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CN-121974786-A - Method for preparing vinyl ether by using ethylene glycol as raw material

CN121974786ACN 121974786 ACN121974786 ACN 121974786ACN-121974786-A

Abstract

The invention discloses a method for preparing vinyl ether by using ethylene glycol as a raw material. The method adopts low-cost industrial raw materials of glycol and alkyl alcohol, and carries out etherification reaction and cracking reaction under catalysis of a solid acid catalyst and a solid base catalyst respectively, so that a vinyl ether product with high added value is prepared.

Inventors

  • ZHANG CHUNLEI
  • TAO HUIQIN
  • CHEN CHENJU
  • WEI CHAO
  • ZHANG SHIHAN
  • SUN YUCHENG

Assignees

  • 上海师范大学
  • 上海师渝元科技有限公司

Dates

Publication Date
20260505
Application Date
20251226

Claims (10)

  1. 1. A method for preparing vinyl ether by using ethylene glycol as a raw material, which is characterized by comprising the reactions shown in one or two of formulas (I), (II) and (III) and (IV): HOCH 2 CH 2 OH + ROH → HOCH 2 CH 2 OR + H 2 O(I); HOCH 2 CH 2 OR + ROH → ROCH 2 CH 2 OR + H 2 O(II); HOCH 2 CH 2 OR → CH 2 =CHOR + H 2 O(III); ROCH 2 CH 2 OR → CH 2 =CHOR + ROH(IV); the catalyst of the reaction shown in the formula (I) and the formula (II) is an acid catalyst; the catalyst of the reaction shown in the formula (III) and the formula (IV) is a base catalyst; The alkali catalyst for the reaction shown in the formula (III) is x [ K 3 A a D b (PO 4 ) c ]/yZ, wherein K 3 A a D b (PO 4 ) is a main catalyst, K is a potassium element, A is a rare earth metal element, D is at least one of B, al, ga, in, cr, fe and Bi elements, Z is a carrier and is at least one of SiO 2 、Al 2 O 3 、TiO 2 、ZrO 2 , diatomite, kaolin, bentonite, attapulgite, all-silicon molecular sieve and silicon-aluminum molecular sieve, 3, a, b and c respectively represent the mole ratio of corresponding elements or phosphate radical in the main catalyst of K, A, D and PO 4 , x and y respectively represent the mass fraction ratio of the main catalyst to the carrier in the catalyst, a=0-0.30, b=0-0.30, x=1-50wt%, and y=50-99wt%; The alkali catalyst for the reaction shown in the formula (IV) is M (Ca 1.00 Mg d M e O f ) -nG, wherein Ca 1.00 Mg d M e O f is a main catalyst, mg is magnesium element, M is at least one of rare earth metal elements, G is a modifier and is at least one of Si simple substance, ge simple substance, inorganic carbide or inorganic nitride, 1.00, d, e and f respectively represent the molar ratio of Ca, mg, M and O corresponding elements in the main catalyst, M and n respectively represent the mass fraction ratio of the main catalyst to the carrier in the catalyst, d=0-5.00, e=0-0.20, m=80-100%, and n=0-20%.
  2. 2. The method of claim 1, wherein in the formulas (I) - (IV), R is C 1 ~C 20 alkyl, C 3 ~C 20 cycloalkyl, C 3 ~C 20 alkenalkyl, C 3 ~C 20 alkenalkyl, C 7 ~C 20 aralkyl, C 3 ~C 20 heterocycloalkyl, or a halo thereof.
  3. 3. The method of claim 1, wherein the acid catalyst is a mesoporous molecular sieve or a silicoaluminomolecular sieve supported heteropolyacid or a salt thereof.
  4. 4. The method according to claim 1, characterized in that it comprises the steps of: S1, etherification reaction, namely mixing ethylene glycol and alkyl alcohol ROH as raw materials according to a metering ratio, sending the raw materials into a preheater for heating to a reaction temperature, and sending the raw materials into an etherification reaction device for etherification reaction shown in a formula (I) and a formula (II) under the action of an acid catalyst to generate an etherification product; S2, separating and refining the etherification product, namely separating and refining the etherification product obtained in the step S1 to obtain a corresponding ethylene glycol monoether or/and ethylene glycol diether product, wherein the separated alkyl alcohol ROH is recycled to be used as an etherification reaction raw material in the step S1; s3, cracking reaction, namely sending the ethylene glycol monoether or/and the ethylene glycol diether obtained in the step S2 into