Catalyst for preparing alkyl vinyl ether through dehydration of alkoxyethanol and application of catalyst

Abstract

The invention discloses a catalyst for preparing alkyl vinyl ether through dehydration of alkoxyethanol and application of the catalyst. The chemical structural formula of the catalyst is x [AaMb (PO4) c]-yG / zZ, wherein AaMb (PO4) c is a main catalyst, A is selected from at least one element of alkali metal and alkaline earth metal, M is selected from at least one element of H, B, Al, Ga, In and Fe, and G is selected from oxide of at least one element of rare earth metal; z is a carrier and is composed of Z-1 and / or Z-2, the carrier Z-1 is a porous material with a high specific surface area, and the carrier Z-2 is a heat-resistant material with high thermal conductivity. The phosphate catalyst provided by the invention is simple and convenient in preparation process and low in manufacturing cost, and particularly, the supported phosphate has excellent catalytic performance when being used for preparing alkyl vinyl ether through dehydration of alkoxyethanol.

Description

Technical Field

[0001] This invention belongs to the field of chemical catalyst technology, specifically, it relates to catalysts for the dehydration of hydroxyl alcohols to prepare hydrocarbon vinyl ethers and their applications. Background Technology

[0002] Hydroxyethanols, also known as ethylene glycol monoalkyl ethers or hydroxyethyl ethers, include methoxy, ethoxy, butoxy, cyclohexyloxy, phenoxy, benzyloxy, hydroxyethoxy, or hydroxyethoxyethoxyethanol. Vinyl ethers, also known as vinyl alkyl ethers or alkyloxyethylene, commonly include: methyl, ethyl, butyl, trifluoromethyl, heptafluoropropyl, 2-hydroxyethyl, 2-hydroxyethoxyethyl, 2-ethyleneoxyethyl, 4-hydroxybutyl, vinyl, allyl, phenyl, benzyl, or furan methyl vinyl ethers. Vinyl ethers are widely used in various industrial fields and can be used in the synthesis of resins, adhesives, glutaraldehyde, etc. Due to the broad application prospects of vinyl ether compounds, the development of vinyl ether series products in my country is of great significance.

[0003] Currently, the main methods for producing hydrocarbon-based vinyl ethers both domestically and internationally are the acetylene addition method and the acetal pyrolysis method. For the acetylene addition method, the focus has been on finding efficient solid catalysts and improving the reaction process. Catalysts have evolved from initially using alkali metal hydroxide solutions to alcohol solutions of alkali metal alkoxides, then to solvent-assisted superbase systems, and finally to supported solid catalysts. The most significant drawbacks of the acetylene addition method are: the use of liquid strong base catalysts, which require large quantities and are prone to deactivation, resulting in serious environmental pollution; the high reaction temperature and pressure pose a high risk of explosion for the acetylene feedstock; and the high requirements for production equipment, making it difficult to scale up single-series reaction units. The acetal gas-phase cracking method has also mainly focused on catalyst research, evolving from early use of precious metal catalysts to relatively inexpensive Lewis acid catalysts. Currently, phosphate catalysts are mainly used, but the reaction temperature is high and the products are complex; acetals easily form peroxides at high temperatures, posing an explosion risk. Therefore, there is an urgent need to develop new process routes for synthesizing vinyl ethers.

[0004] Recently, the production of vinyl ethers from ethylene glycol monoether obtained through the etherification reaction with alcohols using coal-based ethylene glycol as a starting material via gas-phase catalytic dehydration has become highly attractive due to the inexpensive and readily available raw material ethylene glycol and the green and safe process. Patent JP3685942B discloses the gas-phase dehydration of ethylene glycol monoethyl ether (ethoxyethanol) to prepare ethyl vinyl ether under the action of a Cs₂O / SiO₂ catalyst. The reaction was carried out at a temperature of 420°C and a volume hourly space velocity of 1500 h⁻¹. -1At that time, the conversion rate of ethylene glycol monoethyl ether was 72.5%, and the selectivity of ethyl vinyl ether was 84.4%. However, the Cs2O / SiO2 catalyst is relatively expensive, and Cs species are gradually lost as the reaction time increases, leading to catalyst deactivation.

[0005] Therefore, there is an urgent need to develop a safer, more efficient, stable, economical, or environmentally friendly catalyst for the dehydration of hydroxyl ethanol to prepare hydrocarbon vinyl ethers. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a catalyst for the dehydration of hydroxyl ethanol to prepare alkyl vinyl ethers. This catalyst is simple to prepare and relatively inexpensive, and aims to achieve the safe, efficient, economical, environmentally friendly, and highly selective preparation of vinyl ethers.

[0007] In one aspect, the present invention provides a catalyst for the dehydration of hydroxyethyl alcohols to prepare alkyl vinyl ethers, said catalyst having the chemical structural formula x[A a M b (PO4) c ]-yG / zZ; where A a M b (PO4) c The catalyst is composed of: A (selected from at least one element from alkali metals and alkaline earth metals), M (selected from at least one element from H, B, Al, Ga, In, and Fe), and G (selected from an oxide of at least one rare earth metal); Z is the support, composed of Z-1 and / or Z-2, where support Z-1 is a porous material with high specific surface area and support Z-2 is a material with high thermal conductivity and heat resistance; in the catalyst, a, b, and c represent A, M, and (PO4) respectively. 3- The molar ratio in the main catalyst; x, y, and z are the mass fractions of the main catalyst, promoter, and support, respectively; a = 1.0~3.0, b = 0~2.0, c = 1.0~2.0; x = 1~50%, y = 0~25%, z = 50~99%, and the mass ratio of Z-1 to Z-2 is 1.0:0~0.5.

[0008] Preferably, the mass ratio of Z-1 to Z-2 is 1.0:0~0.5.

