Method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides

Abstract

This invention discloses a method for preparing tetramethylolphosphine sulfate using high-concentration hydrides, belonging to the technical field of tetramethylolphosphine sulfate preparation. The method includes the following steps: Step 1: Concentrated sulfuric acid and formaldehyde are added to a reaction vessel and stirred until homogeneous. Then, an organic catalyst and a modified surfactant are added, and stirring continues until the reactants are completely mixed to obtain a mixture. Step 2: The hydride is introduced into the reaction vessel through a pipe to react with the mixture. The reaction is heated, and after the reaction is complete, the pipe is closed to obtain a reaction solution. Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetramethylolphosphine sulfate. The tetramethylolphosphine sulfate prepared by this method has excellent yield and purity.

Description

Technical Field

[0001] This invention belongs to the field of tetrahydroxymethylphosphonic acid preparation technology, specifically relating to a method for preparing tetrahydroxymethylphosphonic acid using high-concentration hydrides. Background Technology

[0002] Tetramethylolphosphine sulfate is a green and environmentally friendly quaternary phosphate bactericide with broad application prospects. It has good water solubility, a low freezing point, and stable chemical properties, and its quality is not affected by long-term storage. Furthermore, tetramethylolphosphine sulfate rapidly degrades into completely harmless substances before and after use, greatly reducing its environmental impact. Therefore, it is widely used in water treatment, oilfield pipelines, aquaculture, fabric flame retardant treatment, leather softening, and papermaking, among other industries. With increasing environmental awareness and the development of industrial automation, the demand for environmentally friendly bactericides in these industries is constantly increasing, driving the expansion of the tetramethylolphosphine sulfate market.

[0003] Chinese invention patent application CN 117680083 B discloses a preparation process and apparatus for tetramethylolphosphine sulfate. The invention includes a preparation tower; a mixing and stirring unit, which includes a formaldehyde inlet pipe fixedly installed on the preparation tower for feeding formaldehyde solution; S1, in preparing the tetramethylolphosphine sulfate aqueous solution, formaldehyde solution and sulfuric acid solution are first injected into the preparation tower through the formaldehyde inlet pipe and sulfuric acid inlet pipe respectively in a molar ratio of 8:1. The advantages are: this invention, by using rotary stirring combined with reciprocating oscillation and interleaving, can fully mix the formaldehyde solution and sulfuric acid solution, and by using a spraying method to ensure sufficient contact and reaction with phosphine gas in a constant temperature environment, effectively increases the contact range and contact time between the formaldehyde / sulfuric acid mixture and phosphine gas, thus improving preparation efficiency. However, there is still room for improvement in the yield and purity of the tetramethylolphosphine sulfate prepared by this method. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing tetrahydroxymethylphosphonic acid using high-concentration hydrides, thereby solving the technical problems of poor purity and yield of tetrahydroxymethylphosphonic acid in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides, comprising the following steps:

[0007] Step 1: Add concentrated sulfuric acid and formaldehyde to the reaction vessel and stir until they are evenly mixed. Then add the organic catalyst and modified surfactant and continue stirring to ensure that the reactants are completely mixed and a mixture is obtained.

[0008] Step 2: Introduce the covalent hydride into the reactor through a pipeline to react with the mixture. Heat the reaction, and after the reaction is complete, close the pipeline to obtain the reaction solution.

[0009] Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetrahydroxymethylphosphoric acid.

[0010] Preferably, in step one, the molar ratio of concentrated sulfuric acid to formaldehyde is (1-1.7):(7.8-13.4), the volume fraction of concentrated sulfuric acid is 96 wt%, the volume fraction of formaldehyde is 96 wt%, the mixing time is 2-4 h, the ratio of concentrated sulfuric acid, organic catalyst and modified surfactant is (10-17) g:(0.55-0.8) g:(0.3-0.5) g, and the stirring time is continued for 30-45 min.

[0011] Preferably, the method for preparing the organic catalyst includes the following steps:

[0012] Q1: Add cyanuric chloride to a container containing acetone, stir and dissolve to obtain a cyanuric chloride solution. At the same time, add sodium azide to a container containing deionized water, stir and dissolve to obtain a sodium azide solution. Slowly add the sodium azide solution to the cyanuric chloride solution and react. After the reaction is complete, extract, take the lower organic phase and wash it. Combine the organic phases, wash, dry, filter, and rotary evaporate to obtain a white powder.

[0013] Q2: In a nitrogen atmosphere, add pyrrolidine and tetrahydrofuran to a container, stir and mix evenly, then slowly add phosphorus trichloride at low temperature. After the addition is complete, allow the temperature to rise naturally to room temperature and react. After the reaction is complete, filter the reaction solution, mix the filtered powder with tetrahydrofuran, then filter again, combine the filtrates, filter under vacuum, and heat and distill under reduced pressure to obtain a white liquid.

