Sunscreen agent, sunscreen composition and preparation method of sunscreen composition

Abstract

The invention provides a sun-screening agent, a sun-screening composition and a preparation method thereof, the sun-screening agent is methyl methoxycinnamate, p-methoxyiodobenzene and methyl acrylate are used as reaction raw materials, palladium Pd is used as a catalyst, and the methyl methoxycinnamate is synthesized through an electrochemical method under a constant potential condition. The method has the advantages of environment friendliness, high conversion rate, high purity and low energy consumption, the whole reaction is non-toxic, high-temperature and high-pressure conditions are not needed, the preparation method is convenient to operate, the reaction conditions are mild, the raw materials are simple and easy to obtain, the raw materials can be used as auxiliary materials to be added into various conventional sun-screening compositions in the market, and the method has huge potential large-scale application value.

Description

Technical Field

[0001] The invention relates to a separation device, and more particularly to a light matter separation device for treating construction waste. Background Art

[0002] As we all know, sun protection is mainly for ultraviolet rays, that is, to prevent ultraviolet rays from harming human skin and hair. Usually, ultraviolet rays are divided into three sections: the wavelength range of 320-400 nm is called A zone (UVA); the wavelength range of 280-320 nm is called B zone (UVB); and the short-wave range of 180-280 nm is called C zone (UVC). Ultraviolet rays in the C zone can cause the denaturation of protein and lipid structures and interfere with nucleic acid metabolism in the human body. People use ultraviolet lamps to disinfect and sterilize based on this. Ultraviolet rays in the B zone are the most important, accounting for about 80-90% of the radiation of ultraviolet rays. Ultraviolet rays in this light zone have many effects on the skin, such as inducing or aggravating phototoxicity, idiopathic photodermatosis such as polymorphic light eruption or solar urticaria; stimulating melanocytes to produce melanin, thereby causing skin darkening; malignant and infectious diseases can also have a negative effect on skin immunosuppression, and in severe cases, skin aging and even skin cancer may occur. UVA includes UVA1 (340-400 nm) and UVA2 (320-340 nm), and UVA2 is even more damaging to insensitive skin than the former.

[0003] Therefore, protection against UVA is particularly urgent. In daily life, people take a number of protective measures, such as minimizing exposure to sunlight or reducing midday sun exposure time, wearing targeted protective clothing, and using sunscreen before sun exposure. Adding UVB and UVA absorbers to sunscreen cosmetics is an effective and widely used method that can prevent sunlight-induced erythema and sunburn. Regular use of sunscreen can also inhibit precancerous skin damage and significantly reduce the occurrence of solar tumors.

[0004] Most methoxycinnamic acid esters such as methyl methoxycinnamate, ethyl methoxycinnamate, isopentyl methoxycinnamate and isooctyl methoxycinnamate are good absorbers in the UVB region, are non-irritating to the skin, and have good safety. They are an ideal sunscreen and are commonly used in cosmetics, textiles, polymers and other products.

[0005] Methyl methoxycinnamate (MMC) has good absorption capacity for 280-320 nm ultraviolet rays and high absorption rate, and can be used as an ultraviolet absorber in cosmetics. It is an intermediate of isooctyl methoxycinnamate and isoamyl methoxycinnamate. In addition, it is also an important pharmaceutical intermediate. It is a white crystal at normal pressure with a melting point of 87-88 ℃. Its structural formula is as follows: .

[0006] In the past decade, many patents have been applied for the preparation of methoxycinnamate and its application as UV absorber abroad, but few people have studied it in China. Therefore, it is urgent to study and develop the synthesis and application of this type of sunscreen. According to the literature at home and abroad, the main synthetic routes are as follows.

[0007] The Perkin reaction is a nucleophilic addition reaction between aromatic aldehydes and acid anhydrides under the catalysis of bases, followed by the loss of a molecule of carboxylic acid to obtain β-aryl-α,β-unsaturated acid. This reaction is one of the most commonly used methods for preparing cinnamic acid compounds, but it has the disadvantages of high reaction temperature, strong alkalinity of the catalyst used, and low yield.

[0008] Knoevenagel reaction preparation This reaction is an improvement on the Perkin reaction. The anhydride is replaced by an active methylene compound with two electron-withdrawing compounds, and the catalyst is an organic weak base such as pyridine. Ethyl p-methoxycinnamate was synthesized by this route, and the acid yield was 70%; the esterification reaction of the acid and ethanol was catalyzed by concentrated sulfuric acid, and the ester yield was 78%.

