Bactericide for oily sewage treatment and preparation method thereof

Abstract

The invention relates to the technical field of bactericides, in particular to an oily sewage treatment bactericide and a preparation method thereof, and the oily sewage treatment bactericide is composed of isothiazolinone, quaternary ammonium salt and the like. Carrying out ultrasonic-assisted loading on the titanium dioxide loaded on the nano-silver; the novel organophosphorus bactericide is synthesized through microwaves; performing molecular modification on the synergist, and performing spray drying on a dispersing agent; the intelligent slow-release microcapsule and the photoresponse polymer are contained, all the components are synergistic, efficient sterilization is achieved, and the effect is lasting. The sterilizing rate of the sterilizing agent is high and reaches 90%-98%, the sterilizing agent contains the intelligent slow-release microcapsules, the effect is lasting, the sterilizing condition is widened through the photoresponse polymer, all the components are stable in complex sewage after being specially treated, and the oil-containing sewage treatment efficiency and quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of bactericides, and particularly to a bactericide for treating oily sewage and a preparation method thereof. Background Art

[0002] In the processes of oil extraction, refining and related industrial production, the amount of oily sewage generated is extremely large. Such sewage not only contains a large amount of petroleum substances, but also various microorganisms, such as sulfate-reducing bacteria and iron bacteria. The massive reproduction of these microorganisms in oily sewage will cause a series of serious problems.

[0003] During metabolism, sulfate-reducing bacteria will reduce sulfate ions to hydrogen sulfide, resulting in the water body turning black and emitting a stench. At the same time, hydrogen sulfide is corrosive, which will cause serious corrosion to sewage treatment equipment, pipelines, etc., shortening the service life of the equipment and increasing the maintenance cost. Iron bacteria will oxidize ferrous ions and form precipitates of iron oxides on the inner walls of equipment and pipelines, causing blockages of the equipment and pipelines, affecting the normal operation of the sewage treatment process and reducing the treatment efficiency.

[0004] When dealing with these problems, traditional bactericides for treating oily sewage have exposed many limitations. On the one hand, the commonly used bactericides have a relatively single composition. For example, relying solely on isothiazolinone or quaternary ammonium salt compounds, it is difficult to achieve an efficient and long-lasting bactericidal effect on various bacteria. Long-term use of bactericides with a single composition is likely to cause bacteria to develop drug resistance, resulting in a significant decline in the bactericidal rate. According to relevant research, in some oily sewage treatment systems that have long used traditional single bactericides, the drug resistance of bacteria can increase by 30%-50% within half a year, greatly reducing the bactericidal effect.

[0005] On the other hand, traditional bactericides have insufficient stability in the complex environment of oily sewage. The water quality of oily sewage varies greatly, and its acidity, salinity, and the types and contents of petroleum substances are different. Conventional bactericides are prone to decomposition, precipitation, etc. in oily sewage with high salinity or extreme pH values, thus losing their bactericidal activity. For example, in oily sewage with a salinity higher than 10000 mg / L, the bactericidal rate of some traditional bactericides will drop suddenly from 70% under normal conditions to below 30%.

[0006] In addition, the action mode of traditional bactericides is relatively passive. They can only play a role after contacting bacteria and cannot adaptively adjust according to the distribution and concentration changes of bacteria in the sewage. Moreover, their action time is short, and it is difficult to continuously inhibit the growth of bacteria for a long time. During the sewage treatment process, it is necessary to frequently add bactericides, which not only increases the operation cost but also may cause secondary pollution to the environment.

[0007] With the increasingly strict environmental protection requirements and the higher pursuit of the quality of oily sewage treatment, it is urgent to develop a bactericide for oily sewage treatment that is efficient, stable, has intelligent adjustment functions and is environmentally friendly. Based on such a background, this patent is committed to solving the problems in the existing technology and bringing new breakthroughs to the field of oily sewage treatment through innovative raw material combinations, unique preparation processes and the introduction of intelligent components. Summary of the Invention

[0008] (1) Technical problems to be solved

[0009] In view of the deficiencies of the existing technology, the present invention provides a bactericide for oily sewage treatment and its preparation method.

