A kind of preparation method of diethylene glycol monovinyl ether

Abstract

The invention discloses a preparation method of diethylene glycol monovinyl ether, which comprises the following steps: adding a catalyst and diethylene glycol into a reaction kettle, heating and stirring until all solids are dissolved, replacing with inert gas, and evacuating; then heating to 140-170° C., maintaining the pressure in the kettle at -0.1-0.05 MPa, introducing acetylene, maintaining the pressure in the kettle at 0.3-0.5 MPa through a pressure reducing valve, reacting for 8-12 hours, and obtaining a crude product of diethylene glycol divinyl ether; stopping the introduction of acetylene, and heat-insulating and aging. , maintaining the pressure in the autoclave at 0.3-0.5 MPa; cooling to 50-80° C., adding catalyst II and diethylene glycol, replacing with inert gas, heating to 180-200° C., reacting for 8-10 hours, and then performing vacuum distillation for purification to obtain the diethylene glycol monovinyl ether. The preparation method is simple, can prepare diethylene glycol monovinyl ether with high selectivity and high yield, and can efficiently separate and purify the monovinyl ether product through conventional vacuum distillation, is easy to industrialize and continuously synthesize, and greatly reduces the energy consumption of distillation.

Description

Technical Field

[0001] The invention belongs to the technical field of organic compound synthesis, and particularly relates to a method for preparing diethylene glycol monovinyl ether. Background Art

[0002] Polycarboxylate superplasticizers synthesized from polyether macromonomers prepared from diethylene glycol monovinyl ether (C6 alcohol head) offer significant advantages over methyl allyl alcohol (C4 alcohol head) and 3-methyl-3-butene-1-ol (C5 alcohol head) in terms of mud resistance and slump retention. Currently, the main methods for preparing C6 alcohol head include the acetylene method, ether group transfer method, reaction of vinyl chloride with alkoxide, acetal thermal decomposition method, dehydrohalogenation method, and ethylene method. The acetylene method is the most industrialized method.

[0003] The acetylene method involves the direct reaction of diethylene glycol and acetylene in the presence of a catalyst. Because diethylene glycol has two hydroxyl groups, the resulting diethylene glycol monovinyl ether reacts further with acetylene to form diethylene glycol divinyl ether as a byproduct. Chinese patent CN112778102A discloses a method for preparing diol monovinyl ether using sodium methoxide, potassium methoxide, potassium tert-butoxide, and metallic sodium as catalysts at 100-130°C. However, the resulting mixture is 48% monovinyl ether and 17% divinyl ether. Chinese patent CN102173982A discloses a method for preparing diol monovinyl ether using a mixture of potassium alkoxide and triphenylphosphine or triphenylphosphine and zinc oxide as catalysts and polyethylene glycol dimethyl ether as a cosolvent at 80-200°C. However, the yield of monovinyl ether in this method is relatively low. Chinese patent CN115650825A discloses a method for preparing glycol monovinyl ether using sodium hydroxide, potassium hydroxide, and sodium or potassium alkoxide as catalysts at 110-180°C. Although this method has high selectivity for monovinyl ether, it requires a large amount of catalyst. Chinese patent CN114478203A discloses a method for preparing glycol monovinyl ether using sodium hydroxide and potassium hydroxide as catalysts at 80-85°C. The yield of monovinyl ether is 65%, but high temperature is required to remove the cyclohexane solvent and unreacted diethylene glycol, making it difficult to scale up safely.

[0004] As can be seen, the prior art discloses methods for producing diethylene glycol monovinyl ether by directly reacting diethylene glycol and acetylene in the presence of a catalyst. However, because diethylene glycol has two hydroxyl groups, the resulting diethylene glycol monovinyl ether will further react with acetylene to form diethylene glycol divinyl ether as a byproduct. However, the boiling points of monovinyl ether, divinyl ether, and the raw material diethylene glycol are similar, particularly since the boiling range difference between monovinyl ether and divinyl ether is generally 5-10°C. This makes the separation and purification of monovinyl ether difficult. This problem persists in the synthesis of C6 alcohols, and methods such as increasing the reaction temperature and adjusting the type and amount of catalyst cannot prevent the formation of divinyl ether as a byproduct. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method for preparing diethylene glycol monovinyl ether. The preparation method is simple and can prepare diethylene glycol monovinyl ether with high selectivity and high yield. The monovinyl ether product can be efficiently separated and purified by conventional reduced pressure distillation, is easy to industrialize and continuously synthesize, and greatly reduces the energy consumption of distillation.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing diethylene glycol monovinyl ether, comprising the following steps:

