Preparation method of modified superfine sodium hypophosphite

Abstract

The invention discloses a preparation method of modified superfine sodium hypophosphite, and belongs to the technical field of sodium hypophosphite preparation. The preparation method of the modified superfine sodium hypophosphite comprises the following steps: (1) mixing quick lime with water to prepare lime milk, then adding a sodium hydroxide solution into a reaction kettle containing the lime milk, and uniformly mixing to obtain a mixed solution; (2) heating the mixed solution, introducing nitrogen at the same time, adding yellow phosphorus into a reaction kettle, carrying out heating reaction to obtain a reaction solution, collecting generated gas through a pipeline in the reaction process, and treating the gas; and (3) adding a modified surfactant into the reaction solution, stirring and mixing, filtering, removing calcium, adjusting the pH value, concentrating, crystallizing, centrifuging and drying to obtain the modified superfine sodium hypophosphite. The sodium hypophosphite prepared by the method has tiny and uniform particle size, and the content of phosphine gas in the preparation process is low.

Description

Technical Field

[0001] The invention belongs to the technical field of sodium hypophosphite preparation, and particularly relates to a method for preparing modified ultrafine sodium hypophosphite. Background Art

[0002] Since the United States first applied sodium hypophosphite to chemical nickel plating in the 1940s, sodium hypophosphite has not only promoted the rapid development of chemical nickel plating technology, but also promoted the overall progress of the hypophosphite industry. In recent years, with the continuous innovation of surface treatment technology and the expansion of application fields, such as fine chemicals, flame retardants, water treatment agents and the synthesis of new materials, the demand for sodium hypophosphite has increased at an annual rate of 10% to 15%. And with the enhancement of environmental awareness and the deepening of the concept of sustainable development, the preparation process of modified ultrafine sodium hypophosphite also pays more attention to greening and low carbonization. Therefore, it is necessary to develop a low-energy consumption and low-emission production process to reduce the generation of by-products and the emission of waste, so as to maximize the utilization of resources and protect the environment.

[0003] Patent CN102502545B discloses a method for preparing sodium hypophosphite, which uses aeration and lime-iron salt method to remove arsenic and fluorine impurities therein to obtain a mixed solution of sodium hypophosphite and sodium phosphite; and uses evaporation concentration, crystallization and ethanol distillation-recrystallization methods to obtain industrial-grade sodium hypophosphite and sodium phosphite products with high purity. This method improves the comprehensive utilization rate of effective element phosphorus in mud phosphorus, wherein the extractant ethanol can be recycled, saving resources and avoiding environmental pollution. However, the particle size uniformity and fineness of the sodium hypophosphite prepared by this method still have room for improvement, and the waste pollution generated in the preparation process still has room for reduction. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing modified ultrafine sodium hypophosphite, which is used to solve the technical problems of uneven particle size of the sodium hypophosphite prepared in the prior art and high concentration of waste gas generated during the preparation process.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing modified ultrafine sodium hypophosphite, comprising the following steps:

[0007] Step (1): mixing quicklime and water, stirring evenly to obtain lime milk, then adding sodium hydroxide solution into a reaction kettle containing the lime milk, turning on a stirring system, and mixing evenly to obtain a mixed solution;

[0008] Step (2): turning on the heating system of the reactor to heat the mixed solution, introducing nitrogen at the same time, adding yellow phosphorus into the reactor, heating for reaction, and continuously stirring to obtain a reaction solution. During the reaction, the generated gas is collected through a pipeline and the gas is treated;

[0009] Step (3): adding a modified surfactant to the reaction solution, stirring and mixing, filtering, removing calcium, adjusting the pH, concentrating, crystallizing, centrifuging, and drying to obtain modified ultrafine sodium hypophosphite.

[0010] Preferably, in step (1), the ratio of quicklime, water and sodium hydroxide solution is (1-3) g: (16-48) mL: (3.6-10.8) mL, the concentration of the sodium hydroxide solution is 1 mol / L, and the mixing time is 5-8 h.

[0011] Preferably, in step (2), the heating temperature is 40-45°C, the usage ratio of yellow phosphorus to the mixed solution is (1-3) g: (20-30) mL, the heating reaction temperature is 95-98°C, and the reaction time is 2-4 h.

[0012] Preferably, in step (2), a tail gas absorption treatment device is used to treat the generated gas, and the tail gas absorption treatment device is composed of a collecting tank, a pressure valve, a mass flow meter, an adsorption oxidation column, a constant temperature water bath, a phosphine detection tube and a tail gas absorption bottle, wherein the adsorption oxidation column contains a modified adsorbent, and the preparation method of the modified adsorbent comprises the following steps:

[0013] Q1: After tetrapropylammonium hydroxide and distilled water are mixed, silica sol is added, and after vigorous stirring, the mixture is added into a reactor, heated for crystallization, and then cooled to obtain a mixed solution;

[0014] Q2: Sodium hydroxide and sodium aluminate are added to distilled water, stirred until completely dissolved, and then silica sol is slowly added dropwise, stirred, and then the mixed solution is added, and stirring is continued to obtain an initial gel, and the initial gel is added to a reactor, heated for reaction, cooled, filtered, washed, dried, roasted, and ion exchanged to obtain solid particles;

[0015] Q3: Add the solid particles into the cerium nitrate solution, treat with ultrasonic vibration to make it completely mixed, dry and roast to obtain a powder material, press, crush and sieve the powder material to obtain a modified adsorbent.