[0014] Q3: Add the white liquid to the container, then add toluene, stir to mix the solution to obtain mixture 1, then add the white powder to the toluene, stir to dissolve to obtain mixture 2, under ice-water bath conditions, slowly add mixture 1 to mixture 2, after the addition is complete, reduce the pressure, heat to react, after the reaction is complete, cool, filter, wash, filter to obtain the organic catalyst.

[0015] The synthesis reaction formula for the organic catalyst in the above process is as follows:

[0016]

[0017] The mass spectrometry analysis results of the white powder were: m / z: 204.04 (100.0%), 205.03 (4.4%), 205.04 (3.2%); the mass spectrometry analysis results of the white liquid were: m / z: 241.17 (100.0%), 242.17 (14.1%); the mass spectrometry analysis results of the organic catalyst were: m / z: 843.53 (100.0%), 844.53 (47.7%), 845.54 (9.0%), 845.53 (2.4%), 846.54 (1.2%).

[0018] Preferably, in Q1, the ratio of cyanuric chloride, acetone, sodium azide, and deionized water is (2-4) g: (50-100) mL: (2.1-4.1) g: (80-160) mL, the reaction time is 6-8 h, dichloromethane is added for extraction, followed by washing with dichloromethane, then washing with saturated sodium chloride solution, and drying with anhydrous magnesium sulfate.

[0019] Preferably, in Q2, the ratio of pyrrolidine, tetrahydrofuran, and phosphorus trichloride is (19-38) mL:(40-80) mL:(5-8) mL, the low temperature is -76 to -80°C, the dropping time is 1-2 h, the reaction time is 10-12 h, and the heating and vacuum distillation temperature is 120-150°C; in Q3, the mass ratio of white liquid to white powder is (3.65-7.3):(1-1.9), the ice-water bath temperature is 0-3°C, the dropping time is 30-45 min, the heating and reaction temperature is 100-110°C, the time is 45-50 h, and the mixture is washed with n-hexane.

[0020] Preferably, the method for preparing the modified surfactant includes the following steps:

[0021] S1: Cesium carbonate and 3-methyl-4-isopropylphenol were added to a container containing acetone and stirred under reflux. After reflux, 1,6-dibromohexane was added and the mixture was heated to continue the reaction. After the reaction was completed, the mixture was filtered under reduced pressure, distilled under reduced pressure, purified, and dried under vacuum to obtain intermediate product 1.

[0022] S2: Add intermediate product 1 and anhydrous potassium carbonate to a container containing a mixed solution of dimethylamine and tetrahydrofuran, heat and stir, after stirring, filter, evaporate by rotary evaporation, purify, and dry under vacuum to obtain intermediate product 2.

[0023] S3: Add intermediate product 2 and ethyl 4-bromobutyrate to a container containing acetonitrile, heat and stir to react. After the reaction is complete, distill under reduced pressure and dry under vacuum. Then add sodium hydroxide and stir to react. After the reaction is complete, filter, wash, dry, wash, centrifuge, and dry under vacuum to obtain the modified surfactant.

[0024] The synthesis reaction formula for the modified surfactant in the above process is as follows:

[0025]

[0026] The mass spectrometry analysis results of intermediate product 1 were: m / z: 312.11 (100.0%), 314.11 (97.5%), 313.11 (17.3%), 315.11 (17.2%), 316.11 (1.6%), 314.12 (1.5%); the mass spectrometry analysis results of intermediate product 2 were: m / z: 277.24 (100.0%), 278.24 (19.9%), 279.25 (1.9%); the mass spectrometry analysis results of modified surfactant were: m / z: 363.28 (100.0%), 364.28 (24.3%), 365.28 (3.4%).

[0027] Preferably, in step S1, the molar ratio of cesium carbonate, 3-methyl-4-isopropylphenol, and 1,6-dibromohexane is (5.74-6.89):(2.87-3.44):(14.36-17.23), the stirring and reflux speed is 700-800 rpm, the reflux time is 1-2 h, the heating and stirring temperature is 60-70 °C, and the time is 4-6 h, with a mixed solution of ethyl acetate and n-hexane at a volume ratio of 1:40 as the eluent for purification.

[0028] Preferably, in step S2, the ratio of intermediate product 1, anhydrous potassium carbonate, dimethylamine, and tetrahydrofuran is (0.2-0.4) g : (0.6-1.2) g : (0.53-1.06) mL : (4.47-8.94) mL, the heating and stirring temperature is 70-80℃, the stirring speed is 700-800 rpm, the time is 10-15 h, and the purification is carried out using a mixed solution of ethyl acetate, methanol, and triethylamine with a volume ratio of 15:1:0.7 as the eluent.

[0029] Preferably, in step S3, the ratio of intermediate product ethyl 2,4-bromobutyrate, acetonitrile, and sodium hydroxide is (0.24-0.48) g : (0.24-0.48) g : (6-12) mL : (7-14) mL. The heating and stirring reaction temperature is 70-80℃, the stirring speed is 700-800 rpm, and the time is 24-28 h. The concentration of sodium hydroxide is 0.1 mmol / L, the stirring speed is 600-700 rpm, and the time is 1-2 h. After washing with ultrapure water and drying, the product is washed with ethyl acetate.