[0010] (2) Technical solutions

[0011] A bactericide for oily sewage treatment is made from the following raw materials in parts by mass:

[0012] Isothiazolinone 15 - 25 parts, quaternary ammonium salt compound 10 - 18 parts, nano-silver loaded titanium dioxide composite 5 - 10 parts, novel organophosphorus bactericide 8 - 12 parts, synergist 3 - 6 parts, dispersant 2 - 5 parts, intelligent slow-release microcapsule 4 - 8 parts, photo-responsive polymer 2 - 4 parts;

[0013] In the nano-silver loaded titanium dioxide composite, the nano-silver particle size is 5 - 15 nm and is loaded on the surface of anatase titanium dioxide with a particle size of 20 - 50 nm, and is prepared through the reaction: AgNO3 + TiO2 → Ag - TiO2 + NO3 - The reaction process is assisted by ultrasonic treatment at 20 - 40 kHz for 30 - 60 min;

[0014] The novel organophosphorus bactericide is O,O - diethyl - N - (2 - pyrimidinyl) thiophosphoramide, and its specific structure is:

[0015]

[0016] It is formed by the nucleophilic substitution reaction of O,O - diethyl thiophosphoryl chloride C2H5O2PSCl and 2 - aminopyrimidine C4H5N3 under the action of a catalyst triethylamine (C2H5)3N, and the reaction formula is:

[0017]

[0018] The synergist is a cationic surfactant with a fluorine content of 10% - 20%, and is spray - dried with a particle size of 5 - 10 μm;

[0019] The intelligent slow - release microcapsule uses PLGA as the wall material, in which the molar ratio of lactic acid to glycolic acid is 3 - 5:1, and the wall thickness is 50 - 100 nm;

[0020] The photo-responsive polymer is poly(N-vinylcarbazole) grafted with benzophenone groups, and the grafting rate is 10%-20%.

[0021] Preferably, the isothiazolinone is a mixture of 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, with a mass ratio of (1-3):1 and a purity of ≥99%.

[0022] Preferably, the quaternary ammonium salt compound is dodecyl dimethyl benzyl ammonium chloride or cetyl trimethyl ammonium bromide, with a purity of ≥95%, and nitrogen is filled for protection during storage.

[0023] Preferably, in the nano-silver loaded titanium dioxide composite material, the mass ratio of nano-silver to titanium dioxide is (0.1-0.3):1, the reaction temperature is 40-60°C, and the loading uniformity is observed by TEM.

[0024] Preferably, when synthesizing the novel organophosphorus fungicide, the reaction temperature is 80-100°C, the pH is adjusted to 6-7 by the buffer potassium dihydrogen phosphate-disodium hydrogen phosphate, the microwave power is 300-500W, and the reaction time is 3-5h.

[0025] Preferably, before adding the synergist, it is emulsified by high-speed shearing at 8000-10000 r / min for 15-20 min, and its surface tension is 18-22 mN / m at 25°C.

[0026] Preferably, the dispersant is a polycarboxylate, with a molecular weight of 5000-10000, a solid content of 30%-40%, and ultrafiltration concentration before spray drying.

[0027] Preferably, the intelligent slow-release microcapsules are prepared by the double emulsion-solvent evaporation method: the core component is dissolved in dichloromethane, mixed with the PLGA solution and emulsified by ultrasonic waves for 5-10 min to form a W / O emulsion, and the ultrasonic power is 200-300W; then it is dispersed in an aqueous solution of polyvinyl alcohol and stirred at 500-700 r / min to form a W / O / W double emulsion, and obtained after vacuum distillation.

[0028] Preferably, the photo-responsive polymer is synthesized with AIBN as an initiator at 60-80°C for 4-6 hours.

[0029] Preferably, according to the preparation method of the bactericide for treating oil-containing sewage described in any one of the foregoing, the following steps are included:

[0030] Preparation of silver nanoparticles loaded titanium dioxide composite: Mix silver nitrate solution with titanium dioxide, add sodium borohydride, ultrasonically treat for 30 - 60 minutes at 20 - 40 kHz, filter with a 0.2 - 0.5 μm filter membrane, wash alternately with deionized water and ethanol 3 - 5 times, and dry;

[0031] Synthesis of novel organophosphorus fungicides: React a phosphorus-containing compound with a nitrogen-containing heterocyclic haloalkane under the catalysis of concentrated sulfuric acid, microwave-assisted heat at 300 - 500 W to 80 - 100 °C for 3 - 5 hours, and purify by column chromatography, where the eluent is petroleum ether - ethyl acetate with a volume ratio of 5 - 8:1;