[0009] In one or more embodiments, A is selected from at least one element chosen from Li, Na, K, Cs, Mg, Ca, Sr, and Ba; M is selected from at least one element chosen from H, Al, Ga, In, and Fe; G is selected from oxides of at least one element chosen from Sc, Y, La, Ce, Nd, Sm, and Th; Z-1 is an oxide with a specific surface area greater than 50 m². 2 / g of porous material, selected from at least one of SiO2, Al2O3, TiO2, ZrO2, clay and molecular sieve; Z-2 is a heat-resistant material with a thermal conductivity greater than 5W / (m·K), selected from at least one of elemental Si, α-SiO2, α-Al2O3, BeO, MgO, SiC, BN, C3N4, AlN, Si3N4, MoS2 and WS2; a = 1.0~3.0, b = 0~2.0 and c = 1.0~2.0; x = 3~30%, y = 0~20% and z = 70~97%.

[0010] Preferably, the mass ratio of Z-1 to Z-2 is 1.0:0~0.4.

[0011] Preferably, A is selected from at least one element chosen from K, Cs, Mg, and Ca; M is selected from at least one element chosen from H, Al, In, or Fe; G is selected from an oxide of at least one element chosen from La, Ce, Nd, and Sm; Z-1 is an oxide with a specific surface area greater than 100 m². 2 / g of porous material, selected from at least one of SiO2, Al2O3, SiO2-Al2O3, ZSM-5, MCM-22, S-1, TS-1, ZRP, MCM-41 and SBA-15; Z-2 is a heat-resistant material with a thermal conductivity greater than 10W / (m·K), selected from at least one of elemental Si, SiC, BN and C3N4; a = 1.0~3.0, b = 0~2.0, c = 1.0~2.0; x = 5~20%, y = 0~15%, z = 80~95%, and the mass ratio of Z-1 to Z-2 is 1.0:0~0.30.

[0012] In one or more embodiments, the hydroxyl group is selected from C1 to C2. 10 Alkoxy, C1~C 10 Haloalkoxy, C2~C6 hydroxyalkoxy, C3~C8 enalkoxy, C3~C6 alkynylalkoxy, C6~C 10 Arylalkoxy, C3~C 10 Heterocyclic alkoxy, C2~C6 olefin, C6~C 10 Aryloxy, C6-C8 haloaryloxy and C6-C8 hydroxyaryloxy.

[0013] Preferably, the hydrocarbon oxygen group is selected from methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentooxy, neopentoxy, hexoxy, octoxy, decoxy, cyclopentoxy, cyclohexyloxy, cyclohexylmethoxy, methylcyclohexyloxy, chloromethoxy, 2-chloroethoxy, trifluoromethoxy, trifluoroethoxy, pentafluoropropoxy, heptafluorobutoxy, perfluorohexylpropoxy, perfluorooctylpropoxy, hydroxyethoxy, hydroxyethoxyethoxy, hydroxypropoxy, hydroxybutoxy, allyloxy, methylallyloxy, propyneoxy, 3-methylpropyneoxy, benzyloxy, phenoxy, cinnamoxy, epoxypropoxy, 2-furanmethoxy, 2-tetrahydrofuranmethoxy, 3-pyridinemethoxy, ethyleneoxy, propoxy, butenoxy, phenoxy, toluoxy, chlorophenoxy, fluorophenoxy, and hydroxyphenoxy.

[0014] More preferably, the hydrocarbon oxygen group is selected from methoxy, ethoxy, butoxy, cyclohexyloxy, trifluoromethoxy, trifluoroethoxy, hydroxyethoxy, hydroxyethoxyethoxy, allyloxy, 2-methylallyloxy, benzyloxy, epoxypropoxy, 2-furanmethoxy, ethyleneoxy, and phenoxy.

[0015] In another aspect, the present invention provides a method for preparing a catalyst according to any embodiment herein, the method comprising step S1 preparation of a support powder, step S2 preparation of a catalyst powder, and step S3 preparation of catalyst particles.

[0016] In one or more embodiments, step S1 is selected from one of the following (1) to (3):

[0017] (1) The carrier Z contains SiO2. Step S1 is as follows: 8~12% (v / v) tetraethyl orthosilicate is added to a 0.8~1.2 mol / L hydrochloric acid aqueous solution at 55~65℃ and stirred continuously for 7~9h to obtain a wet gel; the wet gel is filtered, washed with deionized water, dried at 110~130°C, calcined in an air stream at 450~550°C for 3~5h, and then ball-milled to obtain SiO2 carrier powder;

[0018] (2) The carrier Z contains mesoporous molecular sieve. Step S1 is: placing the mesoporous molecular sieve powder in an air stream and calcining it at 300~400°C for 1~3h and at 500~600°C for 3~5h to obtain mesoporous molecular sieve carrier powder.

[0019] (3) The carrier Z contains aluminosilicate molecular sieve. Step S1 is as follows: place the aluminosilicate molecular sieve powder in an air stream and calcine it at 300~400°C for 1~3h and 500~600°C for 3~5h. Then, ion exchange is performed three times with 0.8~1.2mol / L NH4Cl aqueous solution, each time at 70~80°C for 2~4h. After filtration, washing with softened water, and drying at 130~150°C for 1~3h, the powder is calcineed in an air stream at 300~400°C for 0.5~1.5h and 500~600°C for 2~4h to obtain aluminosilicate molecular sieve carrier powder.

[0020] Step S3 involves adding a pore-forming agent and a binder to the catalyst powder obtained in step S2, mixing thoroughly, forming it into granules, and then calcining it at a constant temperature of 550-650℃ in an air stream for 4-6 hours to obtain catalyst x[A]. a M b (PO4) c ]-yG / zZ particles.

