A kind of preparation method of benzyl salicylate

Abstract

The present application relates to the field of chemical industry, and specifically discloses a method for preparing benzyl salicylate. The preparation method comprises the following steps: S1. Salicylate, benzyl chloride, sodium carbonate and a catalyst are mixed and stirred evenly, and reacted for 5-6 hours at a temperature of 100-140°C; the molar ratio of the salicylate and the benzyl chloride is (1.0-1.2): 1; the catalyst adopts a supported quaternary ammonium salt catalyst, and the amount used is 0.5-1.5% of the weight of salicylate; the amount of sodium carbonate used is 2-2.2% of the weight of salicylate; S2. The obtained product of step S1 is filtered to remove the precipitate and the catalyst, and then the reduced pressure distillation is performed to collect the fraction to obtain the product. The yield of the preparation method benzyl salicylate of the present application is high and the product purity is high, and the preparation method is simple in steps, the production cost is low, and it is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the field of chemical industry, and more specifically, to a method for preparing benzyl salicylate. Background Art

[0002] Salicylic acid is a fat-soluble organic acid that exists in willow bark, white guelder leaves and sweet birch in nature. It is an important fine chemical raw material. Benzyl salicylate, also known as benzyl o-hydroxybenzoate, synthesized from salicylic acid as a raw material, is widely used in the perfume industry as a fixative for cosmetics and soaps because of its scent similar to ambergris and amber.

[0003] Generally, the synthesis of benzyl salicylate is mainly carried out by esterification, in which salicylic acid and benzyl alcohol are heated under acidic conditions for esterification reaction. However, since this method usually uses a strong acid as a catalyst, it will corrode the equipment for a long time, and the amount of waste liquid is large and the processing cost is high. Therefore, in industry, salicylate and benzyl chloride are usually used to synthesize benzyl salicylate under specific conditions. However, the inventors have found that the product quality and product yield obtained from the current process for synthesizing benzyl salicylate still have a large room for improvement. Summary of the invention

[0004] In order to improve the yield of benzyl salicylate, the present application provides a method for preparing benzyl salicylate.

[0005] The present application provides a method for preparing benzyl salicylate, which adopts the following technical scheme:

[0006] A method for preparing benzyl salicylate comprises the following steps:

[0007] S1. Mix salicylate, benzyl chloride, sodium carbonate and catalyst and stir evenly, and react at a temperature of 100-140°C for 5-6h;

[0008] The molar ratio of salicylate to benzyl chloride is (1.0-1.2):1;

[0009] The catalyst is a supported quaternary ammonium salt catalyst, and the amount of the supported quaternary ammonium salt catalyst is 0.5-1.5% of the weight of the salicylate;

[0010] The amount of sodium carbonate used is 2-2.2% by weight of salicylate;

[0011] S2. The resultant of step S1 is filtered to remove the precipitate and the catalyst, and then distilled under reduced pressure, and the fractions are collected to obtain the product.

[0012] By adopting the above technical scheme, the present application uses salicylate and benzyl chloride as raw materials for the reaction, reacts for a certain period of time under the action of a specific catalyst, uses sodium carbonate to consume the incompletely reacted benzyl chloride, and the reaction conditions are mild, so that the reaction of salicylate and benzyl chloride is more thorough, and the yield of benzyl salicylate is improved. At the same time, benzyl salicylate has a good aroma, high purity, and good product quality. In addition, the two raw materials are cheap and easy to obtain, so that the cost of synthesizing benzyl salicylate is low, and it has strong market competitiveness.

[0013] The present application adopts a supported quaternary ammonium salt as a catalyst, which has high catalytic activity, strong selectivity, and is easy to separate from the reaction system. After the reaction stops, it can be recovered by simple filtration. The recovered catalyst can be reused and still maintains a high catalytic activity, meeting the requirements of large-scale continuous production.