[0032] Preparation of intelligent sustained-release microcapsules: Ultrasonically emulsify the core component with a dichloromethane solution of PLGA for 5 - 10 minutes to form a W / O emulsion, disperse it in an aqueous solution of polyvinyl alcohol and stir to form a W / O / W multiple emulsion, and remove the solvent by vacuum distillation;

[0033] Synthesis of photo-responsive polymers: React the monomer with AIBN at 60 - 80 °C for 4 - 6 hours, and detect the molecular weight by GPC;

[0034] Mixing and blending: Weigh each component according to the ratio, stir at 150 - 250 r / min at room temperature for 30 - 60 minutes, and clean the reaction kettle with acid and alkali and sterilize it at high temperature before use.

[0035] (III) Beneficial technical effects

[0036] Compared with the existing technology, the beneficial effects of the present invention are:

[0037] 1. Within 24 hours after treatment, the sterilization rate can reach 90% - 98%; this benefits from its innovative ingredient combination, where isothiazolinone, quaternary ammonium salt compounds and novel organophosphorus fungicides act synergistically to disrupt the cell wall, cell membrane and intracellular physiological metabolic processes of bacteria through different mechanisms; the silver nanoparticles loaded titanium dioxide composite further enhances the sterilization effect under photocatalysis and broadens the sterilization action pathway.

[0038] 2. Each component is carefully designed and processed; the synergist is specially molecularly modified and has good dispersibility and stability at the oil-water interface, which can effectively improve the activity of the fungicide under different water quality conditions; the dispersant is spray-dried, which can better ensure the uniform dispersion of the fungicide components and prevent agglomeration, so as to stably play a role in the complex oily sewage environment.

[0039] 3. By adjusting the thickness and composition ratio of the poly(lactic-co-glycolic acid) (PLGA) wall material, the intelligent slow release of the core bactericidal component can be achieved, and the bactericidal component can be continuously and stably released in oily sewage for 7-10 days; this means that there is no need to frequently add bactericides, which not only reduces the operation cost but also ensures the persistence of the bactericidal effect and effectively reduces the generation of bacterial drug resistance.

[0040] 4. The addition of the light-responsive polymer enables the bactericide to undergo a structural change under light conditions, enhancing its binding ability with bacteria and promoting the photocatalytic reaction of the silver-loaded titanium dioxide composite, thus broadening the bactericidal conditions; it can play a good bactericidal role whether on the surface of the sewage treatment tank with sufficient light or in the darker internal area.

[0041] 5. Technologies such as microwave-assisted synthesis and ultrasonic-assisted treatment not only shorten the reaction time, for example, the synthesis time of the new organophosphorus bactericide is shortened from the conventional 6-10 hours to 3-5 hours, but also improve the product purity and performance; at the same time, the control of various parameters during the preparation process is strict, ensuring the stability of the product quality. Description of the Drawings

[0042] Figure 1 is the preparation flow chart of a bactericide for treating oily sewage proposed by the present invention;

[0043] Figure 2 is the broken line chart for comparing the bactericidal persistence of the examples and the comparative examples;

[0044] Figure 3 is the columnar comparison chart of the bactericidal rates of the examples and the comparative examples in oily sewage with different pH values;

[0045] Figure 4 is the columnar chart of the bactericidal rates of the examples and the comparative examples in normal oily sewage. Detailed Embodiments

[0046] Example 1

[0047] Raw material preparation: Accurately weigh 15 parts of isothiazolinone, in which the mass ratio of 2-methyl-4-isothiazolin-3-one to 5-chloro-2-methyl-4-isothiazolin-3-one is 1:1, and both have been purified by recrystallization with a purity of 99%; 10 parts of quaternary ammonium salt compound is selected as dodecyl dimethyl benzyl ammonium chloride with a purity of 95%, and it is protected by nitrogen filling during storage; 5 parts of nano-silver loaded titanium dioxide composite material, when prepared, the mass ratio of nano-silver to titanium dioxide is 0.1:1, the reaction temperature is 40 °C, and it is assisted by 20 kHz ultrasonic treatment for 30 minutes; 8 parts of a new type of organophosphorus fungicide, when synthesized, microwave-assisted heating is used with a power of 300 W, a reaction temperature of 80 °C, a reaction time of 3 hours, and the pH value of the reaction system is controlled at 6 with a potassium dihydrogen phosphate-disodium hydrogen phosphate buffer pair; 3 parts of synergist is a fluorinated surfactant with a fluorine content of 10%, and it is emulsified at 8000 r / min by a high-speed shear emulsifier for 15 minutes; 2 parts of polycarboxylate dispersant with a solid content of 30%, which is ultrafiltered and concentrated before spray drying to make micropowder with a particle size of 5 μm; 4 parts of intelligent slow-release microcapsules, which are prepared by the double emulsion-solvent evaporation method, and the core bactericidal components contain high-concentration isothiazolinone and a new type of organophosphorus fungicide, and the wall thickness of the poly(lactic-co-glycolic acid) (PLGA) is 50 nm, and the molar ratio of lactic acid to glycolic acid is 3:1; 2 parts of photo-responsive polymer, using azobisisobutyronitrile (AIBN) as an initiator with a dosage of 0.5% of the total mass of the monomers, reacting at 60 °C for 4 hours with a grafting rate of 10%.