[0030] Preferably, in step two, the covalent hydride is phosphine, the ratio of phosphine to the mixed solution is (7-10) g: (20-25) mL, the heating reaction temperature is 50-60℃, and the time is 10-14 h.

[0031] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0032] 1. This invention uses concentrated sulfuric acid, formaldehyde, and hydrides as raw materials to prepare tetramethylolphosphine sulfate. During the preparation process, an organic catalyst prepared from cyanuric chloride, sodium azide, pyrrolidine, and phosphorus trichloride is added. Simultaneously, a modified surfactant prepared from 3-methyl-4-isopropylphenol, 1,6-dibromohexane, dimethylamine, and ethyl 4-bromobutyrate is also added. By adding the organic catalyst and modified surfactant during the preparation process, the purity and yield of tetramethylolphosphine sulfate can be effectively improved.

[0033] 2. This invention uses cyanuric chloride, sodium azide, pyrrolidine, and phosphorus trichloride as raw materials to prepare an organic catalyst. Using this substance as a catalyst in the preparation process of tetrahydroxymethylphosphoric acid can effectively improve its production efficiency and yield. The nitrogen-phosphorus bonds in the organic catalyst give it a higher electron density and more flexible electron transfer capability, making it easier to exchange electrons and convert energy with reactant molecules, thus helping to lower the activation energy of the reaction and increase the reaction rate and yield. The spatial configuration of the pyrrole ring and nitrogen heterocycle in the organic catalyst gives it a higher affinity and selectivity for the target reactant molecules, allowing it to form stable chemical bonds and complexes with the functional groups in the reactant molecules, preventing side reactions. Furthermore, the chemical bonds in the organic catalyst have excellent stability, are not easily damaged or deactivated during the reaction, extend the service life of the organic catalyst, and reduce the frequency and cost of replacement.

[0034] 3. This invention uses 3-methyl-4-isopropylphenol, 1,6-dibromohexane, dimethylamine, and ethyl 4-bromobutyrate as raw materials to prepare a modified surfactant. The hydrophilic and hydrophobic groups contained in the modified surfactant can form micelles or interfacial layers in the solution, changing the surface properties and interfacial tension of the solution. In the preparation of tetramethylol phosphate, the modified surfactant can react with reactant molecules through its hydrophilic groups, promoting the dissolution and dispersion of the reactants. At the same time, the hydrophobic groups can help form a stable product structure, thereby improving the reaction rate and preparation efficiency. Furthermore, the modified surfactant structure formed by covalent bonding is stable and not easily affected by external factors, thus helping to maintain the effectiveness of the modified surfactant in the preparation process and ensuring the stability and quality of the tetramethylol phosphate product. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1: This example discloses a method for preparing an organic catalyst, including the following steps:

[0037] Q1: Add 3g of cyanuric chloride to a container containing 75mL of acetone, stir and dissolve to obtain a cyanuric chloride solution. At the same time, add 3.1g of sodium azide to a container containing 120mL of deionized water, stir and dissolve to obtain a sodium azide solution. Slowly add the sodium azide solution to the cyanuric chloride solution and react for 8 hours. After the reaction is complete, add dichloromethane for extraction. Take the lower organic phase and wash it with dichloromethane. Combine the organic phases, wash with saturated sodium chloride solution, dry with anhydrous magnesium sulfate, filter, and rotary evaporate to obtain a white powder.

[0038] Q2: In a nitrogen atmosphere, add 28.5 mL of pyrrolidine and 60 mL of tetrahydrofuran to a container, stir and mix thoroughly, then slowly add 6.5 mL of phosphorus trichloride at -78°C over 1 hour. After the addition is complete, allow the temperature to rise naturally to room temperature and react for 12 hours. After the reaction is complete, filter the reaction solution, mix the filtered powder with tetrahydrofuran, and then filter again. Combine the filtrates, filter under vacuum, and distill under reduced pressure at 140°C to obtain a white liquid.

[0039] Q3: Add 5.5 mL of white liquid to a container, then add 20 mL of toluene and stir to obtain mixture 1. Then add 1.45 g of white powder to 30 mL of toluene and stir to dissolve to obtain mixture 2. Under an ice-water bath at 0 °C, slowly add mixture 1 to mixture 2 dropwise over a period of 35 min. After the addition is complete, reduce the pressure and heat at 110 °C for 48 h. After the reaction is complete, cool, filter, wash with n-hexane, and filter again to obtain the organic catalyst.

[0040] This embodiment discloses a method for preparing a modified surfactant, including the following steps:

[0041] S1: 2.89 g of cesium carbonate and 1.1 g of 3-methyl-4-isopropylphenol were added to a container containing 60 mL of acetone and stirred under reflux at 800 rpm for 2 h. After reflux, 8.95 g of 1,6-dibromohexane was added and the mixture was heated at 70 °C for 6 h. After the reaction was completed, the mixture was filtered under reduced pressure and distilled under reduced pressure. The product was purified by eluenting with a mixture of ethyl acetate and n-hexane at a volume ratio of 1:40. The product was then dried under vacuum to obtain intermediate product 1.