[0014] At the same time, the application controls the usage of the supported quaternary ammonium salt catalyst within a specific range, increases the contact probability between salicylate and benzyl chloride, effectively improves the catalytic efficiency, and thus improves the yield of benzyl salicylate. If the usage of the catalyst is low, the catalyst has too little contact with the raw material, and cannot play a strong catalytic effect, affecting the reaction speed; if the usage of the catalyst is high, it is easy to agglomerate, which reduces the contact area with the raw material, and cannot play a role in improving the product yield, and also increases the production cost.

[0015] Preferably, the supported quaternary ammonium salt catalyst is prepared by the following method:

[0016] a. Firstly, dissolve phosphotungstic acid in hydrogen peroxide solution to obtain a first mixed solution, and simultaneously dissolve hexadecyltrimethylammonium chloride in hydrogen peroxide solution to obtain a second mixed solution, and then mix the second mixed solution with the first mixed solution, and stir and react for 2-3 hours at a temperature of 40-45°C; wherein the weight ratio of phosphotungstic acid to hydrogen peroxide solution is (5.76-7.76):(45-49); the weight ratio of hexadecyltrimethylammonium chloride to hydrogen peroxide solution is (1.96-3.96):(22-26);

[0017] b. The resultant of step a was cooled to room temperature, allowed to stand, the solid was separated by filtration under reduced pressure, and dried to obtain a quaternary ammonium phosphotungstate;

[0018] c. Mix activated carbon, quaternary ammonium phosphotungstate and water and stir for 6-7h, filter under reduced pressure to obtain a filter cake, wash the filter cake with water and then dry it to obtain an activated carbon-loaded quaternary ammonium phosphotungstate catalyst with a loading amount of 25-30%; wherein the weight ratio of activated carbon to water is 1: (20-30).

[0019] Preferably, the mass concentration of the hydrogen peroxide solution is 30-34%.

[0020] By adopting the above technical scheme, the present application uses activated carbon as a carrier, which can provide a larger specific surface area, so that the quaternary ammonium phosphotungstate can be well dispersed on the activated carbon, has high mechanical strength and is not easy to break, and has a stable structure, suitable shape and size, and high catalytic activity, which can ensure that the catalyst can be reused many times while the activity remains unchanged or slightly reduced.

[0021] The application controls the loading of the supported quaternary ammonium salt catalyst in a specific range at the same time, so that the number of particles and the particle size of phosphotungstate quaternary ammonium salt can be maintained within a preferred range, and these phosphotungstate quaternary ammonium salts can be uniformly loaded on activated carbon, effectively improving the catalytic activity of the supported quaternary ammonium salt catalyst. If the loading is lower than the scope of the application, the number of particles and the particle size of phosphotungstate quaternary ammonium salt can be reduced, thereby reducing the catalytic activity of the catalyst; if the loading is higher than the scope of the application, the phosphotungstate quaternary ammonium salt can not be uniformly dispersed on the activated carbon, and can be piled up to form a crystal cluster, reducing the effective contact area of ​​the catalyst and the raw material, thereby reducing the catalytic effect of the catalyst.

[0022] Preferably, in step c, the loading amount of the activated carbon-supported quaternary ammonium phosphotungstate catalyst is 30%.

[0023] By adopting the above technical scheme, the present application further controls the loading amount of quaternary ammonium phosphotungstate on activated carbon, and can further improve the uniformity of distribution of quaternary ammonium phosphotungstate on activated carbon, thereby further increasing the effective contact area between the activated carbon-loaded quaternary ammonium phosphotungstate catalyst and the raw material, and improving the catalytic activity of the catalyst.

[0024] Preferably, the specific process of mixing the second mixed liquid with the first mixed liquid is: slowly dropping the second mixed liquid into the first mixed liquid while stirring the first mixed liquid.

[0025] By adopting the above technical solution, the present application adopts a method of stirring and dropping when mixing the second mixed liquid with the first mixed liquid, which plays a role of continuous dispersion, and can make the second mixed liquid and the first mixed liquid fully mixed, thereby improving the quality of the product.

[0026] Preferably, in step b, the standing time is 1-2 hours.

[0027] Preferably, in step b, the specific conditions for drying are: vacuum drying at a temperature of 80-90° C. for 8-10 hours.

