Catalyst for preparing 4-hydroxybutyl vinyl ether and preparation method

Abstract

The invention provides a catalyst for preparing 4-hydroxybutyl vinyl ether and a preparation method thereof.The method comprises the following steps that S1, a metal precursor aqueous solution is provided, the metal precursor aqueous solution comprises aluminum salt, cerium salt and a template agent, and the molar ratio of the aluminum element to the cerium element in the metal precursor aqueous solution is 10: (1-3); s2, adjusting the pH value of the metal precursor aqueous solution to 9-10, and aging to obtain a precursor precipitate; s3, carrying out first calcination treatment on the precursor precipitate to remove the template agent and activate the precursor precipitate to obtain a metal oxide carrier; and S4, soaking the metal oxide carrier in a potassium salt solution to load potassium ions on the metal oxide carrier, and carrying out second calcination treatment to obtain the catalyst for preparing 4-hydroxybutyl vinyl ether. The catalyst obtained by the method is especially designed for preparation of 4-hydroxybutyl vinyl ether by addition of acetylene to 1, 4-butanediol, and the catalyst has good catalytic activity and selectivity for the reaction.

Description

Technical Field

[0001] The present application relates to the technical field of catalysts, and particularly relates to a catalyst for preparing 4-hydroxybutyl vinyl ether and a preparation method thereof. Background Art

[0002] 4-Hydroxybutyl vinyl ether (4-HBVE) is an important functional monomer and is widely used in fields such as photocurable coatings, adhesives, medical polymers, and high-performance plastics. Traditionally, the preparation of this monomer mainly relies on the addition reaction of acetylene and 1,4-butanediol (BDO). This reaction is usually carried out under alkaline conditions, and homogeneous catalysts such as potassium hydroxide (KOH) or potassium 1,4-butanediolate (BDO-K) are mostly used as catalysts.

[0003] However, these traditional homogeneous catalysts have many deficiencies. For example, homogeneous KOH or BDO-K is easily soluble and lost in the reaction medium, which is not conducive to the recovery and reuse of the catalyst. At the same time, the catalyst may decompose or sinter under high-temperature conditions, resulting in a decrease in catalytic activity. In addition, due to the too strong alkaline environment in the reaction, it is easy to cause excessive deprotonation of 1,4-butanediol and side reactions (such as dietherification, polymerization, etc.), thereby reducing the selectivity and purity of 4-HBVE and increasing the difficulty of subsequent separation and purification.

[0004] In view of the problems of traditional homogeneous catalysts, there are currently related technologies on the preparation of solid catalysts for the synthesis of 4-hydroxybutyl vinyl ether by the acetylene method. For example, Patent CN108187682A discloses a solid base catalyst for synthesizing 4-hydroxybutyl vinyl ether, its preparation method and application. This catalyst uses zirconia (ZrO2) as the carrier, and Cu and K are the active centers. The mass percentages of each component are: the active component cuprous oxide (Cu2O) is 1% - 15%, potassium oxide (K2O) is 10% - 35%, and the carrier ZrO2 is 50% - 89%. The preparation method is: mixing copper salt, potassium salt and zirconium salt, fully grinding, adding deionized water and stirring evenly, and then obtaining the catalyst through steps such as drying, calcination and liquid-phase reduction.

[0005] Based on this, there is a need to provide a catalyst for preparing 4-hydroxybutyl vinyl ether with good catalytic activity and selectivity. Summary of the Invention

[0006] The present application provides a catalyst for preparing 4-hydroxybutyl vinyl ether and a preparation method thereof. The catalyst prepared by this method has good catalytic activity and selectivity for the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether.

[0007] In a first aspect, the present application provides a method for preparing a catalyst for preparing 4-hydroxybutyl vinyl ether, comprising the following steps:

[0008] S1: Provide an aqueous solution of a metal precursor, the aqueous solution of the metal precursor comprising an aluminum salt, a cerium salt, and a template agent, wherein the molar ratio of aluminum element to cerium element in the aqueous solution of the metal precursor is 10:1 to 3;

[0009] S2: Adjust the pH of the aqueous solution of the metal precursor to 9 to 10, and age to obtain a precursor precipitate;

[0010] S3: Subject the precursor precipitate to a first calcination treatment to remove the template agent and activate it to obtain a metal oxide support;

[0011] S4: Immerse the metal oxide support in a potassium salt solution to load potassium ions onto the metal oxide support, and perform a second calcination treatment to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether.

