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Process for preparing acetoacetic ester

A technology of acetoacetate and preparation process, which is applied in the preparation of ketene/polyketene, organic chemistry and other directions, can solve the problems such as lower acetoacetate product yield, small production scale, complicated operation and the like, and achieves expansion of production. Ability, easy operation, avoid the effect of reaction deanhydride

Inactive Publication Date: 2011-06-22
SHANGHAI HUAYI GRP CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the small production scale of a single batch batch reaction device in the existing preparation process of acetoacetate, the operation is cumbersome, and it is easy to cause danger due to misoperation, and the acetic anhydride in the reaction crude product is difficult to pass through rectification. method to remove, and if using concentrated sulfuric acid or strong base to remove acetic anhydride, it is easy to cause the acetoacetate to decompose and cause defects such as product yield reduction, and a preparation process for acetoacetate is provided

Method used

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  • Process for preparing acetoacetic ester

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Effect test

Embodiment 1

[0029] Add 32g of methanol and 0.057g of catalyst diethylenetriamine into the reaction kettle, add diketene dropwise to react, establish the initial liquid level, add dropwise until the concentration of methanol in the initial reaction liquid is 5% by mass, start continuous feeding: methanol 1ml / min , wherein the catalyst content is 0.5%, refined diketene 1.5ml / min, light component circulation flow 0.8ml / min (wherein, the mass ratio of circulating material and discharging is 1: 5), the control reactor temperature is controlled at 95 ℃, Fine-tune the feed flow rate according to the concentration analysis results, and keep the concentration of methanol in the reaction liquid at 5% by mass; the output flow rate of the reactor is 2.5ml / min, and the temperature of the aging flash tank is controlled at 120°C, operated under normal pressure, and the aging flash is evaporated The output flow rate of the kettle is 2ml / min, and the crude ester liquid is analyzed, and the concentration of...

Embodiment 2

[0031] Add 32g of methanol and 0.057g of catalyst triethylenediamine into the reaction kettle, add diketene dropwise to react, establish the initial liquid level, add dropwise to the concentration of methanol in the initial reaction liquid is 10% by mass, start continuous feeding: methanol 1.5ml / min, wherein the catalyst content is 0.1%; refined diketene 2ml / min; light component circulation flow 0.3ml / min (wherein, the mass ratio of circulating material and discharging is 5: 1); control reactor temperature is controlled at 80 ℃, Fine-tune the feed flow rate according to the concentration analysis results, and keep the concentration of methanol in the reaction solution at 10% by mass; the output flow rate of the reactor is 3.5ml / min, the temperature of the aging flash tank is controlled at 105°C, and the operating pressure is 0.9atm (A) , the output flow rate of the aging flash tank is 2.5ml / min, the crude ester liquid is analyzed, the concentration of the crude ester is stable...

Embodiment 3

[0033] Add 32g of methanol and 0.057g of catalyst triethylamine to the reaction kettle, add diketene dropwise to react, establish the initial liquid level, add dropwise until the concentration of methanol in the initial reaction liquid is 20% by mass, start continuous feeding: methanol 1ml / min, Wherein the catalyst content is 0.35%; Refining diketene 1.5ml / min; Light component circulation flow 0.8ml / min (wherein, the mass ratio of circulating material and discharging is 2: 5); Control reactor temperature is controlled at 60 ℃, according to Concentration analysis results fine-tune the feed flow rate to keep the concentration of methanol in the reaction solution at 20% by mass; the output flow rate of the reactor is 2.5ml / min, the temperature of the aging flash tank is controlled at 130°C, and the aging flash tank is operated under normal pressure. The output flow rate is 2ml / min, and the crude ester liquid is analyzed. The concentration of the crude ester is stable at 96.8%, and...

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Abstract

The invention discloses a process for preparing acetoacetic ester, which comprises the following steps of: continuously feeding diketene and fatty alcohol into a reaction kettle, and performing esterification reaction in the presence of a catalyst; and continuously discharging into an ageing flash tank, distilling out light components and discharging a crude reaction product, wherein the fatty alcohol in the reaction kettle is controlled to be 5 to 20 percent of the total mass of reaction liquid. The preparation process can continuously prepare the acetoacetic ester and improve production capacity, and is easy and convenient to operate, high in safety and low in labor intensity; and the prepared crude acetoacetic ester has high content of target product and hardly contains acetic anhydride impurities which are difficult to remove, and the product quality is ensured.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and mainly relates to a preparation process of acetoacetate. Background technique [0002] Acetoacetate is an important chemical and pharmaceutical intermediate, which can be used in the synthesis of medicines, pesticides, vitamins and chemical raw materials. At present, relevant patents and literature reports on acetoacetate mainly focus on the improvement of catalysts for the synthesis of acetoacetate. For example, Canadian Patent CA 792793 and U.S. Patent US 2351366 have introduced the use of lower amine trimethylamine or triethylamine as catalysts to catalyze the synthesis of acetoacetate; Chinese patent CN 1280122 has reported ethylene amine catalysts, and CN101337890 has reported Composite catalyst of triethylenediamine and concentrated sulfuric acid. [0003] However, there are few related reports on the preparation process of acetoacetate. In the prior art, the preparation of...

Claims

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Application Information

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IPC IPC(8): C07C69/72C07C67/46
Inventor 叶小鹤曾义红王文强陈艳敏蔡兰平石平
Owner SHANGHAI HUAYI GRP CO
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