[0028] Preferably, in step c, the specific conditions for drying are: vacuum drying at a temperature of 85-95° C. for 7-8 hours.

[0029] By adopting the above technical solution, the present application controls the standing time within a specific range, so that the solids can be fully precipitated and the yield of the product is improved. At the same time, the present application controls the drying time and temperature within a specific range, fully removes the moisture in the material, and reduces the possibility of moisture interfering with the reaction.

[0030] Preferably, the specific operation of the reduced pressure distillation is: collecting the fraction at 174-178° C. under a pressure of 0.93-0.95 kPa.

[0031] By adopting the above technical scheme, the present application performs reduced pressure distillation under a specific pressure, collects components at a specific temperature, and obtains benzyl salicylate, and the product yield is high and the purity is high.

[0032] Preferably, the salicylate is one or more of sodium salicylate, potassium salicylate and calcium salicylate.

[0033] By adopting the above technical scheme, the present application uses one or more of sodium salicylate, potassium salicylate and calcium salicylate to react with benzyl chloride under specific reaction conditions, so that the yield of the generated benzyl salicylate is higher and the purity is higher.

[0034] In summary, the present application includes at least one of the following beneficial technical effects:

[0035] 1. The preparation method of the present application allows the reaction of salicylate and benzyl chloride to proceed more thoroughly, the yield of synthesized benzyl salicylate is higher, and the product has higher purity;

[0036] 2. The supported quaternary ammonium salt catalyst used in the preparation method of the present application has high catalytic activity, is easy to separate from the raw materials, can be recycled repeatedly, and can still maintain high catalytic activity after multiple uses;

[0037] 3. The preparation method of the present application has simple steps, mild reaction conditions, low production cost, and is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the embodiments.

[0039] The benzyl chloride in this application was purchased from Shandong Liaocheng Luxi Chemical Group Co., Ltd.;

[0040] The hexadecyl trimethyl ammonium chloride of the present application was purchased from Pande (Shanghai) International Trading Co., Ltd.;

[0041] The phosphotungstic acid used in this application was purchased from Shanghai Kangtuo Chemical Co., Ltd.

[0042] Preparation Example 1

[0043] The supported quaternary ammonium salt catalyst is prepared by the following method:

[0044] a. First, 57.6 g of phosphotungstic acid was dissolved in 450 g of a 30% hydrogen peroxide solution to obtain a first mixed solution, and 19.6 g of hexadecyltrimethylammonium chloride was dissolved in 220 g of a 30% hydrogen peroxide solution to obtain a second mixed solution, and then the second mixed solution was slowly added dropwise to the first mixed solution while stirring the first mixed solution. After all the additions were completed, the reaction was stirred at a temperature of 40°C for 2 h;

[0045] b. The resultant of step a was cooled to room temperature, allowed to stand for 1 h, the solid was separated by filtration under reduced pressure, and dried in vacuo at a temperature of 80 ° C for 8 h to obtain a quaternary ammonium salt of phosphotungstate;

[0046] c. 100 g of activated carbon, quaternary ammonium phosphotungstate and 2000 g of water were mixed and stirred for 6 h, and filtered under reduced pressure to obtain a filter cake. The filter cake was washed with water and vacuum dried at 85 ° C for 7 h to obtain an activated carbon-supported quaternary ammonium phosphotungstate catalyst with a loading of 25%.

[0047] Preparation Example 2

[0048] The supported quaternary ammonium salt catalyst is prepared by the following method:

[0049] a. First, 67.6 g of phosphotungstic acid was dissolved in 470 g of a 32% hydrogen peroxide solution to obtain a first mixed solution, and 29.6 g of hexadecyltrimethylammonium chloride was dissolved in 240 g of a 32% hydrogen peroxide solution to obtain a second mixed solution. Then, the second mixed solution was slowly added dropwise to the first mixed solution while stirring the first mixed solution. After all the additions were completed, the reaction was stirred at a temperature of 42.5 ° C for 2.5 hours;

[0050] b. The resultant of step a was cooled to room temperature, allowed to stand for 1.5 h, the solid was separated by filtration under reduced pressure, and dried under vacuum at a temperature of 85 ° C for 9 h to obtain a quaternary ammonium phosphotungstate;

[0051] c. 100 g of activated carbon, quaternary ammonium phosphotungstate and 2500 g of water were mixed and stirred for 6.5 h, and filtered under reduced pressure to obtain a filter cake. The filter cake was washed with water and vacuum dried at 90 ° C for 7.5 h to obtain an activated carbon-supported quaternary ammonium phosphotungstate catalyst with a loading of 27.5%.