[0012] According to the present application, this method combines the coprecipitation method with a template agent, and loads and introduces K step by step + to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether. The catalyst uses alumina as the main material and cooperates with a template agent to improve the specific surface area and pore uniformity of the catalyst, and improve the mass transfer efficiency of the reactants; through coprecipitation, cerium oxide is loaded, and cerium oxide can form rich oxygen vacancies through the Ce 4+ / Ce 3+ cycle, which can adsorb and activate acetylene in a suitable orientation. The oxygen vacancies will cause the π electron cloud of the acetylene adsorbed nearby to shift, making the carbon-carbon triple bond more easily polarized, and thus more easily undergo a mono-addition reaction with the activated 1,4-butanediol, improving the reaction activity and selectivity; at the same time, the Lewis acid sites provided by alumina in the catalyst cooperate with the loaded K + to provide Lewis base sites. The Lewis acid sites can accept electron pairs and cooperate with the oxygen vacancies to further stably adsorb and activate acetylene. The Lewis base sites can promote the deprotonation of BDO to form a more active BDO - , improving its ability to nucleophilically attack acetylene. The two cooperate with each other to make the activation rates of acetylene and BDO match. Thus, while increasing the reaction rate of the addition of acetylene to 1,4-butanediol, the self-condensation of BDO, the self-polymerization of acetylene, and the double-addition reaction of acetylene and BDO can be reduced through acid-base balance, so that the obtained catalyst has good catalytic activity and selectivity for the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether.

[0013] Specifically, in step S1, a co-precipitation method is used in combination with a templating agent to obtain a precursor precipitate. The molar ratio of aluminum element to cerium element in the metal precursor aqueous solution is 10:1 to 3, and the catalyst uses alumina as the main material. The combination of the templating agent can endow the catalyst with a large specific surface area and uniform pores. At the same time, alumina has good heat resistance and has a good + anchoring effect on K, which can reduce sintering and loss, and endow the catalyst with better thermal stability and catalytic stability; through the co-precipitation method, cerium oxide is uniformly loaded on the alumina main material, and the oxygen vacancies provided by cerium oxide cooperate with the Lewis acid sites of alumina to have a better adsorption and activation effect on acetylene; at the same time, the molar ratio of aluminum element to cerium element in the metal precursor aqueous solution is limited. It can be understood that if the doping amount of cerium oxide is too high, it may lead to unstable catalyst structure, partial sintering resulting in a decrease in specific surface area, and may also lead to an excessive number of basic sites, resulting in a decrease; if the doping amount of cerium oxide is too low, it may make the oxygen vacancy concentration on the catalyst lower, affecting the catalytic activity and selectivity of the catalyst;

[0014] In step S2, by adjusting the pH to 9-10, the metal ions in the metal precursor aqueous solution are precipitated, and the templating agent is coated during the aging process, which can improve the stability of the mesopores in the catalyst;

[0015] In step S3, the precursor precipitate is subjected to a first calcination treatment to remove the templating agent in the precursor precipitate and activate it, so that the obtained metal oxide support has a large surface area and uniform pores, and the obtained catalyst has a faster mass transfer efficiency, thereby enabling the catalyst to have good catalytic activity and selectivity;

[0016] In step S4, the metal oxide support is immersed in a potassium salt solution to load potassium ions. In this application, potassium ions are not synchronously loaded during the co-precipitation process. The reason is that although generally, loading potassium ions during the co-precipitation process will make the loading more uniform, in order to form uniform pores in the catalyst, a templating agent is added to the metal precursor aqueous solution. During the first calcination process, K + may agglomerate or be lost, resulting in a reduction in Lewis base sites on the catalyst, thereby reducing the catalytic activity and selectivity of the catalyst; by performing stepwise loading, the templating agent is fully removed during the first calcination process, and the metal oxide support is activated. The Lewis acid sites of alumina and the oxygen vacancies of cerium oxide have a good + anchoring effect on K, thereby stably loading K + and, through milder second calcination treatment conditions, the agglomeration or loss of K + can be reduced, enabling K +It is more evenly distributed on the catalyst, and in combination with the Lewis acid sites and oxygen vacancies on the metal oxide support, the resulting catalyst has good catalytic activity and selectivity for the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether.

[0017] In some embodiments, the template agent includes a polyoxypropylene-polyoxyethylene copolymer and cetyltrimethylammonium bromide, wherein the mass ratio of the polyoxypropylene-polyoxyethylene copolymer to cetyltrimethylammonium bromide is 1:0.5 to 1.

