阅读说明：本技术 一种一锅法制备丙炔酸乙酯的方法 (Method for preparing ethyl propiolate by one-pot method ) 是由 刘文龙 于 2021-09-18 设计创作，主要内容包括：本发明涉及有机化工原料制备领域,公开了一种一锅法制备丙炔酸乙酯的方法,包括如下步骤：(1)将碳酸氢钠、催化剂加入水中混合得到反应液；(2)向反应液中滴加双氧水和丙炔醇进行反应；(3)向反应后的溶液中加入分子筛,然后滴加碳酸二乙酯进行反应；(4)反应结束后分离得到有机相,将有机相旋干、精馏后得到丙炔酸乙酯产品。本发明通过丙炔酸钠和碳酸二乙酯的反应制备丙炔酸乙酯,制备方法简单,废水量较少,能够得到高收率和高纯度的产品,适合工业化生产。(The invention relates to the field of preparation of organic chemical raw materials, and discloses a method for preparing ethyl propiolate by a one-pot method, which comprises the following steps: (1) adding sodium bicarbonate and a catalyst into water, and mixing to obtain a reaction solution; (2) dropwise adding hydrogen peroxide and propargyl alcohol into the reaction liquid for reaction; (3) adding a molecular sieve into the solution after the reaction, and then dropwise adding diethyl carbonate for reaction; (4) and after the reaction is finished, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain an ethyl propiolate product. The ethyl propiolate is prepared by the reaction of the sodium propiolate and the diethyl carbonate, the preparation method is simple, the waste water amount is less, a product with high yield and high purity can be obtained, and the method is suitable for industrial production.)

1. A method for preparing ethyl propiolate by a one-pot method is characterized by comprising the following steps:

(1) adding propiolic alcohol and a catalyst into water to be mixed to obtain a reaction solution;

(2) dropwise adding hydrogen peroxide into the reaction liquid for reaction;

(3) adding a molecular sieve into the solution after the reaction, and then dropwise adding diethyl carbonate for reaction;

(4) and after the reaction is finished, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain an ethyl propiolate product.

2. The method for preparing ethyl propiolate by a one-pot method according to claim 1, wherein the mass of the catalyst in the reaction solution in the step (1) is 0.01-0.05% of the mass of propiolic alcohol.

3. The method for preparing ethyl propiolate by a one-pot method according to claim 1 or 2, wherein the catalyst in step (1) is ferrous chloride or cuprous chloride.

4. The one-pot method for preparing ethyl propiolate according to claim 1 or 2, wherein the mixing temperature in step (1) is 15-25 ℃.

5. The method for preparing ethyl propiolate by the one-pot method as claimed in claim 1, wherein the molar ratio of hydrogen peroxide to propiolic alcohol in the hydrogen peroxide dropwise added in the step (2) is 3.5-6: 1.

6. The one-pot method for preparing ethyl propiolate according to claim 1 or 5, wherein in the step (2), a saturated sodium bicarbonate solution is used for controlling the pH of the system to be 4-5 in the dropping process of hydrogen peroxide.

7. The method for preparing ethyl propiolate by the one-pot method according to claim 1 or 5, wherein the dropping time of hydrogen peroxide in the step (2) is 1.5-2.5 h, and the dropping temperature is 15-25 ℃; after the dropwise addition, the mixture is firstly subjected to heat preservation and stirring reaction at 15-25 ℃ for 2.5-3.5 h, then the temperature is increased to 60-70 ℃, and the reaction is continued until the reaction solution is uniform and transparent.

8. The method for preparing ethyl propiolate by a one-pot method according to claim 1, wherein the mass of the molecular sieve added in the step (3) is 2-5% of the mass of propiolic alcohol.

9. The method for preparing ethyl propiolate by a one-pot method according to claim 1, wherein the molar ratio of the diethyl carbonate to the propiolic alcohol added in the step (3) is 1-1.2: 1.

10. The one-pot method for preparing ethyl propiolate according to claim 1, 8 or 9, wherein the molecular sieve is added in the step (3), the temperature is raised to 85-90 ℃, then diethyl carbonate is added, and the reaction is kept for 12-24 hours.

Technical Field

The invention relates to the technical field of preparation of organic chemical raw materials, in particular to a method for preparing ethyl propiolate by a one-pot method.

Background

Ethyl propiolate is an important organic chemical raw material and a medical intermediate. In the prior art, ethyl propiolate is obtained by esterification reaction of propiolic acid and ethanol under the action of a catalyst, and the following problems exist in the preparation process: 1. the product is difficult to separate, is easy to form azeotropy with alcohol or solvent, and has generally low yield which is generally below 60 percent; 2. the product has strong irritation, poor operating environment of workers, high raw material cost, complex post-treatment process and no cost advantage, and is difficult to industrially produce.

