Preparation method of slow-release vitamin B1 waste liquid fertilizer

Abstract

The invention discloses a preparation method of a slow-release vitamin B1 waste liquid fertilizer, and relates to the technical field of fertilizer preparation, and the preparation method comprises the following specific steps: step 1, selecting benzaldehyde and acetone as raw materials, and placing the raw materials in a water bath kettle. Carbonyl of benzaldehyde and alpha-hydrogen of acetone are subjected to aldol condensation reaction to generate an intermediate compound, which is an important basis for building an extractant molecular skeleton, nitrobenzene is combined with the generated intermediate compound through Michael addition reaction, nitryl of nitrobenzene, a benzene ring structure and other parts of nitrobenzene participate in the reaction, and the extractant is obtained. The molecular skeleton is extended and expanded on the original basis, the characteristic of functional groups carried by nitrobenzene endows the molecular skeleton of the extracting agent with more chemical activity and specific recognition capability, the extracting agent can be specifically combined with vitamin B1, impurities are further removed, and a solid foundation is laid for subsequent preparation of high-quality fertilizers.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, in particular to a method for preparing a slow-release vitamin B1 waste liquid fertilizer. Background Art

[0002] Vitamin B1, also known as thiamine, is an indispensable trace nutrient in the growth and development of plants. It participates in many important physiological metabolic processes in plants, such as carbohydrate metabolism and energy production. Adequate supply of vitamin B1 helps promote the development of plant roots, making the roots stronger and better absorbing water and other nutrients in the soil. At the same time, it can also enhance the stress resistance of plants and help plants maintain normal growth in the face of adverse environmental factors such as drought, pests and diseases. However, in actual agricultural production, plants have relatively limited access to vitamin B1, and the naturally occurring vitamin B1 content in the soil is often difficult to meet the vigorous growth needs of plants, which requires external fertilization to supplement; The existing technology has certain defects. First, when the existing technology extracts vitamin B1-related components, the extractant is poorly constructed, and it is difficult to make it specifically bind to vitamin B1 through a fine reaction, and the extraction efficiency and purity are limited. Secondly, for the regulation of fertilizer nutrient release, the existing technology may be difficult to achieve adaptive regulation based on light, and cannot accurately meet the nutrient needs of plants at different times. Furthermore, when the existing technology uses waste liquid to prepare fertilizer, it does not pay enough attention to environmental protection and resource utilization, which is easy to cause waste liquid pollution and fertilizer resource waste, and lacks sustainability. For this reason, we propose a preparation method of slow-release vitamin B1 waste liquid fertilizer. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing a slow-release vitamin B1 waste liquid fertilizer.

[0004] In order to solve the problems raised in the above background technology, the present invention provides the following technical solution: a method for preparing a slow-release vitamin B1 waste liquid fertilizer, the preparation method comprising the following specific steps: Step 1, benzaldehyde and acetone are selected as raw materials and placed in a water bath, and then a sodium hydroxide solution catalyst is added to react by stirring, so that the carbonyl group of benzaldehyde and the α-hydrogen of acetone undergo an aldol condensation reaction to generate an intermediate compound, and then nitrobenzene is slowly added dropwise, the temperature is kept constant and stirring is continued, and nitrobenzene and the intermediate compound undergo a Michael addition reaction under alkaline conditions to construct the basic molecular skeleton of the extractant. After the reaction is completed, the reaction mixture is allowed to stand and cool naturally, and after cooling, the reaction mixture is poured into a separatory funnel, ethyl acetate is added and extracted three times, and the organic phase is collected. After the collection is completed, the organic phase is dried with anhydrous sodium sulfate for a period of time to remove the moisture therein, and after the drying is completed, the ethyl acetate is removed by vacuum distillation to obtain a crude product, and after the distillation is completed, the extractant containing specific functional groups is purified by column chromatography using a mixture of petroleum ether and ethyl acetate as an eluent, and these specific functional groups include a carbonyl functional group that can form a hydrogen bond with the amino group of vitamin B1 and an aromatic ring structure that can undergo π-π stacking with the thiazole ring of vitamin B1; Step 2, adding the prepared extractant to the vitamin B1 waste liquid and stirring and mixing, so that the vitamin B1 molecules and the extractant form a specific complex through hydrogen bonding, π-π stacking, and electrostatic attraction, and complete the preliminary extraction of vitamin B1, then transferring the mixture containing vitamin B1 to a separatory funnel, adding ethyl acetate and shaking it thoroughly, and then standing to separate the impurities into the organic phase and vitamin B1 remaining in the aqueous phase, and after separating the aqueous phase, using a reduced pressure distillation method to remove water until a viscous pure vitamin B1 is obtained, and the purification of vitamin B1 is completed; Step 3: Using aniline as a raw material, slowly drop a sodium nitrite solution into a 20% hydrochloric acid solution until the starch-potassium iodide test paper turns blue and the diazotization reaction is completed. Then, drop the generated diazonium salt solution into a mixed solution containing phenol and sodium hydroxide to react to obtain a 4-aminoazobenzene photoresponsive material. At the same time, maleic anhydride grafted polylactic acid is added as a compatibilizer and mixed. The mixture is stirred and mixed evenly using a magnetic stirrer to obtain a complex of vitamin B1 and the composite photoresponsive system. Step 4: Mix the light-responsive material compounded with vitamin B1 with an appropriate amount of water to prepare a liquid fertilizer. Use a stirrer to stir evenly during the mixing process to complete the preparation of the liquid slow-release fertilizer.