[0009] Preparation by aldol condensation reaction: p-methoxybenzaldehyde and methyl acetate are dissolved in conventional hydrocarbons, and reacted under mild conditions using a strong base such as sodium methoxide as a catalyst. The resulting reaction mixture is acidified with a strong polyacid. Then, p-methoxycinnamic acid and its methyl ester and alkanol undergo esterification or transesterification reaction in an alcohol-hydrocarbon suspension of a strong polyacid salt to obtain p-methoxycinnamic acid ester with a yield of more than 85%.

[0010] Preparation by Heck coupling reaction: p-methoxychlorobenzene and isooctyl acrylate are used as raw materials, and react in N-methylpyrroloindole (NMP) under the catalysis of Pd(OAc)2 to generate OMC with a conversion rate of 68%. Halobenzene and acrylate are used as catalysts of Group VII transition metals / bases such as Pd(PPh3)2, Pd(OAc)2, etc., and amines such as CH3NH2, EtN3 are used as base co-catalysts to react in supercritical CO2 or CHF3 at a suitable temperature to give p-methoxycinnamate derivatives with high yields.

[0011] For example, CN110143878A discloses a method for preparing methyl p-methoxycinnamate. Methyl acetate, methanol, sodium methoxide and cyclic ether are added to a condensation reactor and reacted at reflux temperature; then p-methoxybenzaldehyde is added, and the reaction solution is circulated through a reaction bed loaded with a catalyst. After the p-methoxybenzaldehyde is added, the reaction solution is refluxed and kept warm to continue the reaction, and the water generated by the reaction is separated and removed. By adding methanol and cyclic ether and removing the generated water, the amount of catalyst used can be reduced to a very low level. By circulating the reaction solution through a reaction bed loaded with a metal oxide catalyst, the 3-methoxy-3-p-methoxyphenyl propionic acid methyl ester generated during the reaction is promptly converted into p-methoxycinnamate methyl ester, thereby improving the purity and yield of the product. At the same time, no acid-base neutralization process is required, and no excess wastewater and other solid wastes are generated. Compared with traditional processes, the process has a comparable or higher conversion rate and selectivity, lower production costs, and is more environmentally friendly.

[0012] For example, CN110143878B relates to an improved method for preparing cinnamate compounds, which comprises: (a) dissolving C1-C4 alkoxybenzaldehyde and C1-C4 alkyl acetate in a conventional hydrocarbon solvent; (b) reacting the resulting solution under mild conditions and in the presence of an alkali metal strong base; (c) acidifying the resulting mixture; (d) esterifying the acetic acid and stripping the esterified acetic acid from the mixture; (e) reacting the remaining C1-C4 alkoxycinnamate C1-C4 alkyl ester and C1-C4 alkoxycinnamic acid with C5-C 14 (f) recovering the product. The method of the present invention significantly improves the yield and purity of the product.

[0013] For example, CN1083828C relates to an improved method for preparing cinnamate compounds, which comprises: (a) dissolving C1-C4 alkoxybenzaldehyde and C1-C4 alkyl acetate in a conventional hydrocarbon solvent; (b) reacting the resulting solution under mild conditions and in the presence of a strong alkali metal base; (c) acidifying the resulting mixture; (d) esterifying the acetic acid and stripping the esterified acetic acid from the mixture; (e) reacting the remaining C1-C4 alkoxycinnamate C1-C4 alkyl ester and C1-C4 alkoxycinnamic acid with C5-C 14 (f) recovering the product. The method of the present invention significantly improves the yield and purity of the product. Summary of the invention

[0014] Based on the above cognition, the present invention provides a sunscreen, a sunscreen composition and a preparation method thereof, wherein the sunscreen is methyl methoxycinnamate, and methyl methoxycinnamate is synthesized by an electrochemical method under constant potential conditions using p-methoxyiodobenzene and methyl acrylate as reaction raw materials and palladium Pd as a catalyst. The electrochemical preparation of synthetic sunscreens has the advantages of being green and environmentally friendly, having a high conversion rate, high purity and low energy consumption. The entire reaction is non-toxic and does not require high temperature and high pressure conditions. The preparation method is easy to operate, the reaction conditions are mild, and the raw materials are simple and easy to obtain. It can be used as an auxiliary material and added to a variety of conventional sunscreen compositions in the market, and has huge potential large-scale application value.

