阅读说明：本技术 一种光气法合成氯甲酸正己酯的方法 (Method for synthesizing n-hexyl chloroformate by phosgene method ) 是由 李契 张敦河 李国栋 刘亚龙 于 2020-06-10 设计创作，主要内容包括：本发明公开了一种光气法合成氯甲酸正己酯的方法,包括如下步骤：步骤一、底投Ag正己酯于反应装置中；步骤二、反应装置中的物料温度降至设定温度后通过流量计通入光气；光气的累计通入量为Bg；控；步骤三、当光气流量累计至Bg时,停止通光,将反应装置中的物料升温至28±2℃,并保温2小时；步骤四、保温完毕,控制温度15℃±2℃通氮气除去过量的光气与氯化氢,得到氯甲酸正己酯产品。本发明通前期降温抑制副反应生成,当正己醇被逐渐消耗浓度降低后再升温的方法,有效的抑制的副反应的生成,且通过后期升温的方式使得正己醇反应的更加完全,大大降低了后期储存过程中发生副反应导致的涨桶现象制备得到的氯甲酸正己酯收率达到了97％以上。(The invention discloses a method for synthesizing n-hexyl chloroformate by a phosgene method, which comprises the following steps: firstly, adding Ag n-hexyl ester into a reaction device at the bottom; secondly, introducing phosgene through a flowmeter after the temperature of the materials in the reaction device is reduced to a set temperature; the cumulative introduction amount of phosgene is Bg; controlling; step three, stopping light introduction when the phosgene flow is accumulated to Bg, heating the materials in the reaction device to 28 +/-2 ℃, and preserving the heat for 2 hours; and step four, after the heat preservation is finished, controlling the temperature to be 15 +/-2 ℃, and introducing nitrogen to remove excessive phosgene and hydrogen chloride to obtain a chloroformic acid n-hexyl ester product. According to the method, the generation of the side reaction is inhibited through early-stage temperature reduction, and the temperature is raised again after the n-hexanol is gradually consumed and the concentration is reduced, so that the generation of the side reaction is effectively inhibited, the n-hexanol is reacted more completely through a later-stage temperature raising mode, and the yield of the prepared n-hexyl chloroformate is over 97 percent due to the barrel expansion phenomenon caused by the side reaction in the later-stage storage process.)

1. A method for synthesizing n-hexyl chloroformate by a phosgene method is characterized by comprising the following steps:

firstly, adding Ag n-hexyl ester into a reaction device at the bottom, and reducing the temperature of materials in the reaction device to a set temperature, wherein the set temperature is-10 ℃ to-20 ℃;

secondly, introducing phosgene through a flowmeter after the temperature of the materials in the reaction device is reduced to a set temperature; the cumulative introduction amount of phosgene is Bg;

wherein, when the cumulative phosgene feeding amount is less than or equal to ag, the material temperature in the reaction device is controlled to be less than or equal to-10 ℃; when the cumulative introduction amount of the phosgene is less than or equal to ag and less than or equal to bg, controlling the material temperature in the reaction device to be less than or equal to-5 ℃; when the cumulative introduction amount of the phosgene is less than or equal to Bg, controlling the material temperature in the reaction device to be less than or equal to 2 ℃; according to the mass ratio, A: 300:495, a: b: b: 310:410: 495;

step three, stopping light introduction when the phosgene flow is accumulated to B g, heating the materials in the reaction device to 28 +/-2 ℃, and preserving heat for 2 hours;

and step four, after the heat preservation is finished, controlling the temperature to be 15 +/-2 ℃, and introducing nitrogen to remove excessive phosgene and hydrogen chloride to obtain a chloroformic acid n-hexyl ester product.

2. The method for synthesizing n-hexyl chloroformate according to claim 1, further comprising a fifth step of introducing nitrogen to remove excess phosgene and hydrogen chloride to form a reaction tail gas, wherein the reaction tail gas is absorbed by 10% liquid caustic soda.