a heat exchanger, or sending diluent gas into the heat exchanger together with the high-temperature cracking product after reaction, sending the diluent gas into a preheater and heating the heat to the reaction temperature, and sending the heat to a cracking reactor to carry out cracking reaction shown in a formula (III) and/or a formula (IV) under the action of a base catalyst to generate the high-temperature cracking product; s4, separating and refining the cracked product, namely separating and refining the cracked product obtained in the step S3 to obtain a corresponding vinyl ether product, and recycling the separated alkyl alcohol ROH as an etherification raw material in the step S1.
  5. 5. The method according to claim 4, wherein in the step S1, the etherification reaction device is a reactor or a rectifying tower, and the etherification reaction conditions are that the temperature is 100-240 ℃, the pressure is 0.1-10.0 MPa, the molar ratio of ROH to glycol is 1.0-10.0, the reaction time is 0.2-10.0 h or the raw material feed weight hourly space velocity is 0.1-5.0 h -1 .
  6. 6. The method according to claim 4, wherein in the step S3, the cracking reactor is a fixed bed or fluidized bed reactor, and the cracking reaction conditions are selected from any one of the following conditions (1) to (3): (1) The cracking reaction is a reaction shown in a formula (III), wherein the temperature is 380-500 ℃, the pressure is 0.05-1.00 MPa, the weight hourly space velocity of ethylene glycol monoether is 0.1-5.0 h -1 , and the volume space velocity of diluent gas is 0-5000 h -1 ; (2) The cracking reaction is a reaction shown in a formula (IV), the temperature is 360-480 ℃, the pressure is 0.05-1.00 MPa, the weight hourly space velocity of the glycol diether is 0.1-5.0 h -1 , and the volume space velocity of the diluent gas is 0-5000 h -1 ; (3) The cracking reaction is a reaction shown in the formula (III) and the formula (IV), the temperature is 370-500 o ℃, the pressure is 0.05-1.00 MPa, the weight hourly space velocity of the glycol mixed ether is 0.1-5.0 h -1 , and the volume space velocity of the diluent gas is 0-5000 h -1 .
  7. 7. The method according to claim 4, wherein the separation and purification of step S2 and step S4 are each independently selected from at least one of cooling, filtering, distillation, rectification, and osmotic membrane separation.
  8. 8. The method of claim 4, wherein the diluent gas is selected from at least one of N 2 、CO 2 、N 2 -CO 2 、H 2 、N 2 -H 2 , oxygen-depleted air, oxygen-containing N 2 gas, oxygen-containing CO 2 , and industrial tail gas.
  9. 9. A base catalyst characterized in that the base catalyst is x[K 3 A a D b (PO 4 ) c ]/yZ、m(Ca 1.00 Mg d M e O f )-nG or a combination of both; The K 3 A a D b (PO 4 ) is a main catalyst, K is a potassium element, A is a rare earth metal element, D is at least one of B, al, ga, in, cr, fe and Bi element, Z is a carrier and at least one of SiO 2 、Al 2 O 3 、TiO 2 、ZrO 2 , diatomite, kaolin, bentonite, attapulgite, all-silicon molecular sieve and silicon-aluminum molecular sieve, 3, a, b and c respectively represent the mole ratio of K, A, D and PO 4 corresponding elements or phosphate radical in the main catalyst, x and y respectively represent the mass fraction ratio of the main catalyst to the carrier in the catalyst, a=0-0.30, b=0-0.30, x=1-50wt% and y=50-99wt%. The Ca 1.00 Mg d M e O f is a main catalyst, mg is magnesium element, M is at least one of rare earth metal elements, G is a modifier and is at least one of Si simple substance, ge simple substance, inorganic carbide or inorganic nitride, 1.00, d, e and f respectively represent the molar ratio of Ca, mg, M and O corresponding elements in the main catalyst, M and n respectively represent the mass fraction of the main catalyst and the carrier in the catalyst, d=0-5.00, e=0-0.20, m=80-100%, and n=0-20%.
  10. 10. Use of the base catalyst according to claim 9 for the preparation of vinyl ethers for catalyzing reactions of formula (III) and/or formula (IV): HOCH 2 CH 2 OR → CH 2 =CHOR + H 2 O(III); ROCH 2 CH 2 OR → CH 2 =CHOR + ROH(IV)。

