catalyst, high conversion and selectivity were achieved.

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Abstract

Disclosed herein is a process for the reductive alkylation of primary amines to form secondary amines, by high pressure reaction of the primary amine with an alkylating agent and hydrogen in the presence of a catalyst which comprises metallic palladium. A process of the present invention is characterized in having high conversion rates and high selectivities, both greater than 95% on a first pass through the reactor. According to a preferred embodiment, the secondary amine produced comprises at least one 2-alkyl group bonded to the nitrogen atom of the primary amine product.

Description

[0001] The present invention relates generally to catalytic processes for alkylations of amines, and in more particular to selective formation of secondary amines from primary amines. A process according to the invention is especially well-suited for preparing 2-alkyl substituted amines from primary amines.BACKGROUND INFORMATION[0002] Processes for producing organic amines have been known in the art for quite some time. For example, U.S. Pat. No. 3,994,975 relates to the reductive amination of unsaturated cyclic ketones; to cyclic amines prepared thereby; and to uses thereof For example, when isophorone is reductively aminated, trimethyl cyclohexylamines and cyclohexenamines are obtained. The invention includes uses of the amine products as fuel additives for stabilizing distillate fuels.[0003] U.S. Pat. No. 4,521,624 provides a process for the reductive amination of a saturated cyclic ketone which comprises reacting a saturated ketone with an amine in the presence of hydrogen and a...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C07B61/00C07C209/26C07C211/09C07C211/11C07C211/18C07C211/36C07C213/02C07C217/50
CPCC07C209/26C07C2101/14C07C211/11C07C211/36C07C2601/14C07C209/90
Inventor SU, WEI-YAUGNELLI, CHRISTOPHER H.
Owner HUNTSMAN PETROCHEMICAL LLC
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