[0052] Preparation Example 3

[0053] The supported quaternary ammonium salt catalyst is prepared by the following method:

[0054] a. First, 77.6 g of phosphotungstic acid was dissolved in 490 g of a 34% hydrogen peroxide solution to obtain a first mixed solution, and 39.6 g of hexadecyltrimethylammonium chloride was dissolved in 260 g of a 34% hydrogen peroxide solution to obtain a second mixed solution, and then the second mixed solution was slowly added dropwise to the first mixed solution while stirring the first mixed solution. After all the additions were completed, the reaction was stirred at a temperature of 45 ° C for 3 hours;

[0055] b. The resultant of step a was cooled to room temperature, allowed to stand for 2 h, the solid was separated by filtration under reduced pressure, and dried in vacuo at a temperature of 90 ° C for 10 h to obtain a quaternary ammonium phosphotungstate;

[0056] c. 100 g of activated carbon, quaternary ammonium phosphotungstate and 3000 g of water were mixed and stirred for 7 h, and filtered under reduced pressure to obtain a filter cake. The filter cake was washed with water and vacuum dried at 95 ° C for 8 h to obtain an activated carbon-supported quaternary ammonium phosphotungstate catalyst with a loading of 30%.

[0057] Preparation Example 4

[0058] The supported quaternary ammonium salt catalyst is prepared by the following method:

[0059] a. First, 60g of phosphotungstic acid was dissolved in 460g of a 31% hydrogen peroxide solution to obtain a first mixed solution, and 20g of hexadecyltrimethylammonium chloride was dissolved in 230g of a 31% hydrogen peroxide solution to obtain a second mixed solution. Then, the second mixed solution was slowly added dropwise to the first mixed solution while stirring the first mixed solution. After all the additions were completed, the reaction was stirred at a temperature of 42°C for 2.3h.

[0060] b. The resultant of step a was cooled to room temperature, allowed to stand for 1.2 h, the solid was separated by filtration under reduced pressure, and dried in vacuo at a temperature of 82 ° C for 8.5 h to obtain a quaternary ammonium phosphotungstate;

[0061] c. 100 g of activated carbon, quaternary ammonium phosphotungstate and 2300 g of water were mixed and stirred for 6.3 h, and filtered under reduced pressure to obtain a filter cake. The filter cake was washed with water and vacuum dried at 87 ° C for 7.4 h to obtain an activated carbon-supported quaternary ammonium phosphotungstate catalyst with a loading of 26%.

[0062] Preparation Example 5

[0063] The supported quaternary ammonium salt catalyst is prepared by the following method:

[0064] a. First, 70g of phosphotungstic acid was dissolved in 480g of a 33% hydrogen peroxide solution to obtain a first mixed solution, and 30g of hexadecyltrimethylammonium chloride was dissolved in 250g of a 33% hydrogen peroxide solution to obtain a second mixed solution. Then, the second mixed solution was slowly added dropwise to the first mixed solution while stirring the first mixed solution. After all the additions were completed, the reaction was stirred at a temperature of 44°C for 2.8h.

[0065] b. The resultant of step a was cooled to room temperature, allowed to stand for 1.8 h, the solid was separated by filtration under reduced pressure, and dried in vacuo at a temperature of 88 ° C for 9.7 h to obtain a quaternary ammonium phosphotungstate;

[0066] c. 100 g of activated carbon, quaternary ammonium phosphotungstate and 2800 g of water were mixed and stirred for 6.8 h, and filtered under reduced pressure to obtain a filter cake. The filter cake was washed with water and vacuum dried at 93 ° C for 7.8 h to obtain an activated carbon-supported quaternary ammonium phosphotungstate catalyst with a loading of 29%.

