阅读说明：本技术 一种盐酸甲醇和氢氰酸合成原甲酸三甲酯的方法 (Method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid ) 是由 张善荣 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种盐酸甲醇和氢氰酸合成原甲酸三甲酯的方法,本发明制备的原甲酸三甲酯是是直接使用盐酸甲醇和氢氰酸在低温及加入惰性溶剂的环境中进行结晶成盐反应,成盐反应结束物料中氢氰酸全部参与反应转化成无毒的中间产物亚氨盐,亚氨盐经过醇解、离心固液分离进而通过连续精馏制得原甲酸三甲酯成品；通过使用盐酸甲醇和氢氰酸直接反应,减少了氢氰酸的生产使用环节,缩短氢氰酸在反应系统内参与反应时间,降低了反应过程剧毒物料泄漏的危险性。(The invention discloses a method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid, wherein the trimethyl orthoformate prepared by the invention is prepared by directly using methanol hydrochloride and hydrocyanic acid to carry out crystallization salt-forming reaction at low temperature in an environment of adding an inert solvent, all hydrocyanic acid in materials after the salt-forming reaction is finished participates in the reaction and is converted into non-toxic intermediate product, namely, ammoniated salt, and the finished trimethyl orthoformate is prepared by alcoholysis, centrifugal solid-liquid separation and further continuous rectification; by using the direct reaction of the methanol hydrochloride and the hydrocyanic acid, the production and use links of the hydrocyanic acid are reduced, the participation reaction time of the hydrocyanic acid in a reaction system is shortened, and the danger of leakage of highly toxic materials in the reaction process is reduced.)

1. A method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid is characterized by comprising the following steps:

1) salt forming reaction: adding a certain amount of inert solvent into a salt forming kettle, reducing the temperature to-10 ℃, adding a certain amount of hydrochloric acid methanol, continuously reducing the temperature to below-20 ℃, adding a certain amount of hydrocyanic acid, starting crystallization salt forming reaction, controlling the reaction temperature in the salt forming kettle to stably rise to 10-15 ℃ within 2-3 hours, and continuously reacting for 0.5-1 hour to obtain a material A;

2) alcoholysis reaction: transferring the material A into an alcoholysis kettle, adjusting the pH value of the material A to 3-5, adding a proportional amount of methanol, keeping the temperature in the alcoholysis kettle at 35-50 ℃, carrying out alcoholysis reaction for 3-5 hours, and finishing the alcoholysis reaction to obtain a material B;

3) impurity removal treatment: centrifuging the material B to remove ammonium chloride generated in the reaction to obtain a centrifugal solution C;

4) refining treatment: and purifying the centrifugal solution C and then continuously rectifying to obtain a trimethyl orthoformate finished product.

2. The method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid according to claim 1, wherein the mass ratio of methanol hydrochloride, hydrocyanic acid and methanol is 2.2-3.2: 1: 2.5-3.5.

3. The method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid according to claim 2, wherein the mass ratio of methanol hydrochloride, hydrocyanic acid and methanol is 3:1: 3.

4. The method for synthesizing trimethyl orthoformate according to claim 3, wherein the concentration of said methanol hydrochloride is 45-56% and the hydrocyanic acid content is 95-99.5%.

5. The method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid according to any one of claims 1 to 4, wherein the purification treatment in step 4) is performed according to the following steps:

1) putting the centrifugal solution C into a purifying kettle, adding a certain amount of treating agent, carrying out heat preservation treatment at the temperature of 5-10 ℃ for 1.5-2.5 hours, standing the treating solution for 1 hour, then carrying out phase separation, discharging the lower layer, and transferring the upper layer to a drying process, wherein the upper layer is a crude product D;

2) adding industrial potassium hydroxide drying agent 6-7% of the weight of the crude product D, drying at 10 deg.C for 1.5-2.5h, standing the dried solution for 0.5-1 h, separating phases, treating the lower layer product separately, and rectifying the upper layer product.

6. The method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid according to claim 5, wherein the treating agent in step 1) is sodium hydroxide or sodium carbonate aqueous solution.

7. The method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid according to claim 5, wherein the amount of the treating agent used in step 1) is 3-10% by weight of the centrifuged solution C.

Technical Field

The invention relates to the technical field of fine organic chemical industry, in particular to a method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid.

Background

Trimethyl orthoformate, also known as trimethoxymethane, is a colorless liquid with pungent odor, is flammable, is easily decomposed in water, and is soluble in ethanol, ether, etc. Is an important organic synthesis intermediate, and is widely used for medicine synthesis, such as synthesis of vitamin B1, vitamin B, sulfadiazine, pipemidic acid, antibiotics, etc.; a dehydrating agent for preventing polyurethane or epoxy coating from hardening due to hydration in the coating aspect; can also be used for synthesizing dyes and perfumes.