[0016] In the above process, silica sol is used as a silicon source and tetrapropylammonium hydroxide is used as a template agent to prepare a mixed solution under heating conditions. Then, under alkaline conditions, sodium aluminate reacts with silicate ions in the mixed solution to form an aluminosilicate gel. As the reaction proceeds, the aluminosilicate gel gradually forms an initial gel. Heating promotes further condensation and crystallization of the gel to form more stable solid particles. Subsequently, ultrasonic treatment is used to adsorb cerium ions in the cerium nitrate solution onto the surface of the solid particles, resulting in a complex reaction to form a modified adsorbent.

[0017] Preferably, in Q1, the molar ratio of tetrapropylammonium hydroxide, distilled water and silica sol is (0.2-0.4):(20-40):(1-2), the vigorous stirring time is 4-6h, the heating crystallization temperature is 90-100°C, and the crystallization time is 22-24h; in Q2, the molar ratio of sodium hydroxide, sodium aluminate, distilled water and silica sol is (0.05-0.15):(0.013-0.016):(15-35):(1-1.2), the stirring time is 3-5h, the continued stirring time is 1-2h, the heating reaction temperature is 140-180°C, the reaction time is 4-24h, the drying temperature is 90-110°C, and the calcination temperature is 500-600°C.

[0018] Preferably, in Q3, the dosage ratio of solid particles to cerium nitrate solution is (2-4) g: (6-10) mL, the concentration of cerium nitrate solution is 0.8 g / mL, the oscillation treatment time is 2-4 h, the drying temperature is 100-120°C, the time is 10-12 h, and the calcination temperature is 400-500°C, and the time is 5-8 h.

[0019] Preferably, in step (3), the ratio of the reaction solution to the modified surfactant is (20-25) mL: (10-20) g, the stirring mixing time is 6-8 h, and the pH is adjusted to 7-7.4.

[0020] Preferably, the preparation method of the modified surfactant comprises the following steps:

[0021] S1: Potassium carbonate and 1,3-dibromopropane are added to a container, followed by acetonitrile, and heated to reflux under stirring. 3-hydroxybenzaldehyde is added to acetonitrile to obtain a 3-hydroxybenzaldehyde solution after dissolution, which is added dropwise to the container. After the addition is completed, the reaction is continued, and nitrogen is introduced during the reaction. After the reaction is completed, the reaction is cooled and filtered, and the obtained filtrate is added to distilled water and dichloromethane respectively. After sufficient mixing, the organic phase is taken, washed, dried, eluted, dissolved, recrystallized, and vacuum dried to obtain product 1;

[0022] S2: dissolving product 1 in methanol and slowly dropping it into a container containing a diethylamine aqueous solution, continuing the reaction after the addition is completed, introducing nitrogen during the reaction, and after the reaction is completed, rotary evaporation, extraction, combining the organic phases, drying and rotary evaporation, eluting, vacuum rotary evaporation, and drying to obtain product 2;

[0023] S3: dissolving product 2 in acetonitrile, adding butane sultone, stirring and reacting at room temperature, introducing nitrogen during the reaction, and after the reaction is completed, filtering, washing, low-temperature recrystallization, and vacuum drying to obtain a modified surfactant.

[0024] In the above process, the synthetic reaction formula of the modified surfactant is as follows:

[0025]

[0026] The results of mass spectrometry analysis were: m / z: 357.16 (100.0%), 358.16 (19.6%), 359.16 (4.7%), 359.17 (2.7%).

[0027] Preferably, in S1, the mass ratio of potassium carbonate, 1,3-dibromopropane and 3-hydroxybenzaldehyde is (45.3-90.6):(150-300):(20-40), the dropping speed is 1 drop / 2s, and the reaction time is 10-12h.

[0028] Preferably, in S2, the amount ratio of product 1, methanol and diethylamine aqueous solution is (20-24) g: (200-240) mL: (190-228) g, the mass fraction of diethylamine aqueous solution is 40 wt%, and the reaction time is 6-8 h; in S3, the amount ratio of product 2, acetonitrile and butane sultone is (13-26) g: (400-800) mL: (10-20) g, and the stirring reaction time is 110-120 h.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] 1. The present invention firstly uses tetrapropylammonium hydroxide, silica sol, sodium silicate and cerium nitrate as raw materials to prepare a modified adsorbent, and then uses potassium carbonate, 1,3-dibromopropane, 3-hydroxybenzaldehyde, diethylamine and butyl sultone as raw materials to prepare a modified surfactant. The modified adsorbent is used to adsorb phosphine gas generated in the process of preparing modified ultrafine sodium hypophosphite. The modified surfactant is used in the process of preparing modified ultrafine sodium hypophosphite, which can not only obtain highly uniform ultrafine particles, but also reduce the generation of phosphine gas and reduce environmental pollution.