[0021] In one or more embodiments, step S2 is selected from one of the following (1) to (4):

[0022] (1) b = 0, y = 0, the step S2 is: prepare a phosphate solution of A, add it to the carrier powder obtained in step S1 according to the metric ratio, stir for 2~4h, evaporate to dryness, pulverize, and calcine in an air stream at 300~400℃ for 0.5~1.5h, 500~600℃ for 1~3h and 700~800℃ for 4~6h to obtain catalyst powder;

[0023] (2) b>0, y = 0, the step S2 is: prepare phosphoric acid solution, phosphate solution of A and nitrate solution of M respectively, add phosphoric acid solution and phosphate solution of A to the carrier powder obtained in step S1 according to the stoichiometric ratio under stirring, stir for 0.5~1.5h and then add nitrate solution of M, keep the temperature at 50~70℃ and continue stirring for 2~4h, then evaporate to dryness, pulverize, and calcine in air at 300~400℃ for 0.5~1.5h, 500~600℃ for 1~3h and 700~800℃ for 4~6h to obtain catalyst powder;

[0024] (3) b = 0, y > 0, the step S2 is: prepare a phosphate solution of A, add it to the carrier powder obtained in step S1 according to the metric ratio, stir for 2-4 hours, then add the nitrate solution of rare earth metal elements in G, continue stirring for 1-2 hours, then evaporate to dryness and pulverize; then calcine in an air stream at 300-400℃ for 0.5-1.5 hours, at 500-600℃ for 1-3 hours and at 700-800℃ for 4-6 hours to obtain catalyst powder;

[0025] (4) b>0, y>0, the step S2 is as follows: prepare phosphoric acid solution, phosphate solution of A and nitrate solution of M respectively, add phosphoric acid solution and phosphate solution of A to the carrier powder obtained in S1 according to the stoichiometric ratio under stirring, and continue stirring for 0.5~1.5h; then add nitrate solution of M, keep the temperature at 50~70℃ and continue stirring for 2~4h; then add nitrate solution of rare earth metal elements in G, continue stirring for 1~3h and then evaporate to dryness and pulverize; then calcine in air at 300~400℃ for 0.5~1.5h, 500~600℃ for 1~3h and 700~800℃ for 4~6h to obtain catalyst powder.

[0026] In one or more embodiments, in step S3, the pore-forming agent is at least one selected from water, nitric acid, acetic acid, citric acid, sorbic acid, terephthalic acid, stearic acid, ethylene glycol, 1,4-butanediol, glycerol, and vegetable oil, and is added in an amount of 4-10 wt% of the catalyst powder; the binder is at least one selected from guar gum powder, cellulose, methylcellulose, lignin, polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and starch, and is added in an amount of 5-15 wt% of the catalyst powder.

[0027] In another aspect, the present invention provides the application of the catalyst according to any embodiment herein in a reaction for the catalytic dehydration of hydroxyethyl alcohol to prepare alkyl vinyl ethers, wherein the reaction is carried out in a fixed-bed reactor, a fluidized-bed reactor, or a moving-bed reactor; the feed to the reactor includes a dilution gas; and the reaction conditions are: a reaction temperature of 350–500 °C, a system pressure of 0.01–1.00 MPa, and a liquid hourly space velocity (WHSV) of 0.05–5.00 h⁻¹ for hydroxyethyl alcohol. -1 The gas hourly space velocity (VHSV) of the diluent gas is 0–3000 h⁻¹. -1 .

[0028] In one or more embodiments, the diluting gas is at least one of N2, CO2, N2-CO2 mixture, H2, N2-H2 mixture, oxygen-deficient air, oxygen-containing N2, oxygen-containing CO2, or industrial exhaust gas.

[0029] In another aspect, the present invention provides a method for preparing hydrocarbon vinyl ethers, the method comprising catalytically dehydrating hydroxyethyl alcohols using a catalyst according to any embodiment herein to prepare hydrocarbon vinyl ethers.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. This invention provides a phosphate catalyst for the dehydration of hydroxyl ethanol to prepare hydrocarbon vinyl ethers, especially a phosphate catalyst using a trivalent metal element and a rare earth metal oxide as dual promoters, and a high specific surface area porous material and a high thermal conductivity heat-resistant material as dual supports. It has excellent hydroxyl ethanol dehydration reaction performance, high conversion rate of raw material hydroxyl ethanol, high selectivity of target product hydrocarbon vinyl ether, and high stability of dehydration reaction.

[0032] 2. The supported phosphate catalyst prepared by the impregnation method in this invention has a simple preparation process and low manufacturing cost. It is used in the green and safe process route of dehydrating hydroxyl ethanol to prepare alkyl vinyl ethers. It has excellent catalytic performance and overcomes the disadvantages of Cs2O / SiO2 catalysts reported in the literature, such as high price and poor reaction stability. It also avoids the problems of using liquid strong base catalysts in the acetylene addition method, such as large dosage, easy deactivation and environmental pollution. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Unless otherwise specified, all experimental materials used in the following examples are commercially available.

[0035] In the following examples, the catalyst activity evaluation and analysis methods were as follows: the reaction products were analyzed online by gas chromatography with an FID detector and an RTx-624 capillary column, and the conversion rate X of hydroxyethyl alcohol was calculated using the corrected area normalization method. EGME and selective S of hydrocarbon vinyl ethers AVE The calculation formula is as follows:

[0036]

[0037]

[0038] Examples 1-6: Phosphate catalysts and their catalytic performance in the dehydration reaction of ethoxyethanol

[0039] Preparation of catalyst particles: 5 wt% citric acid and 8 wt% guar gum powder were added to K3PO4, K2HPO4, KH2PO4, Ca3(PO4)2, CaHPO4 or Ca(H2PO4)2 powder, mixed well, and then shaped into clover-shaped particles with a diameter of 2.6 mm and a height of 3.0 mm. The particles were then calcined in an air stream at 350℃ for 1.0 h, 550℃ for 2.0 h and 750℃ for 5.0 h to obtain phosphate catalyst particles.

[0040] Ethoxyethanol dehydration reaction: The prepared phosphate catalyst particles were crushed into 40-60 mesh and filled into a micro fixed-bed reactor, with the top-bottom filling sequence being quartz sand-catalyst-quartz sand. The raw material ethoxyethanol was pumped to a preheater, vaporized, and then fed into the reactor for reaction. The reaction conditions were: preheating temperature 300℃, reaction temperature 400℃, system pressure 0.12MPa, and feed weight hourly space velocity 0.37h⁻¹. -1 The volume hourly space velocity (VHSV) of the diluent gas N2 is 1000 h⁻¹. -1 .

