Method for synthesizing high-purity butyl lactate

Abstract

Provided is a method for synthesizing high-purity butyl lactate, and relates to the technical field of organic chemical synthesis. The method comprises the steps of: adopting lactic acid as a raw material, performing a reaction between the lactic acid and alkaline inorganic matter at a ratio in water to obtain lactate, performing distillation to remove water, performing a reaction between the lactate and n-butyl halide, and performing washing and rectification to obtain the high-purity butyl lactate, wherein the molar ratio of the lactic acid, alkaline inorganic matter and n-butyl halide is (1:0.5:1)-(1:1.1:1.5), the alkaline inorganic matter which is used for preparing the lactate includes one or a combination of more selected from sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide and potassium hydroxide, and the n-butyl halide is one or a combination of more selected from n-butyl chloride and n-butyl bromide. The method has the advantages of low-cost raw materials, less equipment investment, mild reaction conditions and simple operation, and since water is adopted as a reaction solvent, the method is environmentally friendly and has low cost; the product can be purified easily, the purity can reach 99% or above, the yield can reach 95% or above, and therefore the method has a high economic value.

Description

technical field [0001] The invention relates to the technical field of organic chemical synthesis, in particular to a method for synthesizing high-purity butyl lactate. Background technique [0002] Butyl lactate is used as a solvent for the production of amine-based and nitro-based paints, as well as spices, synthetic resins, adhesives, etc. It is a relatively valuable intermediate for medicine and pesticides. The molecular structure is as follows: [0003] [0004] With the increasing demand for butyl lactate in food flavors and the increasing demand for high-purity lactic acid in synthetic medicine and pesticides, the market size of high-purity butyl lactate is expanding rapidly. [0005] At present, most of the domestic mainstream butyl lactate production methods use lactic acid and n-butanol to undergo esterification, and the products produced are all low-content products. [0006] The process of preparing high-purity butyl lactate reported in the literature needs t...

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Problems solved by technology

[0006] The process of preparing high-purity butyl lactate reported in the literature needs to catalyze polycondensation of lactic acid into oligomers, and then depolymerize to obtain crude lactide, which is refined, and then refluxed with refined lactide and anhydrous n-butanol for a long time The crude product is obtained by reaction, and then refined to obtain the product. The preparation process is relatively complicated and is not suitable for large-scale production.

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