A kind of preparation method of diethylene glycol vinyl ether

Abstract

The present invention belongs to the field of diethylene glycol vinyl ether, and discloses a method for preparing diethylene glycol vinyl ether, comprising: (1) adding a diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide into a bubbling reactor, adjusting the atmosphere in the bubbling reactor to an inert atmosphere and then heating; starting the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide to circulate in a circulation pipeline of the bubbling reactor, with a circulation flow rate of 1600L / h to 3900L / h; (2) passing acetylene gas from the circulation pipeline into the bubbling reactor after being broken into microbubbles for reaction, and reacting to obtain diethylene glycol vinyl ether. The present invention uses a circulating liquid material to break acetylene gas into microbubbles, reduces mass transfer resistance, accelerates the reaction rate, and obtains a better reaction effect than a traditional process under milder conditions, saves costs, and improves production capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of diethylene glycol vinyl ether, and specifically relates to a preparation method of diethylene glycol vinyl ether. Background Art

[0002] Diethylene glycol vinyl ether is an important chemical intermediate and polymerization monomer. According to the number of vinyl groups contained, it can be divided into two substances: diethylene glycol monovinyl ether and diethylene glycol divinyl ether. Diethylene glycol monovinyl ether can be used as an active diluent for UV curing coatings. Compared with traditional active diluents, it has the advantages of low viscosity, good dilution, complete solvent-free coating, and high safety. It can also be used as a comonomer for polymer modification. Diethylene glycol divinyl ether can be used as a cross-linking agent and a cross-linking comonomer for special resins. The homopolymers and copolymers of diethylene glycol vinyl ether are widely used in many fields such as adhesives, coatings, lubricants, plasticizers, pesticides and surface protection materials.

[0003] There are three commonly used methods for synthesizing vinyl ether: acetylene method, dehydrohalogenation method, acetal thermal decomposition method, etc., among which the acetylene method is the most commonly used. The acetylene method refers to the direct reaction of diethylene glycol and acetylene to obtain diethylene glycol vinyl ether under a certain temperature and pressure. The reaction of diethylene glycol and acetylene is a gas-liquid heterogeneous reaction, and the reaction rate is restricted by gas-phase and liquid-phase mass transfer, and the reaction rate is relatively slow.

[0004] The bubbling reactors used in current research are mainly divided into traditional bubbling reactors, fixed bed reactors and tubular reactors. From the perspective of reaction pressure, it can be divided into normal pressure process, low pressure process (about 0.6MPa) and high pressure process (higher than 6MPa), and the reaction temperature is generally controlled between 165℃ and 185℃. The use of pressurized process is conducive to improving the solubility of acetylene in the liquid phase and accelerating the reaction rate, but it has high requirements for equipment and increases the risk of acetylene explosion. Although increasing the reaction temperature can also accelerate the reaction rate, it also aggravates the occurrence of side reactions and increases the difficulty of product separation and purification. At the same time, in traditional reactors such as bubbling reactors, the bubble diameter is large, usually between 10 and 20mm, the gas-liquid interface area is small, the mass transfer efficiency is low, the reaction rate is slow, the reaction time is long, the equipment volume is large, the production capacity is low, and the production efficiency is low. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention controls the circulation flow rate of a diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide in a bubbling reactor, breaks acetylene gas into microbubbles, and then reacts with the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide to prepare diethylene glycol vinyl ether. The preparation method of the present invention improves the problems of high reaction pressure, high temperature and low mass transfer efficiency of diethylene glycol vinyl ether in a bubbling reactor, and further improves the production efficiency and capacity of diethylene glycol vinyl ether.

[0006] To achieve the above object, the present invention provides a method for preparing diethylene glycol vinyl ether, comprising the following steps:

[0007] (1) adding a diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide into a bubbling reactor, adjusting the atmosphere in the bubbling reactor to an inert atmosphere and then heating the reactor; starting the circulation of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide in a circulation pipeline of the bubbling reactor, wherein the circulation flow rate of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide in the bubbling reactor is 1600 L / h to 3900 L / h;

[0008] (2) The acetylene gas is broken into microbubbles from the circulation pipeline and then introduced into the bubbling reactor for reaction to obtain diethylene glycol vinyl ether.