[0041] The results of the dehydration reaction of ethoxyethanol to prepare vinyl ethers catalyzed by various catalysts are listed in Table 1. Clearly, these phosphate catalysts exhibit poor dehydration activity, with single-pass conversions of ethoxyethanol ranging from 12% to 37%, and selectivity for ethyl vinyl ether ranging from 35% to 78%, generating large amounts of byproducts acetaldehyde, ethanol, and ethylene. In contrast, although potassium phosphate catalysts have lower conversion rates, the selectivity for the target product, ethyl vinyl ether, is higher (72% to 78%), indicating that they primarily catalyze the dehydration reaction of ethoxyethanol. Calcium phosphate catalysts, on the other hand, exhibit a combined selectivity of 57% to 65% for acetaldehyde, ethanol, and ethylene, with limited selectivity for the target product, ethyl vinyl ether, primarily catalyzing the de-alcoholization reaction of ethoxyethanol.

[0042] Table 1: Phosphate catalyst and its catalytic effect on the dehydration of ethoxyethanol

[0043]

[0044] Examples 7-12: SiO2-supported potassium phosphate catalyst and its catalytic performance in the dehydration reaction of ethoxyethanol

[0045] S1: Preparation of SiO2 support: prepared by hydrolysis under acidic conditions. 10% (v / v) tetraethyl orthosilicate (TEOS) was added to a 1.0 mol / L hydrochloric acid aqueous solution and stirred continuously at 60°C for 8 h to obtain a transparent wet gel; then filtered, washed with deionized water, dried at 120°C, calcined in an air stream at 500°C for 4 h, and then ball-milled at 1000 rpm for 10 min to obtain SiO2 support powder with a particle size of less than 150 nm.

[0046] S2: Catalyst powder preparation: Prepare a 0.5 mol / L K3PO4 aqueous solution, add it to the SiO2 support powder obtained in step S1 according to the stoichiometric ratio, stir for 3 h, evaporate to dryness, pulverize, and then calcine in an air stream at 350℃ for 1.0 h, 550℃ for 2.0 h and 750℃ for 5.0 h to obtain K3PO4 / SiO2 catalyst powder.

[0047] S3: Catalyst particle preparation: Add 5wt% citric acid and 8wt% guar gum powder to the catalyst powder obtained in step S2, mix well, and then form into clover-shaped particles with a diameter of 2.6mm and a height of 3.0mm. Then, calcine at a constant temperature of 600℃ for 5h in an air stream to obtain K3PO4 / SiO2 catalyst particles.

[0048] Ethoxyethanol dehydration reaction: K3PO4 / SiO2 catalyst particles were crushed into 40-60 mesh and filled into a micro fixed-bed reactor, with the packing sequence from top to bottom being quartz sand-catalyst-quartz sand. The feedstock ethoxyethanol was pumped to a preheater, vaporized, and then fed into the reactor for reaction. The reaction conditions were: preheating temperature 300℃, reaction temperature 440℃, system pressure 0.12MPa, and ethoxyethanol feed weight hourly space velocity 0.37h⁻¹. -1 The feed volume hourly space velocity (VHSV) of the dilution gas N2 is 1000 h⁻¹. -1 .

[0049] Table 2 shows the results of each catalyst and its catalytic activity in the dehydration of ethoxyethanol. It can be seen that K3PO4 / SiO2 catalysts with loadings of 1–40 wt% all exhibit activity in the dehydration of ethoxyethanol. However, when the loading is too high, exceeding 20 wt%, the activity decreases significantly due to the low dispersion of the active component, potassium phosphate. Conversely, when the loading is too low, as low as 1 wt%, the catalytic activity also decreases considerably due to the insufficient number of active centers. Among these, catalysts with K3PO4 loadings of 5–20 wt% show superior performance, with ethoxyethanol single-pass conversion rates ranging from 68% to 88% and ethyl vinyl ether selectivity greater than 76%.

[0050] Table 2: Potassium phosphate catalysts with different loadings and their catalytic results in the dehydration reaction of ethoxyethanol

[0051]

[0052] Examples 13-16: SiO2-supported phosphate catalysts and their catalytic performance in the dehydration of ethoxyethanol

[0053] The preparation process of SiO2 support and corresponding catalyst according to the method in Example 7 is the same as that of ethoxyethanol dehydration reaction, except that K3PO4 in Example 7 is replaced with KH2PO4, K2HPO4, Na3PO4 or Cs3PO4.

[0054] The chemical composition of each SiO2-supported phosphate catalyst and the reaction results of its catalytic dehydration of ethoxyethanol to prepare ethyl vinyl ether are listed in Table 3. Clearly, SiO2-supported catalysts of 5 wt% KH2PO4, K2HPO4, Na3PO4, or Cs3PO4 all exhibit certain activity in the ethoxyethanol dehydration reaction. The 5 wt% Cs3PO4 / SiO2 catalyst shows particularly good performance, with a single-pass conversion of ethoxyethanol reaching 92% and a selectivity of 82% for ethyl vinyl ether. Furthermore, the 5.0 wt% KH2PO4 / SiO2 catalyst also exhibits good catalytic activity, with a single-pass conversion of ethoxyethanol of 50% and a selectivity of 74% for ethyl vinyl ether.

