A WO 3 -SiO 2 -ZrO 2 Solid acid catalyst and its preparation method

Abstract

The present invention discloses a WO3-SiO2-ZrO2 solid acid catalyst and a preparation method thereof. In this catalyst, the loading amount of WO3 is 5.0-15.0 wt%, the loading amount of SiO2 is 2.5-20.0 wt%, and the balance is ZrO2. The preparation method is as follows: a tungsten-containing compound and a zirconium-containing compound are mixed and dissolved; then silica sol, a surfactant and a precipitant are added to form a gel, which is then obtained through filtration, washing and calcination. Through the gel adsorption effect, the solid acid catalyst enables a strong interaction between the active species and the carrier, thereby improving the recycling utilization rate of the catalyst; it is synthesized in one step by a simple and easy precipitation method, and the raw materials are cheap and easily available; as a heterogeneous catalyst, it is easy to separate, and can effectively reduce the residual amount of heavy metal tungsten in tartaric acid crystallization. It still has a high DL-tartaric acid yield during recycling, reducing the production cost of tartaric acid; it is suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to an acid catalyst and a preparation method thereof, and particularly relates to a WO 3 -SiO 2 -ZrO 2 solid acid catalyst and a preparation method thereof. Background Art

[0002] Tartaric acid (2,3-dihydroxybutanedioic acid) is a carboxylic acid and has wide applications as an additive and a resolving agent in the food and pharmaceutical fields. Using maleic anhydride as a raw material, hydrogen peroxide as an oxidant, and tungstic acid as a catalyst, catalytic oxidation is carried out to generate epoxybutanedioic acid, which is then hydrolyzed to obtain tartaric acid, and then cooled, crystallized, separated, and dried to obtain DL-tartaric acid. Although the tungstic acid catalyst can achieve a relatively high tartaric acid yield, as a homogeneous catalyst, it has the disadvantage of being difficult to separate, which easily causes the heavy metal content in the tartaric acid product to exceed the standard.

[0003] Currently, the heterogeneous catalysts used for the catalytic oxidation of maleic anhydride or maleic acid to tartaric acid are mainly catalysts with WO 3 as the active component supported on different carriers.

[0004] Patent CN1381436 discloses the synthesis of WO 3 -MCM-41 catalyst by a hydrothermal method for the preparation of tartaric acid from maleic acid. After one cycle, the tartaric acid yield decreased by 13%; Hao Jia (Fine Chemicals, 2016, 33: 440-444) used an impregnation method to load phosphotungstic acid onto silica spheres to prepare a PW / SiO 2 catalyst for the preparation of tartaric acid from maleic acid. After one cycle, the tartaric acid yield decreased by 33%. The decrease in the tartaric acid yield is due to the relatively weak interaction between the active species and the carrier, resulting in more active components WO 3 and phosphorus eluting into the reaction solution during the reaction, ultimately leading to more tungsten and phosphorus in the tartaric acid crystal product. In addition, the synthesis period of the WO 3 -MCM-41 catalyst prepared by the hydrothermal method is long and requires high-temperature and high-pressure operation steps. This method has high requirements for production equipment and is not easy to scale up production. The preparation of PW / SiO 2 and WO 3 / TiO 2 catalysts requires the preparation of the carrier first and then impregnation and loading of WO 3 , with a relatively long production cycle and a relatively complex process.

[0005] Therefore, the existing heterogeneous catalysts mainly have the following disadvantages: complex preparation process, long production cycle, inability to be recycled, and easy to cause the high cost of catalyst use, thus increasing the production cost of tartaric acid. Summary of the Invention

[0006] Object of the Invention: The object of the present invention is to provide a WO solid acid catalyst with strong binding force between the active substance and the carrier and easy recycling. 3 -SiO 2 -ZrO 2 ;

[0007] Another object of the present invention is to provide a preparation method of a WO solid acid catalyst with easily available raw materials, simple process and easy recycling. 3 -SiO 2 -ZrO 2