[0018] In some of the above embodiments, when the polyoxypropylene-polyoxyethylene copolymer and cetyltrimethylammonium bromide in the above mass ratio are used as the template agent, the resulting catalyst has better catalytic activity and selectivity. The reason may be that the polyoxypropylene-polyoxyethylene copolymer cooperates with cetyltrimethylammonium bromide, and a stable hierarchical pore structure can be formed through the dual-template effect, which can further increase the specific surface area and pore uniformity of the catalyst, thereby enabling the catalyst to have a faster mass transfer rate, improving the reaction efficiency and reducing side reactions, and making the catalyst have better catalytic activity and selectivity.

[0019] In some embodiments, in the step S1, the metal precursor aqueous solution further includes a titanium salt, and the molar ratio of aluminum element to titanium element in the metal precursor aqueous solution is 10:0.2 to 1.

[0020] In some of the above embodiments, the inventors found that further doping a certain content of titanium dioxide in the catalyst, compared with no doping or further doping other metal oxides (such as zirconium), the catalyst has better catalytic activity and selectivity. The reason may be that the radius of Ti 4+ is smaller than that of Ce 4+ , and appropriate doping can cause lattice distortion and promote Ce 4+ to Ce 3+The transformation can induce the catalyst to form more oxygen vacancies, which can promote the subsequent loading of potassium ions and the adsorption and activation of acetylene. In addition, the surface of titanium dioxide also has strong Lewis acid sites, which can also improve the stability of potassium ion loading, thereby further improving the reaction activity and selectivity of the catalyst. At the same time, titanium dioxide has a high melting point and a stable crystal structure. Compared with increasing the Ce content to increase the oxygen vacancy concentration, appropriately doping titanium dioxide can improve the structural stability of the catalyst, thereby improving its thermal stability while improving the catalytic activity. On the other hand, the inventors found that when the doping amount of titanium dioxide is too much, the selectivity and catalytic stability of the catalyst will be reduced. The reason may be that due to the strong Lewis acidity of titanium dioxide, it will activate the hydroxyl group of BDO, increase its dehydration tendency, and reduce the selectivity of the catalyst; it may also be that acetylene is over-adsorbed and polymerized, and the polymer may be deposited on the surface of the catalyst, affecting the reaction activity of the catalyst.

[0021] In some embodiments, in step S3, the conditions of the first calcination treatment include: calcining in an oxygen-containing atmosphere at 350-450 °C for 1-3 h, and then continuing to calcine in a reducing atmosphere at 550-700 °C for 2-4 h, wherein the reducing atmosphere includes hydrogen and nitrogen, and the volume fraction of hydrogen is 5%-10%.

[0022] In the above-mentioned some embodiments, under the above-mentioned treatment conditions, the obtained catalyst has better catalytic activity and selectivity. The first calcination treatment specifically includes two-stage calcination steps. First, calcine in an oxygen-containing atmosphere at 350-450 °C for 1-3 h. During this process, the template agent can be fully oxidized and decomposed, forming uniform pores in the catalyst, making the catalyst have better mass transfer efficiency. At the same time, the full oxidation and decomposition of the template agent can reduce the deposition of carbon from the template agent in the pores and on the surface of the catalyst, reducing the influence of the deposited carbon on the activity of the catalyst; subsequently, in the second stage, calcine in a reducing atmosphere at 550-700 °C for reduction calcination treatment, which can induce CeO2 to form part of Ce 3+ , thereby increasing the oxygen vacancy concentration on the metal oxide support, fully activating the metal oxide support, and improving the stability of subsequent loading of K + . At the same time, coordinating with the Lewis acid sites of the catalyst, the catalyst has better catalytic activity and selectivity.

[0023] As an example, the reaction formula of CeO2 in the second-stage reduction calcination is:

[0024] CeO2 + xH2 → CeO 2-x + xH2O

[0025] During this process, part of CeO2 is deoxidized and reduced to CeO 2-x , forming oxygen vacancies on the metal oxide support.

[0026] In some ways, in step S4, the conditions for the second calcination treatment include: annealing at 300-400 °C for 2-4 h in a nitrogen atmosphere.

[0027] In some of the above embodiments, the second calcination treatment is carried out by loading potassium ions on a metal oxide support. Therefore, annealing treatment is carried out at 300-400 °C in a nitrogen range. Among them, treatment in a nitrogen atmosphere can reduce the influence of calcination on oxygen vacancies, and utilize the anchoring effect of oxygen vacancies and Lewis acid sites on potassium ions, thereby reducing the migration and loss of potassium ions; annealing and calcination at 300-400 °C can improve the interaction between potassium ions and the support, maintain the dispersion of potassium ions, and reduce the agglomeration and deactivation of potassium ions. Therefore, under these conditions, the second calcination treatment is carried out, and the obtained catalyst has better catalytic activity and selectivity.