[0005] As a further solution of the present invention: in the step 1, the selected benzaldehyde content is 30mL-50mL, the acetone content is 20mL-30mL, the sodium hydroxide solution catalyst concentration is 10%-15%, the addition amount is 20mL-40mL, the oil bath temperature is controlled to be 50°C-60°C, the reaction is stirred for 8h-10h, and the nitrobenzene added after the stirring is completed is 25mL-35mL, and the nitrobenzene is controlled to drip within 30min-40min.

[0006] As a further scheme of the present invention: in the step 1, the mixture is naturally cooled to 25°C-35°C, the amount of ethyl acetate added is 80mL-100mL, the organic phase is collected and dried with anhydrous sodium sulfate for 4h-6h, and after drying, the pressure of the reduced pressure distillation is controlled at 30mmHg-50mmHg, the temperature is controlled at 40°C-50°C, the distillation time is 1h-2h, and the eluent is obtained by mixing petroleum ether and ethyl acetate in a volume ratio of 5:1.

[0007] As a further scheme of the present invention: in the step 2, the extractant is added to the vitamin B1 waste liquid at a volume ratio of 10-13:1 between the waste liquid and the extractant, the pH value of the mixed waste liquid is adjusted to 7.0-8.0 and then stirred and mixed, the temperature is controlled to 25°C-30°C, and the mixture is stirred and mixed under this condition for 30min-60min.

[0008] As a further solution of the present invention: in the step 2, after the mixture containing vitamin B1 is transferred to a separatory funnel, an equal volume of ethyl acetate is added and shaken thoroughly, and then the mixture is allowed to stand for 15 min-20 min to separate the aqueous phase. After that, the reduced pressure distillation method is used to control the temperature to 40°C-50°C and the pressure to 50 mmHg-100 mmHg.

[0009] As a further solution of the present invention: in the step 3, the concentration of the sodium nitrite solution added is 30%, the dropping temperature is 0°C-5°C, the dropping rate is 1-2 drops per minute, and the dropping rate of the diazonium salt solution is 2-3 drops per minute.

[0010] As a further solution of the present invention: in the step 3, the diazonium salt solution is added at a rate of 2-3 drops per minute, the concentration of phenol is 15%-20%, the concentration of sodium hydroxide is 10%-15%, the reaction temperature is controlled at 10°C-15°C, and the reaction time is 2h-3h.

[0011] As a further solution of the present invention: in the step three, the amount of the compatibilizer maleic anhydride grafted polylactic acid added is 5%-7% of the total mass of the photoresponsive material, and a magnetic stirrer is used to stir at a stirring speed of 300r / min-400r / min for 2h-3h.