[0008] Technical Solution: The WO solid acid catalyst described in the present invention has a loading amount of WO of 5.0 - 15.0 wt%, a loading amount of SiO of 2.5 - 20.0 wt%, and the balance is ZrO. 3 -SiO 2 -ZrO 2 Among them, preferably, the loading amount of WO is 7.5 - 15.0 wt%, the loading amount of SiO is 2.5 - 10.0 wt%, and the rest is ZrO. 3 -SiO 2 -ZrO 2 3 2 2

[0009] Among them, the WO solid acid catalyst is synthesized in one step by the precipitation method. The raw materials of the WO solid acid catalyst include tungsten-containing compounds, silicon-containing compounds, and zirconium-containing compounds, and the tungsten-containing compounds are adsorbed on the gels of silicon hydroxide and zirconium hydroxide. 3 2 2

[0010] The preparation method of the above-mentioned WO solid acid catalyst includes the following steps: 3 -SiO 2 -ZrO 2 3 -SiO 2 -ZrO 2

[0011] 3 -SiO 2 -ZrO 2 (1) Mix and dissolve the tungsten-containing compound and the zirconium-containing compound;

[0012] (2) Add silica sol, surfactant and precipitant to form a gel, and then obtain the product after filtration, washing and calcination.

[0013] (2) Add silica sol, surfactant and precipitant to form a gel, and then obtain the product after filtration, washing and calcination.​​​​​​​​​​​

[0014] The tungsten-containing compound is at least one of ammonium metatungstate, ammonium tungstate, sodium tungstate or phosphotungstic acid; the zirconium-containing compound is at least one of zirconium oxychloride, zirconium nitrate or zirconium sulfate. The silica sol is preferably acidic silica sol.

[0015] Wherein, the precipitant is one of ammonia water, NaOH, KOH or urea; the concentration of the precipitant solution is 1.0-12.0 mol / L, preferably 1.0-6.0 mol / L; after adding the precipitant, the pH of the system is 7-14.

[0016] Wherein, the concentration of the zirconium compound solution is 0.1-2.0 mol / L, preferably 0.1-0.5 mol / L.

[0017] Wherein, the surfactant is at least one of polyethylene glycol, polyvinyl alcohol, Tween-80, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and fluorine-containing anionic surfactant.

[0018] Wherein, the dosage of the surfactant is WO 3 -SiO 2 -ZrO 2 ZrO in solid acid catalysts 2 5 to 20 wt% of mass; preferably 10 to 20 wt%.

[0019] The calcination temperature is 350-700°C, and the calcination time is 1-10 hours; preferably, the calcination temperature is 400-550°C for 2-6 hours.

[0020] Basic principle: The present invention makes full use of the principle that the precipitant gel has positive charges around it and can effectively adsorb anions, such as Figure 1 As shown, WO was prepared by precipitation method. 3 -SiO 2 -ZrO 2 In the process of catalyst, when the alkaline solution is added to the above salt solution, Si(OH) is generated. x and Zr(OH) x When the seed is formed, the tungsten-containing anionic compound can be adsorbed immediately, so that the tungsten-containing anionic compound is evenly distributed on the surface of the gel. At the same time, the adsorbed anionic compound can play a steric hindrance effect to inhibit Si(OH) x and Zr(OH) x The growth of seed crystals can promote the formation of WO-Zr bonds and increase the specific surface area of ​​the catalyst during the calcination process, thus leading to the x The species are more evenly dispersed on the catalyst surface, the interaction between the catalyst and the support is stronger, and more Lewis acid can be provided.

