Preparation method of methyl 3-methoxypropionate

Abstract

The invention discloses a preparation method of methyl 3-methoxypropionate, which comprises the following steps: (1) mixing absolute methanol and methyl acrylate in a molar ratio of 3:1-100: 1; (2) putting absolute methanol and methyl acrylate into a first fixed bed reactor, and controlling the acidity to be within 10ppm by using deacidified resin; (3) fixing the composite catalyst in a second fixed bed reactor; then adding the absolute methanol and methyl acrylate obtained in the step (2) into a second fixed bed reactor, and carrying out an addition reaction under the action of a composite catalyst; and (4) rectifying to obtain the methyl 3-methoxypropionate. The combination of the deacidified resin and the composite catalyst can last for more than 6 months, the service life of the catalyst is long, the catalyst can be used for 1-2 years, and frequent regeneration is not needed. The single-pass conversion rate is high and is 98% or above, the product separation is simple, the catalystdoes not need to be damaged and then separated, the quality is good, and the purity is 99.8% or above; three wastes are basically not generated and the environment-friendly requirement is met.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a preparation technology of methyl 3-methoxypropionate. Background technique [0002] Methyl 3-methoxypropionate is an important organic solvent and organic synthesis intermediate, widely used in the coating industry, electronics industry and the synthesis of pharmaceutical intermediates. [0003] The U.S. patent uses methanol and methyl acrylate to obtain methyl 3-methoxypropionate under the catalysis of methanesulfonic acid, the reaction temperature is 120-130 degrees, and the yield is 41%. This scheme needs to be reacted under pressure, which is not convenient for production, and The reaction temperature is high, the side reactions are many, and the cost is too high. [0004] The general literature adopts the potassium fluoride supported by aluminum oxide as a catalyst to synthesize methyl 3-methoxypropionate with methanol and methyl acrylate. The process uses ac...

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Problems solved by technology

[0003] The U.S. patent uses methanol and methyl acrylate to obtain methyl 3-methoxypropionate under the catalysis of methanesulfonic acid, the reaction temperature is 120-130 degrees, and the yield is 41%. This scheme needs to be reacted under pressure, which is not convenient for production, and High reaction temperature, many side reactions, high cost

[0004] The general literature adopts the potassium fluoride supported by aluminum oxide as a catalyst to synthesize methyl 3-methoxypropionate with methanol and methyl acrylate. The process uses acetonitrile as a solvent with a yield of 90%, but a large amount of solvent needs to be reclaimed, and The reaction time is 20 hours, which is too long and affects production efficiency

[0005] Most patents use alkali metals such as sodium metal or alkali metal alkoxides as catalysts to synthesize methyl 3-methoxypropionate with anhydrous methanol and methyl acrylate. The reaction time is shortened to less than 3 hours, and the yield can reach up to 96%. , but there are also catalysts that are extremely sensitive to acid and water. Once they encounter water or acid, they will be destroyed and cannot be regenerated. After the reaction, it is necessary to use acid to destroy the catalyst to make the system neutral or even acidic. This increases the separation steps and produces certain Salt-containing wastewater, and the reaction generates organic salts, which increases the difficulty of product purification, and the high degree of heat release during the neutralization process increases side reactions. The purity of the product is less than 99.8%, which cannot be further processed into electronic grade products for the optoelectronic industry.

[0006] In addition, it has also been reported that anhydrous methanol and methyl acrylate are used to catalyze anhydrous methanol and methyl acrylate to obtain methyl 3-methoxy propionate with strong basic ion exchange resin, but due to the trace acid content in anhydrous methanol and methyl acrylate is generally at 200-500ppm, It will neutralize the strong basic ion exchange resin and lose its catalytic effect, resulting in a large amount of strong basic ion exchange resin (generally about 20% of the mass of methyl acrylate). The service life is short, generally it takes 6-8 hours to lose the catalytic effect, it needs to be regenerated, and it can only be regenerated 7 times at most, and the strong basic ion exchange resin is easy to break and lose its use, the conversion rate is not high, generally between 70-90%, regeneration Strong basic ion exchange resin produces a large amount of waste water, which greatly increases the cost of production and cannot be produced continuously on a large scale