[0048] Preparation process: First, prepare the nano-silver loaded titanium dioxide composite material, mix the silver nitrate solution with titanium dioxide powder, add sodium borohydride as a reducing agent, stir and react, filter with a 0.2 μm microporous filter membrane, and wash alternately with deionized water and ethanol 3 times and then dry; then synthesize the new type of organophosphorus fungicide, and purify it by column chromatography with a petroleum ether-ethyl acetate mixed solution (volume ratio 5:1) as the eluent after the reaction; then prepare the intelligent slow-release microcapsules according to the double emulsion-solvent evaporation method; then synthesize the photo-responsive polymer, and measure the molecular weight and molecular weight distribution by gel permeation chromatography (GPC); finally, add all the raw materials to the reaction kettle, stir at 150 r / min at room temperature for 30 minutes to obtain the fungicide product.

[0049] Example 2

[0050] Raw material preparation: Weigh 20 parts of isothiazolinone, with the mass ratio of 2-methyl-4-isothiazolin-3-one to 5-chloro-2-methyl-4-isothiazolin-3-one being 2:1 and the purity being 99%; 14 parts of cetyltrimethylammonium bromide with a purity of 96%, stored under nitrogen; 7 parts of nano-silver loaded titanium dioxide composite material, with the mass ratio of nano-silver to titanium dioxide being 0.2:1, reacting at 50 °C and assisted by 30 kHz ultrasonic waves for 40 minutes; 10 parts of a new type of organophosphorus fungicide, with a microwave power of 400 W, reacting at 90 °C for 4 hours, and maintaining the pH value at 6.5; 4 parts of synergist with a fluorine content of 15%, emulsifying at a speed of 9000 r / min for 18 minutes; 3 parts of dispersant with a solid content of 35%, spray-dried into 7-μm fine powder; 6 parts of intelligent slow-release microcapsules, with a wall thickness of 70 nm and a molar ratio of lactic acid to glycolic acid of 4:1; 3 parts of photo-responsive polymer, with the dosage of AIBN being 1%, reacting at 70 °C for 5 hours and the grafting rate being 15%.

[0051] Preparation process: Prepare the nano-silver loaded titanium dioxide composite material, filter it with a 0.3-μm filter membrane, and wash it 4 times; After synthesizing the new type of organophosphorus fungicide, assist in purification by thin-layer chromatography; Prepare the intelligent slow-release microcapsules according to the standard process; After synthesizing the photo-responsive polymer, detect the molecular weight; Finally, mix the raw materials and stir at 200 r / min for 40 minutes to obtain the product.

[0052] Example 3

[0053] Raw material preparation: Take 25 parts of isothiazolinone, with a ratio of 3:1 and a purity of 99%; 18 parts of quaternary ammonium salt compound, protected by nitrogen; 10 parts of nano-silver loaded titanium dioxide composite material, with a mass ratio of 0.3:1, reacting at 60 °C and assisted by 40 kHz ultrasonic waves for 60 minutes; 12 parts of a new type of organophosphorus fungicide, with a microwave of 500 W, reacting at 100 °C for 5 hours and the pH value being 7; 6 parts of synergist with a fluorine content of 20%, emulsifying for 20 minutes; 5 parts of dispersant with a solid content of 40%, 10-μm fine powder; 8 parts of intelligent slow-release microcapsules, with a wall thickness of 100 nm and a molar ratio of 5:1; 4 parts of photo-responsive polymer, with a grafting rate of 20%.

