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Process for the reductive amination of aldehydes and ketones via the formation of macrocyclic polyimine intermediates

A technology for amine compounds and products is applied in the field of reductive amination of aldehydes and ketones by forming macrocyclic polyimine intermediates, which can solve the problems of polluted reactors, difficult and expensive purification of crude products, and achieves high selectivity.

Active Publication Date: 2012-05-23
DOW GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the cost of raw material is high and the purification of crude product is difficult and expensive
Polymerization by-products often contaminate the reactor

Method used

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  • Process for the reductive amination of aldehydes and ketones via the formation of macrocyclic polyimine intermediates

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] A mixture of 1,3- and 1,4-cyclohexanedicarbaldehyde (3.08 g, 22 mmol) and 1,3- and 1,4-bis(aminomethyl)cyclohexane (4.26 g, 30 mmol) were dissolved in 11g methanol. Diglyme (2.38 g) was added as an internal standard for gas chromatographic analysis. The mixture was stirred at room temperature for 30 minutes. During this time, the reactants formed an intermediate product mixture containing a majority of macrocyclic polyimine species with a molecular weight of about 490 to 1480.

[0064] A powdered nickel catalyst (Ni-5256W from Engelhard) (0.75 g) was placed in a 160 mL Parr reactor with 30 g of methanol. The reactor was purged three times with 100 psi (689 kPa) nitrogen, charged with 1000 psi (6895 kPa) hydrogen and heated to 200°C for two hours to activate the catalyst. The reactor is then cooled and the hydrogen is pumped off. The intermediate product mixture obtained above was then transferred to a reactor. Anhydrous ammonia (37.7 g, 2.22 mol) was added with sti...

Embodiment 2

[0066] Example 1 was repeated without adding diglyme. After the reductive amination was complete, the catalyst was filtered from the reaction mixture and washed twice with methanol (50 g). Combine the wash solution with the reaction mixture. Methanol was then evaporated off followed by flash evaporation at 70-75 °C / 1 mm Hg in vacuo to produce 6.61 g of 1,3- and 1,4-bis(aminomethyl)cyclohexane (91% yield alone ).

Embodiment 3

[0068] Example 1 was repeated, however the temperature in the hydrogenation step was only 120°C, the reaction time was 3 hours, and the ratio of ammonia to aldehyde groups provided by the 1,3- and 1,4-cyclohexanedicarbaldehyde starting materials 25. The yield of 1,3- and 1,4-bis(aminomethyl)cyclohexane was 88%. About 9% of 3-azabicyclo[3.3.1]nonane was formed. The presence of 3-azabicyclo[3.3.1]nonane indicates that the amination / reduction reaction did not proceed to completion within the time given, at a temperature of 120°C and with the amount of aqueous ammonia used.

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Abstract

Aldehyde or ketone compounds having more than one carbonyl group are reductively aminated to form a product amine compound having more than one primary amino group. The aldehyde or ketone compound is reacted with the product amine compound, to form a reaction mixture that contains one or more intermediates. The intermediate is then reductively aminated to form the desired product. This process produces the desired product in very high yields with low levels of secondary amine impurities.

Description

[0001] This application claims the benefit of US Provisional Patent Application Serial No. 60 / 695,489, filed June 30,2005. technical field [0002] The present invention relates to a process for the preparation of diamines by reductive amination. Background technique [0003] Bis(aminomethyl)cyclohexane is a diamine that can be used as a precursor of aliphatic diisocyanate (bis(isocyanatomethyl)cyclohexane). It can be used as a chain extender in certain polyurethane systems and as an epoxy curing agent. Bis(aminomethyl)cyclohexane exists in the form of many isomers, of which the 1,3-isomer and the 1,4-isomer are of primary interest. The 1,3-isomer and 1,4-isomer can also exist in many diastereomeric forms, since the aminomethyl group can exist both above the plane of the cyclohexane ring and in the cyclohexane ring below the plane. [0004] Mixtures of 1,3- and 1,4-bis(aminomethyl)cyclohexanes can be prepared by a number of synthetic routes. A related pathway starts with...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C209/26C07C211/18
CPCC07C209/26C07C2101/14Y02P20/582C07C2601/14C07C211/36C07C211/49C07C211/50
Inventor M·L·图利钦斯基B·B·菲什
Owner DOW GLOBAL TECH LLC