阅读说明：本技术 一种光气法合成氯甲酸烯丙酯的方法 (Method for synthesizing allyl 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烯丙酯的方法,包括如下步骤：步骤一、底投Ag氯甲酸烯丙酯于反应容器中,并控制反应容器中的物料温度在-2℃～2℃之间；步骤二、通过流量计向反应容器预先通入Bg光气；步骤三、用恒压滴液漏斗滴加烯丙醇至反应容器,控制反应在-2℃～2℃；同时通入光气并且调节单位时间内；步骤四、烯丙醇滴加完毕,停止通光,得到合格的氯甲酸烯丙酯产品。本发明有效防止了副反应的生成,并且在最后升温到15-20℃保温,使得烯丙醇反应更加完全,从而有效降低了产物中烯丙醇的含量,大大提高了产品的纯度,降低了储存时出现涨桶和产品浓度下降的可能性。(The invention discloses a method for synthesizing allyl chloroformate by a phosgene method, which comprises the following steps: firstly, adding Ag allyl chloroformate into a reaction container at the bottom, and controlling the temperature of materials in the reaction container between-2 ℃ and 2 ℃; introducing Bg phosgene into a reaction container in advance through a flowmeter; thirdly, dripping allyl alcohol into a reaction container by using a constant-pressure dropping funnel, and controlling the reaction at-2 ℃; phosgene is simultaneously introduced and the unit time is adjusted; and step four, stopping light transmission after the allyl alcohol is dripped, and obtaining a qualified allyl chloroformate product. The invention effectively prevents the generation of side reaction, and the allyl alcohol is reacted more completely by heating to 15-20 ℃ and preserving heat at last, thereby effectively reducing the content of the allyl alcohol in the product, greatly improving the purity of the product, and reducing the possibility of barrel expansion and product concentration reduction during storage.)

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

firstly, adding Ag allyl chloroformate into a reaction container at the bottom, and controlling the temperature of materials in the reaction container between-2 ℃ and 2 ℃;

introducing Bg phosgene into a reaction container in advance through a flowmeter;

thirdly, dripping allyl alcohol into a reaction container by using a constant-pressure dropping funnel, and controlling the reaction at-2 ℃; introducing phosgene and regulating the mass ratio of the light flow to the dropping flow of the allyl alcohol to be 1: 2.2 in unit time; the total dropping amount of the allyl alcohol is Cg; a: b: c-300: 10-12: 300, respectively;

step four, stopping the light transmission after the allyl alcohol is dripped;

step five, preserving the heat for 1 to 2 hours, and then heating to 15 to 20 ℃;

and sixthly, after the temperature is raised to 15-20 ℃, preserving the heat for 0.5-2 hours, controlling the temperature to be 10-15 ℃, introducing nitrogen to remove excess phosgene and hydrogen chloride, and obtaining the qualified allyl chloroformate product.

2. The method for synthesizing allyl chloroformate according to claim 1, wherein the temperature in each of step five and step six is maintained for 1 hour.

3. The method for synthesizing allyl chloroformate according to claim 1, wherein in step five, the temperature is raised to 15 ℃ to 20 ℃ at a temperature raising rate of 5 ℃/hr.

4. The method for synthesizing allyl chloroformate according to claim 1, further comprising a seventh step of introducing nitrogen to remove excess phosgene and hydrogen chloride to form reaction off-gas, and absorbing the reaction off-gas with 10% liquid caustic soda.

5. The method for synthesizing allyl chloroformate according to claim 1, wherein in step two, allyl alcohol is added dropwise to a reaction vessel using a constant pressure dropping funnel; the flowmeter is an LZB glass rotameter.