[0054] Preparation process: After preparing the nano-silver loaded titanium dioxide composite material, detect the loading stability by thermogravimetric analysis; Assist in the purification of the new type of organophosphorus fungicide by high-performance liquid chromatography; Optimize the stirring speed during the preparation of the intelligent slow-release microcapsules; Characterize the structure of the photo-responsive polymer by infrared spectroscopy after synthesis; Stir at 250 r / min for 60 minutes during mixing to obtain the fungicide.

[0055] Control example

[0056] Raw material preparation: Weigh 20 parts of isothiazolinone without special purification, 15 parts of ordinary quaternary ammonium salt compound, without nano-silver loaded titanium dioxide, new type of organophosphorus fungicide, synergist, dispersant, intelligent slow-release microcapsules and photo-responsive polymer;

[0057] Preparation process: Isoothiazolinone and quaternary ammonium salt compounds are simply mixed and stirred at room temperature for 20 minutes to prepare a traditional fungicide.

[0058] Performance test

[0059] Take the fungicides prepared in Examples 1-3 and the comparative example respectively, add them to the oily sewage samples with the same water quality, react at 25 °C for 24 hours, and detect the contents of sulfate-reducing bacteria and iron bacteria in the sewage; the results show that the bactericidal rates of Examples 1-3 are 92%, 95%, and 97% respectively, while the bactericidal rate of the comparative example is only 60%; in the simulated oily sewage environment with high salt and acidity, Examples 1-3 can still maintain a bactericidal rate of 85%-90%, while the bactericidal rate of the comparative example drops to below 30%, fully demonstrating the excellent performance of the fungicide of this patent.

[0060] Comparison of bactericidal rates between examples and the comparative example in different oily sewage environments:

[0061] sample Example 1 Example 2 Example 3 Comparative example Sterilization rate of normal oily sewage 92％ 95％ 97％ 60％ Sterilization rate of high-salt (15000mg / L) oily sewage 85％ 88％ 90％ 30％ Sterilization rate of acidic (pH value 4) oily sewage 88％ 90％ 92％ 25％ Sterilization rate of alkaline (pH value 10) oily sewage 86％ 89％ 91％ 35％

[0062] Conclusion: This table comprehensively shows the bactericidal rates of Examples 1-3 and the comparative example in different oily sewage environments. In normal, high-salt, acidic, and alkaline environments, the bactericidal rates of the examples are much higher than those of the comparative example, indicating that the fungicide of this patent has strong adaptability to complex water quality and can sterilize stably and efficiently. Due to the limitations of the composition and preparation method, the bactericidal effect of the comparative example is extremely poor in special water quality.

[0063] Comparison of bactericidal persistence between examples and the comparative example (continuously detected for 7 days):

[0064]

[0065]

[0066] Conclusion: This table compares the bactericidal persistence of examples and the comparative example within 7 days. Although the bactericidal rate of the examples decreases within 7 days, it always remains at a relatively high level, thanks to the action of components such as intelligent slow-release microcapsules. The bactericidal rate of the comparative example drops sharply with time, indicating that the bactericidal stability of the fungicide of this patent is much better than that of the traditional comparative example fungicide in the long term.

[0067] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A bactericide for treating oily sewage, characterized in that, It is made from the following raw materials in parts by mass: 15 - 25 parts of isothiazolinone, 10 - 18 parts of quaternary ammonium salt compound, 5 - 10 parts of nano - silver loaded titanium dioxide composite material, 8 - 12 parts of novel organophosphorus fungicide, 3 - 6 parts of synergist, 2 - 5 parts of dispersant, 4 - 8 parts of intelligent slow - release microcapsule, 2 - 4 parts of light - responsive polymer; In the nano silver-loaded titanium dioxide composite material, the particle size of the nano silver is 5-15 nm, and it is loaded on the surface of anatase titanium dioxide with a particle size of 20-50 nm, through the reaction: AgNO3 + TiO2 → Ag-TiO2 + NO3 - It is prepared by ultrasonic treatment at 20-40 kHz for 30-60 min during the reaction process; The novel organophosphorus fungicide is O,O - diethyl - N - (2 - pyrimidinyl) thiophosphoramide, and its specific structure is: It is formed by the nucleophilic substitution reaction of O,O - diethyl thiophosphoryl chloride C2H5O2PSCl and 2 - aminopyrimidine C4H5N3 under the action of the catalyst triethylamine (C2H5)3N, and the reaction formula is: The synergist is a cationic surfactant with a fluorine content of 10% - 20%, which is spray - dried, and the particle size is 5 - 10 μm; The intelligent slow - release microcapsule uses PLGA as the wall material, in which the molar ratio of lactic acid to glycolic acid is 3 - 5:1, and the wall thickness is 50 - 100 nm; The light - responsive polymer is poly(N - vinylcarbazole) grafted with benzophenone groups, and the grafting rate is 10% - 20%.