[0055] Table 3: Different phosphate catalysts and their catalytic results in the dehydration reaction of ethoxyethanol

[0056]

[0057] Examples 17-20: Supported potassium phosphate catalyst and its catalytic performance in the dehydration reaction of ethoxyethanol

[0058] Preparation of molecular sieve supports: Mesoporous molecular sieves MCM-41 and SBA-15 raw powders, and SiO2 / Al2O3=25 silica-alumina molecular sieves ZSM-5 and MCM-22 raw powders, were calcined in an air stream at 350°C for 2.0 h and 550°C for 4.0 h, respectively, to obtain MCM-41 and SBA-15 powder supports, or ZSM-5 and MCM-22 molecular sieve powders with template agent removed. The template-removed ZSM-5 and MCM-22 were ion-exchanged three times with 1.0 mol / L NH4Cl aqueous solution, each time at 80°C for 3.0 h, and then... After filtration, washing with softened water, and drying at 150°C for 2.0 h, the sieves were calcined in an air stream at 350°C for 1.0 h and at 550°C for 3.0 h to obtain HZSM-5 and HMCM-22 molecular sieve powders. HZSM-5 and HMCM-22 were then ion-exchanged twice with 0.1 mol / L KCl or CsCl aqueous solution, each time at 80°C for 3.0 h. After filtration, washing with softened water, and drying at 150°C for 2.0 h, the sieves were calcined in an air stream at 350°C for 1.0 h and at 550°C for 3.0 h to obtain CsZSM-5 and KCM-22 carrier powders.

[0059] The catalyst powder and catalyst particles were prepared according to the method in Example 7, and the ethoxyethanol dehydration reaction was carried out, except that the SiO2 support in Example 7 was replaced with molecular sieve supports CsZSM-5, KMCM-22, MCM-41, or SBA-15. The results of each catalyst and its catalytic ethoxyethanol dehydration reaction are listed in Table 4.

[0060] Table 4: Potassium phosphate catalysts supported on different supports and their catalytic dehydration reaction of ethoxyethanol.

[0061]

[0062] As shown in Table 4, the 5wt% K3PO4 catalysts supported on CsZSM-5, KMCM-22, MCM-41, or SBA-15 all exhibit certain dehydration reaction performance. In particular, the 5wt% K3PO4 / SBA-15 catalyst shows better performance, with a single-pass conversion of ethoxyethanol of 95% and a selectivity of ethyl vinyl ether of 79%. In addition, the alkali metal ion exchange molecular sieve catalyst supported on 5.0wt% K3PO4 also has good catalytic activity, with a single-pass conversion of ethoxyethanol greater than 90% and a selectivity of ethyl vinyl ether greater than 82%.

[0063] Examples 21-24: Potassium phosphate catalyst supported on a support containing auxiliary agent M and its catalytic performance in the dehydration reaction of ethoxyethanol

[0064] The SiO2 support and catalyst particles were prepared according to the method of Example 7, and the ethoxyethanol dehydration reaction was carried out. The difference was that the preparation of the catalyst powder in step S2 of Example 7 was replaced by: preparing 0.5 mol / L phosphoric acid, 0.5 mol / L potassium phosphate and 0.1 mol / L aluminum nitrate or indium nitrate aqueous solution respectively, adding the phosphoric acid solution and potassium phosphate solution to the SiO2 support powder according to the stoichiometric ratio under stirring, stirring for 1 h, and then adding aluminum nitrate or indium nitrate solution, stirring at 60°C for 3 h, then evaporating to dryness, pulverizing, and calcining in an air stream at 350°C for 1.0 h, 550°C for 2.0 h and 750°C for 5.0 h to obtain the supported potassium phosphate catalyst powder with added auxiliary agent M (Al or In).

[0065] The results of each catalyst and its catalytic ethoxyethanol dehydration reaction are listed in Table 5. It can be seen that the catalysts with Al or In as promoters all exhibit good performance in the ethoxyethanol dehydration reaction, with a single-pass conversion rate of 77-82% and a selectivity for ethyl vinyl ether greater than 78-85%.

[0066] Table 5: Potassium phosphate catalyst supported on a support containing element M and its catalytic dehydration reaction of ethoxyethanol

[0067]

[0068] Examples 25-28: Potassium phosphate catalyst with added auxiliary agent G and its catalytic performance in the dehydration reaction of ethoxyethanol

[0069] The SiO2 support and catalyst particles were prepared according to the method of Example 7, and the ethoxyethanol dehydration reaction was carried out. The difference was that the preparation of the catalyst powder in step S2 of Example 7 was replaced by: preparing a 1.0 mol / L K3PO4 aqueous solution, adding it to the SiO2 support powder obtained in step S1 according to the stoichiometric ratio, stirring for 3 h, then adding a 0.5 mol / L rare earth metal (La or Ce) nitrate aqueous solution, continuing to stir for 2 h, evaporating to dryness, and pulverizing; then calcining in an air stream at 350°C for 1.0 h, 550°C for 2.0 h, and 750°C for 5.0 h to obtain the supported potassium phosphate catalyst powder with additive G.

[0070] The results of each catalyst and its catalytic ethoxyethanol dehydration reaction are listed in Table 6. Clearly, the K3PO4 / SiO2 catalysts with added rare earth metal La or Ce oxide promoters all exhibit good ethoxyethanol dehydration performance, with a single-pass conversion rate of ethoxyethanol between 90% and 95% and a selectivity for ethyl vinyl ether greater than 72%.

[0071] Table 6: Potassium phosphate catalyst with added additives and its catalytic dehydration reaction of ethoxyethanol

[0072]

[0073] Examples 29-34: Potassium phosphate catalyst with added dual auxiliaries and its catalytic performance in the dehydration reaction of ethoxyethanol

[0074] The SiO2 support and catalyst particles were prepared according to the method of Example 7, and the ethoxyethanol dehydration reaction was carried out. The difference was that the preparation of the catalyst powder in step S2 of Example 7 was replaced by: preparing 0.5 mol / L phosphoric acid aqueous solution, 0.5 mol / L potassium phosphate aqueous solution and 0.1 mol / L aluminum nitrate, ferric nitrate or indium nitrate aqueous solution respectively, adding the phosphoric acid solution and potassium phosphate solution to the SiO2 support powder in stoichiometric ratio under stirring, and continuing to stir for 1 h; then adding aluminum nitrate, ferric nitrate or indium nitrate solution, and continuing to stir at 60 °C for 3 h; then adding 0.5 mol / L rare earth metal (La or Ce) nitrate aqueous solution, continuing to stir for 2 h, evaporating to dryness, pulverizing, and calcining in an air stream at 350 °C for 1.0 h, 550 °C for 2.0 h and 750 °C for 5.0 h to obtain the supported potassium phosphate catalyst powder with added dual promoters.