[0012] As a further solution of the present invention: in the step 4, the liquid fertilizer is mixed with the light-responsive material compounded with vitamin B1 and water in a mass ratio of 1:4-10. During the mixing process, an agitator is used to fully stir at a speed of 200r / min-300r / min for 30min-60min.

[0013] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are: 1. The present invention uses benzaldehyde and acetone as starting raw materials, and reacts to construct an extractant under the catalysis of sodium hydroxide solution. The carbonyl group of benzaldehyde and the α-hydrogen of acetone undergo an aldol condensation reaction to generate an intermediate compound, which is an important basis for building the molecular skeleton of the extractant. Subsequently, under alkaline conditions, nitrobenzene combines with the generated intermediate compound through a Michael addition reaction. The nitro group of nitrobenzene and its benzene ring structure and other parts participate in the reaction, and on the one hand, chemically bond with specific functional groups and active sites of the intermediate compound to form new carbon-carbon bonds and carbon-nitrogen bonds, so that the molecular skeleton is extended and On the other hand, the functional group characteristics carried by nitrobenzene endow the molecular skeleton of the extractant with more chemical activity and specific recognition ability, so that it can better interact with the vitamin B1 molecule in the subsequent process, ensuring that the extractant can specifically bind to vitamin B1. Then, the initially extracted vitamin B1 mixture is treated. First, the extractant is mixed with the waste liquid to form a complex to complete the initial extraction, and then the impurities are further removed through the separation funnel operation and reduced pressure distillation and other purification methods to obtain pure vitamin B1. This not only improves the purity of vitamin B1, but also lays a solid foundation for the subsequent preparation of high-quality fertilizers. 2. The present invention uses aniline as a raw material, obtains 4-aminoazobenzene photoresponsive material through reaction, and adds maleic anhydride grafted polylactic acid as a compatibilizer, and forms a stable composite system through magnetic stirring, wherein the 4-aminoazobenzene photoresponsive material has a unique photoresponsive property, and its molecular structure changes under different light conditions. This property enables the subsequent compounding with vitamin B1 to adaptively adjust the release of vitamin B1 according to the light conditions, ensuring that the release can be accelerated during the day when plant photosynthesis is active to meet the immediate demand of plants for nutrients, and slow down the release at night or when light is insufficient, reduce nutrient loss, and achieve precise regulation of nutrient supply; 3. The present invention prepares fertilizer by using vitamin B1 waste liquid as raw material, turning waste into treasure, effectively reducing the pollution that may be caused to the environment by waste liquid discharge, realizing the recycling of waste, and complying with the concept of sustainable development. On the other hand, during use, the prepared liquid fertilizer can enable plants to efficiently absorb nutrients such as vitamin B1 due to its precise nutrient release regulation mechanism, reducing the risk of soil and water pollution caused by excessive fertilization or nutrient loss. At the same time, the slow-release characteristics of the fertilizer can reduce the frequency of fertilization, further saving fertilizer resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the method steps in an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0016] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0017] Please see attached Figure 1 The present invention provides a method for preparing a slow-release vitamin B1 waste liquid fertilizer, the preparation method comprising the following specific steps: Step 1, benzaldehyde and acetone are selected as raw materials and placed in a water bath, and then a sodium hydroxide solution catalyst is added to react by stirring, so that the carbonyl group of benzaldehyde and the α-hydrogen of acetone undergo an aldol condensation reaction to generate an intermediate compound, and then nitrobenzene is slowly added dropwise, the temperature is kept constant and stirring is continued, and nitrobenzene and the intermediate compound undergo a Michael addition reaction under alkaline conditions to construct the basic molecular skeleton of the extractant. After the reaction is completed, the reaction mixture is allowed to stand and cool naturally, and after cooling, the reaction mixture is poured into a separatory funnel, ethyl acetate is added and extracted three times, and the organic phase is collected. After the collection is completed, the organic phase is dried with anhydrous sodium sulfate for a period of time to remove the moisture therein, and after the drying is completed, the ethyl acetate is removed by vacuum distillation to obtain a crude product, and after the distillation is completed, the extractant containing specific functional groups is purified by column chromatography using a mixture of petroleum ether and ethyl acetate as an eluent, and these specific functional groups include a carbonyl functional group that can form a hydrogen bond with the amino group of vitamin B1 and an aromatic ring structure that can undergo π-π stacking with the thiazole ring of vitamin B1; Step 2, adding the prepared extractant to the vitamin B1 waste liquid and stirring and mixing, so that the vitamin B1 molecules and the extractant form a specific complex through hydrogen bonding, π-π stacking, and electrostatic attraction, and complete the preliminary extraction of vitamin B1, then transferring the mixture containing vitamin B1 to a separatory funnel, adding ethyl acetate and shaking it thoroughly, and then standing to separate the impurities into the organic phase and vitamin B1 remaining in the aqueous phase, and after separating the aqueous phase, using a reduced pressure distillation method to remove water until a viscous pure vitamin B1 is obtained, and the purification of vitamin B1 is completed; Step 3: Using aniline as a raw material, slowly drop a sodium nitrite solution into a 20% hydrochloric acid solution until the starch-potassium iodide test paper turns blue and the diazotization reaction is completed. Then, drop the generated diazonium salt solution into a mixed solution containing phenol and sodium hydroxide to react to obtain a 4-aminoazobenzene photoresponsive material. At the same time, maleic anhydride grafted polylactic acid is added as a compatibilizer and mixed. The mixture is stirred and mixed evenly using a magnetic stirrer to obtain a complex of vitamin B1 and the composite photoresponsive system. Step 4: Mix the light-responsive material compounded with vitamin B1 with an appropriate amount of water to prepare a liquid fertilizer. Use a stirrer to stir evenly during the mixing process to complete the preparation of the liquid slow-release fertilizer.

