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Preparation of dimethyl acetone-1,3-dicarboxylate

A technology of dimethyl acetone dicarboxylate and acetone dicarboxylic acid, applied in the field of preparation of dimethyl acetone dicarboxylate, can solve the problems of unfavorable industrialized production, poor production safety, high equipment requirements, and achieve outstanding substantive characteristics , to ensure production safety, high purity effect

Inactive Publication Date: 2009-07-08
临安市新联线缆材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Fuming sulfuric acid has high requirements on equipment and poor production safety, which is not conducive to industrial production

Method used

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  • Preparation of dimethyl acetone-1,3-dicarboxylate
  • Preparation of dimethyl acetone-1,3-dicarboxylate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add 400mL of concentrated sulfuric acid into a 1000mL three-neck flask, heat to 65°C, add 384g (2.0mol) of citric acid in batches, keep the reaction at 50°C for 1hr after the addition, and cool down to below 20°C. Add dropwise into 500mL of water, cool to keep the temperature of the system not higher than 35°C, stir and cool to below 10°C after dropping, filter the precipitated crystals, rinse the filter cake with cold water, and dry to obtain 203.7g of acetonedicarboxylic acid with a yield of 69.8% , content 98%.

Embodiment 2

[0028] Add 146g (1.0mol) of acetone dicarboxylic acid prepared in Example 1 and 600mL of anhydrous methanol into a 1000mL three-necked flask, stir and cool to below 20°C, add 130.9g of thionyl chloride dropwise, and reflux for 2 hours after the addition is complete. , then distill off most of the methanol (about 420mL), cool to below 20°C, add dropwise to 500mL of cold water, and control the temperature below 20°C. Stand and separate layers, extract the organic phase with 300mL dichloromethane, combine the dichloromethane layers, wash with water, saturated sodium bicarbonate solution, and water until neutral, dry with anhydrous sodium sulfate, and recover dichloromethane by atmospheric distillation , and then collect the 105°C / 500Pa fraction under reduced pressure to obtain 158g of a white powder product, with a yield of 90.8%, a content of 98.6%, an acidity≤0.3%, and a melting point of 126-127°C.

Embodiment 3

[0030] Add 400L of concentrated sulfuric acid into a 1000L reactor, heat to 65°C, add 384kg (2.0kmol) of citric acid in batches, keep the reaction at 50°C for 1.5hr after the addition, and cool down to below 20°C. Add dropwise into 500L of cold water, cool to make the system temperature not higher than 35°C, stir and cool to below 10°C after dropping, centrifuge the precipitated crystals, rinse with cold water, and dry to obtain 201.5 kg of acetonedicarboxylic acid, with a yield of 69%. Content 98%.

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Abstract

The invention provides a method for preparing Dimethyl 1,3-acetonedicarboxylate. The method comprises: firstly, performing stirring reaction between citric acid and 98 percent concentrated sulfuric acid for 1 to 2 hours at a temperature of between 49 and 52 DEG C, dripping a reaction liquid into water after the reaction is over, stirring the mixture and cooling the mixture to be less than 10 DEG C, separating out crystals, filtrating and washing the crystals, and obtaining acetone dicarboxylic acid; and secondly, dripping anhydrous methanol and thionyl chloride into the prepared acetone dicarboxylic acid, performing reflux reaction for 1 to 3 hours, separating and purifying a reaction liquid after the reaction is over, and obtaining the Dimethyl 1,3-acetonedicarboxylate. The method mainlyhas the advantages of eliminating the prior fuming sulfuric acid and adopting the general concentrated sulfuric acid in the selection of raw materials, shortening the technological flow, reducing theproduction cost and environmental pollution, guaranteeing safe production, realizing high yield and high purity of products, and improving the economic benefit.

Description

(1) Technical field [0001] The invention relates to a method for preparing dimethyl acetone dicarboxylate. (2) Background technology [0002] Dimethyl acetone-1,3-dicarboxylate or 3-oxo-pentanedioic acid, dimethyl ester, CAS: 1830-54-2) is a medical intermediate that was used in atropine in the 20th century , the synthesis of hyoscyamine, in this century, because it was found to have certain antibacterial activity, it has been widely used in the synthesis of antibiotic drugs. [0003] Acetone dicarboxylate dimethyl ester [0004] Acetone dicarboxylic acid dimethyl ester is obtained by the esterification of acetone dicarboxylic acid and methanol. The synthesis of acetone dicarboxylic acid generally uses anhydrous citric acid as raw material, and is produced by oxidative decarboxylation in the presence of fuming sulfuric acid. Oleum has high equipment requirements and poor production safety, which is not conducive to industrial production. (3) Contents of the invention ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/716C07C67/08
Inventor 周贤言潘联根
Owner 临安市新联线缆材料有限公司
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