Description

Method for preparing vinyl ether by using ethylene glycol as raw material Technical Field The invention belongs to the technical field of organic chemical industry, and particularly relates to a method for preparing vinyl ether by using ethylene glycol as a raw material. Background Because the vinyl ether contains double bonds, ether bonds and hydrocarbon groups (such as alkyl, hydroxyalkyl, aryl and the like) in the molecular structure, the vinyl ether has unique chemical properties, is an important organic synthesis intermediate and a high polymer monomer, can undergo addition reaction, polymerization reaction and the like, and has wide application in a plurality of fields of chemical industry, medicine, coating, agriculture and the like. The vinyl ether compound has wide application prospect and has important significance in developing vinyl ether series products in China. At present, the vinyl ether is mainly produced by an acetylene addition method and an acetal pyrolysis method in the industry at home and abroad, but the acetylene addition method has explosion risk as raw material acetylene, has higher requirements on production equipment, is difficult to enlarge a single-series reaction device, has large consumption of a liquid strong alkali catalyst, is easy to inactivate and has serious environmental pollution. The gas phase cracking process of acetal is usually carried out at higher temperature, the product is more complex, the acetal is easy to form peroxide to bring explosion risk, the liquid phase process needs to select proper liquid medium, the product is difficult to separate, the post-treatment process is complex, and all the factors are unfavorable for industrial production. At present, researches on the preparation of vinyl ether by glycol ether cracking are rarely reported. JP3685942B discloses the preparation of vinyl diethyl ether by gas phase dehydration of ethylene glycol monoethyl ether with Cs 2O/SiO2 catalyst. However, the catalyst Cs 2O/SiO2 is expensive, cs species gradually run off along with the extension of the reaction time, so that the catalyst is fast in deactivation, the reaction stability is poor, and the practical value is limited. CN111807937B discloses a method for synthesizing vinyl methyl ether by using ethylene glycol dimethyl ether, which comprises the following steps of carrying out elimination reaction on ethylene glycol dimethyl ether under the catalysis of solid base to obtain vinyl methyl ether and methanol, wherein the solid base is magnesium oxide, cerium oxide, calcium oxide or calcium magnesium mixed oxide. Although the raw materials of the invention are widely available and green, the catalyst is cheap, but the catalyst adopts a single alkaline earth or rare earth oxide catalyst, has small specific surface area, low utilization rate of alkaline active center and easy generation of carbonate to inactivate, thus leading to short service life of the catalyst. CN115772069A provides a synthesis method of vinyl methyl ether, wherein alkali metal sodium or potassium, dibenzofuran and ethylene glycol dimethyl ether with a molar ratio of 1:0.5-10 are used as reaction raw materials, and alkali metal is added in a solid state or a molten state. Although the problems of high reaction temperature and low yield of vinyl methyl ether synthesis in the prior art are solved, because alkali metal is adopted as a catalyst, the alkali metal is added in a solid state or a molten state, so that the alkali metal is difficult to rapidly disperse or dissolve into a reaction system, the catalyst is unevenly distributed and is easy to cause local violent reaction to release heat in a large amount, the purity requirements on raw materials and solvents are extremely high, substances with active hydrogen such as water or alcohol are not allowed to remain, in addition, methanol generated by the reaction can react with the alkali metal to generate alkali metal alkoxide to release hydrogen, so that serious safety risks exist, and the yield of byproduct methanol is reduced and environmental pollution is caused due to the generation of the alkali metal alkoxide. Thus, there is a need to develop safer, more efficient, economical or environmentally friendly methods for preparing vinyl ethers. Disclosure of Invention In order to make up the defects of the prior art, the invention provides a method for preparing vinyl ether by taking coal-based glycol and alkyl alcohol which are widely available and low in price as initial raw materials, and using an acidic catalyst and an alkaline catalyst which have high activity, high selectivity and low price, wherein the acidic catalyst and the alkaline catalyst are respectively used for synthesizing glycol mono/diether and glycol mono/diether through glycol ether synthesis. In one aspect, the present invention provides a process for preparing a vinyl ether comprising the reaction of formula (I), (II), and one or both selected from formulas (III) and (IV)