Preparation method of diethoxymethane

Abstract

The invention relates to the field of preparation of chemical raw materials, and in particular relates to a preparation method of diethoxymethane. The preparation method comprises the steps of raw material preparation, dissolution, reaction and distillation, wherein a combinatorial catalyst of ethylenediamine tetraacetic acid and malic acid is used as an organic combinatorial catalyst, the characteristics of insolubility of ethylenediamine tetraacetic acid and solubility of malic acid in ethyl alcohol are utilized to ensure that an ethanol / formaldehyde solution reactant forms a heterogeneous and homogeneous phase reaction; meanwhile, in order to prevent residual formaldehyde in a product and resulted raw material wastes, the weight ratio of ethanol to formaldehyde is selected to ensure that the formaldehyde can not be remained in the product; moreover, through the recycling of water vapor during distillation, the energy consumption during production is reduced; meanwhile, the catalyst is recycled, so that the production cost is reduced, and the economical benefit is improved.

Description

technical field [0001] The invention relates to the field of preparation of chemical raw materials, in particular to a method for preparing diethoxymethane. Background technique [0002] Diethoxymethane, also known as formaldehyde diethyl acetal, abbreviated as DEM, has a boiling point of 88°C, a flash point of -5°C, a specific gravity (20°C) of 0.8305, and a solubility in water of 20°C of 4.4%. It has good stability under strong alkali and weak acid conditions such as sodium hydride and Grignard reagent, and it is not easy to form peroxide. Not only can it be used as a solvent in organic synthesis, a solvent in batteries, fuel additives, etc., it can also be used as a reagent for organic reactions; it can synthesize many chemical substances and be used as a diesel additive to achieve the purpose of eliminating smoke. [0003] When used as a solvent, it can be used as a solvent in organometallic reactions, such as alkylation, acylation, organolithium reaction, Grignard reac...

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Problems solved by technology

[0006] Therefore, it is of profound significance for the development and application of DEM. Therefore, some researchers have started the research on the production method of DEM. For example, the technology of patent No. CN1272298C uses liquid formaldehyde with a content of 37% and hydrochloric acid with a concentration of 36-38%. Mixing and continuously adding to the reactor, ethanol is added from the rectifying column on the top of the tank to react to obtain a mixture with a DEM content of 68%, and then a high-purity product obtained through liquid-liquid extraction; another example is the technology of patent No. 201210515446.9 using sulfuric acid as The catalyst catalyzes the reaction of ethanol and paraformaldehyde. After the gaseous reaction product passes through the rectification layer of liquid paraffin and condenses, the primary yield reaches 80%. They all use inorganic acids as catalysts to catalyze the reaction to prepare DEM products. ; but often chemical equipment is some metal equipment, which makes the addition of inorganic acid, resulting in corrosion of equipment, resulting in reduced service life of equipment, and the production cost of DEM is too high

[0007] At the same time, using dilute formaldehyde solution as raw material causes the total volume of reaction materials to increase, the amount of waste water to increase, and the use of high-molecular-weight paraformaldehyde and ethanol for longer dissolution times, longer reaction times, and more residual formaldehyde in the kettle, which leads to The cost of DEM production and preparation is high and the yield is poor

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