[0067] Preparation Example 6

[0068] The difference from Preparation Example 2 is that in step c, the loading amount of the activated carbon-supported quaternary ammonium phosphotungstate catalyst is 20%.

[0069] Preparation Example 7

[0070] The difference from Preparation Example 2 is that in step c, the loading amount of the activated carbon-supported quaternary ammonium phosphotungstate catalyst is 40%.

[0071] Preparation Example 8

[0072] The difference from Preparation Example 2 is that in step c, the loading amount of the activated carbon-supported quaternary ammonium phosphotungstate catalyst is 30%.

[0073] Example 1

[0074] A method for preparing benzyl salicylate comprises the following steps:

[0075] S1. 160 g of sodium salicylate (1.0 mol), 127 g of benzyl chloride (1.0 mol), 3.2 g of sodium carbonate and 0.8 g of the supported quaternary ammonium salt catalyst prepared in Preparation Example 1 were mixed and stirred uniformly, and reacted at a temperature of 100 ° C for 5 h;

[0076] S2. The resultant of step S1 is filtered to remove the precipitate and the supported quaternary ammonium salt catalyst, and then distilled under reduced pressure at a pressure of 0.93 kPa, and the fraction at 174-178° C. is collected to obtain benzyl salicylate.

[0077] Example 2

[0078] A method for preparing benzyl salicylate comprises the following steps:

[0079] S1. 193.6 g potassium salicylate (1.1 mol), 127 g benzyl chloride (1.0 mol), 4.0656 g sodium carbonate and 1.936 g supported quaternary ammonium salt catalyst prepared in Preparation Example 2 were mixed and stirred uniformly, and reacted at a temperature of 120° C. for 5.5 h;

[0080] S2. The resultant of step S1 is filtered to remove the precipitate and the supported quaternary ammonium salt catalyst, and then distilled under reduced pressure at a pressure of 0.94 kPa, and the fraction at 174-178° C. is collected to obtain benzyl salicylate.

[0081] Example 3

[0082] A method for preparing benzyl salicylate comprises the following steps:

[0083] S1. 376.8 g of calcium salicylate (1.2 mol), 127 g of benzyl chloride (1.0 mol), 8.2896 g of sodium carbonate and 5.652 g of the supported quaternary ammonium salt catalyst prepared in Preparation Example 3 were mixed and stirred uniformly, and reacted at a temperature of 140 ° C for 6 h;

[0084] S2. The resultant of step S1 is filtered to remove the precipitate and the supported quaternary ammonium salt catalyst, and then distilled under reduced pressure at a pressure of 0.95 kPa, and the fraction at 174-178° C. is collected to obtain benzyl salicylate.

[0085] Example 4

[0086] A method for preparing benzyl salicylate comprises the following steps:

[0087] S1. 168.8 g of salicylate (1 mol of sodium salicylate and 0.05 mol of potassium salicylate), 127 g of benzyl chloride (1.0 mol), 3.4435 g of sodium carbonate and 1.182 g of the supported quaternary ammonium salt catalyst prepared in Preparation Example 4 were mixed and stirred uniformly, and reacted at a temperature of 110° C. for 5.2 h;

[0088] S2. The resultant of step S1 is filtered to remove the precipitate and the supported quaternary ammonium salt catalyst, and then distilled under reduced pressure at a pressure of 0.94 kPa, and the fraction at 174-178° C. is collected to obtain benzyl salicylate.