[0008] (1) Catalyst 1 and diethylene glycol were added to a reaction kettle, heated and stirred until all solids were dissolved, replaced with inert gas, and vacuumed at 105-115°C;

[0009] (2) subsequently raising the temperature to 140-170° C., maintaining the pressure in the autoclave at −0.1-0.05 MPa, introducing acetylene, and maintaining the pressure in the autoclave at 0.3-0.5 MPa via a pressure reducing valve, and reacting for 500-680 min to obtain a crude product of diethylene glycol divinyl ether;

[0010] (3) Stop feeding acetylene, keep warm and mature, maintain the pressure in the autoclave at 0.3-0.5 MPa; cool to 50-80°C, add catalyst II and diethylene glycol, replace with inert gas, heat to 180-200°C, react for 480-600 minutes, and obtain a crude product of diethylene glycol monovinyl ether;

[0011] (4) Purifying the crude product by distillation under reduced pressure to obtain the diethylene glycol monovinyl ether.

[0012] The inert gas is nitrogen or argon, preferably nitrogen.

[0013] In step (1), the mass of the catalyst 1 is 1.5-3.0% of the mass of diethylene glycol, preferably 1.5%.

[0014] In step (1), the catalyst 1 is any one or more of potassium hydroxide, sodium hydroxide, sodium phenolate, sodium hydride, sodium borohydride, sodium tert-butoxide, potassium tert-butoxide, potassium diethylene glycol, and sodium diethylene glycol.

[0015] In step (1), the heating and stirring conditions are 70-90° C. and stirring for 30-60 min.

[0016] In step (3), the mass of the catalyst 2 is 3.0-5.0% of the mass of diethylene glycol, preferably 3.0%.

[0017] In step (3), the second catalyst is any one or more of chromium acetate, mercuric acetate, bismuth acetate, tin acetate, lead acetate, and rare earth acetate.

[0018] The rare earth acetate is any one or more of cerium acetate, lanthanum acetate, yttrium acetate, europium acetate, samarium acetate, erbium acetate, and zirconium acetate.

[0019] In step (3), the heat preservation and aging time is 30 to 90 minutes.

[0020] In step (3), the molar ratio of diethylene glycol to diethylene glycol divinyl ether in the crude product is 1:1.

[0021] In step (4), the conditions for reduced pressure distillation are: pressure -0.1 MPa, temperature 120-130°C.

[0022] The present invention provides a method for preparing diethylene glycol monovinyl ether. First, under the catalysis of a catalyst, diethylene glycol reacts with excess acetylene gas to prepare a crude product having a diethylene glycol divinyl ether content of greater than 96%. The crude product, without purification, is then further reacted with diethylene glycol under the catalysis of the catalyst to produce a crude product of diethylene glycol monovinyl ether. This crude product is subjected to reduced pressure distillation to obtain diethylene glycol monovinyl ether having a purity of greater than 98.0%. The preparation method has a high reaction conversion rate, and the yield of diethylene glycol monovinyl ether prepared by the method is greater than 75%. In addition, the excess diethylene glycol that has not been completely reacted can be recycled and reused, thereby avoiding waste of resources and achieving zero emission and zero pollution.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The preparation method of diethylene glycol monovinyl ether provided by the invention is simple, and solves the technical problems of low selectivity and difficulty in separating monovinyl ether and by-product divinyl ether in traditional synthesis processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a synthetic route diagram of diethylene glycol monovinyl ether in the present invention;

[0026] Figure 2 The gas chromatogram and chromatographic data of the crude product of diethylene glycol divinyl ether in Example 1;

[0027] Figure 3 The gas chromatogram and chromatographic data of the finished product of diethylene glycol monovinyl ether in Example 1;

[0028] Figure 4 The gas chromatogram and chromatographic data of the crude product of diethylene glycol divinyl ether in Example 2;

[0029] Figure 5 The gas chromatogram and chromatographic data of the diethylene glycol monovinyl ether finished product in Example 2;

[0030] Figure 6 The gas chromatogram and chromatographic data of the crude product of diethylene glycol divinyl ether in Example 3;

[0031] Figure 7 The gas chromatogram and chromatographic data of the finished product of diethylene glycol monovinyl ether in Example 3;

[0032] Figure 8 The gas chromatogram and chromatographic data of the crude product of diethylene glycol divinyl ether in Example 4;

[0033] Figure 9 The gas chromatogram and chromatographic data of the diethylene glycol monovinyl ether finished product in Example 4;

[0034] Figure 10 The gas chromatogram and chromatographic data of the crude product of diethylene glycol divinyl ether in Example 5;

[0035] Figure 11 The gas chromatogram and chromatographic data of the diethylene glycol monovinyl ether finished product in Example 5 are shown. DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the embodiments.