[0015] A preparation method of methyl methoxycinnamate sunscreen is as follows: (1) Preparation of electrolyte: (a) Mix N,N-dimethylformamide and methyl acrylate to ensure that they are fully dissolved and uniformly mixed; (b) taking an appropriate amount of p-methoxyiodobenzene and adding it to the mixture of N,N-dimethylformamide / methyl acrylate, and stirring until it is completely dissolved; (c) preparing an appropriate amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide deionized water solution, and then introducing it into the mixed solution of step (b), stirring with a glass rod while adding; (d) taking an appropriate amount of dipotassium hydrogen phosphate, dissolving it in the solution of step (c), and adjusting the pH value with ammonium bicarbonate to ensure that it is within the range required for the esterification reaction; (2) Insert the electrodes and power on: Use the platinum sheet as the anode and the porous nickel foam as the cathode, turn on the power supply, in the constant potential mode, the cathode potential is -1.5V~-1.8V, the temperature is 25-30℃, the time is 4-5h, and the stirring is continuous at 100-120rpm; (3) Stop the reaction, cool to room temperature, extract, and purify by column chromatography to obtain methyl methoxycinnamate.

[0016] In certain embodiments, the amount of p-methoxyiodobenzene is 50-60 mmol, methyl acrylate is 80-100 mmol, the amount of N,N-dimethylformamide solvent is 100-120 mL, the amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide electrolyte is 25-30 mL, the mass fraction is 3-5wt.%, and the amount of dipotassium hydrogen phosphate is 0.1-0.2 mmol; PH=5-6.

[0017] In some embodiments, the porous nickel foam cathode is pre-washed by soaking in 50wt.% hydrochloric acid for 20-30s, then washed with deionized water, dried in an air muffle furnace at 120-150°C for 30-40min, then soaked in 10wt.% Pd(OAc)2 solution for 1-2 hours, and then taken out to serve as a cathode.

[0018] In certain embodiments, the extraction is performed by adding ethyl acetate to the electrochemical reaction solution to be extracted, gently stirring with a glass rod to allow the ethyl acetate to be fully mixed with the solution for about 5 minutes, and using a separatory funnel to separate the organic phase and the aqueous phase.

[0019] In certain embodiments, a polymeric column is selected for column chromatography purification, and a solution of methyl methoxycinnamate in ethyl acetate is loaded onto the column and slowly passed through a mobile phase for elution, wherein the mobile phase is 95 wt.% ethyl acetate + 5 wt.% NaOH solution.

[0020] In certain embodiments, a sunscreen composition includes the following proportions by weight: 5-7 parts of methyl methoxycinnamate, 25-30 parts of titanium dioxide, 40-45 parts of zinc oxide, 10-12 parts of vitamin E, and 5-7 parts of peppermint oil.

[0021] The nickel foam group of the present invention is a cathode, a porous surface is obtained by pretreatment, and an active catalyst Pd is impregnated and loaded. In the electrolyte reagent of the present invention, p-methoxy iodobenzene is used as an aryl halide, methyl acrylate is used as an olefin coupling reagent, Pd(OAc)2 is used as a palladium catalyst, tetrabutylammonium hexafluorophosphate (TBAP) or tetrabutylammonium bromide (TBAB) is used as an electrolyte, N,N-dimethylformamide (DMF) or acetonitrile is used as an organic solvent, and an electrochemical cathode provides electrons. At the cathode, the palladium catalyst Pd(II) is reduced to Pd(0) to form an active metal center, Pd(0) and p-methoxy iodobenzene undergo oxidative addition to generate an aryl palladium intermediate (Ar-Pd(II)-I), the olefin double bond of methyl acrylate is inserted into the Ar-Pd(II) bond to form a β-palladium intermediate, the intermediate undergoes β-H elimination to generate methyl methoxycinnamate, and Pd(0) is regenerated to complete the catalytic cycle, and the electrochemical system continuously provides electrons (cathode) to maintain the active valence state of Pd. The present invention uses dipotassium hydrogen phosphate to stabilize the pH value of the electrolyte, and uses ammonium bicarbonate to adjust the pH value to optimize the reversibility of the esterification reaction. A higher pH may inhibit the reaction process, while a lower pH may affect the electrode activity. In addition, it should be noted that the active ingredient of the present invention, in addition to Pd, does not exclude trace amounts of Pd at the anode.