[0089] Example 5

[0090] A method for preparing benzyl salicylate comprises the following steps:

[0091] S1. 207.1 g of salicylate (1.0 mol of sodium salicylate and 0.15 mol of calcium salicylate), 127 g of benzyl chloride (1.0 mol), 4.3491 g of sodium carbonate and 2.4852 g of the supported quaternary ammonium salt catalyst prepared in Preparation Example 5 were mixed and stirred uniformly, and reacted at a temperature of 130 ° C for 5.8 h;

[0092] S2. The resultant of step S1 is filtered to remove the precipitate and the supported quaternary ammonium salt catalyst, and then distilled under reduced pressure at a pressure of 0.94 kPa, and the fraction at 174-178° C. is collected to obtain benzyl salicylate.

[0093] Example 6

[0094] A method for preparing benzyl salicylate, which is different from Example 2 in that: in step S1, the catalyst is the supported quaternary ammonium salt catalyst prepared in Preparation Example 8.

[0095] Example 7

[0096] A method for preparing benzyl salicylate, which is different from that of Example 2 in that the catalyst used in step S1 is a catalyst recycled 5 times under the conditions of Example 2.

[0097] Example 8

[0098] A method for preparing benzyl salicylate, which is different from that of Example 2 in that the catalyst used in step S1 is a catalyst recycled 10 times under the conditions of Example 2.

[0099] Example 9

[0100] A method for preparing benzyl salicylate, which is different from that of Example 2 in that: in step S1, the catalyst is the supported quaternary ammonium salt catalyst prepared in Preparation Example 6.

[0101] Example 10

[0102] A method for preparing benzyl salicylate, which is different from that of Example 2 in that: in step S1, the catalyst is the supported quaternary ammonium salt catalyst prepared in Preparation Example 7.

[0103] Comparative Example 1

[0104] The difference from Example 2 is that in step S1, polyethylene glycol 200 is used instead of the supported quaternary ammonium salt catalyst.

[0105] Comparative Example 2

[0106] The difference from Example 2 is that in step S1, the reaction time is 20 hours.

[0107] Comparative Example 3

[0108] The difference from Example 2 is that in step S1, the amount of the supported quaternary ammonium salt catalyst used is 0.3872 g.

[0109] Comparative Example 4

[0110] The difference from Example 2 is that in step S1, the amount of the supported quaternary ammonium salt catalyst used is 3.872 g.

[0111] Performance Testing

[0112] The yield and purity of benzyl salicylate prepared by the preparation methods of Examples 1 to 10 and Comparative Examples 1 to 4 were detected and calculated, and the detection results are shown in Table 1.

[0113] Table 1 Test results

[0114] project Product amount (g) Product yield (%) purity(%) Example 1 221.88 96.87 99.54 Example 2 223.31 97.66 99.71 Example 3 221.65 96.68 99.45 Example 4 222.14 97.12 99.68 Example 5 222.78 97.32 99.60 Example 6 224.21 98.12 99.78 Example 7 212.56 92.68 99.41 Example 8 209.41 91.27 99.37 Example 9 208.79 90.85 99.21 Example 10 208.56 90.66 99.11 Comparative Example 1 193.29 81.75 96.43 Comparative Example 2 201.12 85.98 97.47 Comparative Example 3 197.76 84.23 97.11 Comparative Example 4 199.42 85.05 97.24

[0115] As can be seen from Table 1, the product yield of benzyl salicylate prepared in Examples 1-5 of the present application is above 96.5%, the purity is above 99.4%, and benzyl salicylate has a good aroma, indicating that in the preparation methods of Examples 1-5 of the present application, the reaction of salicylate and benzyl chloride is relatively thorough, the yield of benzyl salicylate prepared is high, and the purity of the product is high.

[0116] The product yield of benzyl salicylate obtained in Example 6 is 98.12%, which is higher than the yield in Example 2, indicating that the present application further controls the loading amount of quaternary ammonium phosphotungstate on activated carbon, which can further improve the catalytic activity of the catalyst, thereby improving the yield of benzyl salicylate.

[0117] The product yields of benzyl salicylate obtained in Examples 7-8 were 92.68% and 91.27%, respectively, which were slightly different from the 97.66% yield in Example 2, indicating that the supported quaternary ammonium salt catalyst of the present application can be recycled and can still maintain a high catalytic performance after multiple uses.

