Preparation method and application of a solid superacid catalyst with shape-selective function

Abstract

The invention discloses a preparation method and application of a solid superacid catalyst with a selective function. The method comprises the following steps: 1) dissolving peach aldehyde in an alcohol aqueous solution, adding acid to adjust the pH to 4-5, then adding organic niobium and organic titanium, performing a hydrolysis reaction, and obtaining a precipitate; 2) separating the precipitate, drying it, and placing it in an ammonium sulfate solution for immersion; then taking it out, drying it, and placing it in a transition metal X salt solution for immersion; 3) separating the precipitate, and roasting it in an air atmosphere to obtain a solid superacid catalyst X-S2O8 with a selective function. 2‑ / Nb2O5‑TiO2. The solid superacid catalyst provided by the invention is applied to the reaction of synthesizing peach aldehyde from ω‑undecenoic acid, and has the advantages of high conversion rate and high selectivity, and the catalyst has good stability and long service life.

Description

Technical Field

[0001] The invention relates to a solid superacid catalyst, and in particular to a preparation method and application of a solid superacid catalyst with a shape-selective function. Background Art

[0002] Peach aldehyde (i.e. γ-undecalactone) is a colorless to light yellow viscous liquid with a strong peach aroma. It is widely used in the fields of daily chemical flavors and edible flavors.

[0003] As one of the most commonly used lactone flavors, peach aldehyde is recognized as GRAS (Generally Recognized as Safe) by FEMA (Flavor and Extract Manufacturers Association), approved for consumption by the US FDA, and listed by the European Council as an artificial flavoring that can be used in food without endangering human health. Its structure is as follows:

[0004]

[0005] At present, there are many methods for the synthesis of peach aldehyde at home and abroad:

[0006] Hydroxy esters, hydroxy acids or their derivatives can be directly converted into lactones by intramolecular reactions. However, since the raw materials are not easy to obtain, the use of this method to prepare peach aldehyde has certain limitations.

[0007] Patent CN112275234A reports the synthesis of peach aldehyde by free radical reaction of n-octanol and acrylic acid under the initiation of di-tert-butyl peroxide. Boric acid is used as a homogeneous catalyst, which has the problems of difficult separation of the catalyst, inability to reuse, and high cost.

[0008] Liu Wei reported in "Study on the Synthesis of γ-Undecyllactone" that peach aldehyde was synthesized using ω-undecenoic acid as raw material and sulfuric acid as catalyst, but the product yield was only 47%. Using liquid acid as a catalyst not only has high requirements for equipment, but also produces a large amount of acid-containing wastewater, which is not conducive to production. Summary of the invention

[0009] In order to solve the above technical problems, the present invention proposes a preparation method and application of a solid superacid catalyst with a selective function. The ω-undecenoic acid raw material generated by the cracking of castor oil has a wide source. The present invention synthesizes peach aldehyde from ω-undecenoic acid in X-S2O8 with a selective function 2- In the presence of / Nb2O5-TiO2 solid superacid catalyst, it has a higher conversion rate and selectivity, and after the catalyst is modified by transition metal X, the problem of catalyst carbon deposition is solved and the service life of the catalyst is extended.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing a solid superacid catalyst with a selective shape function comprises the following steps:

[0012] 1) dissolving peach aldehyde in an alcohol aqueous solution, adding acid to adjust the pH to 4-5, and then adding organic niobium and organic titanium to carry out a hydrolysis reaction to obtain a precipitate;

[0013] 2) separating the precipitate and drying it, and then immersing it in an ammonium sulfate solution; then taking it out, drying it, and immersing it in a transition metal X salt solution;

[0014] 3) Separate the precipitate and calcine it in air to obtain a solid superacid catalyst X-S2O8 with selective function. 2- / Nb2O5-TiO2.