[0031] 2. The present invention uses tetrapropylammonium hydroxide, silica sol, sodium silicate and cerium nitrate as raw materials to prepare a modified adsorbent, which is used to absorb phosphine gas generated in the preparation process of sodium hypophosphite. The cerium ions in the modified adsorbent can promote the chemical reaction between phosphine gas and the active sites on the surface of the adsorbent during the adsorption process, accelerate the conversion and fixation of phosphine molecules, and improve the adsorption efficiency. The presence of cerium ions can also enhance the chemical activity of the adsorbent surface, so that phosphine gas molecules can form more stable chemical bonds with the adsorbent surface, which helps to improve the adsorption capacity and stability. The porous structure and large specific surface area of ​​the solid particles provide a chance for the adsorbent to contact with phosphine gas, thereby improving the adsorption efficiency. The formed aluminosilicate matrix is ​​subjected to heating, roasting and other treatments during the preparation process to form a stable chemical structure, thereby ensuring the use effect of the modified adsorbent in complex environments.

[0032] 3. The present invention uses potassium carbonate, 1,3-dibromopropane, 3-hydroxybenzaldehyde, diethylamine and butyl sultone as raw materials to prepare a modified surfactant. The modified surfactant is added to the preparation process of ultrafine sodium hypophosphite, which can effectively improve the particle size uniformity and micronization of the sodium hypophosphite. The molecular structure and properties of the modified surfactant enable the sodium hypophosphite to act as a template or guide in the preparation process. The zwitterionic part contained in the modified surfactant can be adsorbed on the surface of the sodium hypophosphite crystal being formed, and the growth speed and direction of the crystal can be limited through the steric hindrance effect and the charge effect. The uniform distribution of the modified surfactant in the solution is conducive to the formation of a uniform crystal nucleus distribution, avoiding crystal aggregation and uneven particles caused by local oversaturation. At the same time, the modified surfactant can reduce the free energy of the crystal surface, so that the crystal tends to form a more stable and finer structure during the growth process, thereby obtaining finer and uniform sodium hypophosphite particles. DETAILED DESCRIPTION

[0033] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1: This example discloses a method for preparing a modified adsorbent, comprising the following steps:

[0035] Q1: After mixing 1.02 g of tetrapropylammonium hydroxide with 9 mL of distilled water, add 1.5 g of silica sol, stir vigorously for 4 h, add to the reactor, heat at 100 ° C for crystallization for 24 h, and then cool to obtain a mixed solution;

[0036] Q2: Add 0.09g sodium hydroxide and 0.035g sodium aluminate to 7.5mL distilled water, stir until completely dissolved, slowly add 1.1g silica sol, stir for 3h, then add 1.2mL mixed solution, continue stirring for 2h to obtain initial gel, add the initial gel to the reactor, heat at 140℃ for 20h, cool, filter, wash, dry at 100℃, calcine at 550℃, and obtain solid particles after ion exchange;

[0037] Q3: Add 3 g of solid particles into 8 mL of 0.8 g / mL cerium nitrate solution, treat with ultrasonic oscillation for 4 hours to make it completely mixed, dry at 120°C for 12 hours, and calcine at 400°C for 6 hours to obtain a powder material, which is tableted, crushed and sieved to obtain a modified adsorbent.

[0038] This embodiment discloses a method for preparing a modified surfactant, comprising the following steps:

[0039] S1: 68 g potassium carbonate and 225 g 1,3-dibromopropane were added to a container, followed by 250 mL acetonitrile, heated to reflux under stirring, 30 g 3-hydroxybenzaldehyde was added to 20 mL acetonitrile, and a 3-hydroxybenzaldehyde solution was obtained after dissolution, which was added dropwise to the container at a dropping rate of 1 drop / 2 s. After the addition was completed, the reaction was continued for 12 h, and nitrogen was introduced during the reaction. After the reaction was completed, the reaction was cooled and filtered, and the obtained filtrate was added to 250 mL distilled water and 250 mL dichloromethane respectively. After sufficient mixing, the organic phase was taken, washed, dried, eluted, dissolved, recrystallized, and vacuum dried to obtain product 1;

[0040] S2: 22 g of product 1 was dissolved in 220 mL of methanol and then slowly added dropwise to a container containing 209 g of a 40 wt% aqueous solution of diethylamine. After the addition was completed, the reaction was continued for 8 h. Nitrogen was introduced during the reaction. After the reaction was completed, the product was rotary evaporated, extracted, the organic phases were combined, dried, rotary evaporated, eluted, vacuum rotary evaporated, and dried to obtain product 2;

[0041] S3: Dissolve 19.5 g of product 2 in 600 mL of acetonitrile, add 15 g of butane sultone, and react at room temperature with stirring for 120 h. During the reaction, introduce nitrogen. After the reaction, filter, wash, recrystallize at low temperature, and dry in vacuo to obtain a modified surfactant.

