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Preparation method of 4,4-dimethyl-3-keto-methyl valerate

A technology of methyl valerate and dimethyl valerate, applied in the field of organic synthesis, which can solve the problems of high risk, high price, and high content of sodium hydride, and achieve the effects of less raw material consumption, mild reaction, and reduced risk factor

Inactive Publication Date: 2012-07-25
ZHANGJIAGANG CITY ZHENFANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] 2) The sodium hydride content used is high, and the sodium hydride aqueous solution of more than 80Wt.% is relatively dangerous when adding materials, and the price is relatively high

Method used

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  • Preparation method of 4,4-dimethyl-3-keto-methyl valerate
  • Preparation method of 4,4-dimethyl-3-keto-methyl valerate
  • Preparation method of 4,4-dimethyl-3-keto-methyl valerate

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Experimental program
Comparison scheme
Effect test

Embodiment 1-8

[0023] First add dehydrated toluene (1mol pinacolone, dosage 400-410mL) to the kettle, and add anhydrous pinacolone dropwise at a reaction temperature of 55-60°C under different ratios of reaction raw materials, and the dropping time is controlled at 1.5~2h, keep warm at 55~60°C for 3h, then dropwise add water (1mol pinacolone, dosage 100~110mL), cool down to below 30°C, then add dropwise 18Wt.% hydrochloric acid aqueous solution, adjust pH=4~5, Stand still for 1h, remove the aqueous solution layer by layer, wash the upper organic solution layer with water, 10Wt.% sodium bicarbonate aqueous solution, and water until neutral, evaporate toluene and then distill under reduced pressure. 10 3 Pa fraction to obtain the product. The experimental data are shown in Table 1:

[0024] Table 1: Effect of Raw Material Ratio on Product Content and Yield

[0025]

[0026]

[0027] 1) Embodiment 2, 3, 4 and 5 find out: when pinacolone and dimethyl carbonate charge ratio are constant,...

Embodiment 9-13

[0030] Under the same condition of raw material ratio, pinacolone: ​​sodium hydride: dimethyl carbonate is in 1: 2: 2, and the toluene consumption is by 400mL / 1mol pinacolone, reacts and prepares under different temperature, different dropping time, different holding time 4,4-Dimethyl-3-keto-pentanoic acid methyl ester. After the reaction, add water dropwise (1mol pinacolone, dosage 100-110mL), lower the temperature to below 30°C, then add dropwise 18Wt.% hydrochloric acid aqueous solution to adjust the pH=4-5, let it stand for 1h, remove the aqueous solution layer by layer, and the upper layer organic The solution layer was washed with water, 10Wt.% sodium bicarbonate aqueous solution, and water until neutral, evaporated toluene and then distilled under reduced pressure. The collection temperature was 93-95°C and the pressure was 2.7×10 3 Pa fraction to obtain the product. The experimental data is shown in the following table: The experimental data is shown in Table 2:

[0...

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Abstract

The invention discloses a preparation method of 4,4-dimethyl-3-keto-methyl valerate, which comprises the following steps: by using pinacoline, sodium hydride and dimethyl carbonate with the water content of less than 0.2 wt.% as raw materials and using methylbenzene with the water content of less than 0.2 wt.% as a solvent, mixing to react at 55-60 DEG C, cooling, standing to stratify when the pH value is equal to 4-5, removing the solvent, and carrying out reduced pressure distillation to extract the 4,4-dimethyl-3-keto-methyl valerate. The preparation method disclosed by the invention has the advantages of relatively lower raw material consumption and less wastewater treatment amount; and the 60-62 wt.% sodium hydride is used in the reaction process, so the reaction is relatively milder in the feed process, thereby lowering the danger coefficient.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and relates to a preparation method of 4,4-dimethyl-3-keto-valeric acid methyl ester. Background technique [0002] 4,4-Dimethyl-3-keto-pentanoic acid methyl ester is an intermediate in the synthesis of color photographic couplers and some drugs. The molecular structural formula of 4,4-dimethyl-3-keto-pentanoic acid methyl ester is: [0003] [0004] Publication number DE2433108A1 discloses in the patent: Pinacolone, sodium hydride and dimethyl carbonate are reacted at 45~50 ℃ with molar ratio 1:2.5~3:4.5~5.0, and toluene is used as solvent to synthesize 4,4-dimethyl -3-keto-valeric acid methyl ester, what used in the preparation process is more than 80Wt.% sodium hydride. [0005] The shortcoming of above-mentioned preparation method is: [0006] 1) The consumption of raw materials is large, especially the large proportion of dimethyl carbonate, which will be partially decomposed during ac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/716C07C67/00
Inventor 葛鹏圣曹爱春钱志强
Owner ZHANGJIAGANG CITY ZHENFANG CHEM
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