[0037] Example 1

[0038] A method for preparing diethylene glycol monovinyl ether comprises the following steps:

[0039] (1) Add 15 g of potassium hydroxide and 500 g of diethylene glycol to a high-pressure reactor equipped with a stirring device, a heating device, a condensing device, and an inlet and outlet, heat to 80° C., and stir for 30 minutes until all the solids are dissolved; replace the atmosphere with nitrogen twice, and evacuate for 30 minutes;

[0040] (2) The temperature was then raised to 165° C., the pressure in the autoclave was maintained at −0.1 MPa, acetylene was introduced, and the pressure in the autoclave was maintained at 0.5 MPa via a pressure reducing valve. Every 30 minutes, 1 g of sample was taken from the discharge port for gas chromatography. After 500 minutes, the gas chromatography confirmed that the contents of diethylene glycol, diethylene glycol monovinyl ether, and diethylene glycol divinyl ether were 0.79%, 0.75%, and 98.36%, respectively. The gas chromatogram of the crude product is shown in FIG. Figure 2 As shown, the reaction is terminated at this time;

[0041] (3) After the reaction, stop adding acetylene, keep warm and mature for 60 minutes. When the pressure in the autoclave is lower than 0.2 MPa, use nitrogen to maintain the pressure in the autoclave at 0.35 MPa, cool to 80°C, add 15g of chromium acetate and 492g of diethylene glycol, replace the atmosphere with nitrogen twice, start stirring, and heat to 180°C to start the reaction. During the reaction, take 1g of sample from the discharge port and test the gas chromatography to confirm the content of diethylene glycol, monovinyl ether and divinyl ether. When diethylene glycol divinyl ether is completely converted into diethylene glycol monovinyl ether, cool to room temperature and discharge. The reaction time of this step is 480 minutes.

[0042] (4) Purification was carried out by vacuum distillation under the conditions of -0.1 MPa and 120° C. to obtain 1077 g of the target product, diethylene glycol monovinyl ether, with a yield of 88% and a purity of 99.27%. The gas chromatogram of the product is shown in FIG. Figure 3 shown.

[0043] Example 2

[0044] A method for preparing diethylene glycol monovinyl ether comprises the following steps:

[0045] (1) Add 7.5 g of sodium hydroxide and 500 g of diethylene glycol to a high-pressure reactor equipped with a stirring device, a heating device, a condensing device, and an inlet and outlet, heat to 80° C. and stir for 30 minutes until all the solids are dissolved. After nitrogen replacement twice, evacuate for 30 minutes;

[0046] (2) The temperature was then raised to 140° C., the pressure in the autoclave was maintained at −0.1 MPa, acetylene was introduced, and the pressure in the autoclave was maintained at 0.3 MPa via a pressure reducing valve. Every 30 minutes, 1 g of sample was taken from the discharge port for gas chromatography. After 680 minutes, the gas chromatography confirmed that the contents of diethylene glycol, diethylene glycol monovinyl ether, and diethylene glycol divinyl ether were 1.90%, 1.82%, and 96.03%, respectively. The gas chromatogram of the crude product is shown in FIG. Figure 4 As shown;

[0047] (3) After the reaction is completed, stop introducing acetylene, keep warm and mature for 30 minutes, when the pressure in the autoclave is lower than 0.2MPa, use nitrogen to maintain the pressure in the autoclave at 0.3MPa; cool to 50°C, add 15g of cerium acetate and 480g of diethylene glycol, replace the atmosphere with nitrogen twice and start stirring, heat to 180°C and start the reaction, during the reaction, take 1g of sample through the discharge port, test the gas chromatography to confirm the content of diethylene glycol, diethylene glycol monovinyl ether and diethylene glycol divinyl ether, when diethylene glycol divinyl ether is completely converted into diethylene glycol monovinyl ether, cool to room temperature and discharge. The reaction time of this step is 520min;

[0048] (4) Purification was carried out by vacuum distillation under the conditions of -0.1 MPa and 125° C. to obtain 909 g of the target product, diethylene glycol monovinyl ether, with a yield of 76% and a purity of 99.52%. The gas chromatogram of the product is shown in FIG. Figure 5 shown.