Chinese patent publication No. CN101318900B discloses "a method for synthesizing ethyl propiolate", which describes a method for synthesizing ethyl propiolate by a one-pot method under calcium hypochlorite and acetic acid conditions using propiolic alcohol and ethanol as raw materials. The method has easily obtained raw materials and simple process; and the reaction is carried out at room temperature, the reaction condition is mild, and the environment is not polluted. However, the raw materials used in the preparation process are complex, the final product has more impurities and is difficult to separate, and the yield and the purity of the product are low.

Disclosure of Invention

The invention aims to solve the problems of complex preparation process, low product yield and difficulty in industrial production in the method for preparing ethyl propiolate through the esterification reaction of propiolic acid and acetic acid in the prior art, and provides a method for preparing ethyl propiolate by a one-pot method.

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

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding propiolic alcohol and a catalyst into water to be mixed to obtain a reaction solution;

(2) dropwise adding hydrogen peroxide into the reaction liquid for reaction;

(3) adding a molecular sieve into the solution after the reaction, and then dropwise adding diethyl carbonate for reaction;

(4) and after the reaction is finished, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain an ethyl propiolate product.

In the preparation process of ethyl propiolate, the steps (1) and (2) are firstly carried out, hydrogen peroxide reacts with propiolic alcohol, the hydrogen peroxide can generate hydroxyl radicals under the action of a catalyst, and the propiolic alcohol is oxidized into propiolic acid; then, in the step (3), under the existence of the water absorbent molecular sieve, the propiolic acid and the diethyl carbonate react to finally obtain the ethyl propiolate, wherein the reaction mechanism is as follows: protonating carbonyl carbon of diethyl carbonate, nucleophilic attacking carbonyl oxygen of propiolic acid, and removing ethanol and carbon dioxide from diethyl carbonate to generate ethyl propiolate.

When the method is used for preparing the ethyl propiolate, the preparation method is simple, the amount of wastewater in the preparation process is small, the product is easy to separate, the post-treatment process is simple, the high-yield and high-purity ethyl propiolate can be obtained, and the method is suitable for industrial production.

Preferably, in the reaction solution in the step (1), the mass of the catalyst is 0.01 to 0.05% of the mass of the propiolic alcohol.

Preferably, the catalyst in the step (1) is ferrous chloride or cuprous chloride.

Preferably, the mixing temperature in the step (1) is 15 to 25 ℃.

Preferably, the molar ratio of the hydrogen peroxide to the propiolic alcohol in the hydrogen peroxide dripped in the step (2) is 3.5-6: 1.

Preferably, in the step (2), the pH value of the system is controlled to be 4-5 by using a saturated sodium bicarbonate solution in the dropping process of the hydrogen peroxide. In the reaction process, the pH is controlled within a certain range by using a sodium bicarbonate solution, firstly, most propiolic acid generated in the reaction can be changed into sodium propiolate which exists in a system in a salt form, so that further oxidation is avoided; secondly, the generated hydroxyl free radicals can be slowed down, and the oxidability is weakened; and finally, the pH is controlled within a proper range, so that the hydrogen peroxide can be prevented from being decomposed too quickly, and the yield of the product is improved.

Preferably, the dropping time of the hydrogen peroxide in the step (2) is 1.5-2.5 h, and the dropping temperature is 15-25 ℃; after the dropwise addition, the mixture is firstly subjected to heat preservation and stirring reaction at 15-25 ℃ for 2.5-3.5 h, then the temperature is increased to 60-70 ℃, and the reaction is continued until the reaction solution is uniform and transparent. After the hydrogen peroxide is dropwise added, the hydrogen peroxide and the propiolic alcohol are firstly reacted at a low temperature, and then the temperature is raised to decompose the unreacted hydrogen peroxide, so that the safety of subsequent reaction is ensured.

Preferably, the mass of the molecular sieve added in the step (3) is 2-5% of the mass of the propiolic alcohol.

Preferably, the molar ratio of diethyl carbonate to propiolic alcohol added in the step (3) is 1-1.2: 1.

Preferably, the molecular sieve is added in the step (3), the temperature is raised to 85-90 ℃, then diethyl carbonate is added, and the heat preservation reaction is carried out for 12-24 hours.

Therefore, the invention has the following beneficial effects:

(1) the preparation route of ethyl propiolate is changed: firstly oxidizing propiolic alcohol into propiolic acid by using hydrogen peroxide, and then reacting the propiolic acid with diethyl carbonate to finally obtain ethyl propiolate, wherein the preparation method is simple, the waste water amount in the preparation process is less, the product is easy to separate, the post-treatment process is simple, the high-yield and high-purity ethyl propiolate can be obtained, and the method is suitable for industrial production;

(2) in the reaction process of hydrogen peroxide and propiolic alcohol, sodium bicarbonate solution is used for controlling the pH of the system, so that most propiolic acid generated by the reaction can be changed into sodium propiolate, and further oxidation is avoided; and the generated hydroxyl free radicals can be slowed down, and the hydrogen peroxide can be prevented from being decomposed too fast, so that the yield and the purity of the product are further improved.