[0021] Due to WO 3 -SiO 2 -ZrO 2 In the catalyst, the Lewis acid sites provided by WO x (W-OH and W-O-Zr) species can form tungsten-containing peroxides with hydrogen peroxide. The tungsten-containing peroxides combine with maleic acid to form maleic acid - tungsten-containing peroxides, which undergo proton transfer to generate epoxy succinic acid and water, as Figure 2 shown. Under high temperature and acidic conditions, the oxygen in the three-membered ring ether structure of epoxy succinic acid is first protonated, enhancing the polarity of the carbon-hydrogen bond. Water acts as a nucleophile and reacts with the carbon in the three-membered ring ether structure to form DL-tartaric acid. The WO 3 -SiO 2 -ZrO 2 solid acid catalyst prepared by the simple and feasible precipitation method in the present invention is used for the preparation of tartaric acid from maleic anhydride. As a heterogeneous catalyst, it is easy to separate, and the active species WO 3 and SiO 2 -ZrO 2 There is a strong interaction between the composite oxides, enabling the catalyst to be recycled. When recycled, it still has a high DL-tartaric acid yield and a relatively high purity of crude tartaric acid, reducing the production cost of tartaric acid and having important application significance.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects: 1. Through the gel adsorption effect, the active species and the carrier have a strong interaction in the solid acid catalyst, thereby improving the recycling rate of the catalyst; 2. The solid acid catalyst is synthesized in one step by the simple and feasible precipitation method, and the raw materials are cheap and easily available; 3. As a heterogeneous catalyst, it is easy to separate and can effectively reduce the residual amount of heavy metal tungsten in tartaric acid crystallization. When recycled, it still has a high DL-tartaric acid yield, reducing the production cost of tartaric acid; 4. It is suitable for large-scale production. Description of the Drawings

[0023] Figure 1 It is the synthesis mechanism diagram of the catalyst of the present invention;

[0024] Figure 2 It is the reaction mechanism diagram of the catalyst of the present invention for preparing epoxy succinic acid;

[0025] Figure 3 It is the NH 3 -DRTFIR spectrum of the catalyst in Example 3 of the present invention;

[0026] Figure 4 It is the XRD pattern of the catalyst in Example 4 of the present invention;

[0027] Figure 5 It is the BET spectrogram of the catalyst in Example 4 of the present invention;

[0028] Figure 6 It is a schematic diagram of the crude tartaric acid in Example 5 of the present invention;

[0029] Figure 7 It is the HPLC spectrogram of the crude tartaric acid in Example 5 of the present invention;

[0030] Figure 8 It is the XRD pattern of the catalyst after being activated 5 times in Example 10 of the present invention;

[0031] Figure 9 It is the IR spectrogram of the catalyst after being activated 5 times in Example 10 of the present invention. Detailed implementation manners

[0032] The present invention will be further described in detail below with reference to the accompanying drawings of the specification.

[0033] Example 1

[0034] A preparation method of a 7.5% WO 3 -5% SiO 2 -ZrO 2 solid acid catalyst, comprising the following steps

[0035] (1) Under the conditions of a temperature of 25 °C and a stirring rate of 600 r / min, weigh 3.0 g of ammonium metatungstate and 52.2 g of zirconium oxychloride and dissolve them separately in 630 ml of deionized water, heat up to 100 °C and continuously stir for 2 h, and then cool to room temperature;

[0036] (2) Respectively add 5.7 g of acidic silica sol and 2.0 g of polyethylene glycol into it, stir for 30 min until it is fully mixed, then dropwise add 2 mol / L ammonia water solution to the above liquid within 40 min until pH = 9.0, continuously stir, then carry out suction filtration, wash with deionized water until no chloride ions can be detected in the filtrate by using 1 mol / L silver nitrate aqueous solution, take out the filter cake and put it into 200 ml of absolute ethanol for pulping for 15 min, carry out suction filtration on it again, and then wash the filter cake with 500 ml of absolute ethanol again, and calcine the filter cake at 500 °C for 4 h to obtain 7.5% WO 3 -5% SiO 2 -ZrO 2 solid acid catalyst.