[0042] This embodiment discloses a method for preparing ultrafine sodium hypophosphite, comprising the following steps:

[0043] Step (1): 2 g of quicklime and 32 mL of water were mixed and stirred to obtain lime milk, and then 7.2 mL of 1 mol / L sodium hydroxide solution was added to the reactor containing the lime milk, and the stirring system was turned on. After mixing for 6 hours, a mixed solution was obtained;

[0044] Step (2): Turn on the heating system of the reactor, heat 25 mL of the mixed solution to 45° C., introduce nitrogen at the same time, add 2 g of yellow phosphorus to the reactor, react at 98° C. for 4 h, and continue stirring to obtain a reaction solution. During the reaction, the generated gas is collected through a pipeline and the gas is treated. The generated gas is treated by a tail gas absorption treatment device, which is composed of a collection tank, a pressure valve, a mass flow meter, an adsorption oxidation column (containing a modified adsorbent), a constant temperature water bath, a phosphine detection tube and a tail gas absorption bottle;

[0045] Step (3): add 15 g of modified surfactant to 23 mL of reaction solution, stir and mix for 8 h, filter, remove calcium, adjust pH=7, concentrate, crystallize, centrifuge, and dry to obtain modified ultrafine sodium hypophosphite.

[0046] Example 2: This example discloses a method for preparing a modified adsorbent, comprising the following steps:

[0047] Q1: After mixing 0.68g of tetrapropylammonium hydroxide with 12mL of distilled water, add 1g of silica sol, stir vigorously for 4h, add to the reactor, heat at 100℃ for crystallization for 24h, and then cool to obtain a mixed solution;

[0048] Q2: Add 0.03g sodium hydroxide and 0.03g sodium aluminate to 10.5mL distilled water, stir until completely dissolved, slowly drop 1g silica sol, stir for 3h, then add 1.2mL mixed solution, continue stirring for 2h to obtain initial gel, add the initial gel to the reactor, heat at 140℃ for 20h, cool, filter, wash, dry at 100℃, calcine at 550℃, and obtain solid particles after ion exchange;

[0049] Q3: Add 2 g of solid particles into 10 mL of 0.8 g / mL cerium nitrate solution, treat with ultrasonic oscillation for 4 hours to make it completely mixed, dry at 120°C for 12 hours, and calcine at 400°C for 6 hours to obtain a powder material, which is tableted, crushed and sieved to obtain a modified adsorbent.

[0050] This embodiment discloses a method for preparing a modified surfactant, comprising the following steps:

[0051] S1: 45.3 g potassium carbonate and 150 g 1,3-dibromopropane were added to a container, followed by 250 mL acetonitrile, heated to reflux under stirring, 40 g 3-hydroxybenzaldehyde was added to 20 mL acetonitrile, and a 3-hydroxybenzaldehyde solution was obtained after dissolution, which was added dropwise to the container at a dropping rate of 1 drop / 2 s. After the addition was completed, the reaction was continued for 12 h, and nitrogen was introduced during the reaction. After the reaction was completed, the reaction was cooled and filtered, and the obtained filtrate was added to 250 mL distilled water and 250 mL dichloromethane respectively. After sufficient mixing, the organic phase was taken, washed, dried, eluted, dissolved, recrystallized, and vacuum dried to obtain product 1;

[0052] S2: 24 g of product 1 was dissolved in 240 mL of methanol and then slowly added dropwise to a container containing 228 g of a 40 wt% aqueous solution of diethylamine. After the addition was completed, the reaction was continued for 8 h. Nitrogen was introduced during the reaction. After the reaction was completed, the product was rotary evaporated, extracted, the organic phases were combined, dried, rotary evaporated, eluted, vacuum rotary evaporated, and dried to obtain product 2;

[0053] S3: Dissolve 13 g of product 2 in 800 mL of acetonitrile, add 20 g of butane sultone, and react at room temperature with stirring for 120 h. During the reaction, introduce nitrogen. After the reaction, filter, wash, recrystallize at low temperature, and dry in vacuo to obtain a modified surfactant.

[0054] This embodiment discloses a method for preparing ultrafine sodium hypophosphite, comprising the following steps:

[0055] Step (1): 1 g of quicklime was mixed with 16 mL of water, and the mixture was stirred evenly to obtain lime milk. Then, 10.8 mL of 1 mol / L sodium hydroxide solution was added to the reactor containing the lime milk, and the stirring system was turned on. After mixing for 6 hours, a mixed solution was obtained.

[0056] Step (2): Turn on the heating system of the reactor, heat 20 mL of the mixed solution to 45° C., introduce nitrogen at the same time, add 1 g of yellow phosphorus to the reactor, react at 98° C. for 4 h, and continue stirring to obtain a reaction solution. During the reaction, the generated gas is collected through a pipeline and the gas is treated. The generated gas is treated by a tail gas absorption treatment device, which is composed of a collection tank, a pressure valve, a mass flow meter, an adsorption oxidation column (containing a modified adsorbent), a constant temperature water bath, a phosphine detection tube and a tail gas absorption bottle;

[0057] Step (3): add 10 g of modified surfactant to 20 mL of reaction solution, stir and mix for 8 h, filter, remove calcium, adjust pH=7, concentrate, crystallize, centrifuge, and dry to obtain modified ultrafine sodium hypophosphite.