[0018] In one embodiment of the present invention: in step 1, the selected benzaldehyde content is 30mL-50mL, the acetone content is 20mL-30mL, the sodium hydroxide solution catalyst concentration is 10%-15%, the addition amount is 20mL-40mL, the oil bath temperature is controlled to be 50°C-60°C, the reaction is stirred for 8h-10h, and the nitrobenzene added after the stirring is completed is 25mL-35mL, and the nitrobenzene is controlled to drip within 30min-40min.

[0019] In one embodiment of the present invention: in step 1, the mixture is naturally cooled to 25°C-35°C, the amount of ethyl acetate added is 80mL-100mL, the organic phase is collected and dried with anhydrous sodium sulfate for 4h-6h, and after drying, the pressure of the reduced pressure distillation is controlled at 30mmHg-50mmHg, the temperature is controlled at 40°C-50°C, the distillation time is 1h-2h, and the eluent is obtained by mixing petroleum ether and ethyl acetate in a volume ratio of 5:1.

[0020] In one embodiment of the present invention: in step 2, the extractant is added to the vitamin B1 waste liquid at a volume ratio of 10-13:1 between the waste liquid and the extractant, the pH value of the mixed waste liquid is adjusted to 7.0-8.0 and then stirred and mixed, the temperature is controlled to 25°C-30°C, and the mixture is stirred and mixed under this condition for 30min-60min.

[0021] In one embodiment of the present invention: in step 2, after the mixture containing vitamin B1 is transferred to a separatory funnel, an equal volume of ethyl acetate is added and shaken thoroughly, and then the mixture is allowed to stand for 15 min-20 min to separate the aqueous phase. After that, the reduced pressure distillation method is used to control the temperature at 40°C-50°C and the pressure at 50 mmHg-100 mmHg.

[0022] In one embodiment of the present invention: in step 3, the concentration of the sodium nitrite solution added is 30%, the dropping temperature is 0°C-5°C, the dropping rate is 1-2 drops per minute, and the dropping rate of the diazonium salt solution is 2-3 drops per minute.

[0023] In one embodiment of the present invention: in step 3, the diazonium salt solution is added at a rate of 2-3 drops per minute, the concentration of phenol is 15%-20%, the concentration of sodium hydroxide is 10%-15%, the reaction temperature is controlled at 10°C-15°C, and the reaction time is 2h-3h.

[0024] In one embodiment of the present invention: in step three, the amount of the compatibilizer maleic anhydride grafted polylactic acid added is 5%-7% of the total mass of the photoresponsive material, and a magnetic stirrer is used to stir at a stirring speed of 300r / min-400r / min for 2h-3h.