[0037] Example 2

[0038] A preparation method of a 10% WO 3 -5% SiO 2 -ZrO 2 solid acid catalyst, comprising the following steps:

[0039] (1) Under the conditions of a temperature of 25 °C and a stirring rate of 600 r / min, 2.42 g of ammonium tungstate and 57.6 g of zirconium sulfate were respectively dissolved in 330 ml of deionized water, heated to 100 °C and continuously stirred for 2 h, and then cooled to room temperature;

[0040] (2) 5.7 g of acidic silica sol and 4.0 g of Tween-80 were respectively added thereto, and after stirring for 30 min until they were fully mixed, 1 mol / L sodium hydroxide aqueous solution was added dropwise to the above liquid within 40 min until pH = 8.2, and continuously stirred, then filtered by suction, washed with deionized water as a detergent until the conductivity of the filtrate was consistent with that of the detergent, the filter cake was taken out and slurried in 200 ml of absolute ethanol for 15 min, re-filtered by suction, and then the filter cake was washed again with 500 ml of absolute ethanol, and the filter cake was calcined at 550 °C for 3 h to obtain 10% WO 3 -5% SiO 2 -ZrO 2 Solid acid catalyst.

[0041] Example 3

[0042] A preparation method of a 7.5% WO 3 -2.5% SiO 2 -ZrO 2 Solid acid catalyst, comprising the following steps:

[0043] (1) Under the conditions of a temperature of 25 °C and a stirring rate of 600 r / min, 2.31 g of sodium tungstate and 69.5 g of zirconium nitrate were respectively dissolved in 1620 ml of deionized water, heated to 100 °C and continuously stirred for 2 h, and then cooled to room temperature;

[0044] (2) 2.8 g of acidic silica sol and 3.0 g of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer were respectively added thereto, and after stirring for 30 min until they were fully mixed, 4 mol / L potassium hydroxide solution was added dropwise to the above liquid within 40 min until the pH was 7, and continuously stirred, then filtered by suction, washed with 1 wt% ammonium acetate solution as a detergent until the conductivity of the filtrate was consistent with that of the detergent, the filter cake was taken out and slurried in 200 ml of absolute ethanol for 15 min, re-filtered by suction, and then the filter cake was washed again with 500 ml of absolute ethanol, and the filter cake was calcined at 400 °C for 6 h to obtain 7.5% WO 3 -2.5% SiO 2 -ZrO 2 Solid acid catalyst, the NH 3 -DRTFIR spectrum of which is as Figure 3 shown, from Figure 3It can be seen that there are not only a large number of Brønsted acid sites but also a large number of Lewis acid sites in this catalyst, and these acid sites are beneficial to the progress of the catalytic reaction.

[0045] Example 4

[0046] A preparation method of a 15% WO 3 -10% SiO 2 -ZrO 2 solid acid catalyst, comprising the following steps:

[0047] (1) Under the conditions of a temperature of 25 °C and a stirring rate of 600 r / min, weigh 3.11 g of phosphotungstic acid and 37.31 g of zirconyl chloride and dissolve them separately in 1000 ml of deionized water. Heat up to 100 °C and stir continuously for 2 h, then cool to room temperature;

[0048] (2) Add 11.2 g of acidic silica sol and 3.0 g of lauryl alcohol polyoxyethylene ether into it respectively. After stirring for 30 min until they are fully mixed, dropwise add 6 mol / L urea solution to the above liquid within 40 min until pH = 12, stir continuously, then perform suction filtration, wash with deionized water as a detergent until the conductivity of the filtrate is the same as that of the detergent. Take out the filter cake and slurry it in 200 ml of absolute ethanol for 15 min, perform suction filtration on it again, then wash the filter cake with 500 ml of absolute ethanol again. Bake the filter cake at 480 °C for 2 h to obtain a 15% WO 3 -10% SiO 2 -ZrO 2 solid acid catalyst.

[0049] The XRD pattern of this catalyst is as Figure 4 shown. It can be seen that there is only the crystal form of tetragonal zirconia in the catalyst, and no crystal phase diffraction peaks corresponding to SiO 2 and WO 3 are seen, indicating that they are uniformly dispersed on the catalyst surface. The BET spectrum of this catalyst is as Figure 5 shown. It can be seen that the specific surface area of the catalyst is large and the pore channels are regular.

