CN-122010694-A - Preparation process of vinyl diethyl ether

Abstract

The application relates to the field of material science and engineering, and particularly discloses a preparation process of vinyl diethyl ether. The technology comprises the steps of conveying an acetylene and ethanol catalyst solution into a micro-packed bed reactor for continuous gas-liquid reaction, separating and purifying reaction liquid by an extraction rectifying tower under the action of an extractant, strengthening gas-liquid mass transfer by utilizing a micro-pore structure of the micro-packed bed, realizing high-efficiency conversion under mild pressure, remarkably reducing the risk of acetylene explosion, effectively inhibiting acetalation and self-polymerization side reaction by precisely controlling the residence time, solving the problem of reactor scaling, changing the relative volatility of components by utilizing an extraction rectifying technology, breaking the azeotropic system of vinyl diethyl ether and ethanol, and directly obtaining a product with higher purity without water washing.

Inventors

• WANG WEIHUI
• WANG LIDONG
• ZHAO XIAOSONG
• TIAN HUA

Assignees

• 焦作新景科技有限公司

Dates

Publication Date

20260512

Application Date

20260126

Claims (10)

1. 1. A preparation process of vinyl diethyl ether is characterized by comprising the following steps of: s1, dissolving potassium hydroxide in an ethanol solvent to prepare a catalyst solution; S2, introducing the catalyst solution and acetylene gas into an external circulation injection loop reaction system simultaneously, shearing and dispersing the acetylene gas into a liquid phase by using an injector to form a gas-liquid mixed fluid, and carrying out vinylation reaction in a tubular reactor; S3, sending the reacted gas-liquid mixed fluid into a gas-liquid separation device for flash separation, extracting a gas-phase crude product containing vinyl diethyl ether and ethanol from the top of the device, discharging a liquid phase from the bottom of the device, and recycling to the step S2; And S4, introducing the gas-phase crude product into an extraction rectifying tower, spraying an extractant into the tower to perform continuous extraction rectifying, and extracting a vinyl diethyl ether finished product from the top of the tower.
2. 2. The process for preparing vinyl diethyl ether according to claim 1, wherein in step S1, a phase transfer catalyst is further added to the catalyst solution, and the phase transfer catalyst is selected from one or a combination of several of polyethylene glycol dimethyl ether, 18-crown-6 and 15-crown-5.
3. 3. The process for preparing vinyl diethyl ether according to claim 2, wherein the mass fraction of the phase transfer catalyst in the catalyst solution is 0.5% to 2.0%.
4. 4. The process for preparing vinyl diethyl ether according to claim 1, wherein in step S2, the external circulation injection loop reaction system comprises a circulation pump, a venturi injector and a tubular reactor which are sequentially connected, wherein the catalyst solution is pressurized by the circulation pump and then is injected through a nozzle of the venturi injector, and negative pressure is formed at a throat of the venturi injector and acetylene gas is inhaled.
5. 5. The process for producing vinyl diethyl ether according to claim 4, wherein in step S2, the temperature of the vinylation reaction is controlled to be in the range of 130 ℃ to 160 ℃ and the reaction pressure is controlled to be in the range of 1.0MPa to 2.0 MPa.
6. 6. The process for preparing vinyl diethyl ether according to claim 1, wherein in step S3, the gas-liquid separation device is a flash tank, the operation temperature of the flash separation is controlled to be in the range of 140 ℃ to 160 ℃, and the operation pressure is normal pressure or micro positive pressure of 0.01MPa to 0.05 MPa.
7. 7. The process for preparing vinyl diethyl ether according to claim 1, wherein in step S4, the extractant is selected from one or more of ethylene glycol, diethylene glycol, dimethyl sulfoxide, and N-methyl pyrrolidone.
8. 8. The process for preparing vinyl diethyl ether according to claim 7, wherein in step S4, the extractant enters from the upper part of the extractive distillation column, the crude gas phase enters from the middle lower part of the extractive distillation column, and the mass feed ratio of the extractant to the crude gas phase is 1:1 to 3:1.
9. 9. The process for preparing vinyl diethyl ether according to claim 1, wherein in step S4, the vinyl diethyl ether product is continuously injected with a polymerization inhibitor, which is triethylamine or potassium hydroxide solid particles, before or after extraction.
10. 10. The process for preparing vinyl diethyl ether according to claim 1, further comprising a step S5 of feeding the mixed liquid discharged from the bottom of the extraction rectifying tower in the step S4 into a solvent recovery tower for distillation separation, recovering ethanol from the top of the solvent recovery tower and returning to the step S1 or the step S2 for recycling, and recovering the extractant from the bottom of the solvent recovery tower and returning to the step S4 for recycling.