[0025] In one embodiment of the present invention: in step 4, the liquid fertilizer is mixed with the light-responsive material compounded with vitamin B1 and water in a mass ratio of 1:4-10. During the mixing process, an agitator is used to fully stir at a speed of 200r / min-300r / min for 30min-60min.

[0026] In one embodiment of the present invention: in step one, before adding nitrobenzene, an inert gas is first introduced into the reaction system for bubbling treatment, the inert gas is argon, the ventilation rate is 10mL / min-20mL / min, and the ventilation time lasts for 15min-30min. The bubbling treatment can effectively exclude the air in the reaction system, reduce the interference of impurity gases such as oxygen on the subsequent Michael addition reaction, and allow nitrobenzene and the intermediate compound to react in a purer reaction environment, thereby improving the regularity and stability of the constructed extractant molecular skeleton, thereby enhancing the ability of the extractant to specifically bind to vitamin B1 and improving the extraction effect of vitamin B1.

[0027] In one embodiment of the present invention: In step 2, during the process of removing water by reduced pressure distillation, a cooling jacket is arranged on the outside of the condenser of the distillation apparatus, and a coolant with a temperature of -5°C to -10°C circulates in the cooling jacket. Through this enhanced cooling measure, the condensation efficiency in the distillation process can be significantly improved, and the water can be separated out more quickly and completely, thereby shortening the distillation time. At the same time, it can effectively avoid adverse conditions such as decomposition of vitamin B1 due to local overheating, thereby further ensuring the quality of the pure vitamin B1 obtained, and providing a better raw material basis for the subsequent preparation of high-quality sustained-release vitamin B1 waste liquid fertilizer.

[0028] In one embodiment of the present invention: in step three, when the generated diazonium salt solution is added dropwise to a mixed solution containing phenol and sodium hydroxide for reaction, an ultrasonic generator is arranged in the reaction container, the ultrasonic wave is turned on and the frequency is set to 20kHz-40kHz, and the power is 100W-200W. The action of the ultrasonic wave can cause the reactant molecules in the reaction system to vibrate violently, accelerate the collision frequency and effective collision probability between molecules, thereby significantly accelerating the rate of the diazotization reaction and the subsequent reaction with the mixed solution of phenol and sodium hydroxide, shortening the reaction time to 1.5-2 hours, and at the same time, it can also make the crystal structure of the generated 4-aminoazobenzene photoresponsive material more uniform and delicate, improve its photoresponsive performance, and thereby enhance the accuracy and effect of the final fertilizer in regulating the release of vitamin B1 according to light.

[0029] In one embodiment of the present invention: in step 4, after the light-responsive material compounded with vitamin B1 is mixed with water to form a liquid fertilizer and stirred evenly, a biosurfactant with a mass fraction of 0.5%-1% is added to the liquid fertilizer, and the biosurfactant is a sophorolipid. The addition of sophorolipids can effectively reduce the surface tension of the liquid fertilizer, making it easier to spread and penetrate on the surface of soil particles, and promote the absorption efficiency of liquid fertilizer by plant roots. At the same time, it can also enhance the stability of the liquid fertilizer during storage, reduce the problem of uneven nutrient distribution caused by stratification or precipitation, and further improve the effect of the slow-release vitamin B1 waste liquid fertilizer in practical applications.