[0009] As a preferred embodiment of the present invention, the mass ratio of the alkali metal or alkali metal hydroxide to diethylene glycol in the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide is (2-10):100.

[0010] As a preference of the present invention, the feed flow rate of acetylene when introduced is 169 L / h to 394 L / h.

[0011] As a preferred embodiment of the present invention, the size of the microbubbles is 50 μm to 500 μm.

[0012] As a preferred embodiment of the present invention, the reaction temperature is 130°C to 150°C.

[0013] As a preferred embodiment of the present invention, the reaction pressure is 0.1 MPa to 0.4 MPa.

[0014] As a preferred embodiment of the present invention, the reaction time is 1 h to 9 h.

[0015] As a preferred embodiment of the present invention, in step (2), the acetylene gas is broken into microbubbles from the circulation pipeline through a microbubble generator; wherein the microbubble generator comprises a mixing tube for primary liquid shear crushing and a secondary bubble breaker accommodating chamber for secondary liquid shear crushing.

[0016] As a preferred embodiment of the present invention, the microbubble generator is arranged at the gas inlet of the bubbling reactor and is connected to the circulation pipeline, so that the acetylene gas is sheared and crushed into microbubbles by the liquid in the circulation pipeline to form a gas-liquid mixture that enters the bubbling reactor.

[0017] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0018] (1) In the present invention, the acetylene gas entering the bubbling reactor is broken into micron-sized bubbles and enters the circulating liquid raw material. The micron-sized bubbles greatly increase the gas-liquid interface area and volume mass transfer coefficient, accelerate the reaction rate, reduce the reaction pressure and reaction temperature, and improve the reaction efficiency and production capacity.

[0019] In an embodiment of the present invention, acetylene gas is broken into bubbles of 50 μm to 500 μm in size, and the bubble size is reduced by 2 to 3 orders of magnitude. The micron-sized bubbles greatly increase the gas-liquid interface area and volume mass transfer coefficient. Preferably, acetylene gas is passed through a bubbling reactor with a microbubble generator, which is arranged at the gas inlet of the bubbling reactor and connected to the circulation pipeline of the liquid raw material, so that the gas is crushed into micron-sized bubbles and then combined with the liquid to form a continuous reaction process, which is further beneficial to the improvement of reaction efficiency.

[0020] (2) In the present invention, the beneficial effect of controlling the circulation flow rate of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide is to provide sufficient energy for shearing and breaking bubbles to form microbubbles. In a conventional bubbling reactor, bubbles are mainly generated through the sieve holes, and the liquid material may or may not circulate, which will not have a significant effect on the bubble size; and the bubble size generated by the sieve hole structure is relatively large, generally between 10 and 20 mm, the gas-liquid interface area is small, the mass transfer efficiency is low, and the reaction rate is slow.

[0021] Furthermore, the present invention controls the feed flow rate of acetylene when it is introduced, and coordinates the circulating flow rate of diethylene glycol raw material containing alkali metal element, alkali metal hydroxide or alkali metal alcohol salt, so that the circulating liquid raw material shears and breaks the acetylene gas to form microbubbles.

[0022] (3) In the present invention, the reaction temperature of the present invention is controlled to be 130°C to 150°C, and the reaction pressure is 0.1MPa to 0.4MPa. Compared with the traditional preparation method of diethylene glycol vinyl ether using a bubbling reactor, the temperature and pressure conditions of the present invention are milder, the requirements for equipment strength are lower, and the product cost is lower. This is because the gas and liquid materials interact in the microbubble generator, making the generated bubbles smaller, the phase interface area larger, and the volume mass transfer coefficient larger, which accelerates the reaction rate.

[0023] In summary, the present invention uses circulating liquid material to break the feed acetylene gas material into microbubbles, which reduces the mass transfer resistance, accelerates the reaction rate, and obtains better reaction effects than traditional processes under milder reaction conditions, saving costs and improving production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a tower bubbling reaction system for preparing diethylene glycol vinyl ether as exemplified in an embodiment of the present invention;

[0025] Figure 2 The microbubble image at the viewing mirror measured by a USB high-definition digital microscope is exemplified in the embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the structure of a microbubble generator exemplified in an embodiment of the present invention.