[0042] S2: 0.3 g of intermediate product 1 and 0.9 g of anhydrous potassium carbonate were added to a container containing a mixed solution of 0.79 mL of dimethylamine and 6.65 mL of tetrahydrofuran. The mixture was heated and stirred at 80 °C and 800 rpm for 12 h. After stirring, the mixture was filtered and evaporated by rotary evaporation. The product was purified by using a mixed solution of ethyl acetate, methanol and triethylamine with a volume ratio of 15:1:0.7 as the eluent. The product was then dried under vacuum to obtain intermediate product 2.

[0043] S3: 0.36 g of intermediate product 2 and 0.36 g of ethyl 4-bromobutyrate were added to a container containing 9 mL of acetonitrile. The mixture was heated and stirred at 80 °C and 800 rpm for 24 h. After the reaction was completed, the mixture was distilled under reduced pressure and dried under vacuum. Then, 10.5 mL of 0.1 mmol / L sodium hydroxide was added, and the mixture was stirred at 700 rpm for 2 h. After the reaction was completed, the mixture was filtered, washed with ultrapure water, dried, washed with ethyl acetate, centrifuged, and dried under vacuum to obtain the modified surfactant.

[0044] This embodiment discloses a method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides, comprising the following steps:

[0045] Step 1: Add 13.5g of concentrated sulfuric acid (96 wt%) and 32g of formaldehyde (96 wt%) to the reaction vessel and stir for 4 hours. Then add 0.73g of organic catalyst and 0.4g of modified surfactant and continue stirring for 45 minutes to ensure that the reactants are completely mixed and homogeneous, thus obtaining a mixture.

[0046] Step 2: Introduce 8.5g of phosphine into the reactor through a pipeline and react it with 22.5mL of the mixture. Heat the mixture at 60℃ for 12 hours. After the reaction is complete, close the pipeline to obtain the reaction solution.

[0047] Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetrahydroxymethylphosphoric acid.

[0048] Example 2: This example discloses a method for preparing an organic catalyst, including the following steps:

[0049] Q1: Add 4g of cyanuric chloride to a container containing 50mL of acetone, stir and dissolve to obtain a cyanuric chloride solution. At the same time, add 2.1g of sodium azide to a container containing 80mL of deionized water, stir and dissolve to obtain a sodium azide solution. Slowly add the sodium azide solution to the cyanuric chloride solution and react for 8 hours. After the reaction is complete, add dichloromethane for extraction. Take the lower organic phase and wash it with dichloromethane. Combine the organic phases, wash with saturated sodium chloride solution, dry with anhydrous magnesium sulfate, filter, and rotary evaporate to obtain a white powder.

[0050] Q2: In a nitrogen atmosphere, add 19 mL of pyrrolidine and 40 mL of tetrahydrofuran to a container, stir and mix thoroughly, then slowly add 8 mL of phosphorus trichloride at -78°C over 1 hour. After the addition is complete, allow the temperature to rise naturally to room temperature and react for 12 hours. After the reaction is complete, filter the reaction solution, mix the filtered powder with tetrahydrofuran, and then filter again. Combine the filtrates, filter under vacuum, and distill under reduced pressure at 140°C to obtain a white liquid.

[0051] Q3: Add 3.65 mL of white liquid to a container, then add 20 mL of toluene and stir to obtain mixture 1. Then add 1.9 g of white powder to 30 mL of toluene and stir to dissolve to obtain mixture 2. Under an ice-water bath at 0 °C, slowly add mixture 1 to mixture 2 dropwise over a period of 35 min. After the addition is complete, reduce the pressure and heat at 110 °C for 48 h. After the reaction is complete, cool, filter, wash with n-hexane, and filter again to obtain the organic catalyst.

[0052] This embodiment discloses a method for preparing a modified surfactant, including the following steps:

[0053] S1: 3.15 g of cesium carbonate and 1 g of 3-methyl-4-isopropylphenol were added to a container containing 60 mL of acetone and stirred under reflux at 800 rpm for 2 h. After reflux, 9.76 g of 1,6-dibromohexane was added and the mixture was heated at 70 °C for 6 h. After the reaction was completed, the mixture was filtered under reduced pressure and distilled under reduced pressure. The product was purified by eluing with a mixture of ethyl acetate and n-hexane at a volume ratio of 1:40. The product was then dried under vacuum to obtain intermediate product 1.

[0054] S2: 0.2 g of intermediate product 1 and 1.2 g of anhydrous potassium carbonate were added to a container containing a mixed solution of 0.53 mL of dimethylamine and 4.47 mL of tetrahydrofuran. The mixture was heated and stirred at 80 °C and 800 rpm for 12 h. After stirring, the mixture was filtered and evaporated by rotary evaporation. The product was purified by using a mixed solution of ethyl acetate, methanol and triethylamine with a volume ratio of 15:1:0.7 as the eluent. The product was then dried under vacuum to obtain intermediate product 2.