[0015] The present invention uses peach aldehyde as a hard template and ammonium sulfate as a sulfur source, and prepares X-S2O8 by modification with transition metal X. 2- / Nb2O5-TiO2 solid superacid has a selective function on the product in the reaction process of synthesizing peach aldehyde from ω-undecenoic acid, and has a relatively consistent effect on the formation of larger molecular ω-undecenoic acid dimers, trimers and polymers, which can significantly improve the selectivity of peach aldehyde.

[0016] As a preferred embodiment, in step 1), the mass concentration of peach aldehyde in the alcohol aqueous solution is 1.5-4%, preferably 2-3%;

[0017] Preferably, the alcohol content in the alcohol aqueous solution is 40-80%, preferably 50-60%.

[0018] Preferably, the molar ratio of organic niobium to organic titanium is (0.1-0.3):1, such as 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, etc.; wherein the amount of organic titanium added is 2-6 times, such as 2 times, 3 times, 4 times, 5 times, 6 times, etc., of peach aldehyde in terms of molar amount;

[0019] Preferably, in step 1), the hydrolysis reaction temperature is 40-100°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 85°C, 90°C, etc., and the reaction time is 4-8h, for example, 4h, 5h, 6h, 7h, 8h, etc.

[0020] As a preferred embodiment, the organic niobium is selected from one or more of niobium ethoxide, niobium pentoxide, and niobium n-propoxide;

[0021] Preferably, the organic titanium is selected from one or more of tetrabutyl titanate, titanium n-propoxide, tetraethyl titanate, and titanium isooctoxide.

[0022] As a preferred embodiment, the acid used to adjust the pH in step 1) is an organic acid, preferably one or more of formic acid, acetic acid, propionic acid, and butyric acid.

[0023] As a preferred embodiment, the concentration of the ammonium sulfate solution in step 2) is 0.6-1.2 mol / L, preferably 0.8-1.0 mol / L;

[0024] Preferably, the liquid-to-solid ratio of the ammonium sulfate solution impregnation in step 2) is 10-18 mL liquid / 1 g solid, for example, 12 mL liquid / 1 g solid, 14 mL liquid / 1 g solid, 15 mL liquid / 1 g solid, 16 mL liquid / 1 g solid, etc.

[0025] Preferably, the immersion time of the ammonium sulfate solution in step 2) is 1-4 hours, such as 1 hour, 2 hours, 3 hours, 4 hours, etc.

[0026] As a preferred embodiment, the mass concentration of the transition metal X salt solution in step 2) is 4-10%, preferably 6-8%;

[0027] Preferably, in step 2), the liquid-to-solid ratio of the transition metal X salt solution for impregnation is 1-3 mL liquid / 1 g solid, such as 1 mL liquid / 1 g solid, such as 2 mL liquid / 1 g solid, etc.

[0028] Preferably, in step 2), the immersion time of the transition metal X salt solution is 3-12 h, such as 4 h, 5 h, 6 h, 8 h, 10 h, etc.

[0029] As a preferred embodiment, the transition metal X salt is selected from inorganic salts of metals Cr, Mo, Fe, and Mn, preferably selected from one or more of chromium sulfate, chromium trichloride, chromium nitrate, molybdenum pentachloride, molybdenum bromide, ferric chloride, ferrous chloride, manganese nitrate, and manganese chloride.

[0030] As a preferred embodiment, in step 3), the calcination temperature is 500-700° C., preferably 550-650° C., and the calcination time is 6-12 h, preferably 8-10 h.

[0031] The invention discloses a method for preparing peach aldehyde, which uses ω-undecenoic acid as a raw material and synthesizes peach aldehyde under the catalytic action of a solid superacid catalyst with a selective function prepared by the method described above.

[0032] As a preferred embodiment, after adding ω-undecenoic acid, a solid superacid catalyst, and an aromatic hydrocarbon solvent into a reaction container, the temperature is raised to 60-120° C. and the reaction is carried out for 1-3 hours; wherein the amount of the solid superacid catalyst is 0.5-2.0% of the mass of the ω-undecenoic acid, preferably 0.8-1.6%.

