阅读说明：本技术 一种光气法合成氯甲酸正戊酯的方法 (Method for synthesizing n-amyl 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戊酯的方法,包括如下步骤：步骤一、底投Ag正戊酯于反应装置中,将反应装置中的物料温度降至设定温度,设定温度为-10℃到-20℃；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；控制质量比：正戊酯与光气比为1︰1.7；步骤三、当光气流量累计至B g时,停止通光,将反应装置中的物料升温至20℃～25℃,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,得到氯甲酸正戊酯产品。本发明通过特殊的工艺流程,制备得到了氯甲酸正戊酯,且收率达到了97％以上。(The invention discloses a method for synthesizing n-amyl chloroformate by a phosgene method, which comprises the following steps: firstly, feeding Ag-n-amyl 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; controlling the mass ratio: the ratio of n-amyl ester to phosgene is 1: 1.7; step three, stopping light introduction when the phosgene flow is accumulated to B g, heating the materials in the reaction device to 20-25 ℃, 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 the n-amyl chloroformate product. The invention prepares the n-amyl chloroformate through a special process flow, and the yield reaches more than 97 percent.)

1. A method for synthesizing chloroformic acid n-amyl ester by a phosgene method is characterized by comprising the following steps:

firstly, feeding Ag-n-amyl 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: b250: 480, a: b: b is 300:400: 480;

step three, stopping light introduction when the phosgene flow is accumulated to B g, heating the materials in the reaction device to 20-25 ℃, 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 the n-amyl chloroformate product.

2. The method for synthesizing n-pentyl chloroformate according to claim 1, wherein a reaction tail gas is generated by introducing nitrogen to remove excess phosgene and hydrogen chloride, and the reaction tail gas is absorbed by 10% liquid alkali.

3. The method for synthesizing n-pentyl chloroformate according to claim 1, wherein in the second step, the phosgene is introduced at a rate of less than 40g/h when the temperature of the material 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-amyl chloroformate by a phosgene method.

Background

Pentyl chloroformate, also known as n-pentyl chloroformate, of the formula: c₆H₁₁ClO₂Colorless liquid, insoluble in water, soluble in ether. Is an important raw material for organic synthesis. At present, no preparation method of the chloroformic acid n-amyl ester exists in China, and the import is completely relied on. WhileForeign processes usually maintain the reaction temperature constant. However, the company found that in the early stage of the reaction, due to the excessively high concentration of n-pentanol, n-pentanol can undergo a side reaction with the product n-pentyl chloroformate to form di-n-pentyl carbonate, and the reaction formula of the side reaction is as follows:

CH3(CH2)4OH+CH3(CH2)4OCOCL→

CH3(CH2)4OCOO (CH2)4CH3 (di-n-pentyl carbonate) + HCL. Thereby causing more impurity content in the product, low product purity and influencing yield.

Disclosure of Invention

Aiming at the problems, the invention discloses a method for synthesizing chloroformic acid n-amyl ester by a phosgene method, which reduces the reaction temperature in the early stage to inhibit side reactions, and ensures the complete reaction of n-amyl alcohol by heating after the concentration of the n-amyl alcohol is reduced in the later stage to prevent the side reactions from occurring again in the storage process, thereby reducing the impurities in the product, improving the concentration of the reaction product and ensuring the yield to be more than 97 percent.

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

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

firstly, feeding Ag-n-amyl 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: b250: 480, a: b: b is 300:400: 480;

step three, stopping light introduction when the phosgene flow is accumulated to B g, heating the materials in the reaction device to 20-25 ℃, 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 the n-amyl chloroformate product.

The further improvement comprises a fifth step of introducing nitrogen to remove reaction tail gas formed by excessive phosgene and hydrogen chloride, 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.