[0027] Explanation of the reference numerals: 1-raw material storage tank; 2-microbubble generator; 3-centrifugal pump; 4-sampling port; 5-bubble reactor; 6-bottom valve; 7-sight glass; 8-external circulation pipeline; 9-condenser; 10-gas-liquid separator; 11-condensate; 12-tail gas; 21-liquid inlet; 22-injection pipe; 23-suction chamber; 24-nozzle; 25-air inlet; 26-pressure gauge; 27-mixing pipe; 28-connecting pipe; 29-secondary bubble breaker accommodating chamber; 210-discharge port; 211-secondary bubble breaker pipe box; 212-secondary bubble breaker; 213-pipe box connecting pipe; 214-sight glass; 215-bubble reactor wall. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] In an embodiment of the present invention, a method for preparing diethylene glycol vinyl ether by reacting diethylene glycol and acetylene,

[0030] refer to Figure 1 The present invention is a schematic diagram of a tower bubbling reaction system for preparing diethylene glycol vinyl ether, wherein 1 is a raw material storage tank, 2 is a microbubble generator, 3 is a centrifugal pump, 4 is a sampling port, 5 is a bubbling reactor, 6 is a bottom valve, 7 is a sight glass, 8 is an external circulation pipeline, 9 is a condenser, 10 is a gas-liquid separator, 11 is a condensate, and 12 is tail gas.

[0031] In an embodiment of the present invention, diethylene glycol vinyl ether is prepared, specifically comprising the following steps:

[0032] Step 1: adding a diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide into a bubbling reactor 5; introducing an inert gas, such as N2, into the bubbling reactor 5 to replace the air; heating the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide, and starting the condensation cycle of the condenser 9; after the temperature of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide reaches a first preset temperature, starting the centrifugal pump 3 of the bubbling reactor, extracting the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide from the bubbling reactor, entering the external circulation pipeline 8, and entering the bubbling reactor 5 from the liquid inlet, so that the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide circulates in the bubbling reactor 5 and the external circulation pipeline 8.

[0033] Preferably, the diethylene glycol raw material containing alkali metal element, alkali metal hydroxide, or alkali metal alkoxide is extracted from the bubbling reactor, enters the external circulation pipeline 8, and then enters the bubbling reactor 5 from the liquid inlet of the microbubble generator 2.

[0034] The alkali metal element, alkali metal hydroxide or alkali metal alkoxide is dissolved in diethylene glycol to obtain a diethylene glycol raw material containing the alkali metal element, alkali metal hydroxide or alkali metal alkoxide. For example, the alkali metal element is Na or K; the alkali metal hydroxide is NaOH or KOH; the alkali metal alkoxide is potassium diethylene glycol or sodium diethylene glycol.

[0035] The mass ratio of the alkali metal element, alkali metal hydroxide or alkali metal alkoxide to diethylene glycol is (2-10):100, preferably (8-10):100, and more preferably 8:100.

[0036] The diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide is circulated stably in the bubbling reactor, and the circulation flow rate is adjusted to 1600 L / h to 3900 L / h, preferably 3900 L / h.

[0037] After the temperature of the diethylene glycol raw material containing alkali metal element, alkali metal hydroxide, or alkali metal alkoxide reaches the first preset temperature, the external circulation of the bubbling reactor is started. The first preset temperature is between 60° C. and 100° C., which is mainly set according to the liquid level observed in the sight glass 7. Generally, the liquid level should be ensured to be in the middle of the sight glass so that the logistics can circulate.

[0038] Step 2: After the temperature of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide reaches the reaction temperature, acetylene is introduced and mixed with the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide, or an alkali metal alkoxide and enters the bubbling reactor 5.

[0039] The acetylene is introduced into the micro-bubble generator 2 and broken into bubbles of 50 μm to 500 μm by the shearing action of the liquid. The acetylene feed flow rate is controlled to be 169 L / h to 394 L / h, preferably 282 L / h.