[0033] Preferably, the aromatic hydrocarbon solvent is selected from one or more of toluene, p-xylene, o-xylene and m-xylene.

[0034] Preferably, the amount of the aromatic hydrocarbon solvent added may be 1.5-4 times, preferably 2-3 times, the mass of ω-undecenoic acid.

[0035] X-S2O8 provided by the present invention 2- / Nb2O5-TiO2 solid superacid catalyst is used in the reaction of synthesizing peach aldehyde from ω-undecenoic acid, and has the advantages of high conversion agent and high selectivity. In addition, peach aldehyde is prepared by the method of the present invention, and the solid superacid catalyst can be separated and recycled by simple filtration separation after the reaction is completed, and the catalyst has good stability and long service life. DETAILED DESCRIPTION

[0036] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0037] Unless otherwise specified, the raw materials and reagents in the following examples of the present invention were purchased from commercial products.

[0038] The detection methods mainly involved in the following embodiments of the present invention are as follows:

[0039] Peach aldehyde was analyzed by GC-9800 chromatograph, and the chromatographic conditions were as follows: initial temperature 150°C, maintained for 2 min, programmed temperature increase to 280°C at a rate of 15°C / min, maintained for 5 min; vaporization chamber temperature 280°C, detection chamber temperature 280°C; FID detection; injection volume 0.2 μL.

[0040] ω-undecenoic acid was analyzed by liquid chromatography equipped with a UV detector. The liquid chromatograph was Agilent 1200 series equipped with a C18 liquid chromatography column. The column temperature was set at 40°C. Acetonitrile and 5 mmol / L ammonium acetate aqueous solution were used as mobile phases. The flow rate was 1.0 mL / min. The UV detector was used for detection at a wavelength of 360 nm. The external standard method was used for quantification. The sample was appropriately diluted with acetonitrile before injection and then injected for analysis.

[0041] The following examples 1-6 are used to prepare different X-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst:

[0042] [Example 1]

[0043] 12.5 g of peach aldehyde was added to 500 g of ethanol aqueous solution (ethanol accounted for 55.0 wt%), acetic acid was added to adjust the pH to 5, and then 61.9 g of tetraethyl titanate and 15.8 g of niobium n-propoxide were added, the temperature was adjusted to 65 ° C, and a hydrolysis reaction was carried out. After the reaction for 5.5 hours, the precipitate was filtered to obtain a precipitate, which was dried and immersed in a 0.9 mol / L ammonium sulfate solution for 3 hours (solid-liquid ratio of 14 mL solution / 1 g solid), centrifuged and dried, and then immersed in a Cr(NO3)3 solution with a mass concentration of 7 wt% for 8 hours (solid-liquid ratio of 2 mL solution / 1 g solid); finally, the impregnated solid was filtered, washed, and then placed in an air calciner for calcination at a temperature of 600 ° C for 9 hours to obtain Cr-S2O8. 2- / Nb2O5-TiO2 solid super acid catalyst A.

[0044] [Example 2]

[0045] 7.5 g of peach aldehyde was added to 500 g of ethanol aqueous solution (ethanol accounted for 40.0 wt%), acetic acid was added to adjust the pH to 5, and then 55.71 g of tetraethyl titanate was added, and 9.48 g of niobium n-propoxide was added, and the temperature was adjusted to 40 ° C. The hydrolysis reaction was carried out. After the reaction for 8 hours, the precipitate was filtered to obtain a precipitate, which was dried and immersed in a 0.6 mol / L ammonium sulfate solution for 4 hours (the solid-liquid ratio was 18 mL solution / 1 g solid), and then centrifuged and dried, and then immersed in a Cr(NO3)3 solution with a mass concentration of 4 wt% for 12 hours (the solid-liquid ratio was 1 mL solution / 1 g solid); finally, the impregnated solid was filtered, washed, and placed in an air calcination furnace for calcination at a temperature of 500 ° C and a calcination time of 12 hours to obtain Cr-S2O8. 2- / Nb2O5-TiO2 solid super acid catalyst B.