[0050] Example 5

[0051] Weigh 25.0 g of maleic anhydride and add it to 60.0 g of deionized water. Heat up to 50 °C until it is fully dissolved. Add 1.3 g of the catalyst obtained in Example 1 to it. This catalyst accounts for 5.2 wt% of the mass of maleic anhydride. Then add 58.0 g of 30 wt% H 2 O 2Put it in, heat up the reaction solution to 65 °C for epoxidation reaction for 6 h, separate and collect the catalyst by filtration, reheat the reaction solution to 95 °C for hydrolysis for 6 h, concentrate it to half of the original solution volume under the condition of 95 °C, cool and crystallize under the condition of 3 °C, and filter, wash and dry to obtain the crude DL-tartaric acid. The conversion rate of maleic anhydride in the epoxidation reaction is 59.6%, and the actual yield of tartaric acid after the final reaction is 42.3%. Although this yield is lower than the conversion rate of the fresh catalyst in the prior art, the higher conversion rate in the prior art is due to WO 3 After leaching, it participates in the reaction as a homogeneous catalyst, which has the problems of easy metal component residue and inability to recycle the catalyst. Therefore, although the yield of tartaric acid finally obtained in this example is 42.3%, the catalyst can be recycled and there is no problem of metal component residue.

[0052] Schematic diagram of the crude tartaric acid prepared in this example Figure 6 As shown, the HPLC spectrum of this crude tartaric acid is as Figure 7 shown. From Figure 6 and Figure 7 it can be seen that this sample is a white crude DL-tartaric acid with a purity of 98%, indicating that this method can synthesize a crude tartaric acid with less impurities and high purity.

[0053] Example 6

[0054] Weigh 20.8 g of maleic anhydride and add it to 60.0 g of deionized water. Heat it up to 50 °C and wait for it to dissolve completely. Add 2.1 g of the catalyst obtained in Example 2 to it. This catalyst accounts for 10.0 wt% of the mass of maleic anhydride. Then, within 6 min, add 76.0 g of 30 wt% H 2 O 2 Put it in, heat up the reaction solution to 70 °C for epoxidation reaction for 4 h, separate and collect the catalyst by simple filtration, reheat the reaction solution to 90 °C for hydrolysis for 8 h, then concentrate it to half of the original solution volume under the condition of 100 °C, cool and crystallize under the condition of 6 °C, and filter, wash and dry to obtain DL-tartaric acid. The conversion rate of maleic anhydride in the epoxidation reaction is 88.3%, and the actual yield of tartaric acid after the final reaction is 73.2%.

[0055] Example 7

[0056] Weigh 24.0 g of maleic anhydride and dissolve it in 60.0 g of deionized water. Heat it up to 50 °C and wait for it to dissolve completely. Add 3.6 g of the catalyst obtained in Example 3 to it. This catalyst accounts for 15.0 wt% of the mass of maleic anhydride. Then, within 6 min, add 50.0 g of 30 wt% H 2 O 2Put it in, heat up the reaction solution to 72 °C for epoxidation reaction for 5 h, separate and collect the catalyst by simple filtration. After the reaction solution is reheated to 95 °C for hydrolysis for 6 h, it is concentrated to half of the original solution volume under the condition of 90 °C, cooled and crystallized at 9 °C, and filtered, washed and dried to obtain DL-tartaric acid. The conversion rate of maleic anhydride in the epoxidation reaction is 65.1%, and the actual yield of tartaric acid after the final reaction is 48.1%. The reason for the decrease in the yield of this catalyst compared with the conversion rate of the fresh catalyst in the prior art is as described in Example 5.

[0057] Example 8

[0058] Weigh 26.5 g of maleic anhydride and dissolve it in 60.0 g of deionized water. Heat it up to 50 °C and wait for it to dissolve completely. Add 5.3 g of the catalyst obtained in Example 4 to it. This catalyst accounts for 20.0 wt% of the mass of maleic anhydride. Then, within 6 min, add 122 g of 30 wt% H 2 O 2 Put it in, heat up the reaction solution to 75 °C for epoxidation reaction for 3 h, separate and collect the catalyst by simple filtration. After the reaction solution is reheated to 90 °C for hydrolysis for 10 h, it is concentrated to half of the original solution volume under the condition of 95 °C, and cooled and crystallized at 5 °C. The conversion rate of maleic anhydride in the epoxidation reaction is 96.1%, and the actual yield of tartaric acid after the final reaction is 81.4%.