[0028] It can be understood that the cooling process after the second calcination treatment also needs to be carried out in a nitrogen atmosphere to reduce the influence of oxygen vacancies on the catalyst during the cooling process.

[0029] From the above embodiments, it can be seen that if potassium ions are co-precipitated and loaded in an aqueous solution of a metal precursor, in the first oxidative calcination stage of the first calcination treatment, calcination in an oxygen atmosphere may cause agglomeration and loss of potassium ions. And in this process, cerium oxide is not subjected to reduction calcination treatment, and only binds to potassium ions through the Lewis acid sites on the surface of alumina, and the anchoring effect is weak, and potassium ions will be severely lost during this calcination process; in addition, in the subsequent second reduction calcination stage, due to the high calcination temperature, and water is generated during the partial deoxidation and reduction of CeO2 to CeO 2-x process, which may further cause the loss of potassium ions. Therefore, in the preparation method provided in the present application, by loading potassium ions step by step, the stable loading of potassium ions can be more effectively achieved, and the Lewis acid sites and oxygen vacancies on the catalyst are coordinated, so that the catalyst has good catalytic activity and selectivity.

[0030] In some embodiments, in step S1, the molar concentration of aluminum element in the aqueous solution of the metal precursor is 0.1-0.5 mol / L, and the mass percentage content of the template agent in the aqueous solution of the metal precursor is 1%-5%.

[0031] In some of the above embodiments, under the above conditions, a catalyst with a relatively high specific surface area and uniform pores can be obtained, so that the catalyst has better mass transfer efficiency and better catalytic activity and selectivity.

[0032] In some embodiments, step S2 includes: adjusting the pH of the aqueous solution of the metal precursor to 9-10 with ammonia water, stirring and aging for 6-12 h, and filtering to obtain a precursor precipitate.

[0033] In some of the above embodiments, ammonia water is used to adjust the pH of the aqueous solution of the metal precursor to 9-10. Ammonia water is not easily residual during subsequent treatment. A pH of 9-10 can cause the metal ions to precipitate sufficiently, and by stirring and aging for 6-12 hours, the metal precipitate can coat the template agent to obtain a precursor precipitate. This precursor precipitate can obtain a catalyst with good catalytic activity and selectivity through subsequent treatment.

[0034] In some embodiments, step S4 includes: soaking the metal oxide support in an aqueous solution of potassium salt, stirring and impregnating for 6-12 h, filtering to obtain a filter cake, and performing a second calcination treatment on the filter cake to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether; wherein, the molar concentration of potassium element in the aqueous solution of potassium salt is 0.2-0.3 mol / L.

[0035] In some of the above embodiments, it can be understood that by soaking the metal oxide support in an aqueous solution of potassium salt, impregnating for 6-12 h can make the metal oxide support reach the adsorption-desorption equilibrium. By adjusting the molar concentration of potassium element in the aqueous solution of potassium salt, the loading amount of potassium ions in the catalyst can be controlled, so as to provide appropriate Lewis base sites for the catalyst, and at the same time balance the Lewis acid sites on the surface of the metal oxide support, cooperate with the oxygen vacancies on the catalyst, make the activation rates of acetylene and BDO match, and make the obtained catalyst have better catalytic activity and selectivity.

[0036] It should be noted that the metal salts described in this application, including but not limited to aluminum salts, cerium salts, titanium salts and potassium salts, all refer to compounds that can ionize corresponding metal ions in a suitable solvent in a broad sense. For example, potassium salts can include but not limited to potassium nitrate, potassium chloride, potassium hydroxide. As an example, in an embodiment of the present application, Al(NO3)3·9H2O is used as the aluminum salt, Ce(NH4)2(NO3)6 is used as the cerium salt, TiCl4 is used as the titanium salt, and potassium nitrate is used as the potassium salt.

[0037] In a second aspect, the present application provides a catalyst for preparing 4-hydroxybutyl vinyl ether, which is prepared by the method according to any one of the embodiments of the first aspect.

[0038] According to the present application, the catalyst prepared by the method according to any one of the embodiments of the first aspect has good catalytic activity and selectivity for the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether.

[0039] In a third aspect, the present application provides an application of the catalyst according to any one of the embodiments of the second aspect in the preparation of 4-hydroxybutyl vinyl ether by the acetylene method.