[0040] Step 3: When the reaction pressure in the bubbling reactor 5 is 0.1 MPa to 0.4 MPa, preferably 0.35 MPa; the reaction temperature is 130° C. to 150° C., preferably 140° C., after reacting for 1 h to 9 h, the crude diethylene glycol vinyl ether is obtained in the bubbling reactor.

[0041] In an embodiment of the present invention, the acetylene gas is broken through the microbubble generator 2. Specifically, the acetylene gas is sheared into bubbles of a certain size for the first time by the high-speed moving liquid through the mixing tube 27 in the microbubble generator 2; further, it enters the secondary bubble breaker accommodating chamber 29 and rotates at a high speed along the wall of the device, and is further compressed and sheared into smaller bubbles for the second time by the liquid.

[0042] like Figure 2 As shown, this is an image of bubbles at the sight glass measured using a USB high-definition digital microscope. It can be seen that most of the bubbles in the image are evenly distributed, with larger bubbles about 350 μm in size, and small bubbles about 100 μm in size. The bubble size is between 50 μm and 500 μm.

[0043] like Figure 3 As shown, the microbubble generator 2 includes a liquid inlet 21, an injection pipe 22, an air suction chamber 23, a nozzle 24, an air inlet 25, a pressure gauge 26, and a mixing tube 27; a connecting pipe 28, a secondary bubble breaker accommodating chamber 29, a discharge port 210, a secondary bubble breaker pipe box 211, a secondary bubble breaker 212, a pipe box connecting pipe 213, a sight glass 214, and a bubbling reactor wall 215.

[0044] The liquid inlet is connected to the injection pipe 22 and the nozzle 24 in sequence; the injection pipe 22 is located in the suction chamber 23. The liquid material enters the injection pipe 22 at a certain flow rate, and then is ejected at a high speed at the nozzle 24. Due to the high flow rate of the liquid at the nozzle, a negative pressure is generated in the suction chamber, so that the acetylene gas enters the suction chamber 23.

[0045] The air inlet 25 is connected to the air suction chamber 23, the mixing pipe 27, the connecting pipe 28, and the secondary bubble breaker 212 in sequence.

[0046] The gas is simultaneously pumped into the suction chamber 23 by the compressor through the air inlet 25. Then, the liquid ejected from the nozzle and the gas entering from the suction chamber are mixed in the mixing tube 27, where the gas is sheared into bubbles of a certain size for the first time by the high-speed liquid.

[0047] Among them, the secondary bubble breaker 212 is composed of a containing chamber 29, a connecting pipe 28, and a discharge port 210; the containing chamber 29 is a rotating body, and the rotation generatrix is ​​a curve composed of a straight line parallel to the axis of the containing chamber and two arcs, and the straight line and the arc are tangent at the intersection; the secondary bubble breaker 212 is located in the secondary bubble breaker pipe box 211, and the secondary bubble breaker pipe box 211 is connected to the bubbling reactor 5 through the pipe box connecting pipe 213. The gas-liquid mixture enters the secondary bubble generator containing chamber 29 through the mixing tube 27 and the connecting pipe 28. Since the length direction of the connecting pipe 28 is tangent to the circumference of the containing chamber 29, the gas-liquid mixture rotates at high speed along the wall of the containing chamber 29. Due to the density difference, the gas mainly gathers near the axis of the containing chamber 29, and is further compressed and sheared into bubbles of 50μm in size by the liquid for the second time.

[0048] The gas-liquid mixture containing microbubbles leaves the secondary microbubble generator 212 from the discharge port and enters the secondary bubble breaker pipe box 211 , and enters the bubbling reactor 5 through the pipe box connecting pipe 213 .

[0049] In an example of the present invention, gas and liquid raw materials enter into the tower bubbling reaction system through the gas inlet 25 and the liquid inlet 21 of the microbubble generator 2, respectively, and diethylene glycol vinyl ether is prepared according to the method in the above example.