[0118] The product yield of benzyl salicylate obtained in Examples 9-10 is lower than that in Example 2, indicating that too low or too high loading of the supported quaternary ammonium salt catalyst will affect the catalytic performance of the catalyst, thereby reducing the yield of benzyl salicylate.

[0119] The product yield of benzyl salicylate obtained in Comparative Example 1 is lower than that in Example 2, indicating that the catalyst of the present application has higher catalytic performance. The use of the catalyst of the present application can significantly improve the yield of benzyl salicylate.

[0120] The product yield of benzyl salicylate obtained in Comparative Example 2 is lower than that in Example 2, indicating that the reaction time is too long, which increases the side reactions and thus reduces the yield of benzyl salicylate.

[0121] The product yield of benzyl salicylate obtained in Comparative Examples 3-4 is lower than that in Example 2, indicating that the amount of the supported quaternary ammonium salt catalyst used is not within the scope of the present application, which will reduce its catalytic activity and thus reduce the yield of benzyl salicylate.

[0122] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing benzyl salicylate, characterized in that: The following steps are involved: S1. Mix salicylate, benzyl chloride, sodium carbonate and catalyst and stir evenly, and react at a temperature of 100-140°C for 5-6h; The molar ratio of salicylate to benzyl chloride is (1.0-1.2):1; The catalyst is a supported quaternary ammonium salt catalyst, and the amount of the supported quaternary ammonium salt catalyst is 0.5-1.5% of the weight of the salicylate; The amount of sodium carbonate used is 2-2.2% by weight of salicylate; S2. The resultant of step S1 is filtered to remove the precipitate and the catalyst, and then distilled under reduced pressure to collect fractions to obtain a product; The supported quaternary ammonium salt catalyst is prepared by the following method: a. Firstly, dissolve phosphotungstic acid in hydrogen peroxide solution to obtain a first mixed solution, and simultaneously dissolve hexadecyltrimethylammonium chloride in hydrogen peroxide solution to obtain a second mixed solution, and then mix the second mixed solution with the first mixed solution, and stir and react for 2-3 hours at a temperature of 40-45°C; wherein the weight ratio of phosphotungstic acid to hydrogen peroxide solution is (5.76-7.76):(45-49); the weight ratio of hexadecyltrimethylammonium chloride to hydrogen peroxide solution is (1.96-3.96):(22-26); b. The resultant of step a was cooled to room temperature, allowed to stand, the solid was separated by filtration under reduced pressure, and dried to obtain a quaternary ammonium phosphotungstate; c. Mix activated carbon, quaternary ammonium phosphotungstate and water and stir for 6-7h, filter under reduced pressure to obtain a filter cake, wash the filter cake with water and then dry it to obtain an activated carbon-loaded quaternary ammonium phosphotungstate catalyst with a loading of 30%; wherein the weight ratio of activated carbon to water is 1: (20-30).

2. The method for preparing benzyl salicylate according to claim 1, characterized in that: The mass concentration of the hydrogen peroxide solution is 30-34%.

3. The method for preparing benzyl salicylate according to claim 1, characterized in that: The specific process of mixing the second mixed liquid with the first mixed liquid is: slowly dropping the second mixed liquid into the first mixed liquid while stirring the first mixed liquid.

4. The method for preparing benzyl salicylate according to claim 1, characterized in that: In step b, the standing time is 1-2h.

5. The method for preparing benzyl salicylate according to claim 1, characterized in that: Step b, the specific conditions of the drying are: vacuum drying at a temperature of 80-90° C. for 8-10 hours.

6. The method for preparing benzyl salicylate according to claim 1, characterized in that: In step c, the specific conditions of the drying are: vacuum drying at a temperature of 85-95° C. for 7-8 hours.

7. The method for preparing benzyl salicylate according to claim 1, characterized in that: The specific operation of the reduced pressure distillation is: collecting the fraction at 174-178° C. under a pressure of 0.93-0.95 kPa.

8. The method for preparing benzyl salicylate according to claim 1, characterized in that: The salicylate is one or more of sodium salicylate, potassium salicylate and calcium salicylate.