[0055] S3: 0.24 g of intermediate product 2 and 0.48 g of ethyl 4-bromobutyrate were added to a container containing 12 mL of acetonitrile. The mixture was heated and stirred at 80 °C and 800 rpm for 24 h. After the reaction was completed, the mixture was distilled under reduced pressure and dried under vacuum. Then, 14 mL of 0.1 mmol / L sodium hydroxide was added, and the mixture was stirred at 700 rpm for 2 h. After the reaction was completed, the mixture was filtered, washed with ultrapure water, dried, washed with ethyl acetate, centrifuged, and dried under vacuum to obtain the modified surfactant.

[0056] This embodiment discloses a method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides, including the following steps:

[0057] Step 1: Add 17g of concentrated sulfuric acid (96 wt%) and 23.8g of formaldehyde (96 wt%) to the reaction vessel and stir for 4 hours. Then add 0.55g of organic catalyst and 0.5g of modified surfactant and continue stirring for 45 minutes to ensure that the reactants are completely mixed and homogeneous, thus obtaining a mixture.

[0058] Step 2: Introduce 7g of phosphine into the reactor through a pipeline and react it with 20mL of the mixture. Heat the mixture at 60℃ for 12 hours. After the reaction is complete, close the pipeline to obtain the reaction solution.

[0059] Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetrahydroxymethylphosphoric acid.

[0060] Example 3: This example discloses a method for preparing an organic catalyst, including the following steps:

[0061] Q1: Add 2g of cyanuric chloride to a container containing 100mL of acetone, stir to dissolve and obtain a cyanuric chloride solution. At the same time, add 4.1g of sodium azide to a container containing 160mL of deionized water, stir to dissolve and obtain a sodium azide solution. Slowly add the sodium azide solution to the cyanuric chloride solution and react for 8 hours. After the reaction is complete, add dichloromethane for extraction. Take the lower organic phase and wash it with dichloromethane. Combine the organic phases, wash them with saturated sodium chloride solution, dry them with anhydrous magnesium sulfate, filter, and rotary evaporate to obtain a white powder.

[0062] Q2: In a nitrogen atmosphere, add 38 mL of pyrrolidine and 80 mL of tetrahydrofuran to a container, stir and mix thoroughly, then slowly add 5 mL of phosphorus trichloride at -78°C over 1 hour. After the addition is complete, allow the temperature to rise naturally to room temperature and react for 12 hours. After the reaction is complete, filter the reaction solution, mix the filtered powder with tetrahydrofuran, and then filter again. Combine the filtrates, filter under vacuum, and distill under reduced pressure at 140°C to obtain a white liquid.

[0063] Q3: Add 7.3 mL of white liquid to a container, then add 20 mL of toluene and stir to obtain mixture 1. Then add 1 g of white powder to 30 mL of toluene and stir to dissolve to obtain mixture 2. Under an ice-water bath at 0 °C, slowly add mixture 1 to mixture 2 dropwise over a period of 35 min. After the addition is complete, reduce the pressure and heat at 110 °C for 48 h. After the reaction is complete, cool, filter, wash with n-hexane, and filter again to obtain the organic catalyst.

[0064] This embodiment discloses a method for preparing a modified surfactant, including the following steps:

[0065] S1: 2.63 g of cesium carbonate and 1.2 g of 3-methyl-4-isopropylphenol were added to a container containing 60 mL of acetone and stirred under reflux at 800 rpm for 2 h. After reflux, 8.14 g of 1,6-dibromohexane was added and the mixture was heated at 70 °C for 6 h. After the reaction was completed, the mixture was filtered under reduced pressure and distilled under reduced pressure. The product was purified by eluenting with a mixture of ethyl acetate and n-hexane at a volume ratio of 1:40. The product was then dried under vacuum to obtain intermediate product 1.

[0066] S2: 0.4 g of intermediate product 1 and 0.6 g of anhydrous potassium carbonate were added to a container containing a mixed solution of 1.06 mL of dimethylamine and 8.94 mL of tetrahydrofuran. The mixture was heated and stirred at 80 °C and 800 rpm for 12 h. After stirring, the mixture was filtered and rotary evaporated. The product was purified by using a mixed solution of ethyl acetate, methanol and triethylamine with a volume ratio of 15:1:0.7 as the eluent. The product was then dried under vacuum to obtain intermediate product 2.

[0067] S3: 0.48 g of intermediate product 2 and 0.24 g of ethyl 4-bromobutyrate were added to a container containing 6 mL of acetonitrile. The mixture was heated and stirred at 80 °C and 800 rpm for 24 h. After the reaction was completed, the mixture was distilled under reduced pressure and dried under vacuum. Then, 7 mL of 0.1 mmol / L sodium hydroxide was added, and the mixture was stirred at 700 rpm for 2 h. After the reaction was completed, the mixture was filtered, washed with ultrapure water, dried, washed with ethyl acetate, centrifuged, and dried under vacuum to obtain the modified surfactant.