Technical Field

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

Background

Allyl chloroformate is a chemical substance with molecular formula of C₄H₅ClO₂Molecular weight of 120.53, is mainly used as organic synthesis reagent and is a raw material of various medicines. The existing allyl chloroformate synthesis method generally comprises the steps of firstly synthesizing allyl chloroformateAdding allyl alcohol, and introducing phosgene to react to generate allyl chloroformate. However, no matter how the reaction conditions are adjusted, the content of the product before rectification is only about 94 percent, and the content of impurities is higher. The research personnel of the company find that the allyl chloroformate is generated due to the overhigh concentration of the allyl alcohol in the initial reaction, and the allyl chloroformate can continue to react with the allyl alcohol to generate the diester carbonate. The method comprises the following specific steps:

side reaction CH2 ═ CHCH2OH + CH2 ═ CHCH2 OCOCOCL →

CH2 ═ CHCH2OCOOCH2CH ═ CH2 (carbonic acid diester) + HCL

In addition, the production temperature of the existing phosgene method is limited to be 0-2 ℃ and is not more than 8 ℃ at most, so that the allyl alcohol in the product is not completely reacted, usually 0.7-0.9%, and during production and storage of the product, the allyl alcohol can continue to react with allyl chloroformate to generate side reaction, so that the phenomena of barrel expansion and product concentration reduction are easy to occur during storage.

Disclosure of Invention

The invention discloses a method for synthesizing allyl chloroformate by a phosgene method, which comprises the steps of adding allyl chloroformate at the bottom, introducing excessive phosgene, and dissolving part of phosgene in the allyl chloroformate, so that an environment with excessive phosgene is formed in the initial reaction stage, the generation of side reaction is effectively prevented, and finally heating to 15-20 ℃ for heat preservation, so that allyl alcohol is reacted more completely, the content of allyl alcohol in a product is effectively reduced, the purity of the product is greatly improved, and the possibility of barrel expansion and product concentration reduction during storage is reduced.

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

a method for synthesizing allyl chloroformate by a phosgene method comprises the following steps:

firstly, adding Ag allyl chloroformate into a reaction container at the bottom, and controlling the temperature of materials in the reaction container between-2 ℃ and 2 ℃;

introducing Bg phosgene into a reaction container in advance through a flowmeter;

thirdly, dripping allyl alcohol into a reaction container by using a constant-pressure dropping funnel, and controlling the reaction at-2 ℃; introducing phosgene and regulating the mass ratio of the light flow to the dropping flow of the allyl alcohol to be 1: 2.2 in unit time; the total dropping amount of the allyl alcohol is Cg; a: b: c-300: 10-12: 300, respectively;

step four, stopping the light transmission after the allyl alcohol is dripped;

step five, preserving the heat for 0.5 to 2 hours, and then heating to 15 to 20 ℃;

and sixthly, after the temperature is raised to 15-20 ℃, preserving the heat for 0.5-2 hours, controlling the temperature to be 10-15 ℃, introducing nitrogen to remove excess phosgene and hydrogen chloride, and obtaining the qualified allyl chloroformate product.

In a further improvement, the temperature is kept for 1 hour in both the fifth step and the sixth step.

In the fifth step, the temperature is increased to 15-20 ℃ at a temperature increase rate of 5 ℃/hour.

The further improvement comprises a seventh step of introducing nitrogen to remove excessive phosgene and hydrogen chloride to form reaction tail gas, and absorbing the reaction tail gas by using 10% liquid caustic soda.

In the second step, allyl alcohol is dripped into the reaction vessel by using a constant-pressure dropping funnel; the flowmeter is an LZB glass rotameter.

Compared with the traditional intermittent synthesis process, the synthesis method has the following advantages:

1. the product quality is stable, and the product content can reach 98.5-99.1% without rectification.

2. Effectively inhibiting the polymerization phenomenon in the production process and improving the yield and productivity of the product.

3. The production is guaranteed to be stopped and started immediately, and when phosgene is stopped due to the fault of an upper working section, the dripping of allyl alcohol can be stopped synchronously, so that the product in a reaction system is qualified. In the traditional intermittent synthesis process, phosgene is stopped for a little long time, excessive allyl alcohol gradually reacts with allyl chloroformate due to phosgene-free reaction, so that the increase of diester carbonate is caused, and the product quality and yield are correspondingly reduced.

Detailed Description

The technical solution is further explained below.