[0050] The bubbling reactor 5 is connected to the external circulation pipeline 8 , the centrifugal pump 3 , and the microbubble generator 2 in sequence, so that the diethylene glycol raw material containing the alkali metal element, the alkali metal hydroxide, or the alkali metal alkoxide circulates in the bubbling reactor 5 and the external circulation pipeline 8 .

[0051] Furthermore, the sampling port 4 involved in this circulation pipeline is located on the centrifugal pump discharge pipe, and is used to collect liquid samples for gas chromatography analysis during the reaction process; further, the raw material storage tank 1 involved in this circulation pipeline is located above the bubble breaker, and is used to store the diethylene glycol raw material containing alkali metal elements, alkali metal hydroxides, or alkali metal alcohol salts.

[0052] Furthermore, the bottom valve 6 in the bubbling reaction system is used to release the liquid crude product from the bubbling reactor 5 .

[0053] The bubbling reactor 5, the condenser 9 and the gas-liquid separator 10 are connected in sequence to separate the liquid product carried out by the unreacted acetylene from the gas, and to collect the crude liquid product.

[0054] The raw material storage tank 1 is connected to the centrifugal pump 3 .

[0055] The sight glass 7 is located at the top of the bubbling reactor and is used to observe the liquid level in the bubbling reactor.

[0056] The following are specific examples to further illustrate the implementation methods of the present invention and the beneficial effects achieved.

[0057] Example 1

[0058] Based on the above bubbling reactor, and passing acetylene gas into the bubbling reactor through a microbubble generator, the following is a method for preparing diethylene glycol vinyl ether at different catalyst dosages, comprising the following steps:

[0059] (1) 0.44 kg KOH and 22 kg diethylene glycol are added to a stirred tank, and KOH is completely dissolved in diethylene glycol to obtain a raw material containing a catalyst potassium diglycolate, and the raw material is added to a raw material storage tank and pumped into a bubbling reactor by a pump; N2 is introduced into the bubbling reactor to replace air three times, the raw material containing a catalyst potassium diglycolate is heated, and a condensation cycle of a condenser is started; after the temperature of the reaction material reaches a first preset temperature of 80° C., an external circulation pump of the bubbling reactor is started to extract the raw material containing a catalyst potassium diglycolate from the bubbling reactor, enter the external circulation pipeline 8, and then enter the bubbling reactor 5 from the liquid inlet of the microbubble generator 2, so that the raw material containing a catalyst potassium diglycolate circulates in the bubbling reactor 5 and the external circulation pipeline 8. The circulation flow rate of the raw material containing a catalyst potassium diglycolate is controlled to be 3900 L / h.

[0060] (2) After the temperature of the catalyst-containing potassium diglycolate raw material rises to the reaction temperature of 140° C., acetylene is directly introduced from the air inlet of the microbubble generator 2, mixed with the catalyst-containing potassium diglycolate raw material and enters the bubbling reactor 5, wherein the acetylene gas is broken into microbubbles by the shearing action of the liquid in the microbubble generator 2 and then enters the bubbling reactor. After the pressure in the bubbling reactor reaches the set value of 0.4 MPa, the acetylene flow rate is adjusted to 226 L / h.

[0061] (3) During the reaction, a sample is taken from the sampling port 4 every 2 hours, and the composition is analyzed by gas chromatography. When the reaction reaches the set reaction time of 9 hours, the reaction is completed, and the crude diethylene glycol vinyl ether is obtained in the bubbling reactor 5. All the reaction products are discharged, weighed, and sampled for analysis. The final product mass composition is: 40.23% diethylene glycol monovinyl ether, 5.03% diethylene glycol divinyl ether, 52.99% diethylene glycol, and the rest are other impurities. According to calculations, the conversion rate of diethylene glycol is 43.66%, the yield of diethylene glycol monovinyl ether is 34.35%, and the yield of total vinyl ether is 37.93%.

[0062] The same steps as above were followed to change the amount of catalyst precursor KOH to investigate the effect of the catalyst amount, and the reaction results were listed in Table 1. It can be seen that the preferred mass ratio of catalyst precursor KOH to diethylene glycol is 8:100 and 10:100, and more preferably 8:100.