[0058] Example 3: This example discloses a method for preparing a modified adsorbent, comprising the following steps:

[0059] Q1: After mixing 1.36 g of tetrapropylammonium hydroxide with 6 mL of distilled water, add 2 g of silica sol, stir vigorously for 4 h, add to the reactor, heat at 100 ° C for crystallization for 24 h, and then cool to obtain a mixed solution;

[0060] Q2: Add 0.15g sodium hydroxide and 0.04g sodium aluminate to 4.5mL distilled water, stir until completely dissolved, slowly drop 1.2g silica sol, stir for 3h, then add 1.2mL mixed solution, continue stirring for 2h to obtain initial gel, add the initial gel to the reactor, heat at 140℃ for 20h, cool, filter, wash, dry at 100℃, calcine at 550℃, and obtain solid particles after ion exchange;

[0061] Q3: Add 4 g of solid particles into 6 mL of 0.8 g / mL cerium nitrate solution, treat with ultrasonic oscillation for 4 hours to make it completely mixed, dry at 120°C for 12 hours, and calcine at 400°C for 6 hours to obtain a powder material, which is tableted, crushed and sieved to obtain a modified adsorbent.

[0062] This embodiment discloses a method for preparing a modified surfactant, comprising the following steps:

[0063] S1: 90.6 g potassium carbonate and 300 g 1,3-dibromopropane were added to a container, followed by 250 mL acetonitrile, heated to reflux under stirring, 20 g 3-hydroxybenzaldehyde was added to 20 mL acetonitrile, and a 3-hydroxybenzaldehyde solution was obtained after dissolution, which was added dropwise to the container at a dropping rate of 1 drop / 2 s. After the addition was completed, the reaction was continued for 12 h, and nitrogen was introduced during the reaction. After the reaction was completed, the reaction was cooled and filtered, and the obtained filtrate was added to 250 mL distilled water and 250 mL dichloromethane respectively. After sufficient mixing, the organic phase was taken, washed, dried, eluted, dissolved, recrystallized, and vacuum dried to obtain product 1;

[0064] S2: 20 g of product 1 was dissolved in 200 mL of methanol and then slowly added dropwise to a container containing 190 g of a 40 wt% aqueous solution of diethylamine. After the addition was completed, the reaction was continued for 8 h. Nitrogen was introduced during the reaction. After the reaction was completed, the mixture was rotary evaporated, extracted, the organic phases were combined, dried, rotary evaporated, eluted, vacuum rotary evaporated, and dried to obtain product 2;

[0065] S3: Dissolve 26 g of product 2 in 40 mL of acetonitrile, add 10 g of butane sultone, and react at room temperature with stirring for 120 h. During the reaction, introduce nitrogen. After the reaction, filter, wash, recrystallize at low temperature, and dry in vacuo to obtain a modified surfactant.

[0066] This embodiment discloses a method for preparing ultrafine sodium hypophosphite, comprising the following steps:

[0067] Step (1): 3 g of quicklime was mixed with 48 mL of water, and the mixture was stirred to obtain lime milk. Then, 3.6 mL of 1 mol / L sodium hydroxide solution was added to the reactor containing the lime milk, and the stirring system was turned on. After mixing for 6 h, a mixed solution was obtained.

[0068] Step (2): start the heating system of the reactor, heat 30 mL of the mixed solution to 45° C., introduce nitrogen at the same time, add 3 g of yellow phosphorus to the reactor, react at 98° C. for 4 h, and continuously stir to obtain a reaction solution. During the reaction, collect the generated gas through a pipeline and treat the gas. Use a tail gas absorption treatment device to treat the generated gas. The tail gas absorption treatment device consists of a collection tank, a pressure valve, a mass flow meter, an adsorption oxidation column (containing a modified adsorbent), a constant temperature water bath, a phosphine detection tube and a tail gas absorption bottle;

[0069] Step (3): add 20 g of modified surfactant to 25 mL of reaction solution, stir and mix for 8 h, filter, remove calcium, adjust pH=7, concentrate, crystallize, centrifuge, and dry to obtain modified ultrafine sodium hypophosphite.

[0070] Example 4: This example discloses a method for preparing a modified adsorbent, comprising the following steps:

[0071] Q1: After mixing 0.85 g of tetrapropylammonium hydroxide with 7.5 mL of distilled water, 1.2 g of silica sol was added, and the mixture was stirred vigorously for 4 h. The mixture was added to a reactor, and the mixture was heated at 100 °C for crystallization for 24 h, and then cooled to obtain a mixed solution.

[0072] Q2: Add 0.06g sodium hydroxide and 0.032g sodium aluminate to 6mL distilled water, stir until completely dissolved, slowly drop 1.05g silica sol, stir for 3h, then add 1.2mL mixed solution, continue stirring for 2h to obtain initial gel, add the initial gel to the reactor, heat at 140℃ for 20h, cool, filter, wash, dry at 100℃, calcine at 550℃, and obtain solid particles after ion exchange;

[0073] Q3: Add 2.5 g of solid particles into 7 mL of 0.8 g / mL cerium nitrate solution, treat with ultrasonic oscillation for 4 hours to make it completely mixed, dry at 120°C for 12 hours, and calcine at 400°C for 6 hours to obtain a powdery substance, which is tableted, crushed and sieved to obtain a modified adsorbent.

