Continuous synthesis method of dimethyl acetylsuccinate

Abstract

The invention discloses a continuous synthesis method of dimethyl acetylsuccinate, which comprises the following steps of: continuously pouring dimethyl maleate and acetaldehyde as raw materials into a high-pressure reactor for reaction in the presence of a radical initiator by using a high-pressure pump, continuously blanking reaction liquid, and finally obtaining the dimethyl acetylsuccinate. The method has the advantages of short reaction period, 95% or higher of conversion rate and 99% or higher of product purity. The dimethyl acetylsuccinate is the key intermediate for preparing novel environment-friendly food colors, such as dimethyl acetylsuccinate ketone carboxylate, namely lemon yellow, and the like.

Description

technical field

[0001] The invention belongs to chemical industry synthesis technology, in particular to a synthesis method of dimethyl acetylsuccinate. Background technique

[0002] The structural formula of dimethyl acetylsuccinate is as follows:

[0003]

[0004] Dimethyl acetylsuccinate is a key intermediate in the production of a new type of environmentally friendly dimethyl acetylsuccinate carboxylate ketone food additive -- tartrazine, which is widely used in various foods in Europe and America. Lemon yellow is one of the 6 kinds of food coloring approved by our country. It is stipulated in my country's "Hygienic Standards for the Use of Food Additives" (GB2760-1996) that lemon yellow can be used in fruit juice drinks, prepared wine, candy, cakes, canned food, pickled products, plants, etc. Protein drinks and lactic acid bacteria drinks.

[0005] The synthetic method of dimethyl acetylsuccinate reported both at home and abroad is that dimethyl maleate and acetalde...

Examples

Embodiment 1

[0017] This reaction is carried out in a stainless steel high-pressure reactor, which is equipped with a temperature control device and a temperature measuring device for heating and cooling devices, an electromagnetic stirring device, a pressure measuring device, a high-pressure continuous discharge device, and a liquid in and out valves, and a high-pressure syringe pump.

[0018] The batching container is placed under an ice-water bath, sequentially add 1000 g of dimethyl maleate, 1220 g of acetaldehyde, and 22 g of benzoyl peroxide, stir to dissolve, and set aside. Add 300ml of the prepared solution into a 500ml stainless steel high-pressure reactor, and close the reactor; stir and heat up, and react at 125°C for 120 minutes, then use a high-pressure syringe pump to continuously feed materials into the reactor at a speed of 12.5ml / min, and open the outlet at the same time. The material is discharged at the same speed. During the reaction, the reaction temperature is control...

Embodiment 2

[0021] Azobisisobutyronitrile was used instead of benzoyl peroxide, and other conditions were the same as in Example 1. The reaction liquid gas chromatography analysis conversion rate was 95.1%, and the gas chromatography analysis content of the crystalline product was 99.17%.

Embodiment 3

[0023] A high-pressure syringe pump feeds into the reactor at a speed of 15 ml / min. Other conditions are the same as in Example 1. The reaction liquid gas chromatography analysis conversion rate is 93.64%, and the crystallization product gas chromatography analysis content is 98.88%.

technical field

[0001] The invention belongs to chemical industry synthesis technology, in particular to a synthesis method of dimethyl acetylsuccinate. Background technique

[0002] The structural formula of dimethyl acetylsuccinate is as follows:

[0003]

[0004] Dimethyl acetylsuccinate is a key intermediate in the production of a new type of environmentally friendly dimethyl acetylsuccinate carboxylate ketone food additive -- tartrazine, which is widely used in various foods in Europe and America. Lemon yellow is one of the 6 kinds of food coloring approved by our country. It is stipulated in my country's "Hygienic Standards for the Use of Food Additives" (GB2760-1996) that lemon yellow can be used in fruit juice drinks, prepared wine, candy, cakes, canned food, pickled products, plants, etc. Protein drinks and lactic acid bacteria drinks.

[0005] The synthetic method of dimethyl acetylsuccinate reported both at home and abroad is that dimethyl maleate and acetalde...

Examples

Embodiment 1

[0017] This reaction is carried out in a stainless steel high-pressure reactor, which is equipped with a temperature control device and a temperature measuring device for heating and cooling devices, an electromagnetic stirring device, a pressure measuring device, a high-pressure continuous discharge device, and a liquid in and out valves, and a high-pressure syringe pump.

[0018] The batching container is placed under an ice-water bath, sequentially add 1000 g of dimethyl maleate, 1220 g of acetaldehyde, and 22 g of benzoyl peroxide, stir to dissolve, and set aside. Add 300ml of the prepared solution into a 500ml stainless steel high-pressure reactor, and close the reactor; stir and heat up, and react at 125°C for 120 minutes, then use a high-pressure syringe pump to continuously feed materials into the reactor at a speed of 12.5ml / min, and open the outlet at the same time. The material is discharged at the same speed. During the reaction, the reaction temperature is control...

Embodiment 2

[0021] Azobisisobutyronitrile was used instead of benzoyl peroxide, and other conditions were the same as in Example 1. The reaction liquid gas chromatography analysis conversion rate was 95.1%, and the gas chromatography analysis content of the crystalline product was 99.17%.

Embodiment 3

[0023] A high-pressure syringe pump feeds into the reactor at a speed of 15 ml / min. Other conditions are the same as in Example 1. The reaction liquid gas chromatography analysis conversion rate is 93.64%, and the crystallization product gas chromatography analysis content is 98.88%.

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