3. The method for synthesizing n-hexyl chloroformate according to claim 1, wherein in step two, the phosgene is introduced at a rate of less than 40g/h when the temperature of the materials in the reaction apparatus is less than or equal to-10 ℃; when the temperature of the materials in the reaction device is less than or equal to-10 ℃ and less than or equal to-5 ℃, the introducing speed of phosgene is 60 g/h; when the temperature of the materials in the reaction device is more than or equal to-5 ℃ and less than or equal to 2 ℃, the introducing speed of the phosgene is gradually increased from 40g/h to 60g/h along with the temperature increase.

Technical Field

The invention belongs to the field of chemistry, and particularly relates to a method for synthesizing n-hexyl chloroformate by a phosgene method.

Background

The n-hexyl chloroformate is a chemical product with the molecular formula of C₇H₁₃ClO₂Is mainly used as an organic synthesis reagent and is a raw material of various medicines. At present, no preparation method of the chloroformic acid n-hexyl ester exists in China, and the import is completely relied on. When the product is produced by a phosgene method abroad, the whole reaction temperature is usually kept constant, but the impurity content of the prepared product is high, and the product yield is low. Since n-hexanol will undergo a side reaction with the product n-hexyl chloroformate to form di-n-hexyl carbonate:

side reactions

CH₃(CH₂)₅OH+CH₃(CH₂)₅OCOCL→

CH₃(CH₂)5 OCOO(CH₂)₅CH₃Di-n-hexyl (carbonate) + HCL.

Disclosure of Invention

The invention discloses a method for synthesizing n-hexyl chloroformate by a phosgene method, which aims at the problems, reduces the temperature at the early stage to inhibit the generation of side reaction, reduces the consumption concentration of n-hexanol gradually and then raises the temperature, effectively inhibits the generation of side reaction, ensures that the n-hexanol reacts more completely by a later-stage heating mode, and greatly reduces the barrel expansion phenomenon caused by the side reaction in the later-stage storage process, so that the yield of the n-hexyl chloroformate prepared by the method reaches more than 97 percent.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for synthesizing n-hexyl chloroformate by a phosgene method comprises the following steps:

firstly, adding Ag n-hexyl ester into a reaction device at the bottom, and reducing the temperature of materials in the reaction device to a set temperature, wherein the set temperature is-10 ℃ to-20 ℃;

secondly, introducing phosgene through a flowmeter after the temperature of the materials in the reaction device is reduced to a set temperature; the cumulative introduction amount of phosgene is Bg;

wherein, when the cumulative phosgene feeding amount is less than or equal to ag, the material temperature in the reaction device is controlled to be less than or equal to-10 ℃; when the cumulative introduction amount of the phosgene is less than or equal to ag and less than or equal to bg, controlling the material temperature in the reaction device to be less than or equal to-5 ℃; when the cumulative introduction amount of the phosgene is less than or equal to Bg, controlling the material temperature in the reaction device to be less than or equal to 2 ℃; according to the mass ratio, A: 300:495, a: b: b: 310:410: 495;

step three, stopping light introduction when the phosgene flow is accumulated to B g, heating the materials in the reaction device to 28 +/-2 ℃, and preserving heat for 2 hours;

and step four, after the heat preservation is finished, controlling the temperature to be 15 +/-2 ℃, and introducing nitrogen to remove excessive phosgene and hydrogen chloride to obtain a chloroformic acid n-hexyl ester product.

The further improvement comprises a fifth step of introducing nitrogen to remove excessive phosgene and hydrogen chloride to form reaction tail gas, and the reaction tail gas is absorbed by 10 percent liquid caustic soda.

In the second step, when the temperature of the materials in the reaction device is less than or equal to-10 ℃, the introducing speed of phosgene is less than 40 g/h; when the temperature of the materials in the reaction device is less than or equal to-10 ℃ and less than or equal to-5 ℃, the introducing speed of phosgene is 60 g/h; when the temperature of the materials in the reaction device is more than or equal to-5 ℃ and less than or equal to 2 ℃, the introducing speed of the phosgene is gradually increased from 40g/h to 60g/h along with the temperature increase.

Detailed Description

The technical solution is further explained below.