[0022] Beneficial technical effects: The present invention uses electrochemical synthesis means for the first time to prepare methyl methoxycinnamate, using p-methoxyiodobenzene and methyl acrylate as reaction raw materials, palladium Pd / nickel foam as catalyst, and synthesizing methyl methoxycinnamate by an electrochemical method under constant potential conditions. The electrochemical means can promote the rapid progress of the reaction and reduce side reactions. The product yield is about 82.3-87.4%, the melting point of the prepared methyl methoxycinnamate is 87-89°C, and the purity of the product tested by gas chromatography is greater than 99.9%. DETAILED DESCRIPTION Example 1

[0023] A method for preparing an organic methyl p-methoxycinnamate sunscreen agent, (1) Preparation of electrolyte: (a) Mix N,N-dimethylformamide and methyl acrylate to ensure that they are fully dissolved and uniformly mixed; (b) taking an appropriate amount of p-methoxyiodobenzene and adding it to the mixture of N,N-dimethylformamide / methyl acrylate, and stirring until it is completely dissolved; (c) preparing an appropriate amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide deionized water solution, and then introducing it into the mixed solution of step (b), stirring with a glass rod while adding; (d) taking an appropriate amount of dipotassium hydrogen phosphate, dissolving it in the solution of step (c), and adjusting the pH value with ammonium bicarbonate to ensure that it is within the range required for the esterification reaction; (2) Insert the electrodes and apply power: Use the platinum sheet as the anode and the porous nickel foam as the cathode. Turn on the power supply. In the constant potential mode, the cathode potential is -1.5 V, the temperature is 25 °C, the time is 4 h, and the stirring is continuous at 100 rpm. (3) Stop the reaction, cool to room temperature, extract, and purify by column chromatography to obtain methyl methoxycinnamate.

[0024] The amounts of the various reagents used in the above electrolyte preparation process are as follows: 50 mmol of p-methoxyiodobenzene, 80 mmol of methyl acrylate, 100 mL of N,N-dimethylformamide solvent, 25 mL of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide electrolyte, 3 wt.%, and 0.1 mmol of dipotassium hydrogen phosphate; pH=5.

[0025] Porous nickel foam cathode The nickel foam is pre-washed in 50wt.% hydrochloric acid for 20s, then washed with deionized water, dried in an air muffle furnace at 120°C for 30min, and then soaked in 10wt.% Pd(OAc)2 solution for 1-2 hours. After being taken out, it is used as a cathode with porosity and high specific surface area.

[0026] The extraction is performed by adding ethyl acetate to the solution after the electrochemical reaction to be extracted, and gently stirring with a glass rod to allow the ethyl acetate to be fully mixed with the solution for about 5 minutes, and using a separatory funnel to separate the organic phase and the aqueous phase.

[0027] For column chromatography purification, a polymeric column was selected, and the methyl methoxycinnamate solution in ethyl acetate was loaded onto the column and slowly passed through a mobile phase for elution. The mobile phase was 95 wt.% ethyl acetate + 5 wt.% NaOH solution. Example 2

[0028] A method for preparing an organic methyl p-methoxycinnamate sunscreen agent, (1) Preparation of electrolyte: (a) Mix N,N-dimethylformamide and methyl acrylate to ensure that they are fully dissolved and uniformly mixed; (b) taking an appropriate amount of p-methoxyiodobenzene and adding it to the mixture of N,N-dimethylformamide / methyl acrylate, and stirring until it is completely dissolved; (c) preparing an appropriate amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide deionized water solution, and then introducing it into the mixed solution of step (b), stirring with a glass rod while adding; (d) taking an appropriate amount of dipotassium hydrogen phosphate, dissolving it in the solution of step (c), and adjusting the pH value with ammonium bicarbonate to ensure that it is within the range required for the esterification reaction; (2) Insert the electrodes and apply power: Use the platinum sheet as the anode and the porous nickel foam as the cathode. Turn on the power supply. In the constant potential mode, the cathode potential is -1.65 V, the temperature is 27.5 °C, the time is 4.5 h, and the stirring is continuous at 110 rpm. (3) Stop the reaction, cool to room temperature, extract, and purify by column chromatography to obtain methyl methoxycinnamate.