[0040] According to the present application, since the catalyst provided in the second aspect has good catalytic activity and selectivity for the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether, when it is applied to the preparation of 4-hydroxybutyl vinyl ether by the acetylene method, the conversion rate of BDO can be effectively increased, and the yield of the product 4-hydroxybutyl vinyl ether can be increased.

[0041] In a fourth aspect, the present application provides a method for preparing 4-hydroxybutyl vinyl ether. 1,4-butanediol and acetylene are catalyzed by the catalyst according to any one of the embodiments of the second aspect to obtain 4-hydroxybutyl vinyl ether.

[0042] According to the present application, since the catalyst provided in the second aspect has good catalytic activity and selectivity for the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether, it can effectively increase the conversion rate of BDO and increase the yield of the product 4-hydroxybutyl vinyl ether.

[0043] In some embodiments, dimethyl sulfoxide is further added to the reaction system. Based on the above embodiments, adding an appropriate amount of dimethyl sulfoxide as a solvent in the system can synergistically with the catalyst to further increase the conversion rate of BDO and the yield of the product 4-hydroxybutyl vinyl ether.

[0044] Compared with the prior art, the beneficial effects of the present application are at least as follows:

[0045] The catalyst for preparing 4-hydroxybutyl vinyl ether prepared by the method provided in the present application is combined with alumina as the main material and a templating agent, so that the catalyst has a large specific surface area and uniform possible pores, has a fast mass transfer efficiency, and has Lewis acid sites, Lewis base sites and oxygen vacancies suitable for catalyzing the addition of acetylene to 1,4-butanediol to prepare 4-hydroxybutyl vinyl ether. Therefore, the catalyst has good catalytic activity and selectivity for the preparation of 4-hydroxybutyl vinyl ether by the acetylene method.

[0046] Using this catalyst for the preparation of 4-hydroxybutyl vinyl ether by the acetylene method can effectively increase the conversion rate of BDO and increase the yield of the product 4-hydroxybutyl vinyl ether. Specific Embodiments

[0047] In the present specification, the embodiments or implementation schemes are described in a progressive manner. The key points of each embodiment are all the differences from other embodiments.

[0048] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0049] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0050] In the expressions of this specification, unless otherwise specified, "parts" all refer to "parts by mass".

[0051] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application and cannot be understood as a limitation to the present application. For those technical or conditions not specified in the embodiments, they shall be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For the reagents or instruments whose manufacturers are not indicated, they are all conventional products that can be obtained through commercial purchase.

[0052] The polyoxypropylene polyoxyethylene copolymer, with a CAS number of 106392 - 12 - 5 and a number - average molecular weight Mn of 2500, was purchased from Hubei Dalili Chemical Co., Ltd.

[0053] Example 1

[0054] Preparation of the catalyst for preparing 4 - hydroxybutyl vinyl ether:

[0055] Dissolve Al(NO3)3·9H2O, Ce(NH4)2(NO3)6, and TiCl4 in water to obtain an aqueous metal precursor solution, where the concentration of Al 3+ is 0.2 mol / L, and the molar ratio of Al 3+ , Ce 4+ , Ti 4+ is 10:2:1. Then add a templating agent, which is a polyoxypropylene polyoxyethylene copolymer and cetyltrimethylammonium bromide with a mass ratio of 1:0.5, and the concentration of the templating agent is 3 wt%, and mix evenly;

[0056] Add 25 wt% ammonia water to the above aqueous solution, adjust the pH to 10, stir and age for 10 h, filter to obtain the precursor precipitate, and wash it with water three times;

[0057] Then place the precursor precipitate in a tubular furnace, introduce air, heat it to 400 °C at a heating rate of 10 °C / min and hold for 2 h, then introduce a hydrogen-nitrogen mixture (V / V is 5 / 95), heat it to 600 °C at a heating rate of 10 °C / min and hold for 3 h, and cool it to room temperature in the above mixture to obtain a metal oxide support;

[0058] Then soak the metal oxide in an aqueous solution of potassium nitrate with a concentration of 0.3 mol / L, stir and impregnate for 6 - 12 h, filter to obtain a filter cake, wash it with water three times, then place the filter cake in a tubular furnace, introduce nitrogen, heat it to 350 °C at a heating rate of 10 °C / min and hold for 3 h, and cool it to room temperature in a nitrogen atmosphere to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether.

[0059] Example 2

[0060] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0061] It is substantially the same as Example 1, except that the template agent is a polyoxypropylene-polyoxyethylene copolymer.