[0030] Example 1, please refer to the attached Figure 1First, 50 mL of benzaldehyde and 30 mL of acetone were selected as raw materials and placed in an oil bath pot, and then 40 mL of a 15% sodium hydroxide solution catalyst was added, the oil bath temperature was controlled to be 60°C, and the reaction was stirred for 10 hours to allow the carbonyl group of benzaldehyde to react with the α-hydrogen of acetone to undergo an aldol condensation reaction to generate an intermediate compound, and then 35 mL of nitrobenzene was slowly added dropwise, and the nitrobenzene was controlled to be dripped within 40 minutes, the temperature was kept constant and stirring was continued, and nitrobenzene and the intermediate compound under alkaline conditions underwent a Michael addition reaction to construct the basic molecular skeleton of the extractant. After the reaction was completed, the reaction mixture was allowed to stand and naturally cool to 35°C. After cooling, the reaction mixture was poured into a separatory funnel, and 100 mL of ethyl acetate was added for extraction three times and the extracted product was collected. The organic phase was collected and dried with anhydrous sodium sulfate for 6 hours to remove the water therein. After drying, the ethyl acetate was removed by vacuum distillation to obtain a crude product. The pressure of the vacuum distillation device was set at 50 mmHg, the temperature was controlled at 50°C, and the distillation time was 2 hours. After distillation, the extractant containing specific functional groups was purified by column chromatography using a mixture of petroleum ether and ethyl acetate in a volume ratio of 5:1 as an eluent. These specific functional groups include carbonyl functional groups that can form hydrogen bonds with the amino group of vitamin B1 and aromatic ring structures that can form π-π stacking effects with the thiazole ring of vitamin B1. Then, the prepared extractant was added to the vitamin B1 waste liquid at a volume ratio of 13:1 between the waste liquid and the extractant, and the pH value of the mixed waste liquid was adjusted to 8.0, control the temperature to 30℃, stir and mix for 60min under this condition, so that the vitamin B1 molecules and the extractant form specific complexes through hydrogen bonds, π-π stacking and electrostatic attraction, and complete the preliminary extraction of vitamin B1. Then, transfer the mixture containing vitamin B1 to a separatory funnel, add an equal volume of ethyl acetate, shake it thoroughly, and let it stand for 20min to separate the impurities into the organic phase and vitamin B1 remains in the aqueous phase. After separating the aqueous phase, use vacuum distillation to remove water, control the temperature to 50℃ and the pressure to 100mmHg, until viscous pure vitamin B1 is obtained, and complete the purification of vitamin B1. Then, use aniline as a raw material, slowly add a 30% sodium nitrite solution in a 20% hydrochloric acid solution at a temperature of 0℃, at a rate of 2 drops per minute, until the starch-potassium iodide test paper shows blue. After the diazotization reaction is completed, the generated diazonium salt solution is then added at a rate of 3 drops per minute to a mixed solution containing 20% ​​phenol and 15% sodium hydroxide, and the reaction is carried out at a temperature of 10°C for 3 hours to obtain a 4-aminoazobenzene photoresponsive material. At the same time, maleic anhydride grafted polylactic acid accounting for 7% of the total mass of the photoresponsive material is added as a compatibilizer, and a magnetic stirrer is used to stir at a stirring speed of 400r / min for 3 hours to obtain a complex of vitamin B1 and a composite photoresponsive system. Finally, the photoresponsive material composited with vitamin B1 is mixed with an appropriate amount of water at a mass ratio of 1:10 between the photoresponsive material composited with vitamin B1 and water. During the mixing process, a stirrer is used to fully stir at a speed of 300r / min for 60 minutes to complete the preparation of a liquid slow-release fertilizer. .

