阅读说明：本技术 氯甲酸乙酯的制备方法 (Method for preparing ethyl chloroformate ) 是由 耿斌 李国鹏 吴瑞磊 孙新 于 2020-06-24 设计创作，主要内容包括：本发明属于化学合成技术领域,具体涉及一种氯甲酸乙酯的制备方法。本发明提供的氯甲酸乙酯的制备方法,采用乙醇蒸汽代替液态乙醇与光气反应来制备氯甲酸乙酯,反应条件为压力-90kPa～-5kPa、温度为30℃～80℃、摩尔比为1:(1.00～1.05)。反应物以气态形式混合,接触面积增大,使得光气与乙醇在接近理论摩尔比下即可反应完全,在保证产品收率的前提下减少了光气用量,从而减少了副反应发生,提高了产品纯度。(The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of ethyl chloroformate. The preparation method of ethyl chloroformate provided by the invention adopts ethanol steam to replace liquid ethanol to react with phosgene to prepare the ethyl chloroformate, and the reaction conditions are that the pressure is-90 kPa to-5 kPa, the temperature is 30 ℃ to 80 ℃, and the molar ratio is 1 (1.00 to 1.05). The reactants are mixed in a gaseous state, the contact area is increased, so that phosgene and ethanol can completely react under the condition of approaching to the theoretical molar ratio, the phosgene usage is reduced on the premise of ensuring the product yield, the side reaction is reduced, and the product purity is improved.)

1. The preparation method of ethyl chloroformate is characterized by comprising the following steps:

mixing ethanol steam with phosgene, and reacting at the temperature of 30-80 ℃ under negative pressure to obtain ethyl chloroformate;

2. the method according to claim 1, wherein the negative pressure is-90 kPa to-5 kPa.

3. The method for preparing ethyl chloroformate according to claim 1 or 2, wherein the molar ratio of the ethanol vapor to the phosgene is 1: (1.00-1.05).

4. The method for preparing ethyl chloroformate according to claim 3, wherein a tower reactor is used for the reaction, and the temperature difference is controlled to be less than or equal to 5 ℃ during the reaction.

5. The method according to claim 4, wherein the ethyl chloroformate produced in the reaction is condensed to obtain the product.

6. The method according to claim 5, wherein the tail gas generated by the reaction is treated with water and alkali sequentially.

Technical Field

The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of ethyl chloroformate.

Background

The ethyl chloroformate is mainly used as chemical solvent, amino protecting agent and chemical products for producing medicines, herbicides, etc., and has a molecular formula of CN20S0599A₃H₅CN20S0599AlO₂The molecular weight is 108.53, and the liquid is colorless transparent liquid, has pungent odor, and is flammable, toxic, and corrosive.

The industrial synthesis of ethyl chloroformate is carried out by esterification of liquid ethanol and 5-20% excess phosgene, removing impurities, dewatering, fractionating and refining. In order to ensure a higher yield of ethyl chloroformate, the molar ratio of phosgene to liquid ethanol is generally controlled to be higher, for example, 10-15% excess phosgene. However, with the excess of phosgene, side reactions increase in the reaction process, so that the impurities of the ethyl chloroformate product increase, and the performance of the ethyl chloroformate in various chemical applications is seriously influenced; moreover, phosgene is a highly toxic gas, and excessive phosgene has great potential safety hazard in laboratories or industrial production. Therefore, how to reduce the side reactions in the preparation process of ethyl chloroformate and how to reduce the potential safety hazards caused by excessive phosgene are urgent to solve on the premise of ensuring that the yield is not reduced.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defects of increased side reactions and safety caused by excessive phosgene in the existing ethyl chloroformate preparation process, so that the method for preparing ethyl chloroformate is safe and reliable and has high purity and yield.

In order to solve the technical problems, the invention adopts the technical scheme that:

the invention provides a preparation method of ethyl chloroformate, which comprises the following steps:

mixing ethanol steam with phosgene, and reacting at the temperature of 30-80 ℃ under negative pressure to obtain ethyl chloroformate;

preferably, the negative pressure of the preparation method of the ethyl chloroformate is-90 kPa to-5 kPa.

Preferably, in the method for preparing ethyl chloroformate, the molar ratio of the ethanol vapor to the phosgene is 1: (1.00-1.05).

Further preferably, the ethyl chloroformate preparation method adopts a tower reactor in the reaction, and the temperature difference is controlled to be less than or equal to 5 ℃ in the reaction process.

Further preferably, in the method for preparing ethyl chloroformate, the ethyl chloroformate generated in the reaction is condensed to obtain the product.

Further preferably, in the method for preparing ethyl chloroformate, tail gas generated by the reaction is treated by water and alkali sequentially.

The technical scheme of the invention has the following advantages:

1. according to the preparation method of ethyl chloroformate, ethyl chloroformate is prepared by adopting ethanol steam to replace liquid ethanol to react with phosgene, reactants are mixed in a gaseous form, the contact area is increased, phosgene and ethanol can completely react under the condition of approaching to a theoretical molar ratio, and the using amount of phosgene is reduced on the premise of ensuring the product yield, so that the side reaction is reduced, and the product purity is improved.

2. According to the preparation method of ethyl chloroformate, the negative pressure is controlled to be-90 kPa to-5 kPa and the temperature is controlled to be 30 ℃ to 80 ℃ in the reaction process, so that the yield and the purity of ethyl chloroformate are improved.

3. The preparation method of ethyl chloroformate provided by the invention controls the molar ratio of ethanol steam to phosgene to be 1: (1.00-1.05), compared with the prior art, the phosgene ratio is reduced, the side reaction is reduced, the product purity is improved, the potential safety hazard is reduced to the minimum, and the unification of high yield, high purity and high safety is realized.

4. According to the preparation method of ethyl chloroformate, the reaction adopts the tower reactor, so that the continuous operation of ethyl chloroformate preparation is realized, the efficiency is improved, and the preparation method has high implementation value and social and economic benefits; the temperature difference is controlled to be less than or equal to 5 ℃ in the reaction process, so that the reaction is stably carried out, side reactions are few, and the product purity is high.

5. According to the preparation method of ethyl chloroformate provided by the invention, the ethyl chloroformate generated by the reaction is condensed to obtain a product with high purity, and refining processes such as impurity removal, dehydration, fractionation and the like are not required, so that the process is simplified.

6. According to the preparation method of ethyl chloroformate provided by the invention, tail gas generated by reaction is treated by water and alkali in sequence, hydrochloric acid and the like can be recovered, and three wastes are not generated.

Detailed Description

In order to facilitate understanding of the objects, technical solutions and gist of the present invention, embodiments of the present invention will be described in further detail below. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, this embodiment is provided so that this disclosure will be thorough and complete and will fully convey the concept of the invention to those skilled in the art, and the present invention will only be defined by the appended claims.

The raw materials used in the examples of the present invention are all commercially available unless otherwise specified.