[0059] Example 9

[0060] Weigh 20.8 g of maleic anhydride and add it to 60.0 g of deionized water. Heat it up to 50 °C and wait for it to dissolve completely. Add 2.1 g of the catalyst obtained in Example 1 to it. This catalyst accounts for 10.0 wt% of the mass of maleic anhydride. Then, within 6 min, add 53.0 g of 30 wt% H 2 O 2 Put it in, heat up the reaction solution to 70 °C for epoxidation reaction for 4 h, separate and collect the catalyst by simple filtration. After the reaction solution is reheated to 90 °C for hydrolysis for 8 h, it is concentrated to half of the original solution volume under the condition of 80 °C, cooled and crystallized at 6 °C, and filtered, washed and dried to obtain DL-tartaric acid. The collected catalyst is washed, dried, activated at 300 °C for 12 h and then used for the next reaction. As shown in Tables 1 and 2, the performance of the catalyst in recycling is investigated, and the reaction is cycled 5 times in total.

[0061] Table 1 7.5% WO 3 -5% SiO 2 -ZrO 2 Catalyst recycling reaction

[0062] Number of reactions Conversion rate of maleic anhydride (%) Yield of DL-tartaric acid (%) 1 68.2 51.2 2 66.9 49.1 3 64.9 49.8 4 65.6 46.7 5 61.8 47.1

[0063] Table 2 7.5% WO 3 - 5% SiO 2 - ZrO 2 Analysis of Element Content of the Catalyst before and after Reaction (XRF)

[0064] Catalyst <![CDATA[WO 3 (wt%)]]> <![CDATA[SiO 2 (wt%)]]> <![CDATA[7.5% WO 3 - 5% SiO 2 - ZrO 2 (Before reaction)]]> 7.72 4.96 <![CDATA[7.5% WO 3 - 5% SiO 2 - ZrO 2 (after reaction)]]> 7.56 4.77

[0065] As can be seen from Table 1 and Table 2, 7.5% WO 3 - 5% SiO 2 - ZrO 2 After the catalyst was recycled 5 times, the conversion rate and actual yield only decreased by 6.4% and 4.1% respectively, and the losses of WO x species and SiO x species were small, indicating that the catalyst had good performance in the cyclic reaction of maleic anhydride epoxidation to DL - tartaric acid. After 5 reactions, the activity of the catalyst was relatively stable and still had a high DL - tartaric acid yield.

[0066] Example 10

[0067] Weigh 20.8 g of maleic anhydride and add it to 60.0 g of deionized water. Heat it to 50 °C until it is fully dissolved. Then add 2.1 g of the catalyst obtained in Example 2, and this catalyst accounts for 10.0 wt% of the mass of maleic anhydride. Then, within 6 minutes, add 76.0 g of 30 wt% H 2 O 2 to it. Heat the reaction solution to 70 °C for epoxidation reaction for 4 h. Separate and collect the catalyst by simple filtration. After the reaction solution is reheated to 100 °C for hydrolysis for 8 h, it is concentrated to half of the original solution volume at 80 °C, and then cooled and crystallized at 6 °C, and filtered, washed and dried to obtain DL - tartaric acid. The collected catalyst is washed, dried, activated at 600 °C for 1 h and then used for the next reaction. As shown in Table 3, the performance of the catalyst in cyclic use was investigated, and a total of 5 cyclic reactions were carried out.

