阅读说明：本技术 一种羟基乙酸正丁酯的合成方法 (Synthesis method of n-butyl glycolate ) 是由 程雪莲 袁志文 李成果 李娟� 任再杰 张健 张伟 于 2020-07-27 设计创作，主要内容包括：本发明涉及化学合成技术领域,具体公开一种羟基乙酸正丁酯的合成方法。所述羟基乙酸正丁酯的合成方法具体是以羟基乙酸甲酯和正丁醇为反应原料,在酸性催化剂的作用下,加热至70-150℃进行反应得到。本发明中羟基乙酸正丁酯可由羟基乙酸甲酯和正丁醇经过一步反应得到,整个反应过程操作简单、反应周期短、反应收率高且催化剂用量少,显著降低了羟基乙酸正丁酯的合成成本,且本发明的羟基乙酸正丁酯的合成方法不会产生尾水或固废,符合绿色环保的生产要求。(The invention relates to the technical field of chemical synthesis, and particularly discloses a method for synthesizing n-butyl glycolate. The synthesis method of n-butyl glycolate specifically comprises the steps of taking methyl glycolate and n-butanol as reaction raw materials, and heating to 70-150 ℃ to react under the action of an acid catalyst to obtain the n-butyl glycolate. The n-butyl glycolate can be obtained by one-step reaction of methyl glycolate and n-butanol, the whole reaction process is simple to operate, the reaction period is short, the reaction yield is high, the catalyst dosage is small, the synthesis cost of the n-butyl glycolate is remarkably reduced, and the synthesis method of the n-butyl glycolate does not generate tail water or solid waste, and meets the production requirement of environmental protection.)

1. A synthetic method of n-butyl glycolate is characterized by comprising the following steps: the preparation method comprises the steps of taking methyl glycolate and n-butanol as reaction raw materials, and reacting at 70-150 ℃ under the action of an acid catalyst to obtain the methyl glycolate.

2. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: the molar ratio of the methyl glycolate to the n-butanol is 1: 1-2.

3. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: the acidic catalyst is at least one of concentrated sulfuric acid, p-toluenesulfonic acid and butyl titanate.

4. The process for the synthesis of n-butyl glycolate according to claim 3, characterized in that: the acidic catalyst is butyl titanate.

5. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: the amount of the acidic catalyst added is 0.1-0.5% by mass of the methyl glycolate.

6. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: the temperature of the reaction is 110-150 ℃.

7. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: methanol produced is withdrawn during the reaction.

8. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: and stopping the reaction process when the mass of the methyl glycolate is less than or equal to 3 percent of the total mass of the reaction system.

9. The process for the synthesis of n-butyl glycolate according to claim 1, characterized in that: after the reaction is completed, the synthesized n-butyl glycolate is refined.

10. The process for the synthesis of n-butyl glycolate according to claim 9, characterized in that: the refining method comprises the following steps: the distillation purification is carried out under vacuum conditions below 600 Pa.

Technical Field

The invention relates to the technical field of chemical synthesis, in particular to a method for synthesizing n-butyl glycolate.

Background

The n-butyl glycolate has functional groups such as alpha-H, hydroxyl, ester group and the like, so that the n-butyl glycolate has chemical properties of alcohol and ester at the same time, and can perform carbonylation reaction, oxidation reaction, hydrolysis reaction, substitution reaction of alpha-H and the like, so that the n-butyl glycolate is not only widely used in various fields such as chemical industry, medicines, feeds, pesticides, dyes, spices and the like, but also widely used as additives of cleaning agents, cosmetics, coatings and the like, and has wide market prospect.

The traditional synthesis method of n-butyl glycolate takes glycolic acid and n-butanol as raw materials and synthesizes the glycolic acid and the n-butanol under the action of an acidic catalyst (a large amount of super acid). Glycolic acid itself has carboxyl and ester groups, so that it can itself be dehydrated and etherified under acidic conditions, and also can itself be subjected to polycondensation, and there are many side reactions, so that the yield and purity of esterification are not high regardless of using concentrated sulfuric acid or other super strong acids as catalysts. In the synthesis process of n-butyl glycolate, the using amount of the super acidic catalyst is larger and reaches about 2.4 of the total amount of glycolic acid and n-butyl alcohol, and the feeding amount of n-butyl alcohol is larger (the feeding amount of n-butyl alcohol is 3-4 times of the mole number of glycolic acid). In the traditional n-butyl glycolate synthesis methods, some of the n-butyl glycolate synthesis methods also gradually reduce the product yield along with the recycling of the ion exchange resin, the discharge of a buffer solution for cleaning and activating the ion exchange resin causes certain pollution to the environment, and the product yield and purity are not obviously improved. Meanwhile, the existing method for synthesizing the glycolic acid adopts hydroxyacetonitrile to sequentially carry out acidolysis and esterification to obtain methyl glycolate, and then the methyl glycolate is hydrolyzed and the methanol is distilled to obtain the glycolic acid.