[0049] Example 3

[0050] A method for preparing diethylene glycol monovinyl ether comprises the following steps:

[0051] (1) Add 15 g of sodium phenolate and 500 g of diethylene glycol into an autoclave equipped with a stirring device, a heating device, a condensing device, and an inlet and outlet, heat to 80° C. and stir for 30 minutes until all the solids are dissolved, replace the air with nitrogen twice, and evacuate for 30 minutes;

[0052] (2) The temperature was then raised to 170° C., the pressure in the autoclave was maintained at 0.05 MPa, acetylene was introduced, and the pressure in the autoclave was maintained at 0.5 MPa through a pressure reducing valve. Every 30 minutes, 1 g of sample was taken from the discharge port for gas chromatography. After 550 minutes, the gas chromatography confirmed that the contents of diethylene glycol, diethylene glycol monovinyl ether, and diethylene glycol divinyl ether were 1.28%, 1.27%, and 97.29%, respectively. The gas chromatogram of the crude product is shown in FIG. Figure 6 As shown;

[0053] (3) After the reaction is completed, stop adding acetylene, keep warm and mature for 90 minutes, when the pressure in the autoclave is lower than 0.2 MPa, use nitrogen to maintain the pressure in the autoclave at 0.5 MPa; cool to 80°C, add 25g of lead acetate and 486g of diethylene glycol, replace the nitrogen twice and start stirring, heat to 200°C to start the reaction, take a sample of 1g through the discharge port, test the gas chromatography to confirm the content of diethylene glycol, monovinyl ether and divinyl ether, and when diethylene glycol divinyl ether is completely converted into diethylene glycol monovinyl ether, cool to room temperature and discharge. The reaction time of this step is 550 minutes;

[0054] (4) Purification was carried out by vacuum distillation under the conditions of -0.1 MPa and 130° C. to obtain 969 g of the target product, diethylene glycol monovinyl ether, with a yield of 80% and a purity of 98.07%. The gas chromatogram of the product is shown in FIG. Figure 7 shown.

[0055] Example 4

[0056] A method for preparing diethylene glycol monovinyl ether comprises the following steps:

[0057] (1) Add 10 g of potassium tert-butoxide and 500 g of diethylene glycol to an autoclave equipped with a stirring device, a heating device, a condensing device, and an inlet and outlet. Heat to 80°C and stir for 30 minutes until all the solids are dissolved. After argon replacement twice, evacuate for 30 minutes.

[0058] (2) The temperature was then raised to 165°C, the pressure in the autoclave was maintained at 0 MPa, acetylene was introduced, and the pressure in the autoclave was maintained at 0.4 MPa via a pressure reducing valve. Every 30 minutes, 1 g of sample was taken from the discharge port for gas chromatography. After 600 minutes, the gas chromatography confirmed that the contents of diethylene glycol, diethylene glycol monovinyl ether, and diethylene glycol divinyl ether were 1.33%, 1.28%, and 97.22%, respectively. The gas chromatogram of the crude product is shown in FIG. Figure 8 As shown;

[0059] (3) After the reaction is completed, stop adding acetylene, keep warm and mature for 70 minutes, when the pressure in the autoclave is lower than 0.2MPa, use nitrogen to maintain the pressure in the autoclave at 0.4MPa; cool to 60°C, add 20g of zirconium acetate and 486g of diethylene glycol, replace the gas with argon twice, start stirring, heat to 190°C to start the reaction, take a sample of 1g through the discharge port, test the gas chromatography to confirm the content of diethylene glycol, monovinyl ether and divinyl ether, and when diethylene glycol divinyl ether is completely converted into diethylene glycol monovinyl ether, cool to room temperature and discharge. The reaction time of this step is 600min;

[0060] (4) Purification was performed by vacuum distillation under the conditions of -0.1 MPa and 120° C. to obtain 944 g of the target product, diethylene glycol monovinyl ether, with a yield of 78% and a purity of 98.69%. The gas chromatogram of the product is shown in FIG. Figure 9 shown.