[0062] Example 3

[0063] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0064] It is substantially the same as Example 1, except that the template agent is cetyltrimethylammonium bromide.

[0065] Example 4

[0066] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0067] It is substantially the same as Example 1, except that TiCl4 is not added to the metal precursor aqueous solution.

[0068] Example 5

[0069] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0070] It is substantially the same as Example 1, except that the molar ratio of Al 3+ 、Ce 4+ 、Ti 4+ in the metal precursor aqueous solution is 10:2:0.2.

[0071] Example 6

[0072] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0073] It is substantially the same as Example 1, except that: in the aqueous solution of metal precursor, the molar ratio of Al 3+ , Ce 4+ , Ti 4+ is 10:2:1.5.

[0074] Example 7

[0075] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0076] It is substantially the same as Example 1, except that: TiCl4 is not added to the aqueous solution of metal precursor, ZrOCl2·8H2O is added, and the molar ratio of Al 3+ , Ce 4+ , Zr 4+ in the aqueous solution of metal precursor is 10:2:1.

[0077] Example 8

[0078] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0079] It is substantially the same as Example 1, except that: the conditions for the first calcination treatment of the precursor precipitate are different. Specifically:

[0080] Then place the precursor precipitate in a tubular furnace, introduce air, heat it to 400°C at a heating rate of 10°C / min and hold for 2 h, then heat it to 600°C at a heating rate of 10°C / min and hold for 3 h, and cool it to room temperature in an air atmosphere to obtain the metal oxide support.

[0081] Example 9

[0082] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0083] It is substantially the same as Example 1, except that: the conditions for the first calcination treatment of the precursor precipitate are different. Specifically:

[0084] Then place the precursor precipitate in a tubular furnace, introduce a hydrogen-nitrogen mixture (V / V is 5 / 95), heat it to 400°C at a heating rate of 10°C / min and hold for 2 h, then heat it to 600°C at a heating rate of 10°C / min and hold for 3 h, and cool it to room temperature in the above mixture to obtain the metal oxide support.

[0085] Example 10

[0086] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0087] It is substantially the same as Example 1, except that: the concentration of the potassium nitrate aqueous solution in which the metal oxide support is immersed is 0.2 mol / L.

[0088] Example 11

[0089] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0090] It is substantially the same as Example 1, except that: the concentration of the potassium nitrate aqueous solution in which the metal oxide support is immersed is 0.5 mol / L.

[0091] Comparative Example 1

[0092] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0093] Dissolve Al(NO3)3·9H2O in water to obtain an aqueous metal precursor solution, where the concentration of Al 3+ is 0.26 mol / L, then add a templating agent, the templating agent is a polyoxypropylene polyoxyethylene copolymer and cetyltrimethylammonium bromide with a mass ratio of 1:0.5, and mix evenly;

[0094] Drop 25 wt% ammonia water into the above aqueous solution, adjust the pH to 10, stir and age for 10 h, filter to obtain a precursor precipitate, and wash it 3 times with water;

[0095] Then place the precursor precipitate in a tube furnace, introduce air, heat it to 400 °C at a heating rate of 10 °C / min and hold for 2 h, then introduce a hydrogen-nitrogen mixture (V / V is 5 / 95), heat it to 600 °C at a heating rate of 10 °C / min and hold for 3 h, and cool it to room temperature in the above mixture to obtain a metal oxide support;

[0096] Then immerse the metal oxide in a 0.3 mol / L potassium nitrate aqueous solution, stir and impregnate for 6 - 12 h, filter to obtain a filter cake, wash the filter cake 3 times with water, then place the filter cake in a tube furnace, introduce nitrogen, heat it to 350 °C at a heating rate of 10 °C / min and hold for 3 h, and cool it to room temperature in a nitrogen atmosphere to obtain the catalyst for preparing 4-hydroxybutyl vinyl ether.

[0097] Comparative Example 2

[0098] Preparation of the catalyst for preparing 4-hydroxybutyl vinyl ether:

[0099] Dissolve Al(NO3)3·9H2O, Ce(NH4)2(NO3)6, TiCl4, and KNO3 in water to obtain an aqueous metal precursor solution, where the concentration of Al 3+ is 0.2 mol / L, Al 3+ , Ce 4+ , Ti4+ The molar ratio of is 10:2:1, K + The concentration of is 0.3 mol / L. Then add a templating agent, which is a copolymer of polyoxypropylene and polyoxyethylene with a mass ratio of 1:0.5 and cetyltrimethylammonium bromide, and mix evenly;

[0100] Drop 25 wt% ammonia water into the above aqueous solution, adjust the pH to 10, stir and age for 10 h, filter to obtain a precursor precipitate, and wash it 3 times with water;

[0101] Then place the precursor precipitate in a tube furnace, introduce air, heat it to 400 °C at a heating rate of 10 °C / min and hold for 2 h, then introduce a hydrogen-nitrogen mixture (V / V is 5 / 95), heat it to 600 °C at a heating rate of 10 °C / min and hold for 3 h, and cool it to room temperature in the above mixture to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether.