[0029] The amounts of the various reagents used in the above electrolyte preparation process are as follows: 55 mmol of p-methoxyiodobenzene, 90 mmol of methyl acrylate, 110 mL of N,N-dimethylformamide solvent, 27.5 mL of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide electrolyte, 4 wt.%, and 0.15 mmol of dipotassium hydrogen phosphate; pH=5.5.

[0030] Porous nickel foam cathode The nickel foam was pre-pickled in 50wt.% hydrochloric acid for 25s, then washed with deionized water, dried at 135°C in an air muffle furnace for 35min, and then soaked in 10wt.% Pd(OAc)2 solution for 1.5 hours. After being taken out, it was used as a cathode with porosity and high specific surface area. Example 3

[0031] A method for preparing an organic methyl p-methoxycinnamate sunscreen agent, (1) Preparation of electrolyte: (a) Mix N,N-dimethylformamide and methyl acrylate to ensure that they are fully dissolved and uniformly mixed; (b) taking an appropriate amount of p-methoxyiodobenzene and adding it to the mixture of N,N-dimethylformamide / methyl acrylate, and stirring until it is completely dissolved; (c) preparing an appropriate amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide deionized water solution, and then introducing it into the mixed solution of step (b), stirring with a glass rod while adding; (d) taking an appropriate amount of dipotassium hydrogen phosphate, dissolving it in the solution of step (c), and adjusting the pH value with ammonium bicarbonate to ensure that it is within the range required for the esterification reaction; (2) Insert the electrodes and apply power: Use the platinum sheet as the anode and the porous nickel foam as the cathode. Turn on the power supply. In the constant potential mode, the cathode potential is -1.8 V, the temperature is 30 °C, the time is 5 h, and the stirring is continuous at 120 rpm. (3) Stop the reaction, cool to room temperature, extract, and purify by column chromatography to obtain methyl methoxycinnamate.

[0032] The amounts of the various reagents used in the above electrolyte preparation process are as follows: 60 mmol of p-methoxyiodobenzene, 100 mmol of methyl acrylate, 120 mL of N,N-dimethylformamide solvent, 30 mL of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide electrolyte, 5 wt.%, and 0.2 mmol of dipotassium hydrogen phosphate; pH=6.

[0033] Porous nickel foam cathode The nickel foam was pre-pickled in 50wt.% hydrochloric acid for 30s, then washed with deionized water, dried at 150°C in an air muffle furnace for 40min, and then soaked in 10wt.% Pd(OAc)2 solution for 2 hours. After being taken out, it was used as a cathode with porosity and high specific surface area.

[0034] Comparative Example 1 Preparation method of organic methyl p-methoxycinnamate sunscreen (1) Preparation of electrolyte: (a) Mix N,N-dimethylformamide and methyl acrylate to ensure that they are fully dissolved and evenly mixed; (b) taking an appropriate amount of p-methoxyiodobenzene and adding it to the mixture of N,N-dimethylformamide / methyl acrylate, and stirring until it is completely dissolved; (c) preparing an appropriate amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide deionized water solution, and then introducing it into the mixed solution of step (b), stirring with a glass rod while adding; (2) Insert the electrodes and apply power: Use the platinum sheet as the anode and the porous nickel foam as the cathode. Turn on the power supply. In the constant potential mode, the cathode potential is -1.65 V, the temperature is 27.5 °C, the time is 4.5 h, and the stirring is continuous at 110 rpm. (3) Stop the reaction, cool to room temperature, extract, and purify by column chromatography to obtain methyl methoxycinnamate.

[0035] The amounts of the various reagents used in the above electrolyte preparation process are as follows: 55 mmol of p-methoxyiodobenzene, 90 mmol of methyl acrylate, 110 mL of N,N-dimethylformamide solvent, 27.5 mL of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide electrolyte, with a mass fraction of 4 wt.%.

[0036] Porous nickel foam cathode The nickel foam was pre-pickled in 50wt.% hydrochloric acid for 25s, then washed with deionized water, dried at 135°C in an air muffle furnace for 35min, and then soaked in 10wt.% Pd(OAc)2 solution for 1.5 hours. After being taken out, it was used as a cathode with porosity and high specific surface area.

[0037] The product yields of methyl methoxycinnamate in Examples 1-3 were 82.3%, 87.4% and 84.2%, respectively. In comparison, the conversion rate of Comparative Example 1 was 41.7%.