[0031] Example 2, please refer to the attached Figure 1First, 30 mL of benzaldehyde and 20 mL of acetone were selected as raw materials and placed in an oil bath pot, and then 20 mL of a 10% sodium hydroxide solution catalyst was added, the oil bath temperature was controlled to be 50°C, and the reaction was stirred for 8 hours to allow the carbonyl group of benzaldehyde to react with the α-hydrogen of acetone to undergo an aldol condensation reaction to generate an intermediate compound, and then 25 mL of nitrobenzene was slowly added dropwise, and the nitrobenzene was controlled to be dripped within 30 minutes, the temperature was kept constant and stirring was continued, and nitrobenzene and the intermediate compound under alkaline conditions underwent a Michael addition reaction to construct the basic molecular skeleton of the extractant. After the reaction was completed, the reaction mixture was allowed to stand and naturally cool to 25°C. After cooling, the reaction mixture was poured into a separatory funnel, and 80 mL of ethyl acetate was added for extraction three times and the organic matter was collected. After the organic phase is collected, it is dried with anhydrous sodium sulfate for 4 hours to remove the water therein. After the drying is completed, the ethyl acetate is removed by vacuum distillation to obtain a crude product. The pressure of the vacuum distillation device is set at 30 mmHg, the temperature is controlled at 40°C, and the distillation time is 1 hour. After the distillation is completed, the extractant containing specific functional groups is purified by column chromatography using a mixture of petroleum ether and ethyl acetate in a volume ratio of 5:1 as an eluent. These specific functional groups include a carbonyl functional group that can form a hydrogen bond with the amino group of vitamin B1 and an aromatic ring structure that can form a π-π stacking effect with the thiazole ring of vitamin B1. Then, the prepared extractant is added to the vitamin B1 waste liquid at a volume ratio of 10:1 between the waste liquid and the extractant, and the pH value of the mixed waste liquid is adjusted to 7.0, control the temperature to 25℃, stir and mix for 30min under this condition, so that the vitamin B1 molecules and the extractant form specific complexes through hydrogen bonds, π-π stacking and electrostatic attraction, and complete the preliminary extraction of vitamin B1. Then, transfer the mixture containing vitamin B1 to a separatory funnel, add an equal volume of ethyl acetate, shake it thoroughly, and let it stand for 15min to separate the impurities into the organic phase and vitamin B1 remains in the aqueous phase. After separating the aqueous phase, use vacuum distillation to remove water, control the temperature to 40℃ and the pressure to 50mmHg, until viscous pure vitamin B1 is obtained, and complete the purification of vitamin B1. Then, use aniline as a raw material, slowly add a 30% sodium nitrite solution in a 20% hydrochloric acid solution at a temperature of 0℃, and the dripping rate is 1 drop per minute, until the starch-potassium iodide test paper shows blue. After the diazotization reaction is completed, the generated diazonium salt solution is then added to a mixed solution containing 15% phenol and 10% sodium hydroxide at a rate of 2 drops per minute, and the reaction is carried out at a temperature of 10°C for 2 hours to obtain a 4-aminoazobenzene photoresponsive material. At the same time, maleic anhydride grafted polylactic acid accounting for 5% of the total mass of the photoresponsive material is added as a compatibilizer, and a magnetic stirrer is used to stir at a stirring speed of 300r / min for 2 hours to obtain a complex of vitamin B1 and a composite photoresponsive system. Finally, the photoresponsive material composited with vitamin B1 is mixed with an appropriate amount of water at a mass ratio of 1:4 between the photoresponsive material composited with vitamin B1 and water. During the mixing process, a stirrer is used to fully stir at a speed of 200r / min for 30 minutes to complete the preparation of a liquid slow-release fertilizer. .

[0032] According to the above two groups of embodiments, it can be concluded that in terms of the extraction and purification of vitamin B1, high-purity vitamin B1 is successfully extracted from the waste liquid through a series of fine operations, providing a high-quality nutrient source for subsequent fertilizer preparation. In the compounding link of fertilizer components, a complex containing specific light-responsive materials is accurately prepared, so that the fertilizer has the ability to adaptively adjust the release of vitamin B1 according to light conditions, which can better meet the nutrient needs of plants at different times. In the preparation of liquid fertilizer, a uniform and stable liquid slow-release fertilizer is formed by reasonably controlling the proportion of each material and stirring conditions, which is easy for plants to absorb and utilize. On the whole, the preparation method effectively realizes the transformation from waste liquid to high-quality, high-performance liquid slow-release vitamin B1 waste liquid fertilizer, and has remarkable effects in accurately supplying plant nutrients and improving crop yield and quality. It has outstanding technical advantages and broad application prospects.