[0102] Testing part

[0103] Detection of the catalytic activity and selectivity of the catalyst:

[0104] Add 20 g of BDO and 3 g of the catalyst to be tested into a three-necked flask, configure a gas conduit, a thermometer and a condenser, connect the reaction device well, open the nitrogen valve to purge the reaction device and then heat it to 160 °C, close the nitrogen valve, open the acetylene valve, and introduce acetylene into the reaction solution at a flow rate of 0.15 L / min. React for 8 h. After the reaction is completed, introduce nitrogen to cool it to room temperature, take a sample of the reaction solution, use gas chromatography to detect the conversion rate of BDO and the yield of 4-HBVE, and calculate the selectivity of the catalyst to be tested. The test results are shown in Table 1.

[0105] Gas chromatography conditions:

[0106] Instrument: FULI-9790 type gas chromatograph;

[0107] Chromatographic column: DB-FFAP type capillary column, specification Φ0.25 mm * 30 m;

[0108] Detector: Hydrogen flame ionization detector;

[0109] Detection conditions:

[0110] Vaporization temperature: 220 °C;

[0111] Detection temperature: 240 °C;

[0112] Column temperature (programmed temperature rise): initial temperature 100 °C, heating rate 10 °C / min, final temperature 220 °C, hold for 30 minutes;

[0113] Carrier gas gauge pressure:

[0114] Nitrogen: 0.08 MPa;

[0115] Hydrogen: 0.15 MPa;

[0116] Air: 0.035 MPa;

[0117] Sample injection volume: 0.4 μL.

[0118] Table 1

[0119]

[0120]

[0121] As can be seen from Table 1, compared with each comparative example, the catalysts obtained in each example have higher BDO conversion rate and selectivity, indicating that the catalyst provided by the present application has good catalytic activity and selectivity for the addition of acetylene to BDO to prepare 4-HBVE. The reason may be that in Comparative Example 1, only alumina is used as the catalyst carrier, lacking oxygen vacancies, having poor anchoring ability for potassium ions, and poor adsorption and activation effect on acetylene, so its catalytic activity and selectivity are poor; in Comparative Example 2, potassium ions are loaded by coprecipitation. Since the catalyst is not activated, the anchoring ability for potassium ions is poor, and potassium ions are likely to migrate and lose during the subsequent calcination process, resulting in poor catalytic activity and selectivity of the catalyst.

[0122] As can be seen from Examples 1 to 3, using different template agents has a certain influence on the catalytic activity and selectivity of the catalyst. When using polyoxypropylene polyoxyethylene copolymer and cetyltrimethylammonium bromide as template agents in a certain mass ratio, the catalytic activity and selectivity of the catalyst are better.

[0123] As can be seen from Examples 1, 4 to 7, further doping a certain content of metal oxide on the basis of alumina and ceria has a certain influence on the catalytic activity and selectivity of the catalyst. When doping titanium oxide and the molar ratio of aluminum element to titanium element is 10:0.2 to 1, the catalytic activity and selectivity of the catalyst are better.

[0124] As can be seen from Examples 1, 8, 9, the conditions of the first calcination treatment on the precursor precipitate have a certain influence on the catalytic activity and selectivity of the catalyst. The metal oxide carrier obtained by first performing oxidative calcination and then calcination activation, and the further prepared catalyst has better catalytic activity and selectivity.

[0125] As can be seen from Examples 1, 10, 11, loading potassium ions on the metal oxide carrier in different concentrations of potassium salts has a certain influence on the catalytic activity and selectivity of the catalyst. When the potassium salt concentration is 0.2 to 0.3 mol / L, the obtained catalyst has better catalytic activity and selectivity.