[0075] The results of each catalyst and its catalytic dehydration reaction of ethoxyethanol are listed in Table 7. As can be seen from Table 7, the catalysts with dual promoters, which simultaneously add Al, Fe or In elements and rare earth metal La or Ce oxide promoters, all have good performance in the dehydration reaction of ethoxyethanol, with a single-pass conversion rate of 85-93% and a selectivity of 78-85% for ethyl vinyl ether.

[0076] Table 7: Potassium phosphate catalyst with added dual auxiliaries and its catalytic dehydration reaction of ethoxyethanol

[0077]

[0078] Examples 35-38: Potassium phosphate catalysts with added dual promoters and dual supports and their catalytic dehydration reaction performance

[0079] The SiO2 support and catalyst particles were prepared according to the method of Example 7, and the ethoxyethanol dehydration reaction was carried out. The difference was that the preparation of the catalyst powder in step S2 of Example 7 was replaced by: preparing 0.5 mol / L of phosphoric acid, 0.5 mol / L of potassium phosphate and 0.1 mol / L of aluminum nitrate or indium nitrate aqueous solution respectively, and adding the phosphoric acid solution and potassium phosphate solution to the composite support powder composed of SiO2 or SBA-15 and C3N4 or SiC (pre-ball-milled to a particle size of less than 200 nm) according to the stoichiometric ratio under stirring, and continuing to stir for 1 h; then adding aluminum nitrate or indium nitrate solution, and continuing to stir at 60 °C for 3 h; then adding 0.5 mol / L of rare earth metal (La) nitrate aqueous solution, and continuing to stir for 2 h, then evaporating to dryness, pulverizing, and calcining in an air stream at 350 °C for 1.0 h, 550 °C for 2.0 h and 750 °C for 5.0 h to obtain the supported potassium phosphate catalyst powder with added dual promoters and dual supports.

[0080] The results of each catalyst and its catalytic ethoxyethanol dehydration reaction are listed in Table 8. Clearly, the catalysts with both Al / In and La2O3 dual promoters exhibit excellent ethoxyethanol dehydration performance, with a single-pass conversion of ethoxyethanol greater than 93% and a selectivity for ethyl vinyl ether exceeding 83%.

[0081] Table 8: Potassium phosphate catalysts with added dual promoters and dual supports and their catalytic results in the dehydration reaction of ethoxyethanol

[0082]

[0083] Examples 39-45: Investigation of process conditions for the dehydration reaction of ethoxyethanol using SiO2-supported potassium phosphate catalyst

[0084] The SiO2 support and catalyst particles were prepared according to the method in Example 7, and the ethoxyethanol dehydration reaction was carried out, except that the reaction conditions were different. The specific conditions and the results of the ethoxyethanol dehydration reaction are listed in Table 8.

[0085] It can be seen that the weight hourly space velocity (WHSV) is 0.37–0.93 h⁻¹ when the reaction temperature is 380–420 °C, the system pressure is 0.12–0.50 MPa, and the ethoxyethanol feed solution is used. -1 When diluted with N2 gas, the volume hourly space velocity is 500~3000. -1At the specified temperatures, the 5.0 wt% K3(PO4) / SiO2 catalyst exhibited activity in the dehydration of ethoxyethanol. Comparison of data from Example 7 and Examples 39-45 in Table 9 shows that higher temperature, higher pressure, and lower space velocity are more favorable for the dehydration of ethoxyethanol to ethyl vinyl ether.

[0086] Table 9: Dehydration performance of ethoxyethanol by 5.0 wt% K3(PO4) / SiO2 catalyst under different process conditions

[0087]

[0088] Examples 46-53: Performance of supported potassium phosphate catalysts on the dehydration reaction of different hydroxyl ethanols

[0089] The SiO2 support and catalyst particles were prepared according to the method in Example 7, and an ethoxyethanol dehydration reaction was carried out, except that the ethoxyethanol was replaced with other hydroxyl ethanols. The specific raw materials and the results of the hydroxyl ethanol dehydration reaction are listed in Table 10.

[0090] As shown in Table 10, the 5.0 wt% K3PO4 / SiO2 catalyst exhibits good catalytic performance for the dehydration of various hydrocarbon oxyethanols, such as methoxyethanol, butoxyethanol, trifluoromethoxyethanol, 2-hydroxyethoxyethanol, cyclohexyloxyethanol, phenoxyethanol, benzyloxyethanol, and epoxypropoxyethanol, to form hydrocarbon vinyl ethers. The single-pass conversion rate is between 88% and 94%, and the selectivity for hydrocarbon vinyl ethers is between 76% and 95%.

[0091] Table 10: Catalytic performance of 5.0wt% K3PO4 / SiO2 catalyst in the dehydration reaction of different hydroxyl groups of ethanol

[0092]

[0093] Example 54: Dehydration reaction stability of 5.0wt% K3PO4-5.0wt% La2O3 / SiO2 catalyst particles

[0094] The catalyst particles (3.0 wt% K3PO4-5.0 wt% La2O3 / SiO2, clover-shaped particles with a diameter of 3.0 mm and a height of 3.0 mm) from Example 25 were used and loaded into a fixed-bed particle evaluation reactor. Ethoxyethanol was pumped to a preheater, vaporized, and then fed into the reactor for reaction. The reaction conditions were: preheating temperature 300°C, reaction temperature 440°C, system pressure 0.12 MPa, and feed weight hourly space velocity 0.50 h⁻¹. -1 The volume hourly space velocity (VHSV) of the diluent gas N2 is 1500 h⁻¹. -1 The results of the stability study of the ethoxyethanol dehydration reaction are listed in Table 11.