[0068] The XRD pattern and IR spectrum of the catalyst after 5 activations are shown respectively as Figure 8 、 9 shown. From Figure 8 it can be seen that only the diffraction peaks of tetragonal zirconia exist on the catalyst, and no diffraction peaks of SiO 2 and WO 3 are seen, indicating that the active species are still highly dispersed on the catalytic surface. From Figure 9 it can be seen that only the infrared stretching vibration peaks corresponding to ZrO 2 exist on the activated catalyst, and no infrared stretching vibration peaks related to maleic acid, epoxy succinic acid or DL - tartaric acid are seen.

[0069] Table 3 10% WO3 -5% SiO 2 -ZrO 2 Catalyst recycle reaction

[0070] Number of reactions Conversion rate of maleic anhydride (%) Yield of DL-tartaric acid (%) 1 88.1 73.4 2 85.6 70.5 3 83.4 68.1 4 82.1 67.1 5 80.3 65.3

[0071] From Figure 8 、 Figure 9 and Table 3, it can be seen that after activation, for 10% WO 3 -5% SiO 2 -ZrO 2 the structure of the catalyst and the dispersion state of the active components have not changed, there is no organic matter covering the catalyst surface, and after 5 cycles of use, the conversion rate and the actual yield only decreased by 7.8% and 8.1% respectively, indicating that the catalyst has good performance in the recycle reaction of maleic anhydride epoxidation to DL-tartaric acid after simple high-temperature activation. After 5 reactions, the catalyst activity is relatively stable and still has a high DL-tartaric acid yield.

Claims

1. A WO 3 -SiO 2 -ZrO 2 Preparation method of solid acid catalyst It is characterized in that The said WO 3 -SiO 2 -ZrO 2 The solid acid catalyst is synthesized in one step by the precipitation method and comprises the following steps: (1) Mix and dissolve tungsten-containing compounds and zirconium-containing compounds; (2) Add silica sol, surfactant and precipitant to form a gel, and then obtain the product through filtration, washing and calcination; The dosage of the surfactant is WO 3 -SiO 2 -ZrO 2 ZrO in the solid acid catalyst 2 5 to 20 wt% of the mass; the surfactant is at least one of polyethylene glycol, polyvinyl alcohol, Tween-80, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer, and fluorinated anionic surfactant; The WO 3 -SiO 2 -ZrO 2 The loading amount of WO 3 in the solid acid catalyst is 5.0 - 15.0 wt%, and the loading amount of SiO 2 is 2.5 - 20.0 wt%, with the balance being ZrO 2 .

2. The WO according to claim 1 3 -SiO 2 -ZrO 2 Method for preparing a solid acid catalyst It is characterized in that The precipitant is one of ammonia water, NaOH, KOH or urea.

3. According to claim 1, WO 3 -SiO 2 -ZrO 2 Method for preparing a solid acid catalyst It is characterized in that The tungsten-containing compound is at least one of ammonium metatungstate, ammonium tungstate, sodium tungstate or phosphotungstic acid.

4. The WO according to claim 1 3 -SiO 2 -ZrO 2 A method for preparing a solid acid catalyst, It is characterized in that The zirconium-containing compound is at least one of zirconium oxychloride, zirconium nitrate or zirconium sulfate.

5. The WO according to claim 1 3 -SiO 2 -ZrO 2 Method for preparing a solid acid catalyst It is characterized in that The calcination temperature is 350-700 °C, and the calcination time is 1-10 h.

6. WO obtained by the method according to claim 1 3 -SiO 2 -ZrO 2 solid acid catalyst It is characterized in that The WO 3 -SiO 2 -ZrO 2 The loading amount of WO 3 in the solid acid catalyst is 5.0 - 15.0 wt%, the loading amount of SiO 2 is 2.5 - 20.0 wt%, and the balance is ZrO 2 .

7. The WO according to claim 6 3 -SiO 2 -ZrO 2 solid acid catalyst It is characterized in that The WO 3 -SiO 2 -ZrO 2 The raw materials of the solid acid catalyst include tungsten-containing compounds, silicon-containing compounds, and zirconium-containing compounds, and the tungsten-containing compounds are adsorbed on silicon hydroxide and zirconium hydroxide gels.

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