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Synthetic method of 2,3-dimethylpentanal

A technology of dimethylvaleraldehyde and synthetic methods, applied in the preparation of heterocyclic compounds, organic chemistry, etc., can solve the problem of high equipment requirements, and achieve the effects of simple equipment, low production cost, and convenient operation

Inactive Publication Date: 2012-07-04
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In 2002, the U.S. Patent (US6444637B1) reported that 2-butene and propylene oxide were used as raw materials, Lewis acid catalyzed, and one-step synthesis of 2,3-dimethylpentanal, but the yield was only 33%, and the equipment requirements were high

Method used

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  • Synthetic method of 2,3-dimethylpentanal
  • Synthetic method of 2,3-dimethylpentanal
  • Synthetic method of 2,3-dimethylpentanal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] In a 1-liter flask equipped with a mechanical stirrer, a thermometer, and a solid addition funnel, add 90 g (0.9 mol) of 3-methyl-2-pentanone, 108.5 g (1 mol) of methyl chloroacetate and 100 mL of toluene, and cool the reaction solution to -20°C, add 64.8g (1.2mol) of sodium methoxide, control the reaction temperature to about -15°C, and complete the addition in about 3 hours.

[0029] After the addition, continue to keep warm and stir to react for 2 hours, then stir at room temperature for 1 hour, add dropwise 72g of sodium hydroxide and 400mL of methanol solution, and react at room temperature for 4 hours.

[0030] Recover methanol under reduced pressure at 20KPa. When no more distillate comes out, add 300mL of ice water, stir for about 5min, let stand for 30min, separate the toluene layer, acidify the water layer with concentrated hydrochloric acid to pH=1~2, and use Extract with ether three times, add 0.9g of copper powder, recover the solvent, and collect fractions...

Embodiment 2

[0032] In a 1-liter flask equipped with a mechanical stirrer, a thermometer, and a solid addition funnel, add 100 g (1 mol) of 3-methyl-2-pentanone and 108.5 g (1 mol) of methyl chloroacetate, and cool the reaction solution to -10°C. Add 64.8 g (1.2 mol) of sodium methoxide, control the reaction temperature to about -7°C, and complete the addition in about 3 hours.

[0033] After the addition, continue to keep warm and stir to react for 2 hours, then stir at room temperature for 1 hour, add dropwise 80 g of sodium hydroxide and 400 mL of methanol solution, and react at room temperature for 4 hours.

[0034] Recover methanol under reduced pressure at 20KPa. When no more distillate comes out, add 300mL of ice water, stir for about 5min, let stand for 30min, separate the toluene layer, acidify the water layer with concentrated hydrochloric acid to pH=1~2, and use Extract with ether three times, add 1g of copper powder, recover the solvent, and collect fractions at 72-75°C by 5KPa...

Embodiment 3

[0036] In a 1-liter flask equipped with a mechanical stirrer, a thermometer, and a solid addition funnel, add 90 g (0.9 mol) of 3-methyl-2-pentanone, 167 g (1 mol) of ethyl bromoacetate and 100 mL of toluene, and cool the reaction solution to - 0°C, add 95g (1.1mol) of sodium ethylate, control the reaction temperature at about 5°C, and complete the addition in about 3 hours.

[0037] After the addition, continue to insulate and stir the reaction for 2 hours, add dropwise 72g of sodium hydroxide and 400mL of methanol solution, and react at room temperature for 4 hours.

[0038] Recover methanol under reduced pressure at 20KPa. When no more distillate comes out, add 300mL of ice water, stir for about 5min, let stand for 30min, separate the toluene layer, and acidify the water layer with 25% sulfuric acid to pH = 1-2. Extract with ether three times, add 0.9g of copper powder, recover the solvent, and collect fractions at 72-75°C by 5KPa vacuum distillation to obtain 40g of 2,3-di...

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Abstract

The invention discloses a synthetic method of 2,3-dimethylpentanal. The synthetic method comprises the following steps: taking 3-methyl-2-pentanone and alpha-haloacetate as raw materials, allowing a condensation reaction under the action of strong alkali to generate epoxy carboxylic ester, and allowing a saponification reaction, an acidification reaction and a decarboxylation reaction to obtain the product of the invention. The synthetic method of 2,3-dimethylpentanal has molar yield up to 40-70%, simple equipment, convenient operation, good selectivity, few by-products and little pollution, and is applicable to industrialized production.

Description

technical field [0001] The invention relates to a method for synthesizing 2,3-dimethylpentanal. Background technique [0002] 2,3-Dimethylpentanal is an important intermediate in organic synthesis. Currently, there are several methods reported in the literature: [0003] The British patent (GB974818) reports that methoxyacetone is used as a raw material for addition reaction with 2-bromobutane magnesium Grignard reagent, and the intermediate is obtained 2,3-dimethylpentanal under the action of a strong acid ion resin. This process has low yield, many impurities and difficult separation; [0004] U.S. Patent (US3359324) reports that crotonaldehyde, crotyl alcohol, etc. are used as raw materials to obtain 2,3-dimethylvaleraldehyde through acetalization, catalytic cracking rearrangement, and selective hydrogenation. This process has many steps and low yield; [0005] French patent (Fr1377141) reports to be raw material with 3-methyl-2-pentanone, and chloromethyl methyl ether...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C47/02C07C45/58
Inventor 王之建贾卫民李喜彦
Owner SHANGHAI INST OF TECH
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