2. The fungicide according to claim 1, wherein The isothiazolinone is a mixture of 2 - methyl - 4 - isothiazolin - 3 - one and 5 - chloro - 2 - methyl - 4 - isothiazolin - 3 - one, with a mass ratio of (1 - 3):1 and a purity of ≥99%.

3. The fungicide according to claim 1, characterized in that, The quaternary ammonium salt compound is dodecyl dimethyl benzyl ammonium chloride or cetyl trimethyl ammonium bromide, with a purity of ≥95%, and is protected by nitrogen during storage.

4. The fungicide according to claim 1, characterized in that, In the nano - silver loaded titanium dioxide composite material, the mass ratio of nano - silver to titanium dioxide is (0.1 - 0.3):1, the reaction temperature is 40 - 60 °C, and the loading uniformity is observed by TEM.

5. The fungicide according to claim 1, characterized in that, When synthesizing the novel organophosphorus fungicide, the reaction temperature is 80 - 100 °C, the pH is adjusted to 6 - 7 by the buffer potassium dihydrogen phosphate - disodium hydrogen phosphate, the microwave power is 300 - 500 W, and the reaction time is 3 - 5 h.

6. The fungicide according to claim 1, characterized in that, Before adding the synergist, it is subjected to high - speed shear emulsification at 8000 - 10000 r / min for 15 - 20 min, and its surface tension at 25 °C is 18 - 22 mN / m.

7. The fungicide according to claim 1, characterized in that, The dispersant is a polycarboxylate, with a molecular weight of 5000 - 10000, a solid content of 30% - 40%, and is ultrafiltration - concentrated before spray - drying.

8. The fungicide according to claim 1, characterized in that, The intelligent slow - release microcapsule is prepared by the double - emulsion solvent evaporation method: The core component is dissolved in dichloromethane, mixed with the PLGA solution and ultrasonically emulsified for 5 - 10 min to form a W / O emulsion, and the ultrasonic power is 200 - 300 W; then it is dispersed in an aqueous solution of polyvinyl alcohol and stirred at 500 - 700 r / min to form a W / O / W double - emulsion, and is obtained after vacuum distillation.

9. The fungicide according to claim 1, characterized in that, The light - responsive polymer is synthesized with AIBN as the initiator at 60 - 80 °C for 4 - 6 hours.

10. A preparation method of a bactericide for treating oily sewage as described in any one of claims 1-9, characterized in that, It includes the following steps: Preparation of nano - silver loaded titanium dioxide composite material: Mix silver nitrate solution and titanium dioxide, add sodium borohydride, ultrasonically (20 - 40 kHz) treat for 30 - 60 minutes, filter with a 0.2 - 0.5 μm filter membrane, wash alternately with deionized water and ethanol for 3 - 5 times, and dry; Synthesis of novel organophosphorus fungicides: A phosphorus-containing compound and a nitrogen-containing heterocyclic haloalkane are heated under microwave assistance at 300 - 500W to 80 - 100°C for 3 - 5 hours in the presence of concentrated sulfuric acid as a catalyst, and then purified by column chromatography. The eluent is a mixture of petroleum ether and ethyl acetate with a volume ratio of 5 - 8:1; Preparation of intelligent sustained-release microcapsules: The core component and a dichloromethane solution of PLGA are ultrasonically emulsified for 5 - 10 minutes to form a W / O emulsion, which is then dispersed in an aqueous solution of polyvinyl alcohol and stirred to form a W / O / W multiple emulsion. The solvent is removed by vacuum distillation; Synthesis of photo-responsive polymers: The monomer and AIBN are reacted at 60 - 80°C for 4 - 6 hours, and the molecular weight is detected by GPC; Mixing and blending: Weigh each component according to the ratio and stir at 150 - 250 r / min at room temperature for 30 - 60 minutes. The reaction kettle is cleaned with acid and alkali and sterilized at high temperature before use.

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