[0074] This embodiment discloses a method for preparing a modified surfactant, comprising the following steps:

[0075] S1: Add 56.65g potassium carbonate and 250g 1,3-dibromopropane to a container, then add 250mL acetonitrile, heat to reflux under stirring, add 25g 3-hydroxybenzaldehyde to 20mL acetonitrile, dissolve to obtain 3-hydroxybenzaldehyde solution, add it dropwise to the container, the dropping speed is 1 drop / 2s, after the addition is completed, continue to react for 12h, introduce nitrogen during the reaction, after the reaction is completed, cool, filter, add the obtained filtrate to 250mL distilled water and 250mL dichloromethane respectively, mix well, take the organic phase, wash,

[0076] Drying, eluting, dissolving, recrystallization, and vacuum drying to obtain product 1;

[0077] S2: 21 g of product 1 was dissolved in 230 mL of methanol and then slowly added dropwise to a container containing 199.5 g of a 40 wt% aqueous solution of diethylamine. After the addition was completed, the reaction was continued for 8 h. Nitrogen was introduced during the reaction. After the reaction was completed, the product was rotary evaporated, extracted, the organic phases were combined, dried, rotary evaporated, eluted, vacuum rotary evaporated, and dried to obtain product 2;

[0078] S3: Dissolve 15 g of product 2 in 500 mL of acetonitrile, add 12 g of butane sultone, and react at room temperature with stirring for 120 h. During the reaction, introduce nitrogen. After the reaction, filter, wash, recrystallize at low temperature, and dry in vacuo to obtain a modified surfactant.

[0079] This embodiment discloses a method for preparing ultrafine sodium hypophosphite, comprising the following steps:

[0080] Step (1): 2.5 g of quicklime was mixed with 30 mL of water, and the mixture was stirred to obtain lime milk. Then, 9 mL of 1 mol / L sodium hydroxide solution was added to the reaction kettle containing the lime milk, and the stirring system was turned on. After mixing for 6 h, a mixed solution was obtained.

[0081] Step (2): start the heating system of the reactor, heat 28 mL of the mixed solution to 45° C., introduce nitrogen at the same time, add 1.5 g of yellow phosphorus to the reactor, react at 98° C. for 4 h, and continuously stir to obtain a reaction solution. During the reaction, the generated gas is collected through a pipeline and the gas is treated. The generated gas is treated by a tail gas absorption treatment device, which is composed of a collection tank, a pressure valve, a mass flow meter, an adsorption oxidation column (containing a modified adsorbent), a constant temperature water bath, a phosphine detection tube, and a tail gas absorption bottle;

[0082] Step (3): add 12 g of modified surfactant to 21 mL of reaction solution, stir and mix for 8 h, filter, remove calcium, adjust pH=7, concentrate, crystallize, centrifuge, and dry to obtain modified ultrafine sodium hypophosphite.

[0083] Example 5: This example discloses a method for preparing a modified adsorbent, comprising the following steps:

[0084] Q1: After mixing 1.19 g of tetrapropylammonium hydroxide with 10.5 mL of distilled water, 1.7 g of silica sol was added, and the mixture was stirred vigorously for 4 h. The mixture was added to a reactor, and the mixture was heated at 100 °C for crystallization for 24 h, and then cooled to obtain a mixed solution.

[0085] Q2: Add 0.12g sodium hydroxide and 0.038g sodium aluminate to 9mL distilled water, stir until completely dissolved, slowly drop 1.15g silica sol, stir for 3h, then add 1.2mL mixed solution, continue stirring for 2h to obtain initial gel, add the initial gel to the reactor, heat at 140℃ for 20h, cool, filter, wash, dry at 100℃, calcine at 550℃, and obtain solid particles after ion exchange;

[0086] Q3: Add 3.5 g of solid particles into 9 mL of 0.8 g / mL cerium nitrate solution, treat with ultrasonic oscillation for 4 hours to make it completely mixed, dry at 120°C for 12 hours, and calcine at 400°C for 6 hours to obtain a powder material, which is tableted, crushed and sieved to obtain a modified adsorbent.

[0087] This embodiment discloses a method for preparing a modified surfactant, comprising the following steps:

[0088] S1: Add 79.3g potassium carbonate and 175g 1,3-dibromopropane to a container, then add 250mL acetonitrile, heat to reflux under stirring, add 35g 3-hydroxybenzaldehyde to 20mL acetonitrile, dissolve to obtain 3-hydroxybenzaldehyde solution, add it dropwise to the container, the dropping speed is 1 drop / 2s, after the addition is completed, continue to react for 12h, introduce nitrogen during the reaction, after the reaction is completed, cool, filter, add the obtained filtrate to 250mL distilled water and 250mL dichloromethane respectively, mix well, take the organic phase, wash,

[0089] Drying, eluting, dissolving, recrystallization, and vacuum drying to obtain product 1;

[0090] S2: 23 g of product 1 was dissolved in 210 mL of methanol and then slowly added dropwise to a container containing 218.5 g of a 40 wt% aqueous solution of diethylamine. After the addition was completed, the reaction was continued for 8 h. Nitrogen was introduced during the reaction. After the reaction was completed, the product was rotary evaporated, extracted, the organic phases were combined, dried, rotary evaporated, eluted, vacuum rotary evaporated, and dried to obtain product 2;

[0091] S3: Dissolve 21 g of product 2 in 700 mL of acetonitrile, add 18 g of butane sultone, and react at room temperature with stirring for 120 h. During the reaction, introduce nitrogen. After the reaction, filter, wash, recrystallize at low temperature, and dry in vacuo to obtain a modified surfactant.