[0068] This embodiment discloses a method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides, including the following steps:

[0069] Step 1: Add 10g of concentrated sulfuric acid (96 wt%) and 41g of formaldehyde (96 wt%) to the reaction vessel and stir for 4 hours. Then add 0.8g of organic catalyst and 0.3g of modified surfactant and continue stirring for 45 minutes to ensure that the reactants are completely mixed and homogeneous, thus obtaining a mixture.

[0070] Step 2: Introduce 10g of phosphine into the reactor through a pipe and react it with 25mL of the mixture. Heat the mixture at 60℃ for 12 hours. After the reaction is complete, close the pipe to obtain the reaction solution.

[0071] Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetrahydroxymethylphosphoric acid.

[0072] Example 4: This example discloses a method for preparing an organic catalyst, including the following steps:

[0073] Q1: Add 2.5g of cyanuric chloride to a container containing 80mL of acetone, stir and dissolve to obtain a cyanuric chloride solution. At the same time, add 2.8g of sodium azide to a container containing 100mL of deionized water, stir and dissolve to obtain a sodium azide solution. Slowly add the sodium azide solution to the cyanuric chloride solution and react for 8 hours. After the reaction is complete, add dichloromethane for extraction. Take the lower organic phase and wash it with dichloromethane. Combine the organic phases, wash them with saturated sodium chloride solution, dry them with anhydrous magnesium sulfate, filter, and rotary evaporate to obtain a white powder.

[0074] Q2: In a nitrogen atmosphere, add 22 mL of pyrrolidine and 45 mL of tetrahydrofuran to a container, stir and mix thoroughly, then slowly add 6 mL of phosphorus trichloride at -78°C over 1 hour. After the addition is complete, allow the temperature to rise naturally to room temperature and react for 12 hours. After the reaction is complete, filter the reaction solution, mix the filtered powder with tetrahydrofuran, and then filter again. Combine the filtrates, filter under vacuum, and distill under reduced pressure at 140°C to obtain a white liquid.

[0075] Q3: Add 6.12 mL of white liquid to a container, then add 20 mL of toluene and stir to obtain mixture 1. Then add 1.2 g of white powder to 30 mL of toluene and stir to dissolve to obtain mixture 2. Under an ice-water bath at 0 °C, slowly add mixture 1 to mixture 2 dropwise over a period of 35 min. After the addition is complete, reduce the pressure and heat at 110 °C for 48 h. After the reaction is complete, cool, filter, wash with n-hexane, and filter again to obtain the organic catalyst.

[0076] This embodiment discloses a method for preparing a modified surfactant, including the following steps:

[0077] S1: 2.77 g of cesium carbonate and 1.05 g of 3-methyl-4-isopropylphenol were added to a container containing 60 mL of acetone and stirred under reflux at 800 rpm for 2 h. After reflux, 8.53 g of 1,6-dibromohexane was added and the mixture was heated at 70 °C for 6 h. After the reaction was completed, the mixture was filtered under reduced pressure and distilled under reduced pressure. The product was purified by eluing with a mixture of ethyl acetate and n-hexane at a volume ratio of 1:40. The product was then dried under vacuum to obtain intermediate product 1.

[0078] S2: 0.25 g of intermediate product 1 and 0.7 g of anhydrous potassium carbonate were added to a container containing a mixed solution of 0.68 mL of dimethylamine and 5.12 mL of tetrahydrofuran. The mixture was heated and stirred at 80 °C and 800 rpm for 12 h. After stirring, the mixture was filtered and rotary evaporated. The product was purified by using a mixed solution of ethyl acetate, methanol and triethylamine with a volume ratio of 15:1:0.7 as the eluent. The product was then dried under vacuum to obtain intermediate product 2.

[0079] S3: 0.25 g of intermediate product 2 and 0.27 g of ethyl 4-bromobutyrate were added to a container containing 7 mL of acetonitrile. The mixture was heated and stirred at 80 °C and 800 rpm for 24 h. After the reaction was completed, the mixture was distilled under reduced pressure and dried under vacuum. Then, 9 mL of 0.1 mmol / L sodium hydroxide was added, and the mixture was stirred at 700 rpm for 2 h. After the reaction was completed, the mixture was filtered, washed with ultrapure water, dried, washed with ethyl acetate, centrifuged, and dried under vacuum to obtain the modified surfactant.

[0080] This embodiment discloses a method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides, including the following steps:

[0081] Step 1: Add 11g of concentrated sulfuric acid (96 wt%) and 25.7g of formaldehyde (96 wt%) to the reaction vessel and stir for 4 hours. Then add 0.67g of organic catalyst and 0.35g of modified surfactant and continue stirring for 45 minutes to ensure that the reactants are completely mixed and homogeneous, thus obtaining a mixture.