[0063] Table 1: Effect of KOH dosage on catalyst precursor of the present invention

[0064]

[0065] Example 2

[0066] Based on the above bubbling reactor, and introducing acetylene gas into the bubbling reactor through a microbubble generator, diethylene glycol vinyl ether was prepared at different circulation flow rates of the raw materials as follows. For specific steps, refer to Example 1.

[0067] 1.76 kg of KOH and 22 kg of diethylene glycol were added into a stirred tank, and KOH was completely dissolved in diethylene glycol to obtain a catalyst-containing potassium diethylene glycol raw material.

[0068] Among them, after the pressure in the bubbling reactor reached the set value of 0.35MPa and the reaction temperature reached 140°C, the acetylene flow rate was adjusted to 339L / h.

[0069] Based on the above steps, the circulation flow rate of the catalyst-containing potassium diglycol raw material was changed to 1600 L / h and 3900 L / h, and two groups of experiments were carried out.

[0070] During the reaction, a sample was taken from the sampling port 4 every 2 hours, and the composition was analyzed by gas chromatography. When the reaction reached the set reaction time of 9 hours, the reaction was completed, and the crude diethylene glycol vinyl ether was obtained in the bubbling reactor 5. All the reaction products were discharged, weighed, and sampled for analysis.

[0071] The same steps as above were followed, but the circulation rate of the catalyst-containing potassium diglycolate raw material was changed to 1600 L / h and 3900 L / h, and two groups of experiments were performed. The reaction results obtained are listed in Table 2, as follows:

[0072] Table 2: Influence of the circulation flow rate of the catalyst potassium diglycolate raw material of the present invention

[0073]

[0074] Example 3

[0075] Based on the above bubbling reactor, and introducing acetylene gas into the bubbling reactor through a microbubble generator, diethylene glycol vinyl ether was prepared at different acetylene feed flow rates as follows. For specific steps, refer to Example 1.

[0076] 1.76 kg of KOH and 22 kg of diethylene glycol were added into a stirred tank, and KOH was completely dissolved in diethylene glycol to obtain a catalyst-containing potassium diethylene glycol raw material.

[0077] Among them, the circulation flow rate of the reaction raw materials containing the catalyst potassium diglycol is 3900L / h.

[0078] Wherein, after the pressure in the bubbling reactor reaches the set value of 0.4 MPa and the reaction temperature reaches 140° C., acetylene is adjusted at different flow rates to prepare diethylene glycol vinyl ether.

[0079] The reaction was completed after the set reaction time of 9 hours, and the crude diethylene glycol vinyl ether was obtained in the bubbling reactor. All the reaction products were discharged, weighed, and sampled for analysis.

[0080] The same steps as above were followed to change the acetylene feed flow rate, and the effect of the acetylene feed flow rate was investigated. The reaction results are listed in Table 3. As can be seen from Table 3, the preferred acetylene feed flow rate is 282 L / h.

[0081] Table 3: Effect of acetylene feed flow rate of the present invention

[0082]

[0083] Example 4

[0084] Based on the above bubbling reactor, and introducing acetylene gas into the bubbling reactor through a microbubble generator, diethylene glycol vinyl ether was prepared at different reaction pressures as follows. The specific steps refer to Example 1.

[0085] 1.76 kg of KOH and 22 kg of diethylene glycol were added into a stirred tank, and KOH was completely dissolved in diethylene glycol to obtain a catalyst-containing potassium diethylene glycol raw material.

[0086] Among them, the circulation flow rate of the reaction raw materials containing the catalyst potassium diglycol is 3900L / h.

[0087] Among them, after the pressure in the bubbling reactor reaches the set value and the reaction temperature reaches 140°C, the flow rate of acetylene is adjusted to 339L / h.

[0088] The reaction was completed after the set reaction time of 9 hours, and the crude diethylene glycol vinyl ether was obtained in the bubbling reactor. All the reaction products were discharged, weighed, and sampled for analysis.

[0089] The reaction pressure was changed in the same manner as above to investigate the effect of the reaction pressure. The reaction results are listed in Table 4. As can be seen from Table 4, the preferred reaction pressure is 0.35 MPa.