[0046] [Example 3]

[0047] 20 g of peach aldehyde was added to 500 g of ethanol aqueous solution (ethanol accounted for 80.0 wt%), acetic acid was added to adjust the pH to 5, and then 49.52 g of tetraethyl titanate was added, and 25.29 g of niobium n-propoxide was added, and the temperature was adjusted to 100 ° C. for hydrolysis reaction. After reacting for 4 hours, the precipitate was filtered to obtain a precipitate, which was dried and immersed in a 1.2 mol / L ammonium sulfate solution for 1 hour (solid-liquid ratio was 10 mL solution / 1 g solid), and then centrifugally dried, and then immersed in a Cr(NO3)3 solution with a mass concentration of 10 wt% for 3 hours (solid-liquid ratio was 3 mL solution / 1 g solid); finally, the immersed solid was filtered, washed, and placed in an air roasting furnace for roasting at a temperature of 700 ° C and a roasting time of 6 hours to obtain Cr-S2O8. 2- / Nb2O5-TiO2 solid super acid catalyst C.

[0048] [Example 4]

[0049] 12.5 g of peach aldehyde was added to 500 g of ethanol aqueous solution (ethanol accounted for 60.0 wt%), acetic acid was added to adjust the pH to 5, and then 57.84 g of titanium n-propoxide and 21.51 g of niobium pentoxide were added, the temperature was adjusted to 80 ° C, and a hydrolysis reaction was carried out. After the reaction for 5 hours, the precipitate was filtered to obtain a precipitate, which was dried and immersed in a 0.7 mol / L ammonium sulfate solution for 2.5 hours (solid-liquid ratio was 16 mL solution / 1 g solid), centrifuged and dried, and then immersed in a MoCl5 solution with a mass concentration of 8 wt% for 4 hours (solid-liquid ratio was 1 mL solution / 1 g solid); finally, the impregnated solid was filtered, washed, and placed in an air calciner for calcination at a temperature of 650 ° C for 8 hours to obtain Mo-S2O8. 2- / Nb2O5-TiO2 solid super acid catalyst D.

[0050] [Example 5]

[0051] 7.5 g of peach aldehyde was added to 500 g of ethanol aqueous solution (ethanol accounted for 45.0 wt%), acetic acid was added to adjust the pH to 5, and then 46.26 g of titanium n-propoxide and 21.51 g of niobium pentoxide were added, the temperature was adjusted to 75 ° C, and a hydrolysis reaction was carried out. After the reaction for 7 hours, the precipitate was filtered to obtain a precipitate, which was dried and immersed in a 1 mol / L ammonium sulfate solution for 1.5 hours (solid-liquid ratio was 12 mL solution / 1 g solid), centrifuged and dried, and then immersed in a MoCl5 solution with a mass concentration of 6 wt% for 8 hours (solid-liquid ratio was 3 mL solution / 1 g solid); finally, the impregnated solid was filtered, washed, and placed in an air calciner for calcination at a temperature of 600 ° C for 9 hours to obtain Mo-S2O8. 2- / Nb2O5-TiO2 solid super acid catalyst E.

[0052] [Example 6]

[0053] 20 g of peach aldehyde was added to 500 g of ethanol aqueous solution (ethanol accounted for 70.0 wt%), acetic acid was added to adjust the pH to 5, and then 124.58 g of titanium n-propoxide and 34.75 g of niobium pentoxide were added, the temperature was adjusted to 60 ° C, and a hydrolysis reaction was carried out. After the reaction for 6 hours, the precipitate was filtered to obtain a precipitate, which was dried and immersed in a 0.9 mol / L ammonium sulfate solution for 2 hours (solid-liquid ratio was 15 mL solution / 1 g solid), centrifuged and dried, and then immersed in a MoCl5 solution with a mass concentration of 9 wt% for 10 hours (solid-liquid ratio was 2 mL solution / 1 g solid); finally, the impregnated solid was filtered, washed, and placed in an air calciner for calcination at a temperature of 550 ° C and a calcination time of 11 hours to obtain Mo-S2O8. 2- / Nb2O5-TiO2 solid super acid catalyst F.

