CN111689858A - Method for preparing ethyl chloroformate - Google Patents
Method for preparing ethyl chloroformate Download PDFInfo
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- CN111689858A CN111689858A CN202010589626.6A CN202010589626A CN111689858A CN 111689858 A CN111689858 A CN 111689858A CN 202010589626 A CN202010589626 A CN 202010589626A CN 111689858 A CN111689858 A CN 111689858A
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- ethyl chloroformate
- phosgene
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C68/00—Preparation of esters of carbonic or haloformic acids
- C07C68/02—Preparation of esters of carbonic or haloformic acids from phosgene or haloformates
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C68/00—Preparation of esters of carbonic or haloformic acids
- C07C68/08—Purification; Separation; Stabilisation
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Abstract
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.
Description
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.
Example 1
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-80 kPa and the temperature to be 30-35 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 2
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-60 kPa and the temperature to be 40-45 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 3
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-40 kPa and the temperature to be 50-55 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 4
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-20 kPa and the temperature to be 60-65 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 5
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure of-5 kPa and the temperature of 78-80 ℃ in the tower reactor, liquefying the generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing the tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 6
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-90 kPa and the temperature to be 30-32 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 7
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.03 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-80 kPa and the temperature to be 30-35 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Example 8
This embodiment provides a method for preparing ethyl chloroformate, including the following steps:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.00 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-80 kPa and the temperature to be 30-35 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid (the concentration is about 30 percent), and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Comparative example 1
The comparative example provides a method of preparing ethyl chloroformate, comprising the steps of:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.10 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-80 kPa and the temperature to be 30-35 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid, and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Comparative example 2
The comparative example provides a method of preparing ethyl chloroformate, comprising the steps of:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure of 15kPa and the temperature of 85-90 ℃ in the tower reactor, liquefying the generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid, and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Comparative example 3
The comparative example provides a method of preparing ethyl chloroformate, comprising the steps of:
continuously introducing ethanol steam and phosgene with the molar ratio of 1:1.05 into a tower reactor internally provided with a heat exchange device, a temperature measuring device, a vacuumizing device at the bottom and a condensing device at the top, controlling the pressure in the tower reactor to be-100 kPa and the temperature to be 30-35 ℃, liquefying generated gaseous ethyl chloroformate by the condensing device and entering a receiving tank, absorbing tail gas by deionized water to prepare hydrochloric acid, and absorbing the rest phosgene by dilute alkali liquor. After the reaction is finished, weighing the product in the receiving tank.
Comparative example 4
The comparative example provides a method of preparing ethyl chloroformate, comprising the steps of:
liquid ethanol and phosgene with the molar ratio of 1:1.15 are continuously introduced into a reactor with heat exchange and temperature measurement arranged inside, the temperature is 30-35 ℃, the generated gaseous ethyl chloroformate is liquefied by a condensing device and enters a receiving tank, the tail gas is absorbed by deionized water to prepare hydrochloric acid, and the rest phosgene is absorbed by dilute alkali solution. After the reaction is finished, weighing the product in the receiving tank.
Table 1 ethyl chloroformate yields and purities for different embodiments
As can be seen from Table 1, the yield and purity of ethyl chloroformate prepared in examples 1 to 8 by reacting ethanol vapor with phosgene were greatly improved as compared with those of comparative example 4; compared with the comparative examples 1-3, the ethanol vapor and the phosgene in the examples 1-8 are mixed at the pressure of-90 kPa to-5 kPa, the temperature of 30 to 80 ℃ and the molar ratio of 1: (1.00-1.05) the ethyl chloroformate prepared under the condition has better yield and purity; preferably, the embodiment 7 has the highest yield and purity under the conditions of pressure of-80 kPa, temperature of 30-35 ℃ and molar ratio of 1: 1.03. With a constant reactant ratio, the higher the negative pressure (as in example 6 for example 1), the better the yield and purity, but too high a negative pressure will lead to increased costs and does not suggest an optimal choice in the actual preparation.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (6)
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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010589626.6A CN111689858B (en) | 2020-06-24 | 2020-06-24 | Method for preparing ethyl chloroformate |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010589626.6A CN111689858B (en) | 2020-06-24 | 2020-06-24 | Method for preparing ethyl chloroformate |
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| CN111689858A true CN111689858A (en) | 2020-09-22 |
| CN111689858B CN111689858B (en) | 2022-09-09 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112300001A (en) * | 2020-11-10 | 2021-02-02 | 宁夏瑞泰科技股份有限公司 | Production method for co-production of ethyl chloroformate and ethyl chloride |
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| CN107459458A (en) * | 2017-08-01 | 2017-12-12 | 安徽东至广信农化有限公司 | A kind of process for purification of methylchloroformate |
| CN109574848A (en) * | 2018-12-29 | 2019-04-05 | 安徽广信农化股份有限公司 | A kind of preparation method of ethyl chloroformate |
| CN109593038A (en) * | 2018-12-29 | 2019-04-09 | 安徽广信农化股份有限公司 | A kind of exhaust gas treating method preparing ethyl chloroformate |
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2020
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102167681A (en) * | 2010-12-30 | 2011-08-31 | 常州药物研究所 | Method for preparing insect repellant icaridin |
| CN107459458A (en) * | 2017-08-01 | 2017-12-12 | 安徽东至广信农化有限公司 | A kind of process for purification of methylchloroformate |
| CN109574848A (en) * | 2018-12-29 | 2019-04-05 | 安徽广信农化股份有限公司 | A kind of preparation method of ethyl chloroformate |
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Cited By (1)
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| CN112300001A (en) * | 2020-11-10 | 2021-02-02 | 宁夏瑞泰科技股份有限公司 | Production method for co-production of ethyl chloroformate and ethyl chloride |
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