[0095] As shown in Table 11, during the 100-hour observation period, the ethoxyethanol conversion rate of the 5.0wt%K3PO4-5.0wt%La2O3 / SiO2 catalyst remained above 91% and the selectivity of ethyl vinyl ether remained at around 78%, indicating that the catalyst has good reaction stability for the dehydration of ethoxyethanol to ethyl vinyl ether.

[0096] Table 11: Stability of ethoxyethanol dehydration reaction of 5.0 wt% K3PO4-5.0 wt% La2O3 / SiO2 catalyst

[0097]

[0098] Example 55: 7.0 wt% K 2.4 Al 0.2 Reaction stability of PO4-1.0wt%La2O3 / SBA-15 catalyst

[0099] The catalyst 7.0 wt% K was prepared according to the method of Example 29. 2.4 Al 0.2 The catalyst used was PO4-1.0wt%La2O3 / SBA-15, differing only in the amount of aluminum nitrate and lanthanum nitrate added as precursors to maintain stoichiometric ratios. The fixed-bed particle evaluation reactor and ethoxyethanol dehydration reaction conditions were identical to those in Example 54, and the results of the reaction stability study are listed in Table 12. It can be seen that within the 100-hour observation period, the ethoxyethanol conversion and ethyl vinyl ether selectivity remained above 85%, indicating that the catalyst exhibits good stability in the dehydration reaction.

[0100] Table 12: 7.0wt%K 2.4 Al 0.2 Stability of ethoxyethanol dehydration reaction of PO4-1.0wt%La2O3 / SBA-15 catalyst

[0101]

[0102] Example 56: 5.0%K 2.1 Al 0.3 PO4-1.0%La2O3 / 89.0%SBA-15-5.0%C3N4 Reaction Stability

[0103] The catalyst 5.0% K was prepared according to the method in Example 35. 2.1 Al 0.3The catalyst composition was PO4-1.0%La2O3 / 89.0%SiO2-5.0%C3N4. The fixed-bed particle evaluation reaction apparatus and ethoxyethanol dehydration reaction conditions were the same as in Example 54, and the reaction stability results are listed in Table 13. It can be seen that during the 200-hour observation period, the ethoxyethanol conversion and ethyl vinyl ether selectivity remained above 91% and 87%, respectively, indicating that the catalyst exhibits good reactivity, selectivity, and stability.

[0104] Table 13: 5.0%K 2.1 Al 0.3 Stability of the dehydration reaction of the PO4-1.0%La2O3 / 89.0%SiO2-5.0%C3N4 catalyst

[0105]

[0106] In summary, the catalyst of this invention is prepared by impregnation, which is simple, uses inexpensive and readily available raw materials, and has low manufacturing costs. The phosphates used all possess certain catalytic activity for the dehydration of hydroxyl ethanol. However, phosphates without a support or with excessively high loading exhibit poor catalytic activity due to low dispersion. Moderate loading, such as 5-20 wt% phosphate, provides good catalytic dehydration activity. Potassium phosphate or cesium phosphate exhibits superior dehydration performance. In particular, potassium phosphate catalysts using high specific surface area porous materials such as SiO2, mesoporous molecular sieves SBA-15, or alkali metal ion-exchange silica-alumina molecular sieves, and high thermal conductivity heat-resistant materials such as C3N4 or SiC as dual supports, and supported with aluminum, indium, or iron elements and rare earth oxides as dual promoters, demonstrate excellent catalytic dehydration performance. They not only exhibit high hydroxyl ethanol conversion and selectivity for hydrocarbon vinyl ethers, but also good reaction stability.

[0107] Special Note: The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A catalyst for the dehydration of hydroxyethyl alcohol to prepare alkyl vinyl ethers, characterized in that, The chemical structural formula of the catalyst is as follows: x [A a M b (PO4) c ]- y G / z Z; where A a M b (PO4) c The catalyst is composed of: A (selected from at least one element from alkali metals and alkaline earth metals), M (selected from at least one element from H, B, Al, Ga, In, and Fe), and G (selected from an oxide of at least one rare earth metal); Z is the support, composed of Z-1 and / or Z-2, where support Z-1 is a porous material with high specific surface area, and support Z-2 is a material with high thermal conductivity and heat resistance; in the catalyst, a、b and c They represent A, M, and (PO4) respectively. 3- The molar ratio in the main catalyst; x, y and z These represent the mass fractions of the main catalyst, auxiliary agent, and support, respectively. a = 1.0~3.0, b = 0~2.0, c= Version 1.0~2.0; x = 1~50%, y = 0~25%, z = 50~99%.

2. The catalyst according to claim 1, characterized in that, A is selected from at least one element from Li, Na, K, Cs, Mg, Ca, Sr, and Ba; M is selected from at least one element from H, Al, Ga, In, and Fe; G is selected from oxides of at least one element from Sc, Y, La, Ce, Nd, Sm, and Th; Z-1 is an oxide with a specific surface area greater than 50 m². 2 / g of porous material, selected from at least one of SiO2, Al2O3, TiO2, ZrO2, clay, and molecular sieve; Z-2 is a heat-resistant material with a thermal conductivity greater than 5W / (m·K), selected from elemental Si, α -SiO2、 α -At least one of Al2O3, BeO, MgO, SiC, BN, C3N4, AlN, Si3N4, MoS2 and WS2; a = 1.0~3.0、 b = 0~2.0 and c = 1.0~2.0; x = 3~30% y = 0~20% and z = 70~97%.

3. The catalyst according to claim 1, characterized in that, The hydroxyl group is selected from C1~C6. 10 Alkoxy, C1~C 10 Haloalkoxy, C2~C6 hydroxyalkoxy, C3~C8 enalkoxy, C3~C6 alkynylalkoxy, C6~C 10 Arylalkoxy, C3~C 10 Heterocyclic alkoxy, C2~C6 olefin, C6~C 10 Aryloxy, C6-C8 haloaryloxy and C6-C8 hydroxyaryloxy.