[0126] In addition, the catalytic stability of the catalyst obtained in Example 1 was tested. After the reaction, the catalyst was filtered and washed, placed in a tubular furnace, heated to 350 °C at a heating rate of 10 °C / min and held for 3 h to obtain a recovered catalyst. Then, the catalytic activity and selectivity of the above catalyst were detected, and the cycle test was carried out 4 times. The catalytic activity and selectivity of the catalyst recovered for the 4th time were detected. The BDO conversion rate and 4-HBVE yield were 75.6% and 73.5% respectively, and its selectivity was calculated to be 97.2%. This shows that the catalyst has good catalytic stability. At the same time, it can be understood that when its catalytic activity and selectivity are significantly reduced, activation loading can be carried out again according to the situation, and catalytic activity regeneration can be achieved. Therefore, the catalyst provided in this application is easy to be recovered and reused multiple times.

[0127] Furthermore, during the process of detecting the catalytic activity and selectivity of the catalyst obtained in Example 1, the inventor further added 10 g of dimethyl sulfoxide to the reaction system and tested under the same other conditions. At this time, the BDO conversion rate and 4-HBVE yield were 88.5% and 87.3% respectively, and the selectivity was calculated to be 98.6%. As a control group, 3 g of potassium hydroxide was used as the catalyst, and 10 g of dimethyl sulfoxide was added, and the test was carried out under the same other conditions. At this time, the BDO conversion rate and 4-HBVE yield were 79.2% and 46.8% respectively, and the selectivity was calculated to be 59.1%.

[0128] This shows that the catalyst provided in this application in combination with dimethyl sulfoxide can further improve the BDO yield and 4-HBVE yield. Compared with using potassium hydroxide as the catalyst in the control group, it can improve the BDO yield and 4-HBVE yield, especially the 4-HBVE yield.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a catalyst for preparing 4-hydroxybutyl vinyl ether, characterized in that: The following steps are involved: S1: providing a metal precursor aqueous solution, wherein the metal precursor aqueous solution comprises an aluminum salt, a cerium salt and a template, wherein the molar ratio of the aluminum element to the cerium element in the metal precursor aqueous solution is 10:1-3; S2: adjusting the pH of the metal precursor aqueous solution to 9-10, and aging to obtain a precursor precipitate; S3: subjecting the precursor precipitate to a first calcination treatment to remove the template and activate it to obtain a metal oxide support; S4: soaking the metal oxide support in a potassium salt solution to load potassium ions on the metal oxide support, and performing a second calcination treatment to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether.

2. The method according to claim 1, characterized in that The template agent comprises polyoxypropylene polyoxyethylene copolymer and hexadecyl trimethyl ammonium bromide, wherein the mass ratio of the polyoxypropylene polyoxyethylene copolymer to the hexadecyl trimethyl ammonium bromide is 1:0.5-1.

3. The method according to claim 1, characterized in that: In the step S1, The metal precursor aqueous solution also includes titanium salt, and the molar ratio of aluminum element to titanium element in the metal precursor aqueous solution is 10:0.2-1.

4. The method according to any one of claims 1 to 3, characterized in that: In the step S3, The conditions of the first calcination treatment include: calcination treatment at 350-450°C in an oxygen-containing atmosphere for 1-3 hours, and then calcination treatment at 550-700°C in a reducing atmosphere for 2-4 hours, wherein the reducing atmosphere includes hydrogen and nitrogen, and the volume fraction of hydrogen is 5%-10%.

5. The method according to claim 4, characterized in that In the step S4, The conditions of the second calcination treatment include: annealing treatment at 300-400° C. for 2-4 hours in a nitrogen atmosphere.

6. The method according to claim 1, characterized in that In the step S1, The molar concentration of aluminum element in the metal precursor aqueous solution is 0.1-0.5 mol / L, and the mass percentage of the template agent in the metal precursor aqueous solution is 1%-5%.

7. The method according to claim 1, characterized in that The step S2 comprises: Ammonia water is used to adjust the pH of the metal precursor aqueous solution to 9-10, and the solution is stirred and aged for 6-12 hours, and the precursor precipitate is obtained by filtration.

8. The method according to claim 5, characterized in that The step S4 comprises: The metal oxide support is immersed in a potassium salt aqueous solution, stirred and immersed for 6 to 12 hours, filtered to obtain a filter cake, and the filter cake is subjected to a second calcination treatment to obtain a catalyst for preparing 4-hydroxybutyl vinyl ether; wherein the molar concentration of potassium element in the potassium salt aqueous solution is 0.2 to 0.3 mol / L.

9. A catalyst for preparing 4-hydroxybutyl vinyl ether, characterized in that Prepared according to the method according to any one of claims 1 to 8.

10. A method for preparing 4-hydroxybutyl vinyl ether, characterized in that: 1,4-butanediol and acetylene are reacted with the catalyst according to claim 9 to obtain 4-hydroxybutyl vinyl ether.

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