Detailed Description

The invention is further described with reference to specific embodiments.

In the present invention, all the raw materials are commercially available or commonly used in the industry, and the methods in the following examples are conventional in the art unless otherwise specified.

Example 1:

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding 112g (2mol) of propiolic alcohol, 1.6g of ferrous chloride catalyst and 100g of water into a reaction kettle, stirring and mixing to obtain a reaction solution, and keeping the temperature in the reaction kettle at 20 ℃;

(2) 906g of hydrogen peroxide with the mass concentration of 30% is dripped into the reaction liquid by using a dropping funnel, the dripping time is 2 hours, the pH value of the system is controlled between 4 and 5 by using a saturated sodium bicarbonate solution in the dripping process, and the temperature of the reaction kettle is kept at 20 ℃; after the dropwise addition, the mixture is firstly stirred and reacted for 3 hours under the heat preservation at the temperature of 20 ℃, and then sampling and detection are carried out, so that the propiolic alcohol reaction is finished; then slowly heating to 60 ℃ within 2h, and continuously carrying out heat preservation reaction until the reaction solution is uniform and transparent;

(3) adding 5g of HZSM-5 type molecular sieve (Jiangsu Xiancheng nano material science and technology limited) into the reacted solution, heating to 90 ℃, then dropwise adding 260g (2.2mol) of diethyl carbonate, and carrying out heat preservation reaction for 12 hours;

(4) and after the reaction is finished, cooling to room temperature, standing for layering, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain the ethyl propiolate product.

Example 2:

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding 112g (2mol) of propiolic alcohol, 3g of cuprous chloride catalyst and 100g of water into a reaction kettle, stirring and mixing to obtain a reaction solution, and keeping the temperature in the reaction kettle at 15 ℃;

(2) dropwise adding 1020g of 30% hydrogen peroxide solution into the reaction solution by using a dropping funnel, wherein the dropwise adding time is 1.5h, the pH value of the system is controlled to be 4-5 by using a saturated sodium bicarbonate solution in the dropwise adding process, and the temperature of the reaction kettle is kept at 15 ℃; after the dropwise addition, the reaction is carried out for 3.5h by heat preservation and stirring at 15 ℃, and sampling detection is carried out to ensure that the propiolic alcohol reaction is finished; then slowly heating to 65 ℃ within 2h, and continuously carrying out heat preservation reaction until the reaction solution is uniform and transparent;

(3) adding 5.6g of HZSM-5 type molecular sieve (Jiangsu Xiancheng nano material science and technology limited) into the reacted solution, heating to 85 ℃, then dropwise adding 236g (2mol) of diethyl carbonate, and carrying out heat preservation reaction for 18 h;

(4) and after the reaction is finished, cooling to room temperature, standing for layering, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain the ethyl propiolate product.

Example 3:

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding 112g (2mol) of propiolic alcohol, 2g of ferrous chloride catalyst and 100g of water into a reaction kettle, stirring and mixing to obtain a reaction solution, and keeping the temperature in the reaction kettle at 25 ℃;

(2) dropwise adding 800g of hydrogen peroxide with the mass concentration of 30% into the reaction liquid by using a dropping funnel, wherein the dropwise adding time is 2.5h, the pH value of the system is controlled to be 4-5 by using a saturated sodium bicarbonate solution in the dropwise adding process, and the temperature of the reaction kettle is kept at 25 ℃; after the dropwise addition is finished, firstly, preserving heat at 25 ℃, stirring and reacting for 2.5 hours, and sampling and detecting to finish the reaction of the propiolic alcohol; then slowly heating to 70 ℃ within 2h, and continuously carrying out heat preservation reaction until the reaction solution is uniform and transparent;

(3) adding 2.3g of HZSM-5 type molecular sieve (Jiangsu Xiancheng nano material science and technology limited) into the reacted solution, heating to 90 ℃, then dropwise adding 283g (2.4mol) of diethyl carbonate, and carrying out heat preservation reaction for 24 hours;

(4) and after the reaction is finished, cooling to room temperature, standing for layering, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain the ethyl propiolate product.