[0038] The methyl p-methoxycinnamate prepared by the present invention is a chemical substance with an aromatic odor, mild, non-irritating, good hydrophilicity and oil-water balance. The mixed use of the methyl p-methoxycinnamate and traditional sunscreens such as zinc oxide can significantly improve the sunscreen effect while improving the product's use experience and tolerance. The composition relates to a sunscreen agent, including the following mass proportions: 6 parts of methyl methoxycinnamate, 27.5 parts of titanium dioxide, 42.5 parts of zinc oxide, 11 parts of vitamin E, and 6 parts of peppermint oil. According to the "Sunscreen Cosmetics Sunscreen Index Determination Method" and "Sunscreen Cosmetics Long-wave Ultraviolet Protection Index Determination Method" of the "Cosmetics Hygiene Standards", the SPF value of the sunscreen lotion is 33.4 and the PFA value is 12.7.

[0039] Finally, it should be noted that the above embodiments are only used to describe the preferred implementation methods of the present invention, rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that various modifications and improvements made by modifying or equivalently replacing the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A sunscreen, wherein the sunscreen is methyl p-methoxycinnamate, characterized in that Methyl methoxycinnamate was synthesized by electrochemical method under constant potential condition with p-methoxyiodobenzene and methyl acrylate as raw materials and palladium / nickel foam as catalyst.

2. The sunscreen according to claim 1, characterized in that The preparation method of methyl methoxycinnamate is as follows: (1) Preparation of electrolyte: (a) Mix N,N-dimethylformamide and methyl acrylate to ensure that they are fully dissolved and uniformly mixed; (b) taking an appropriate amount of p-methoxyiodobenzene and adding it to the mixture of N,N-dimethylformamide / methyl acrylate, and stirring until it is completely dissolved; (c) preparing an appropriate amount of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide deionized water solution, and then introducing it into the mixed solution of step (b), stirring with a glass rod while adding; (d) taking an appropriate amount of dipotassium hydrogen phosphate, dissolving it in the solution of step (c), and adjusting the pH value with ammonium bicarbonate to ensure that it is within the range required for the esterification reaction; (2) Insert the electrodes and power on: Use the platinum sheet as the anode and the porous nickel foam as the cathode, turn on the power supply, in the constant potential mode, the cathode potential is -1.5V~-1.8V, the temperature is 25-30℃, the time is 4-5h, and the stirring is continuous at 100-120rpm; (3) Stop the reaction, cool to room temperature, extract, and purify by column chromatography to obtain methyl methoxycinnamate.

3. The sunscreen according to claim 2, characterized in that The dosage of p-methoxyiodobenzene is 50-60mmol, methyl acrylate is 80-100mmol, the dosage of N,N-dimethylformamide solvent is 100-120mL, the dosage of tetrabutylammonium hexafluorophosphate or tetrabutylammonium bromide electrolyte is 25-30mL, the mass fraction is 3-5wt.%, the dosage of dipotassium hydrogen phosphate is 0.1-0.2mmol; pH=5-6.

4. The sunscreen according to claim 2, characterized in that Porous nickel foam cathode The nickel foam is pre-washed by soaking in 50wt.% hydrochloric acid for 20-30s, then washed with deionized water, dried in an air muffle furnace at 120-150°C for 30-40min, then soaked in 10wt.% Pd(OAc)2 solution for 1-2 hours, taken out, and used as a cathode.

5. The sunscreen according to claim 2, characterized in that The extraction is performed by adding ethyl acetate to the solution after the electrochemical reaction to be extracted, and gently stirring with a glass rod to allow the ethyl acetate to be fully mixed with the solution for about 5 minutes, and using a separatory funnel to separate the organic phase and the aqueous phase.

6. The sunscreen according to claim 2, characterized in that For column chromatography purification, a polymeric column was selected, and the methyl methoxycinnamate solution in ethyl acetate was loaded onto the column and slowly passed through a mobile phase for elution. The mobile phase was 95 wt.% ethyl acetate + 5 wt.% NaOH solution.

7. A sunscreen composition prepared using the methyl methoxycinnamate sunscreen according to any one of claims 1 to 2, characterized in that The invention comprises the following proportions by weight: 5-7 parts of methyl methoxycinnamate, 25-30 parts of titanium dioxide, 40-45 parts of zinc oxide, 10-12 parts of vitamin E and 5-7 parts of peppermint oil.