[0090] Table 4: Effect of pressure in the reaction system of the present invention

[0091]

[0092] Example 5

[0093] Based on the above bubbling reactor, and introducing acetylene gas into the bubbling reactor through a microbubble generator, diethylene glycol vinyl ether was prepared at different reaction temperatures as follows. For specific steps, refer to Example 1.

[0094] 1.76 kg of KOH and 22 kg of diethylene glycol were added into a stirred tank, and KOH was completely dissolved in diethylene glycol to obtain a catalyst-containing potassium diethylene glycol raw material.

[0095] Among them, the circulation flow rate of the reaction raw materials containing the catalyst potassium diglycol is 3900L / h.

[0096] Among them, after the pressure in the bubbling reactor reaches the set value of 0.4 MPa and the reaction temperature reaches the preset temperature, the acetylene flow rate is adjusted to the set value of 282 L / h.

[0097] The reaction was completed after the set reaction time of 9 hours, and the crude diethylene glycol vinyl ether was obtained in the bubbling reactor. All the reaction products were discharged, weighed, and sampled for analysis.

[0098] The same steps as above were followed, but the reaction temperature was changed, and the other conditions were kept constant. The effect of the reaction temperature was investigated, and the reaction results were listed in Table 5. As can be seen from Table 5, the preferred reaction temperature is 140°C.

[0099] Table 5 Effect of reaction temperature

[0100]

[0101] Comparative Example 1

[0102] The microbubble generator was replaced with a conventional sieve bubble generator evenly arranged along the air inlet pipe, with a sieve hole diameter of 3 mm. The experimental steps were as follows: Referring to Example 1, the specific experimental conditions were set as follows: the mass ratio of KOH to diethylene glycol was 8:100, the acetylene feed flow rate was 339 L / h, the catalyst-containing potassium diethylene glycol raw material circulation flow rate was 3900 L / h, the reaction pressure was 0.4 MPa, and the reaction temperature was 140°C.

[0103] At the end of the experiment, the conversion rate of diethylene glycol was 86.98%, the yield of diethylene glycol monovinyl ether was 45.78%, and the total yield of vinyl ether was 73.35%. Under the same conditions, the microbubble generator of the present invention was used, and the results obtained were that the conversion rate of diethylene glycol was 93.75%, the yield of diethylene glycol monovinyl ether was 46.75%, and the total yield of vinyl ether was 83.77%. It can be seen that the reaction effect is significantly better when the microbubble generator of the present invention is used.

[0104] Table 6 lists the changes in the mass content of diethylene glycol over time during the reaction process of Comparative Example 1. It can be seen that after installing the microbubble generator of the present invention, the concentration of diethylene glycol decreases significantly faster, indicating that the reaction rate is significantly faster.

[0105] Table 6 Comparison of the change of diethylene glycol mass content over time

[0106]

[0107]

[0108] Comparative Example 2

[0109] The microbubble generator was replaced with a conventional sieve bubble generator evenly arranged along the air inlet pipe, with a sieve hole diameter of 3 mm. The experimental steps were the same as in Example 1, and the experimental conditions were set as a mass ratio of KOH to diethylene glycol of 8:100, an acetylene feed flow rate of 282 L / h, a circulating flow rate of a catalyst-containing potassium diethylene glycol raw material of 3900 L / / h, a reaction pressure of 0.4 MPa, and a reaction temperature of 140°C.

[0110] At the end of the experiment, the conversion rate of diethylene glycol was 84.93%, the yield of diethylene glycol monovinyl ether was 48.38%, and the total yield of vinyl ether was 70.4%. Under the same conditions, the microbubble generator of the present invention was used, and the results obtained were that the conversion rate of diethylene glycol was 87.19%, the yield of diethylene glycol monovinyl ether was 65.93%, and the total yield of vinyl ether was 84.35%. It can be seen that the reaction effect is significantly better when the microbubble generator of the present invention is used.

[0111] Table 7 lists the changes in the mass content of diethylene glycol over time during the reaction process. It can be seen that after the microbubble generator of the present invention is installed, the concentration of diethylene glycol decreases significantly faster, indicating that the reaction rate is significantly faster.