Example 4:

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding 112g (2mol) of propiolic alcohol, 1.6g of ferrous chloride catalyst and 100g of water into a reaction kettle, stirring and mixing to obtain a reaction solution, and keeping the temperature in the reaction kettle at 20 ℃;

(2) 906g of hydrogen peroxide with the mass concentration of 30 percent is dripped into the reaction liquid by using a dropping funnel, the dripping time is 2 hours, and the temperature of the reaction kettle is kept at 20 ℃ in the dripping process; after the dropwise addition, the mixture is firstly stirred and reacted for 3 hours under the heat preservation at the temperature of 20 ℃, and then sampling and detection are carried out, so that the propiolic alcohol reaction is finished; then slowly heating to 60 ℃ within 2h, and continuously carrying out heat preservation reaction until the reaction solution is uniform and transparent;

(3) adding 5g of molecular sieve into the reacted solution, heating to 90 ℃, then dropwise adding 260g (2.2mol) of diethyl carbonate, and reacting for 12 hours under the condition of heat preservation;

(4) and after the reaction is finished, cooling to room temperature, standing for layering, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain the ethyl propiolate product.

Example 5:

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding 112g (2mol) of propiolic alcohol, 1.6g of ferrous chloride catalyst and 100g of water into a reaction kettle, stirring and mixing to obtain a reaction solution, and keeping the temperature in the reaction kettle at 20 ℃;

(2) 906g of hydrogen peroxide with the mass concentration of 30% is dripped into the reaction liquid by using a dropping funnel, the dripping time is 2 hours, the pH value of the system is controlled between 6 and 7 by using a saturated sodium bicarbonate solution in the dripping process, and the temperature of the reaction kettle is kept at 20 ℃; after the dropwise addition, the mixture is firstly stirred and reacted for 3 hours under the heat preservation at the temperature of 20 ℃, and then sampling and detection are carried out, so that the propiolic alcohol reaction is finished; then slowly heating to 60 ℃ within 2h, and continuously carrying out heat preservation reaction until the reaction solution is uniform and transparent;

(3) adding 5g of HZSM-5 type molecular sieve (Jiangsu Xiancheng nano material science and technology limited) into the reacted solution, heating to 90 ℃, then dropwise adding 260g (2.2mol) of diethyl carbonate, and carrying out heat preservation reaction for 12 hours;

(4) and after the reaction is finished, cooling to room temperature, standing for layering, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain the ethyl propiolate product.

Comparative example 1:

a method for preparing ethyl propiolate by a one-pot method comprises the following steps:

(1) adding 112g (2mol) of propiolic alcohol, 1.6g of ferrous chloride catalyst and 100g of water into a reaction kettle, stirring and mixing to obtain a reaction solution, and keeping the temperature in the reaction kettle at 20 ℃;

(2) 906g of hydrogen peroxide with the mass concentration of 30% is dripped into the reaction liquid by using a dropping funnel, the dripping time is 2 hours, the pH value of the system is controlled between 4 and 5 by using a saturated sodium bicarbonate solution in the dripping process, and the temperature of the reaction kettle is kept at 20 ℃; after the dropwise addition, the mixture is firstly stirred and reacted for 3 hours under the heat preservation at the temperature of 20 ℃, and then sampling and detection are carried out, so that the propiolic alcohol reaction is finished; then slowly heating to 60 ℃ within 2h, and continuously carrying out heat preservation reaction until the reaction solution is uniform and transparent;

(3) heating the reacted solution to 90 ℃, then dropwise adding 260g (2.2mol) of diethyl carbonate, and carrying out heat preservation reaction for 12 hours;

(4) and after the reaction is finished, cooling to room temperature, standing for layering, separating to obtain an organic phase, and carrying out spin drying and rectification on the organic phase to obtain the ethyl propiolate product.

The product yields and purities in the above examples and comparative examples were tested, and the results are shown in table 1.

Table 1: the yield and purity of the product were tested.

	Product yield (%)	Purity of the product (%)
			Example 1	86.0	99.8
Example 2	81.0	99.8
			Example 3	82.3	99.5
Example 4	35.4	99.6
			Example 5	51.7	99.2
Comparative example 1	54.6	95.7

As can be seen from table 1, in examples 1 to 3, when the method of the present invention is used to prepare ethyl propiolate, the yield of the product can be more than 80%, and the purity can be more than 99.5%. In example 4, the pH of the system was controlled without adding a saturated sodium bicarbonate solution during the reaction of hydrogen peroxide and propargyl alcohol, and although the purity of the product was high, the yield of the product was significantly reduced, which may be caused by further oxidation of propiolic acid formed during the reaction to carbon dioxide and water, resulting in a decrease in the yield of the product. In example 5, the yield of the product was also decreased in comparison with example 1 because the pH of the system was too high during the reaction of hydrogen peroxide and propiolic alcohol, and it is likely that the yield of the product was decreased because propiolic alcohol could not be efficiently oxidized to propiolic acid due to too fast decomposition of hydrogen peroxide at too high a pH. In the comparative example 1, no molecular sieve is added in the reaction process of propiolic acid and diethyl carbonate, and the product generated by the reaction is slow, so that other generated byproducts have more impurities, and the yield and the purity of the product are both obviously reduced.