[0054] The following examples 7-12 are used to prepare peach aldehyde:

[0055] [Example 7]

[0056] 200 g of ω-undecenoic acid and 600 g of o-xylene were added to the reactor, followed by 2.4 g of Cr-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst A, the reaction temperature was raised to 90°C, and the reaction was carried out for 2 hours. After the reaction was completed, a saturated sodium carbonate solution was slowly added to the reaction solution until the pH of the solution was neutral, and the organic phase was collected after phase separation, and separated by rectification to obtain peach aldehyde.

[0057] In this example, the conversion rate of ω-undecenoic acid was 98.5%, and the selectivity was 95.6%.

[0058] After the reaction in this embodiment is completed, the catalyst is filtered out and washed several times until the solution is neutral, and the same method as in Example 7 is used in a cycle to prepare peach aldehyde. The effects of the catalyst after multiple uses are shown in Table 1:

[0059] Table 1. Catalyst recycling performance test

[0060] Catalyst application times Conversion rate / % Selectivity / % 0 98.5 95.6 10 98.3 95.5 30 98.0 95.3 50 97.5 95.0

[0061] [Example 8]

[0062] 200 g of ω-undecenoic acid and 300 g of o-xylene were added to the reactor, followed by 1 g of Cr-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst B, the reaction temperature was raised to 60°C, and the reaction was carried out for 3 hours. After the reaction was completed, a saturated sodium carbonate solution was slowly added to the reaction solution until the pH of the solution was neutral, and the organic phase was collected after phase separation, and separated by rectification to obtain peach aldehyde.

[0063] In this example, the conversion rate of ω-undecenoic acid was 95.8%, and the selectivity was 93.1%.

[0064] [Example 9]

[0065] 200 g of ω-undecenoic acid and 800 g of o-xylene were added to the reactor, followed by 4 g of Cr-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst C, the reaction temperature was raised to 120°C, and the reaction was carried out for 1 hour. After the reaction was completed, a saturated sodium carbonate solution was slowly added to the reaction solution until the pH of the solution was neutral, and the organic phase was collected after phase separation, and separated by rectification to obtain peach aldehyde.

[0066] In this example, the conversion rate of ω-undecenoic acid was 99.1% and the selectivity was 91.5%.

[0067] [Example 10]

[0068] 200 g of ω-undecenoic acid and 500 g of toluene were added to the reactor, followed by 1.2 g of Mo-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst D, the reaction temperature was raised to 100°C, and the reaction was carried out for 1.5 hours. After the reaction was completed, a saturated sodium carbonate solution was slowly added to the reaction solution until the pH of the solution was neutral, and the organic phase was collected after phase separation, and separated by rectification to obtain peach aldehyde.

[0069] In this example, the conversion rate of ω-undecenoic acid was 95.2%, and the selectivity was 92.4%.

[0070] [Example 11]

[0071] 200 g of ω-undecenoic acid and 800 g of toluene were added to the reactor, followed by 3 g of Mo-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst E, the reaction temperature was raised to 120°C, and the reaction was carried out for 1 hour. After the reaction was completed, a saturated sodium carbonate solution was slowly added to the reaction solution until the pH of the solution was neutral, and the organic phase was collected after phase separation, and separated by rectification to obtain peach aldehyde.

[0072] In this example, the conversion rate of ω-undecenoic acid was 99.5%, and the selectivity was 82.5%.