The existing trimethyl orthoformate preparation process has many reaction steps, and the production period from feeding to finished product output is long; the used severe toxic materials of hydrocyanic acid are all involved in the whole process of material preparation and metering, chlorination reaction and salt forming reaction, stay in the whole production system and participate in the reaction for a long time, and because the production links involving hydrocyanic acid are more, the risk of poisoning accidents and environmental pollution accidents caused by leakage of the severe toxic materials is higher.

Disclosure of Invention

The invention aims to provide a method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for synthesizing trimethyl orthoformate from methanol hydrochloride and hydrocyanic acid comprises the following steps:

1) salt forming reaction: adding a certain amount of inert solvent into a salt forming kettle, reducing the temperature to-10 ℃, adding a certain amount of hydrochloric acid methanol, continuously reducing the temperature to below-20 ℃, adding a certain amount of hydrocyanic acid, starting crystallization salt forming reaction, controlling the reaction temperature in the salt forming kettle to stably rise to 10-15 ℃ within 2-3 hours, and continuously reacting for 0.5-1 hour to obtain a material A;

2) alcoholysis reaction: transferring the material A into an alcoholysis kettle, adjusting the pH value of the material A to 3-5, adding a proportional amount of methanol, keeping the temperature in the alcoholysis kettle at 35-50 ℃, carrying out alcoholysis reaction for 3-5 hours, and finishing the alcoholysis reaction to obtain a material B;

3) impurity removal treatment: centrifuging the material B to remove ammonium chloride generated in the reaction to obtain a centrifugal solution C;

4) refining treatment: and purifying the centrifugal solution C and then continuously rectifying to obtain a trimethyl orthoformate finished product.

As a further scheme of the invention: the mass ratio of the hydrochloric acid methanol to the hydrocyanic acid to the methanol is 2.2-3.2: 1: 2.5-3.5.

As a still further scheme of the invention: the mass ratio of the hydrochloric acid methanol to the hydrocyanic acid to the methanol is 3:1: 3.

As a still further scheme of the invention: the concentration of the hydrochloric acid methanol is 45-56%, and the hydrocyanic acid content is 95-99.5%.

As a still further scheme of the invention: the purification treatment in the step 4) is carried out according to the following steps:

1) putting the centrifugal solution C into a purifying kettle, adding a certain amount of treating agent, carrying out heat preservation treatment at the temperature of 5-10 ℃ for 1.5-2.5 hours, standing the treating solution for 1 hour, then carrying out phase separation, discharging the lower layer, and transferring the upper layer to a drying process, wherein the upper layer is a crude product D;

2) adding industrial potassium hydroxide drying agent 6-7% of the weight of the crude product D, drying at 10 deg.C for 1.5-2.5h, standing the dried solution for 0.5-1 h, separating phases, treating the lower layer product separately, and rectifying the upper layer product.

As a still further scheme of the invention: the treating agent in the step 1) is sodium hydroxide or sodium carbonate aqueous solution.

As a still further scheme of the invention: the dosage of the treating agent in the step 1) is 3-10% of the weight of the centrifugal solution C.

Compared with the prior art, the invention has the beneficial effects that:

the trimethyl orthoformate prepared by the invention is prepared by directly using methanol hydrochloride and hydrocyanic acid to carry out crystallization salt-forming reaction at low temperature in an environment of adding an inert solvent, wherein all hydrocyanic acid in materials after the salt-forming reaction is reacted and converted into non-toxic intermediate product, namely, imino salt, and the final trimethyl orthoformate product is prepared by alcoholysis, centrifugal solid-liquid separation and further continuous rectification of the imino salt; the hydrochloric acid methanol and the hydrocyanic acid are directly reacted, so that the production and use links of the hydrocyanic acid are reduced, the participation reaction time of the hydrocyanic acid in a reaction system is shortened, and the danger of leakage of highly toxic materials in the reaction process is reduced; meanwhile, through reducing the production and use links of hydrocyanic acid, the loss of hydrocyanic acid in the reaction process is reduced, raw materials are saved, the reaction yield of finished products is improved, the pressure of harmless treatment of virulent tail gas of an environment-friendly tail gas treatment device is reduced, the safe and stable control of crystallization and salt formation reaction temperature is achieved, the generation amount of reaction byproducts is reduced, the main crystallization and salt formation reaction is promoted to be carried out, and the purpose of increasing the crystallization and salt formation amount to improve the reaction yield is achieved.

Detailed Description

The technical solution of the present invention will be described in further detail with reference to specific embodiments.