4. A method for preparing the catalyst according to any one of claims 1-3, characterized in that, The method includes step S1, preparation of support powder, step S2, preparation of catalyst powder, and step S3, preparation of catalyst particles.

5. The method according to claim 4, characterized in that, Step S1 is selected from one of the following (1) to (3): (1) The carrier Z contains SiO2. Step S1 is as follows: 8~12% (v / v) tetraethyl orthosilicate is added to a 0.8~1.2mol / L hydrochloric acid aqueous solution at 55~65℃ and stirred continuously for 7~9h to obtain a wet gel; the wet gel is filtered, washed with deionized water, dried at 110~130°C, calcined in an air stream at 450~550°C for 3~5h, and then ball-milled to obtain SiO2 carrier powder; (2) The carrier Z contains mesoporous molecular sieve. Step S1 is: placing the mesoporous molecular sieve powder in an air stream and calcining it at 300~400°C for 1~3h and at 500~600°C for 3~5h to obtain mesoporous molecular sieve carrier powder. (3) The carrier Z contains aluminosilicate molecular sieve. Step S1 is as follows: the aluminosilicate molecular sieve powder is calcined in an air stream at 300-400°C for 1-3 hours and at 500-600°C for 3-5 hours. It is then ion-exchanged three times with 0.8-1.2 mol / L NH4Cl aqueous solution, each time at 70-80°C for 2-4 hours. After filtration, washing with softened water, and drying at 130-150°C for 1-3 hours, it is calcined in an air stream at 300-400°C for 0.5-1.5 hours and at 500-600°C for 2-4 hours to obtain aluminosilicate molecular sieve carrier powder. Step S3 involves adding a pore-forming agent and a binder to the catalyst powder obtained in step S2, mixing thoroughly, forming it into granules, and then calcining it at a constant temperature of 550-650℃ in an air stream for 4-6 hours to obtain the catalyst. x [A a M b (PO4) c ]- y G / z Z-particles.

6. The method according to claim 4 or 5, characterized in that, Step S2 is selected from one of the following (1) to (4): (1) b = 0, y = 0, the step S2 is as follows: prepare a phosphate solution of A, add it to the carrier powder obtained in step S1 according to the stoichiometric ratio, stir for 2-4 hours, evaporate to dryness, pulverize, and then calcine in an air stream at 300-400℃ for 0.5-1.5 hours, 500-600℃ for 1-3 hours and 700-800℃ for 4-6 hours to obtain catalyst powder; (2) b >0, y = 0, step S2 is as follows: prepare phosphoric acid solution, phosphate solution of A and nitrate solution of M respectively, add phosphoric acid solution and phosphate solution of A to the carrier powder obtained in step S1 according to the stoichiometric ratio while stirring, stir for 0.5~1.5h and then add nitrate solution of M, keep the temperature at 50~70℃ and continue stirring for 2~4h, then evaporate to dryness, pulverize, and calcine in air at 300~400℃ for 0.5~1.5h, 500~600℃ for 1~3h and 700~800℃ for 4~6h to obtain catalyst powder; (3) b = 0, y >0, step S2 is as follows: prepare a phosphate solution of A, add it to the carrier powder obtained in step S1 according to the stoichiometric ratio, stir for 2-4 h, then add the nitrate solution of rare earth metal elements in G, continue stirring for 1-2 h, evaporate to dryness and pulverize; then calcine in an air stream at 300-400℃ for 0.5-1.5 h, at 500-600℃ for 1-3 h and at 700-800℃ for 4-6 h to obtain catalyst powder; (4) b >0, y If >0, step S2 is as follows: prepare phosphoric acid solution, phosphate solution of A and nitrate solution of M respectively, and add phosphoric acid solution and phosphate solution of A to the carrier powder obtained in S1 according to the stoichiometric ratio while stirring, and continue stirring for 0.5~1.5h; then add nitrate solution of M, and continue stirring at 50~70℃ for 2~4h; then add nitrate solution of rare earth metal elements in G, and continue stirring for 1~3h before evaporating and pulverizing; then calcine in an air stream at 300~400℃ for 0.5~1.5h, 500~600℃ for 1~3h and 700~800℃ for 4~6h to obtain catalyst powder.

7. The method according to claim 4 or 5, characterized in that, In step S3, the pore-forming agent is at least one of water, nitric acid, acetic acid, citric acid, sorbic acid, terephthalic acid, stearic acid, ethylene glycol, 1,4-butanediol, glycerol, and vegetable oil, and the amount added is 4-10 wt% of the catalyst powder; the binder is at least one of guar gum powder, cellulose, methylcellulose, lignin, polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and starch, and the amount added is 5-15 wt% of the catalyst powder.

8. The use of the catalyst according to any one of claims 1-3 in the reaction for catalytic dehydration of hydroxyethyl alcohol to prepare alkyl vinyl ethers, characterized in that, The reaction is carried out in a fixed-bed reactor, a fluidized-bed reactor, or a moving-bed reactor; the feed to the reactor includes a dilution gas; the reaction conditions are: reaction temperature 350~500℃, system pressure 0.01~1.00MPa, and hydroxyl alcohol liquid hourly space velocity 0.05~5.00h⁻¹. -1 The gas hourly space velocity (VHSV) of the diluent gas is 0–3000 h⁻¹. -1 .

9. The application according to claim 8, characterized in that, The diluting gas is at least one of N2, CO2, N2-CO2 mixture, H2, N2-H2 mixture, oxygen-deficient air, oxygen-containing N2, oxygen-containing CO2, or industrial exhaust gas.

10. A method for preparing hydrocarbon vinyl ethers, characterized in that, The method includes preparing hydrocarbon vinyl ethers by catalytic dehydration of hydroxyl alcohol using the catalyst according to any one of claims 1-3.

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