[0082] Step 2: Introduce 9g of phosphine into the reactor through a pipe and react it with 21mL of the mixture. Heat the mixture at 60℃ for 12 hours. After the reaction is complete, close the pipe to obtain the reaction solution.

[0083] Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetrahydroxymethylphosphoric acid.

[0084] Comparative Example 1: Compared with Example 1, Comparative Example 1 did not add cyanuric chloride during the preparation of the organic catalyst, and all other conditions remained unchanged.

[0085] Comparative Example 2: Compared with Example 1, Comparative Example 2 did not add 3-methyl-4-isopropylphenol during the preparation of the modified surfactant, and all other conditions remained unchanged.

[0086] Comparative Example 3: Compared with Example 1, no organic catalyst was added in the preparation of tetrahydroxymethylphosphoric acid in Comparative Example 3, and all other conditions remained unchanged.

[0087] Comparative Example 4: Compared with Example 1, Comparative Example 4 did not add a modified surfactant during the preparation of tetramethylol phosphate, and all other conditions remained unchanged.

[0088] Experimental Example: The mass fraction of tetramethylolphosphine sulfate was determined by iodometric titration. Tetramethylolphosphine sulfate and iodine have a stoichiometric relationship, and their reaction equation is as follows: (CH2OH)4P2SO4 + I2 + NaHCO3 → (CH2OH)3PO + Na2SO4 + CO2 + H2O. The obtained product was weighed and placed in an iodine flask. 1% soluble starch indicator was added, and titration was performed with iodine standard solution until the solution turned blue at the midpoint. The volume of iodine standard solution consumed was recorded. According to the formula: Mass fraction of tetramethylolphosphine sulfate (%) = {[C] I2 ·(V1-V2)·406] / 1000×m 样品}×100%, where C I2 V1 is the concentration of the iodine standard solution, V2 is the volume of iodine standard solution consumed in the titration of the sample, and m is the volume of iodine standard solution consumed in the titration of the blank. 样品 For the mass of the sample, and according to the yield (%) = (m 产量 / m 理论值 The test results, calculated as 100%, are shown in Table 1.

[0089] Table 1

[0090] project Yield / % mass fraction / % Example 1 84.65 94.17 Example 2 84.47 94.12 Example 3 84.52 93.88 Example 4 84.03 93.83 Comparative Example 1 80.58 90.27 Comparative Example 2 80.23 90.24 Comparative Example 3 78.47 89.48 Comparative Example 4 78.21 89.23

[0091] As shown in Table 1, the methods in Examples 1-4 yield tetramethylolphosphine sulfate with excellent yield and purity. The mass fraction results represent the purity of the product. Comparing Comparative Example 1 with Examples 1-4, it is evident that adding cyanuric chloride improves the yield and purity of tetramethylolphosphine sulfate. Comparing Comparative Example 2 with Examples 1-4, it is evident that adding 3-methyl-4-isopropylphenol improves the yield and purity of tetramethylolphosphine sulfate. Comparing Comparative Example 3 with Examples 1-4, it is evident that adding an organic catalyst improves the yield and purity of tetramethylolphosphine sulfate. Comparing Comparative Example 4 with Examples 1-4, it is evident that adding a modified surfactant improves the yield and purity of tetramethylolphosphine sulfate.

[0092] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0093] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides, characterized in that, Includes the following steps: Step 1: Add concentrated sulfuric acid and formaldehyde to the reaction vessel and stir until homogeneous. Then add the organic catalyst and modified surfactant and continue stirring until the reactants are completely mixed to obtain a mixture. The molar ratio of concentrated sulfuric acid to formaldehyde is (1-1.7):(7.8-13.4), the volume fraction of concentrated sulfuric acid is 96 wt%, the volume fraction of formaldehyde is 96 wt%, the mixing time is 2-4 h, and the ratio of concentrated sulfuric acid, organic catalyst and modified surfactant is (10-17) g:(0.55-0.8) g:(0.3-0.5) g. Continue stirring for 30-45 min. Step 2: The covalent hydride is introduced into the reaction vessel through a pipeline to react with the mixture. The reaction is heated. After the reaction is completed, the pipeline is closed to obtain the reaction solution. The covalent hydride is phosphine. The ratio of phosphine to the mixture is (7-10) g: (20-25) mL. The heating temperature is 50-60℃ and the time is 10-14 h. Step 3: The reaction solution is concentrated under reduced pressure and recrystallized to obtain tetrahydroxymethylphosphoric acid. In step one, the organic catalyst has the following structural formula: ； The modified surfactant has the following structural formula: 。 2. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 1, characterized in that, The method for preparing the organic catalyst includes the following steps: Q1: Add cyanuric chloride to a container containing acetone, stir and dissolve to obtain a cyanuric chloride solution. At the same time, add sodium azide to a container containing deionized water, stir and dissolve to obtain a sodium azide solution. Slowly add the sodium azide solution to the cyanuric chloride solution and react. After the reaction is complete, extract, take the lower organic phase and wash it. Combine the organic phases, wash, dry, filter, and rotary evaporate to obtain a white powder. Q2: In a nitrogen atmosphere, pyrrolidine and tetrahydrofuran are added to a container and stirred until homogeneous. Phosphorus trichloride is then slowly added at a low temperature. After the addition is complete, the temperature is naturally raised to room temperature for reaction. After the reaction is complete, the reaction solution is filtered. The filtered powder is mixed and stirred with tetrahydrofuran and then filtered again. The filtrates are combined, filtered under vacuum, and heated and distilled under reduced pressure to obtain a white liquid. The low temperature environment is -76~-80℃. Q3: Add the white liquid to the container, then add toluene, stir to mix the solution to obtain mixture 1, then add the white powder to the toluene, stir to dissolve to obtain mixture 2, under ice-water bath conditions, slowly add mixture 1 to mixture 2, after the addition is complete, reduce the pressure, heat to react, after the reaction is complete, cool, filter, wash, filter to obtain the organic catalyst.

3. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 2, characterized in that, In Q1, the ratio of cyanuric chloride, acetone, sodium azide, and deionized water is (2-4) g: (50-100) mL: (2.1-4.1) g: (80-160) mL, the reaction time is 6-8 h, dichloromethane is added for extraction, followed by washing with dichloromethane, then washing with saturated sodium chloride solution, and drying with anhydrous magnesium sulfate.

4. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 2, characterized in that, In Q2, the ratio of pyrrolidine, tetrahydrofuran, and phosphorus trichloride is (19-38) mL: (40-80) mL: (5-8) mL, the low temperature is -76~-80℃, the dropping time is 1-2 h, the reaction time is 10-12 h, and the heating and vacuum distillation temperature is 120-150℃; In Q3, the mass ratio of white liquid to white powder is (3.65-7.3): (1-1.9), the ice-water bath temperature is 0-3℃, the dropping time is 30-45 min, the heating and reaction temperature is 100-110℃, the time is 45-50 h, and the product is washed with n-hexane.

5. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 1, characterized in that, The method for preparing the modified surfactant includes the following steps: S1: Cesium carbonate and 3-methyl-4-isopropylphenol were added to a container containing acetone and stirred under reflux. After reflux, 1,6-dibromohexane was added, and the mixture was heated to continue the reaction. After the reaction was completed, the mixture was filtered under reduced pressure, distilled under reduced pressure, purified, and dried under vacuum to obtain intermediate product 1. Intermediate product 1 is... ; S2: Intermediate product 1 and anhydrous potassium carbonate were added to a container containing a mixed solution of dimethylamine and tetrahydrofuran. The mixture was heated and stirred. After stirring, the mixture was filtered, rotary evaporated, purified, and dried under vacuum to obtain intermediate product 2. Intermediate product 2 is... ; S3: Add intermediate product 2 and ethyl 4-bromobutyrate to a container containing acetonitrile, heat and stir to react. After the reaction is complete, distill under reduced pressure and dry under vacuum. Then add sodium hydroxide and stir to react. After the reaction is complete, filter, wash, dry, wash, centrifuge, and dry under vacuum to obtain the modified surfactant.

6. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 5, characterized in that, In step S1, the molar ratio of cesium carbonate, 3-methyl-4-isopropylphenol, and 1,6-dibromohexane is (5.74-6.89):(2.87-3.44):(14.36-17.23). The stirring and reflux speed is 700-800 rpm, the reflux time is 1-2 h, the heating and stirring temperature is 60-70℃, and the time is 4-6 h. Purification is carried out using a mixed solution of ethyl acetate and n-hexane with a volume ratio of 1:40 as the eluent.

7. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 5, characterized in that, In step S2, the ratio of intermediate product 1, anhydrous potassium carbonate, dimethylamine, and tetrahydrofuran is (0.2-0.4) g : (0.6-1.2) g : (0.53-1.06) mL : (4.47-8.94) mL. The heating and stirring temperature is 70-80℃, the stirring speed is 700-800 rpm, and the time is 10-15 h. Purification is carried out using a mixed solution of ethyl acetate, methanol, and triethylamine with a volume ratio of 15:1:0.7 as the eluent.

8. The method for preparing tetrahydroxymethylphosphine sulfate using high-concentration hydrides according to claim 5, characterized in that, In step S3, the ratio of intermediate product ethyl 2,4-bromobutyrate, acetonitrile, and sodium hydroxide is (0.24-0.48) g : (0.24-0.48) g : (6-12) mL : (7-14) mL. The heating and stirring reaction temperature is 70-80℃, the stirring speed is 700-800 rpm, and the time is 24-28 h. The concentration of sodium hydroxide is 0.1 mmol / L, the stirring speed is 600-700 rpm, and the time is 1-2 h. After washing with ultrapure water and drying, it is washed with ethyl acetate.

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