[0073] [Example 12]

[0074] 200 g of ω-undecenoic acid and 600 g of toluene were added to the reactor, followed by 2 g of Mo-S2O8 2- / Nb2O5-TiO2 solid superacid catalyst F, the reaction temperature was raised to 80°C, and the reaction was carried out for 2.5 hours. After the reaction was completed, a saturated sodium carbonate solution was slowly added to the reaction solution until the pH of the solution was neutral, and the organic phase was collected after phase separation, and separated by rectification to obtain peach aldehyde.

[0075] In this example, the conversion rate of ω-undecenoic acid was 91.8%, and the selectivity was 90.6%.

[0076] [Comparative Example 1]

[0077] A catalyst was prepared in substantially the same manner as in Example 1, except that niobium n-propoxide was not added. The prepared catalyst was recorded as Catalyst G.

[0078] [Comparative Example 2]

[0079] The catalyst was prepared in the same manner as in Example 1, except that tetraethyl titanate was not added. The prepared catalyst was recorded as Catalyst H.

[0080] [Comparative Example 3]

[0081] The catalyst was prepared in the same manner as in Example 1, except that after the ammonium sulfate solution was impregnated, no Cr(NO3)3 solution was added for impregnation. The prepared catalyst was recorded as Catalyst I.

[0082] [Comparative Example 4]

[0083] Peach aldehyde was prepared in substantially the same manner as in Example 7, except that the reaction catalyst was replaced by catalyst G.

[0084] In this comparative example, the conversion rate of ω-undecenoic acid was 85.9% and the selectivity was 87.5%.

[0085] [Comparative Example 5]

[0086] Peach aldehyde was prepared in substantially the same manner as in Example 7, except that the reaction catalyst was replaced by catalyst H.

[0087] In this comparative example, the conversion rate of ω-undecenoic acid was 48.9% and the selectivity was 60.4%.

[0088] [Comparative Example 6]

[0089] Peach aldehyde was prepared according to the method substantially the same as Example 7, except that the reaction catalyst was replaced by catalyst I.

[0090] In this comparative example, the conversion rate of ω-undecenoic acid was 98.4% and the selectivity was 95.3%.

[0091] After the reaction of this comparative example is completed, the catalyst is filtered out and washed several times until the solution is neutral, and the same method is used for recycling to prepare peach aldehyde. The effects of the catalyst after multiple applications are shown in Table 1:

[0092] Table 1. Catalyst recycling performance test

[0093]

[0094]

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a solid superacid catalyst having a selective function, characterized in that: The following steps are involved: 1) dissolving peach aldehyde in an alcohol aqueous solution, adding acid to adjust the pH to 4-5, and then adding organic niobium and organic titanium to carry out a hydrolysis reaction to obtain a precipitate; 2) separating the precipitate and drying it, and then immersing it in an ammonium sulfate solution; then taking it out, drying it, and immersing it in a transition metal X salt solution; the transition metal X salt is selected from inorganic salts of metals Cr, Mo, Fe, and Mn; 3) Separate the precipitate and calcine it in air to obtain a solid superacid catalyst X-S2O8 with selective function. 2- / Nb2O5-TiO2.

2. The method for preparing a solid superacid catalyst having a selective shape function according to claim 1, characterized in that: In step 1), the mass concentration of peach aldehyde in the alcohol aqueous solution is 1.5-4%.

3. The method for preparing a solid superacid catalyst having a selective shape function according to claim 2, characterized in that: In step 1), the mass concentration of peach aldehyde in the alcohol aqueous solution is 2-3%.

4. The method for preparing a solid superacid catalyst having a selective shape function according to claim 2, characterized in that: The molar ratio of organic niobium to organic titanium is (0.1-0.3):1; wherein the added amount of organic titanium is 2-6 times of peach aldehyde in terms of molar amount.

5. The method for preparing a solid superacid catalyst having a selective shape function according to claim 2, characterized in that: In step 1), the hydrolysis reaction temperature is 40-100° C. and the reaction time is 4-8 h.