[0061] Example 5

[0062] A method for preparing diethylene glycol monovinyl ether comprises the following steps:

[0063] (1) Add 15 g of sodium hydride and 500 g of diethylene glycol to a high-pressure reactor equipped with a stirring device, a heating device, a condensing device, and an inlet and outlet, heat to 80° C., stir for 30 minutes until all the solids are dissolved, replace the atmosphere with nitrogen twice, and evacuate for 30 minutes;

[0064] (2) The temperature was then raised to 165° C., the pressure in the autoclave was maintained at −0.1 MPa, acetylene was introduced, and the pressure in the autoclave was maintained at 0.5 MPa via a pressure reducing valve. Every 30 minutes, 1 g of sample was taken from the discharge port for gas chromatography. After 650 minutes, the gas chromatography confirmed that the contents of diethylene glycol, diethylene glycol monovinyl ether, and diethylene glycol divinyl ether were 0.99%, 0.89%, and 98.00%, respectively. The gas chromatogram of the crude product is shown in FIG. Figure 10 As shown;

[0065] (3) After the reaction is completed, stop adding acetylene, keep warm and mature for 60 minutes, when the pressure in the autoclave is lower than 0.2MPa, use nitrogen to maintain the pressure in the autoclave at 0.35MPa; cool to 80°C, add 15g of chromium acetate and 490g of diethylene glycol, replace the nitrogen twice and start stirring, heat to 180°C to start the reaction, take 1g of sample through the discharge port, test the gas chromatography to confirm the content of diethylene glycol, monovinyl ether and divinyl ether, and when diethylene glycol divinyl ether is completely converted into diethylene glycol monovinyl ether, cool to room temperature and discharge. The reaction time of this step is 500min;

[0066] (4) Purification was carried out by vacuum distillation under the conditions of -0.1 MPa pressure and 125° C. to obtain 1013 g of the target product diethylene glycol monovinyl ether with a yield of 83% and a purity of 99.43%. The gas chromatogram of the product is shown in FIG. Figure 11 shown.

[0067] It can be seen from the above examples that the preparation method of diethylene glycol monovinyl ether provided by the present invention is simple, the product is easy to separate, and the yield is high.

[0068] The detailed description of the preparation method of diethylene glycol monovinyl ether with reference to the above examples is illustrative rather than restrictive, and several examples can be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for preparing diethylene glycol monovinyl ether, characterized in that: The preparation method comprises the following steps: (1) Add catalyst 1 and diethylene glycol into the reactor, heat and stir until all solids are dissolved, replace with inert gas, and evacuate; (2) The temperature is then raised to 140-170°C, the pressure in the autoclave is maintained at -0.1-0.05 MPa, acetylene is introduced, and the pressure in the autoclave is maintained at 0.3-0.5 MPa via a pressure reducing valve. The reaction is continued for 500-680 min to obtain a crude product of diethylene glycol divinyl ether; (3) Stop feeding acetylene, keep warm and mature, maintain the pressure in the autoclave at 0.3~0.5 MPa; cool to 50~80℃, add catalyst II and diethylene glycol, replace with inert gas, heat to 180~200℃, react for 480~600min, and obtain crude product of diethylene glycol monovinyl ether; (4) purifying the crude product by vacuum distillation to obtain the diethylene glycol monovinyl ether; In step (1), the catalyst 1 is any one or more of potassium hydroxide, sodium hydroxide, sodium phenolate, sodium hydride, sodium borohydride, sodium tert-butoxide, potassium tert-butoxide, potassium diglycol, and sodium diglycol; In step (3), the second catalyst is any one or more of chromium acetate, mercuric acetate, bismuth acetate, tin acetate, lead acetate, and rare earth acetate.

2. The preparation method according to claim 1, characterized in that In step (1), the mass of catalyst 1 is 1.5-3.0% of the mass of diethylene glycol.

3. The preparation method according to claim 1, characterized in that In step (1), the heating and stirring conditions are 70-90° C. and stirring for 30-60 min.

4. The preparation method according to claim 1, characterized in that In step (3), the mass of the catalyst 2 is 3.0-5.0% of the mass of diethylene glycol.

5. The preparation method according to claim 1, characterized in that The rare earth acetate is any one or more of cerium acetate, lanthanum acetate, yttrium acetate, europium acetate, samarium acetate, erbium acetate, and zirconium acetate.

6. The preparation method according to claim 1, characterized in that In step (3), the heat preservation and aging time is 30 to 90 minutes.

7. The preparation method according to claim 1, characterized in that In step (3), the molar ratio of diethylene glycol to diethylene glycol divinyl ether in the crude product is 1:

1.

8. The preparation method according to claim 1, characterized in that In step (4), the conditions for reduced pressure distillation are: pressure -0.1 MPa, temperature 120~130°C.

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