Method for separating cis-3,5-dimethylpiperidine from a mixture of its geometrical isomers

A technology of dimethylpiperidine and geometric isomerization, applied in the separation/purification of lactam, chemical instruments and methods, organic chemistry, etc., can solve uneconomical and time-consuming problems

Inactive Publication Date: 2008-10-08
JUBILANT ORGANOSYS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The isolation of cis-3,5-dimethylpiperidine from a commercially available, 4:1 mixture of cis:trans-3,5-dimethylpiperidine involves several steps, including Heating, filtration, extraction, crystallization and drying; the process also involves the use of organic solvents and other chemicals such as acids and bases, making the process both time-consuming and uneconomical

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] 880 grams of 3,5-lutidine and 220 grams of water were charged into a 2-liter high-pressure steam reactor, and 4.4 grams of ruthenium alumina (5% ruthenium) were further added to the solution. The high-pressure steam reactor was closed, filled with nitrogen three times, and then filled with hydrogen twice. The high pressure steam reactor is pressurized with hydrogen and the reactants are heated to 190-200°C. After reaching 190-200°C, the pressure of hydrogen will increase to 45-55kg / cm 2 , and the pressure will continue until the hydrogen is exhausted. A sample was tested to confirm complete conversion of the 3,5-lutidine, yielding 1120 g of the reaction crude product. Gas chromatography (G.C.) analysis showed that the cis product accounted for 81.12%, and the trans product accounted for 17.99%. The crude product was decanted and the catalyst was reused in the hydrogenation reaction.

[0030]The crude product was fractionated with 75 grams of fresh or recycled water ...

Embodiment 2

[0032] 880 grams of 3,5-lutidine were charged into a 2-liter high-pressure steam reactor, and then 4.4 grams of ruthenium alumina (5% ruthenium) were added. The high-pressure steam reactor was closed, filled with nitrogen three times, and then filled with hydrogen twice. The high pressure steam reactor was pressurized with hydrogen and the reactants were heated to 190-200°C. After reaching 190-200°C, the pressure of hydrogen increases to 45-55kg / cm 2 , and the pressure will continue until the hydrogen is exhausted. A sample was tested to confirm sufficient conversion of the 3,5-lutidine and 1120 grams of reaction crude product were obtained. Gas chromatography analysis showed that the cis product accounted for 68%, and the trans product accounted for 31.2%. The crude product is decanted and the catalyst can be reused in the hydrogenation reaction

[0033] The crude product was subjected to fractional distillation with 75 grams of water in a two meter long, one inch diamete...

Embodiment 3

[0035] 880 grams of 3,5-lutidine and 220 grams of water were charged into a 2-liter high-pressure steam reactor, and 4.4 grams of ruthenium alumina (5% ruthenium) were further added to the solution. The high pressure steam reactor was closed and filled with nitrogen three times and hydrogen twice. The high pressure steam reactor is pressurized with hydrogen and the reactants are heated to 190-200°C. When the temperature reaches 190-200°C, the pressure of hydrogen will increase to 45-55kg / cm 2 , and the pressure will continue until the hydrogen is exhausted. A sample was tested to confirm complete conversion of the 3,5-lutidine to yield 1120 mg of reaction crude product. The crude product is decanted, and the catalyst can be used repeatedly 10 times in the hydrogenation reaction (the operating loss is 0.3-0.5 g). After the 11th use of the catalyst, the resulting reactant contained 82.0% cis isomer and 17% trans isomer.

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PUM

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Abstract

Disclosed is a single step process for separating Cis-3,5-dimethylpiperidine from a mixture of its geometrical isomers. The method comprises hydrogenation of 3,5-lutidine in the presence of water and 5% ruthenium on alumina as the catalyst at a predetermined range of temperature and pressure and does not involve the use of any organic solvent.

Description

technical field [0001] The present invention generally relates to methods of isolating compounds from mixtures of geometric isomers of the compounds. More specifically, the present invention relates to a process for the one-step separation of cis-3,5-dimethylpiperidine from a mixture of cis- and trans-3,5-dimethylpiperidine without using any organic solvent. Background technique [0002] Methods for isolating compounds from mixtures are important at both the laboratory and commercial levels. Purification of compounds depends largely on purification steps, in which compounds are separated from other products produced by chemical reactions. Separation of compounds from their isomers such as cis and trans isomers is difficult to achieve. [0003] The methods disclosed in the known art for isolating a compound from its isomers include preferentially using a salt-forming reaction. But these methods are expensive and time-consuming. Therefore, it is very important to devise an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D211/12C07D201/16
Inventor 尼可赫什·钱德拉·巴德瓦南赫·莱·楚瑞萨普偌迪普·古马·沃尔玛阿素托史·阿伽瓦
Owner JUBILANT ORGANOSYS LTD
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