[0112] Table 7 Comparison of changes in diethylene glycol mass content over time

[0113]

[0114] Comparative Example 3

[0115] The microbubble generator was replaced with a conventional sieve bubble generator evenly arranged along the air inlet pipe, with a sieve hole diameter of 3 mm. The experimental steps were the same as in Example 1, and the experimental conditions were set as a mass ratio of KOH to diethylene glycol of 8:100, an acetylene feed flow rate of 169 L / h, a circulating flow rate of a catalyst-containing potassium diethylene glycol raw material of 3900 L / / h, a reaction pressure of 0.4 MPa, and a reaction temperature of 140°C.

[0116] At the end of the experiment, the conversion rate of diethylene glycol was 60.36%, the yield of diethylene glycol monovinyl ether was 44.53%, and the total yield of vinyl ether was 54.02%. Under the same conditions, the microbubble generator of the present invention was used, and the results obtained were that the conversion rate of diethylene glycol was 75.17%, the yield of diethylene glycol monovinyl ether was 47.4%, and the total yield of vinyl ether was 69.69%. It can be seen that the reaction effect is significantly better when the microbubble generator of the present invention is used.

[0117] Table 8 lists the changes in the mass content of diethylene glycol over time during the reaction process. It can be seen that after the microbubble generator of the present invention is installed, the concentration of diethylene glycol decreases significantly faster, indicating that the reaction rate is significantly faster.

[0118] Table 8 Comparison of changes in diethylene glycol mass content over time

[0119]

[0120] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing diethylene glycol vinyl ether, It is characterized in that The steps include: (1) adding a diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide into a bubbling reactor, adjusting the atmosphere in the bubbling reactor to an inert atmosphere and then heating; starting the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide to circulate in a circulation pipeline of the bubbling reactor, wherein the circulation flow rate of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide in the bubbling reactor is 3900 L / h; and the mass ratio of the diethylene glycol raw material containing an alkali metal element, an alkali metal hydroxide or an alkali metal alkoxide to the diethylene glycol is 8:100; (2) acetylene gas is introduced into the bubbling reactor from the circulation pipeline after being broken into microbubbles by a microbubble generator to react and obtain diethylene glycol vinyl ether; wherein the microbubble generator comprises a mixing tube for primary liquid shearing and crushing, and a secondary bubble breaker accommodating chamber for secondary liquid shearing and crushing; the feed flow rate of the acetylene gas during the introduction is 339 L / h, the reaction temperature is 140° C., the reaction pressure is 0.35 MPa, and the reaction time is 9 h; The structure of the microbubble generator includes a liquid inlet, an injection pipe, an air suction chamber, a nozzle, an air inlet, a pressure gauge, the mixing pipe, a connecting pipe, a secondary bubble breaker pipe box, a secondary bubble breaker and a pipe box connecting pipe; wherein the liquid inlet is connected to the injection pipe and the nozzle in sequence, the injection pipe is located in the air suction chamber, and the air inlet is connected to the air suction chamber, the mixing pipe, the connecting pipe and the secondary bubble breaker in sequence; the secondary bubble breaker is composed of a accommodating chamber, the connecting pipe and a discharge port; the accommodating chamber is in the shape of a rotating body, and the rotary generatrix is ​​a curve composed of a straight line parallel to the axis of the accommodating chamber and two arcs, and the straight line and the arc are tangent at the intersection; the secondary bubble breaker is located in the secondary bubble breaker pipe box, and the secondary bubble breaker pipe box is connected to the bubbling reactor through the pipe box connecting pipe.

2. The method for preparing diethylene glycol vinyl ether according to claim 1, It is characterized in that The size of the microbubbles is 50 μm to 500 μm.

3. The method for preparing diethylene glycol vinyl ether according to claim 1, It is characterized in that The microbubble generator is arranged at the gas inlet of the bubbling reactor and is connected to the circulation pipeline, so that the acetylene gas is sheared and crushed into microbubbles by the liquid in the circulation pipeline, forming a gas-liquid mixture that enters the bubbling reactor.

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