[0092] This embodiment discloses a method for preparing ultrafine sodium hypophosphite, comprising the following steps:

[0093] Step (1): 1.5 g quicklime was mixed with 44 mL water, and the mixture was stirred to obtain lime milk. Then, 5.4 mL of 1 mol / L sodium hydroxide solution was added to the reaction kettle containing the lime milk.

[0094] The stirring system was turned on and mixed for 6 h to obtain a mixed solution;

[0095] Step (2): Turn on the heating system of the reactor, heat 22 mL of the mixed solution to 45° C., introduce nitrogen at the same time, add 2.5 g of yellow phosphorus to the reactor, react at 98° C. for 4 h, and continue stirring to obtain a reaction solution. During the reaction, the generated gas is collected through a pipeline and the gas is treated. The generated gas is treated by a tail gas absorption treatment device, which is composed of a collection tank, a pressure valve, a mass flow meter, an adsorption oxidation column (containing a modified adsorbent), a constant temperature water bath, a phosphine detection tube and a tail gas absorption bottle;

[0096] Step (3): add 18 g of modified surfactant to 24 mL of reaction solution, stir and mix for 8 h, filter, remove calcium, adjust pH=7, concentrate, crystallize, centrifuge, and dry to obtain modified ultrafine sodium hypophosphite.

[0097] Comparative Example 1: Compared with Example 1, in the process of preparing the modified adsorbent in Comparative Example 1, no cerium nitrate solution was added, and other conditions remained unchanged.

[0098] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the preparation of the modified surfactant, no 3-hydroxybenzaldehyde was added, and other conditions remained unchanged.

[0099] Comparative Example 3: Compared with Example 1, in Comparative Example 3, during the preparation of the modified ultrafine sodium hypophosphite, no modified adsorbent was added, and other conditions remained unchanged.

[0100] Comparative Example 4: Compared with Example 1, in Comparative Example 4, during the preparation of modified ultrafine sodium hypophosphite, no modified surfactant was added, and other conditions remained unchanged.

[0101] Experimental example: The phosphine gas content generated during the production process was measured using an HL-210 phosphine gas concentration detector, and the particle size of sodium hypophosphite was measured using a laser particle size measurement method. The test results are shown in Table 1:

[0102] Table 1

[0103] project <![CDATA[Phosphine concentration / mg·m -3 > Particle size range / μm Example 1 0.10 0.04-0.07 Example 2 0.11 0.05-0.07 Example 3 0.11 0.05-0.08 Example 4 0.12 0.06-0.09 Example 5 0.13 0.06-0.09 Comparative Example 1 0.25 0.07-0.10 Comparative Example 2 0.13 0.09-0.17 Comparative Example 3 0.28 0.06-0.10 Comparative Example 4 0.14 0.10-0.19

[0104] It can be seen from the test results in Table 1 that the sodium hypophosphite prepared in Examples 1-5 of the present invention has a small particle size and a uniform particle size range, and the concentration of phosphine generated during the preparation process is low. By comparing Comparative Example 1 with Examples 1-5, it can be seen that the addition of cerium nitrate solution can effectively reduce the content of phosphine gas during the preparation process; by comparing Comparative Example 2 with Examples 1-5, it can be seen that the addition of 3-hydroxybenzaldehyde can effectively improve the uniformity and smallness of the particle size of sodium hypophosphite; by comparing Comparative Example 3 with Examples 1-5, it can be seen that the addition of a modified adsorbent can effectively reduce the content of phosphine gas during the preparation process; by comparing Comparative Example 4 with Examples 1-5, it can be seen that the addition of a modified surfactant can effectively improve the uniformity and smallness of the particle size of sodium hypophosphite.

[0105] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0106] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing modified ultrafine sodium hypophosphite, characterized in that: The following steps are involved: Step (1): mixing quicklime and water, stirring evenly to obtain lime milk, then adding sodium hydroxide solution into a reaction kettle containing the lime milk, turning on a stirring system, and mixing evenly to obtain a mixed solution; Step (2): turning on the heating system of the reactor to heat the mixed solution, introducing nitrogen at the same time, adding yellow phosphorus into the reactor, heating for reaction, and continuously stirring to obtain a reaction solution. During the reaction, the generated gas is collected through a pipeline and the gas is treated; Step (3): adding a modified surfactant to the reaction solution, stirring and mixing, filtering, removing calcium, adjusting the pH, concentrating, crystallizing, centrifuging, and drying to obtain modified ultrafine sodium hypophosphite.

2. The method for preparing modified ultrafine sodium hypophosphite according to claim 1, characterized in that: In the step (1), the usage ratio of quicklime, water and sodium hydroxide solution is (1-3) g: (16-48) mL: (3.6-10.8) mL, the concentration of the sodium hydroxide solution is 1 mol / L, and the mixing time is 5-8 h.