In conclusion, the existing method for synthesizing n-butyl glycolate has the defects of low synthesis yield, high production cost, complicated operation and inevitable generation of tail water or solid waste in the production process. Because of the increasing environmental protection situation and the increasing market competition, it is important to improve the quality of n-butyl glycolate, reduce the production cost and seek a green and environment-friendly synthesis method for the market.

Disclosure of Invention

Aiming at the problems of low synthesis yield, high production cost, complex operation and generation of a large amount of tail water or solid waste in the existing synthesis method of n-butyl glycolate, the invention provides a synthesis method of n-butyl glycolate.

In order to achieve the purpose of the invention, the embodiment of the invention adopts the following technical scheme:

a synthetic method of n-butyl glycolate specifically uses methyl glycolate and n-butanol as reaction raw materials, and the reaction is carried out by heating to 70-150 ℃ under the action of an acid catalyst.

Compared with the prior art, the synthesis method of n-butyl glycolate provided by the invention is obtained by directly reacting methyl glycolate with n-butanol by heating to 70-150 ℃ under the action of an acid catalyst. Namely, n-butyl glycolate can be obtained by one-step reaction of methyl glycolate and n-butanol, the whole reaction process is simple to operate, the reaction period is short, the selectivity is high, the side reactions are few, the reaction yield is high, the catalyst dosage is small, and the synthesis cost of the n-butyl glycolate is obviously reduced. Meanwhile, the synthetic method of n-butyl glycolate does not generate tail water or solid waste, meets the production requirement of environmental protection, and is suitable for popularization and application.

Preferably, the molar ratio of the methyl glycolate to the n-butanol is 1: 1-2.

Preferably, the acidic catalyst is one of concentrated sulfuric acid, p-toluenesulfonic acid and butyl titanate.

The preferable acidic catalyst can improve the selectivity of the reaction of the methyl glycolate and the n-butanol, ensure the smooth proceeding of the ester exchange reaction, avoid the generation of byproducts and further accelerate the reaction rate of the methyl glycolate and the n-butanol.

Preferably, the acidic catalyst is butyl titanate.

The butyl titanate is used as a catalyst for the reaction of the methyl glycolate and the n-butyl alcohol, so that the reaction period can be obviously shortened, the reaction process is accelerated, and the butyl titanate can ensure that more than 99.9 percent of methyl glycolate reacts to generate n-butyl glycolate under the condition of enough n-butyl alcohol.

Preferably, the amount of the acidic catalyst added is 0.1 to 0.5% by mass based on the mass of the methyl glycolate.

The method selects methyl glycolate and n-butanol as raw materials, and a reaction for synthesizing n-butyl glycolate can be realized by adding a very small amount of catalyst (equivalent to 0.1-0.5% of the mass of the methyl glycolate) at 70-150 ℃.

Preferably, the temperature of the reaction is 110-150 ℃.

The preferable reaction temperature can further shorten the whole reaction period, so that the synthesis process of the n-butyl glycolate is shortened to be within 3-4 h.

Preferably, the methanol produced is withdrawn during the reaction.

The reaction process can be further accelerated by extracting the methanol generated in the reaction process, and the reaction period is shortened.

Preferably, the reaction process is stopped when the mass of the methyl glycolate is less than or equal to 3% of the total mass of the reaction system.

Preferably, after the completion of the reaction, the synthesized n-butyl glycolate is purified.

Preferably, the refining method comprises the following steps: the distillation purification is carried out under vacuum conditions below 600 Pa.

The preferred purification process described above can provide high quality n-butyl glycolate, and the purity of n-butyl glycolate obtained by the purification process can be stabilized to 99.7% or more.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.