[0033] Although the present invention is disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a slow-release vitamin B1 waste liquid fertilizer, characterized in that: The preparation method comprises the following specific steps: Step 1, benzaldehyde and acetone are selected as raw materials and placed in a water bath, and then a sodium hydroxide solution catalyst is added to react by stirring, and then nitrobenzene is slowly added dropwise, the temperature is kept constant and stirring is continued, after the reaction is completed, the reaction mixture is allowed to stand and naturally cool, after cooling, the reaction mixture is poured into a separatory funnel, ethyl acetate is added to extract three times and the organic phase is collected, after the collection is completed, the organic phase is dried with anhydrous sodium sulfate for a period of time, after the drying is completed, the ethyl acetate is removed by reduced pressure distillation to obtain a crude product, and after the distillation is completed, the extraction agent containing a specific functional group is purified by column chromatography using a mixture of petroleum ether and ethyl acetate as an eluent; Step 2: Add the prepared extractant to the vitamin B1 waste liquid and stir to form a specific complex, then transfer the vitamin B1-containing mixture to a separatory funnel, add ethyl acetate and shake thoroughly, then stand to separate the layers, separate the aqueous phase and remove the water by vacuum distillation until a viscous pure vitamin B1 is obtained, thereby completing the purification of the vitamin B1; Step 3: Using aniline as a raw material, slowly drop a sodium nitrite solution into a 20% hydrochloric acid solution until the starch-potassium iodide test paper turns blue to complete the diazotization reaction, then drop the generated diazonium salt solution into a mixed solution containing phenol and sodium hydroxide to react, thereby obtaining a 4-aminoazobenzene photoresponsive material, and at the same time, add maleic anhydride grafted polylactic acid as a compatibilizer, and stir and mix evenly using a magnetic stirrer; Step 4: Mix the light-responsive material compounded with vitamin B1 with an appropriate amount of water to prepare a liquid fertilizer. Use a stirrer to stir evenly during the mixing process to complete the preparation of the liquid slow-release fertilizer.

2. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 1, the selected benzaldehyde content is 30mL-50mL, the acetone content is 20mL-30mL, the sodium hydroxide solution catalyst concentration is 10%-15%, the added amount is 20mL-40mL, the oil bath temperature is controlled to be 50°C-60°C, the stirring reaction is carried out for 8h-10h, and after the stirring is completed, 25mL-35mL of nitrobenzene is added, and the nitrobenzene is controlled to drip within 30min-40min.

3. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 1, the mixture is naturally cooled to 25°C-35°C, the amount of ethyl acetate added is 80mL-100mL, the organic phase is collected and dried with anhydrous sodium sulfate for 4h-6h, and after drying, the pressure of the reduced pressure distillation is controlled at 30mmHg-50mmHg, the temperature is controlled at 40°C-50°C, the distillation time is 1h-2h, and the eluent is obtained by mixing petroleum ether and ethyl acetate in a volume ratio of 5:

1.

4. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 2, the extractant is added to the vitamin B1 waste liquid at a volume ratio of 10-13:1 between the waste liquid and the extractant, the pH value of the mixed waste liquid is adjusted to 7.0-8.0 and then stirred and mixed, the temperature is controlled to 25°C-30°C, and the mixture is stirred and mixed for 30min-60min under this condition.

5. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 2, after the mixture containing vitamin B1 is transferred to a separatory funnel, an equal volume of ethyl acetate is added and the mixture is shaken thoroughly and then allowed to stand for 15-20 minutes to separate the aqueous phase. After that, the reduced pressure distillation method is used to control the temperature at 40°C-50°C and the pressure at 50mmHg-100mmHg.

6. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 3, the concentration of the sodium nitrite solution added is 30%, the dropping temperature is 0°C-5°C, the dropping rate is 1-2 drops per minute, and the dropping rate of the diazonium salt solution is 2-3 drops per minute.

7. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 3, the diazonium salt solution is added at a rate of 2-3 drops per minute, the concentration of phenol is 15%-20%, the concentration of sodium hydroxide is 10%-15%, the reaction temperature is controlled at 10°C-15°C, and the reaction time is 2h-3h.

8. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step three, the amount of the compatibilizer maleic anhydride grafted polylactic acid added is 5%-7% of the total mass of the photoresponsive material, and a magnetic stirrer is used to stir at a stirring speed of 300r / min-400r / min for 2h-3h.

9. The method for preparing a slow-release vitamin B1 waste liquid fertilizer according to claim 1, characterized in that: In the step 4, the liquid fertilizer is mixed with the light-responsive material compounded with vitamin B1 and water in a mass ratio of 1:4-10. During the mixing process, a stirrer is used to fully stir at a speed of 200r / min-300r / min for 30min-60min.

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