3. The method for preparing modified ultrafine sodium hypophosphite according to claim 1, characterized in that: In the step (2), the heating temperature is 40-45° C., the usage ratio of yellow phosphorus to the mixed solution is (1-3) g: (20-30) mL, the heating reaction temperature is 95-98° C., and the reaction time is 2-4 h.

4. The method for preparing modified ultrafine sodium hypophosphite according to claim 1, characterized in that: In the step (2), a tail gas absorption treatment device is used to treat the generated gas, and the tail gas absorption treatment device is composed of a collection tank, a pressure valve, a mass flow meter, an adsorption oxidation column, a constant temperature water bath, a phosphine detection tube and a tail gas absorption bottle, wherein the adsorption oxidation column contains a modified adsorbent, and the preparation method of the modified adsorbent comprises the following steps: Q1: After tetrapropylammonium hydroxide and distilled water are mixed, silica sol is added, and after vigorous stirring, the mixture is added into a reactor, heated for crystallization, and then cooled to obtain a mixed solution; Q2: Sodium hydroxide and sodium aluminate are added to distilled water, stirred until completely dissolved, and then silica sol is slowly added dropwise, stirred, and then the mixed solution is added, and stirring is continued to obtain an initial gel, and the initial gel is added to a reactor, heated for reaction, cooled, filtered, washed, dried, roasted, and ion exchanged to obtain solid particles; Q3: Add the solid particles into the cerium nitrate solution, treat with ultrasonic vibration to make it completely mixed, dry and roast to obtain a powder material, press, crush and sieve the powder material to obtain a modified adsorbent.

5. The method for preparing modified ultrafine sodium hypophosphite according to claim 4, characterized in that: In the Q1, the molar ratio of tetrapropylammonium hydroxide, distilled water and silica sol is (0.2-0.4): (20-40): (1-2), the vigorous stirring time is 4-6 hours, the heating crystallization temperature is 90-100°C, and the crystallization time is 22-24 hours; in the Q2, the molar ratio of sodium hydroxide, sodium aluminate, distilled water and silica sol is (0.05-0.15): (0.013-0.016): (15-35): (1-1.2), the stirring time is 3-5 hours, the continued stirring time is 1-2 hours, the heating reaction temperature is 140-180°C, the reaction time is 4-24 hours, the drying temperature is 90-110°C, and the calcination temperature is 500-600°C.

6. The method for preparing modified ultrafine sodium hypophosphite according to claim 4, characterized in that: In the Q3, the dosage ratio of solid particles and cerium nitrate solution is (2-4) g: (6-10) mL, the concentration of cerium nitrate solution is 0.8 g / mL, the oscillation treatment time is 2-4 h, the drying temperature is 100-120° C., the time is 10-12 h, and the calcination temperature is 400-500° C., and the time is 5-8 h.

7. The method for preparing modified ultrafine sodium hypophosphite according to claim 1, characterized in that: In the step (3), the ratio of the reaction solution to the modified surfactant is (20-25) mL: (10-20) g, the stirring mixing time is 6-8 h, and the pH is adjusted to 7-7.

4.

8. The method for preparing modified ultrafine sodium hypophosphite according to claim 1, characterized in that: The preparation method of the modified surfactant comprises the following steps: S1: Potassium carbonate and 1,3-dibromopropane are added to a container, followed by acetonitrile, and heated to reflux under stirring. 3-hydroxybenzaldehyde is added to acetonitrile to obtain a 3-hydroxybenzaldehyde solution after dissolution, which is added dropwise to the container. After the addition is completed, the reaction is continued, and nitrogen is introduced during the reaction. After the reaction is completed, the reaction is cooled and filtered, and the obtained filtrate is added to distilled water and dichloromethane respectively. After sufficient mixing, the organic phase is taken, washed, dried, eluted, dissolved, recrystallized, and vacuum dried to obtain product 1; S2: dissolving product 1 in methanol and slowly dropping it into a container containing a diethylamine aqueous solution, continuing the reaction after the addition is completed, introducing nitrogen during the reaction, and after the reaction is completed, rotary evaporation, extraction, combining the organic phases, drying and rotary evaporation, eluting, vacuum rotary evaporation, and drying to obtain product 2; S3: dissolving product 2 in acetonitrile, adding butane sultone, stirring and reacting at room temperature, introducing nitrogen during the reaction, and after the reaction is completed, filtering, washing, low-temperature recrystallization, and vacuum drying to obtain a modified surfactant.

9. The method for preparing modified ultrafine sodium hypophosphite according to claim 8, characterized in that: In the S1, the mass ratio of potassium carbonate, 1,3-dibromopropane and 3-hydroxybenzaldehyde is (45.3-90.6):(150-300):(20-40), the dropping speed is 1 drop / 2s, and the reaction time is 10-12h.

10. The method for preparing modified ultrafine sodium hypophosphite according to claim 8, characterized in that: In S2, the amount ratio of product 1, methanol and diethylamine aqueous solution is (20-24) g: (200-240) mL: (190-228) g, the mass fraction of diethylamine aqueous solution is 40wt%, and the reaction time is 6-8h; in S3, the amount ratio of product 2, acetonitrile and butane sultone is (13-26) g: (400-800) mL: (10-20) g, and the stirring reaction time is 110-120h.

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