Description

Preparation process of vinyl diethyl ether Technical Field The application relates to the field of material science and engineering, in particular to a preparation process of vinyl diethyl ether. Background Vinyl ethyl ether is an important intermediate for organic chemical industry and a fine chemical raw material. Because of the active vinyl and ethoxy groups contained in the molecular structure, the polymer has unique chemical properties in polymerization reaction and organic synthesis. In industry, vinyl diethyl ether is widely used for producing glutaraldehyde, perfume, lubricating oil additive and special paint, and is also a key raw material for synthesizing medicines and pesticides, and at present, the main technical route for industrially preparing vinyl diethyl ether is based on a Rapa chemical method, namely, taking acetylene and absolute ethyl alcohol as raw materials, and carrying out nucleophilic addition reaction in a liquid phase in the presence of a strong base catalyst to synthesize the vinyl diethyl ether. The reaction is a heterogeneous exothermic reaction of gas and liquid. The existing vinyl diethyl ether industrial production technology generally adopts a traditional kettle type stirring reactor to be combined with a conventional rectifying tower for production, and the specific technical process generally comprises the steps of dissolving potassium hydroxide in excessive absolute ethyl alcohol to prepare a catalytic liquid, loading the catalytic liquid into a reaction kettle with a mechanical stirring device and a heating jacket, bubbling acetylene gas into the bottom of the reaction kettle through a distributor, and reacting the acetylene gas with ethanol in a liquid phase in the rising process under the conditions of pressurization and heating. The crude product generated by the reaction then enters a rectifying unit, distillation and separation are carried out through a conventional plate tower or a packing tower by utilizing the boiling point difference of vinyl ethyl ether and ethanol, the product is extracted from the top of the tower, and the unreacted ethanol at the bottom of the tower is recycled. In the prior art, the traditional kettle-type reactor has large bubbles generated by stirring, small gas-liquid contact area, low conversion rate caused by mass transfer control limitation, forced adoption of a high-temperature and high-pressure process for maintaining productivity, not only increased energy consumption and more remarkably improved potential safety hazard of acetylene decomposition explosion, but also azeotropic phenomenon of vinyl ethyl ether and raw material ethanol, incapability of separation due to conventional rectification thermodynamic limitation, and further long process and large wastewater amount, and secondly, the product in the kettle-type reactor has overlong residence time in a high-temperature and strong alkali environment, and is extremely easy to generate secondary addition or self-polymerization reaction, thereby not only reducing selectivity and yield, but also leading to scale formation of the reaction kettle and shortening the running period of equipment. Disclosure of Invention The application provides a preparation process of vinyl diethyl ether, which aims to solve the problems of large bubbles, small gas-liquid contact area and low conversion rate caused by mass transfer control limitation in the traditional kettle type reactor in the prior art. The first aspect of the invention provides a continuous preparation and separation method of vinyl diethyl ether, which comprises the following steps: Raw material pretreatment, namely dissolving an alkaline catalyst in ethanol to prepare a reaction liquid phase; the continuous synthesis reaction, namely conveying acetylene gas and the reaction liquid phase into a micro-packed bed reactor through a feeding device, and carrying out gas-liquid two-phase continuous contact reaction under the action of a catalyst to obtain a crude reaction mixture containing vinyl diethyl ether, unreacted ethanol and acetylene; Gas-liquid separation, namely, gas-liquid separation is carried out on the crude reaction mixture, the separated gas phase is recycled or recovered, and the liquid phase enters a subsequent separation working section; and (3) extracting, rectifying and separating, namely introducing a liquid phase after gas-liquid separation into an extracting and rectifying tower, changing the relative volatility of vinyl diethyl ether and ethanol by using an extracting agent, breaking an azeotropic system, extracting a high-purity vinyl diethyl ether product from the top of the tower, and extracting a mixed liquid containing ethanol and the extracting agent from the bottom of the tower. The micro-packed bed reactor is internally filled with a filler with a micron-level to millimeter-level pore structure, and macroscopic gas-liquid two-phase flow is cut into micron-level micro-fluid. The structure greatly increa