6. The method for preparing a solid superacid catalyst having a selective shape function according to claim 2, characterized in that: The organic niobium is selected from one or more of niobium ethoxide, niobium pentoxide, and niobium n-propoxide.

7. The method for preparing a solid superacid catalyst having a selective shape function according to claim 6, characterized in that: The organic titanium is selected from one or more of tetrabutyl titanate, titanium n-propoxide, tetraethyl titanate, and titanium isooctoxide.

8. The method for preparing a solid superacid catalyst having a selective shape function according to any one of claims 1 to 7, characterized in that: The acid used to adjust the pH in step 1) is an organic acid.

9. The method for preparing a solid superacid catalyst having a selective shape function according to claim 8, characterized in that: The acid used to adjust the pH in step 1) is one or more of formic acid, acetic acid, propionic acid and butyric acid.

10. The method for preparing a solid superacid catalyst having a selective shape function according to claim 1, characterized in that: The concentration of the ammonium sulfate solution in step 2) is 0.6-1.2 mol / L.

11. The method for preparing a solid superacid catalyst having a selective shape function according to claim 10, characterized in that: The concentration of the ammonium sulfate solution in step 2) is 0.8-1.0 mol / L.

12. The method for preparing a solid superacid catalyst having a selective shape function according to claim 10, characterized in that: In step 2), the liquid-to-solid ratio of the ammonium sulfate solution for impregnation is 10-18 mL of liquid / 1 g of solid.

13. The method for preparing a solid superacid catalyst having a selective shape function according to claim 10, characterized in that: The immersion time of the ammonium sulfate solution in step 2) is 1-4 hours.

14. The method for preparing the solid superacid catalyst with shape-selective function according to any one of claims 10 to 13, characterized in that: The mass concentration of the transition metal X salt solution in step 2) is 4-10%.

15. The method for preparing a solid superacid catalyst having a selective shape function according to claim 14, characterized in that: The mass concentration of the transition metal X salt solution in step 2) is 6-8%.

16. The method for preparing a solid superacid catalyst having a selective shape function according to claim 14, characterized in that: In step 2), the liquid-to-solid ratio of the transition metal X salt solution impregnation is 1-3 mL liquid / 1 g solid.

17. The method for preparing a solid superacid catalyst with a selective shape function according to claim 14, characterized in that: In step 2), the immersion time of the transition metal X salt solution is 3-12 hours.

18. The method for preparing a solid superacid catalyst having a selective shape function according to claim 1, characterized in that: The transition metal X salt is selected from one or more of chromium sulfate, chromium trichloride, chromium nitrate, molybdenum pentachloride, molybdenum bromide, ferric chloride, ferrous chloride, manganese nitrate and manganese chloride.

19. The method for preparing a solid superacid catalyst having a selective shape function according to claim 1, characterized in that: In step 3), the calcination temperature is 500-700° C. and the calcination time is 6-12 hours.

20. The method for preparing a solid superacid catalyst with a selective shape function according to claim 19, characterized in that: In step 3), the calcination temperature is 550-650° C. and the calcination time is 8-10 hours.

21. A method for preparing peach aldehyde, characterized in that: With ω-undecenoic acid as a raw material, peach aldehyde is synthesized under the catalytic action of a solid superacid catalyst with a selective function prepared by the method described in any one of claims 1 to 20.

22. The method for preparing peach aldehyde according to claim 21, characterized in that: After adding ω-undecenoic acid, solid superacid catalyst and aromatic hydrocarbon solvent into a reaction container, the temperature is raised to 60-120° C. and the reaction is carried out for 1-3 hours; wherein the amount of the solid superacid catalyst is 0.5-2.0% of the mass of the ω-undecenoic acid.

23. The method for preparing peach aldehyde according to claim 22, characterized in that: The usage of the solid superacid catalyst is 0.8-1.6% of the mass of ω-undecenoic acid.

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