Preparation method of sodium hydrosulfite

Abstract

The invention discloses a preparation method of sodium hydrosulfite. The preparation method comprises the following steps: preparing raw materials including sodium formate, sodium pyrosulfite, water and methanol into a mixed solution according to a certain proportion; adding a sulfur dioxide methanol absorption solution into the mixed solution to prepare a reaction stock solution; adding the reaction stock solution into a sodium hydrosulfite reactor for reaction, and slowly adding sulfur dioxide methanol absorption liquid into the sodium hydrosulfite reactor in the reaction process to control the reaction PH value to obtain a product solution; and carrying out suction filtration on the product liquid, washing with methanol, and drying to obtain a dry sodium hydrosulfite product. The preparation method of the sodium hydrosulfite is simple and convenient in operation process and has high feasibility in industrial automation application, and meanwhile, the requirement for manual judgment is reduced; under the condition that ethylene oxide is not added in the production process, high-content sodium hydrosulfite can still be efficiently generated, the content of synthesized sodium hydrosulfite is guaranteed, and the problems that a traditional production process is poor in safety and pollutes the environment are solved.

Description

Technical Field

[0001] The invention relates to the technical field of synthetic chemistry, and in particular to a method for preparing hydrosulfur powder. Background Art

[0002] Sodium Hydrosulfite, scientific name Sodium Hydrosulfite, has a molecular formula of Na2S2O4, a molecular weight of 174.11, a hazard code of 42012, a UN number of 1384, and a CAS number of 7775-14-6. As an important organic compound, sodium hydrosulfite is widely used in reduction dyeing, reduction cleaning, printing and decolorization in the textile industry, and is used for bleaching of silk, wool, nylon and other fabrics. Since it does not contain heavy metals, the color of the bleached fabric is very bright and not easy to fade. In terms of various substances, it can also be used for food bleaching, such as gelatin, sucrose, candied fruit, and bleaching of soap, animal (plant) oil, bamboo, porcelain clay, etc. It can also be used in organic synthesis, such as the production of dyes and medicines as a reducing agent or bleaching agent. Sodium hydrosulfite is the most suitable bleaching agent for wood pulp papermaking.

[0003] At present, the equipment for preparing sodium hydrosulfite mainly adopts a multi-step process. During the preparation process, the amount of materials fed and the overall reaction time are highly dependent on the operator's experience, which is difficult to achieve automation, thus affecting the safe and efficient production of sodium hydrosulfite. In addition, ethylene oxide, which is harmful to the environment and human body, must be added during the reaction to inhibit the formation of by-products.

[0004] 1. Main reaction formula: Formula 1:

[0005] Formula 2:

[0006] Formula 3:

[0007] (II) Overall reaction formula: Formula 4:

[0008] (III) Side reaction formula: Formula 5:

[0009] Formula 6:

[0010] (IV) Side reaction inhibition reaction (reaction of ethylene oxide and sodium thiosulfate) formula: Formula 7:

[0011] Formula 8:

[0012] Formula 9:

[0013] In the existing sodium formate process, the entire reaction process is divided into three stages: pH adjustment, large drop addition, and small drop addition. In each stage, it is necessary to control a certain temperature and different material addition speeds, and continuously add ethylene oxide throughout the process. Due to the complex process, it is not conducive to the automated operation of the system, and manual judgment and debugging are required. At the same time, ethylene oxide must be added continuously to control the unstable factors in the reaction process, which increases the harm to personnel and equipment.

[0014] In summary, the current method for preparing hydrosulfite has problems such as complex process, environmental pollution and high instability. In addition, the large amount of ethylene oxide used leads to increased costs and causes great harm to the environment and human body.

[0015] Therefore, it is urgent to develop a new preparation method to improve the preparation efficiency of insurance powder, simplify the production process, reduce energy consumption and safety risks, and promote the development of the insurance powder industry towards automated, intelligent and unmanned efficient production. Summary of the invention

[0016] The purpose of the present invention is to provide a method for preparing sodium hydrosulfite to solve the problems raised in the above background technology. To achieve the above purpose, the present invention provides the following technical solutions: A method for preparing hydrosulfur powder comprises the following steps: S1. The raw materials sodium formate, sodium metabisulfite, water and methanol are prepared into a mixed solution in a certain proportion; S2. adding sulfur dioxide methanol absorption liquid to the mixed solution to prepare a reaction stock solution; S3. The reaction solution is added to the insurance powder reactor for reaction, and during the reaction, sulfur dioxide methanol absorption liquid is slowly added to the insurance powder reactor to control the reaction pH value to obtain a product liquid; S4. The product liquid is filtered, washed with methanol, and dried to obtain a dry product of the hydrosulfite.

[0017] Preferably, in step S1, the molar mass ratio of sodium formate, methanol, water and sodium metabisulfite is 1: 2.5-5: 1.5-4: 0.1-0.9, preferably 1: 3-4: 2-3: 0.25-0.5.

[0018] Preferably, the step S1 further comprises grinding the raw material or the mixed solution to reduce the particle size of particles in the mixed solution to 80-200 meshes.

[0019] Preferably, the step S1 further comprises the step of removing dissolved oxygen from the mixed solution, and the method for removing dissolved oxygen comprises: any one or more of ultrasonic treatment, grinding treatment under nitrogen protection and grinding treatment under negative pressure protection.

[0020] Preferably, in step S2, the molar mass ratio of sodium formate to sulfur dioxide in the reaction stock solution is 1:0.1-0.9, preferably 1:0.4-0.65.

[0021] Preferably, in step S3, the reaction temperature in the hydrosulfur powder reactor is set to 60-85°C, preferably 78-83°C; and the pressure is 0.15-0.25Mpa.

[0022] Preferably, in step S3, the reaction pH value in the hydrosulfur powder reactor is controlled to be 4.1-4.9, preferably 4.5-4.8.

[0023] Preferably, in step S3, the addition flow rate of the sulfur dioxide methanol absorption liquid is less than 2.5% of the total volume of the reaction stock solution per minute.

[0024] Preferably, the step S3 further comprises the step of stirring the solution in the hydrosulfur powder reactor, with a stirring speed of 40-360 rpm and a linear speed of 0.8-4 m / s.

[0025] Preferably, the sulfur dioxide content of the sulfur dioxide methanol absorption liquid is 350-500 g / L, preferably 380-430 g / L.

[0026] Preferably, in step S4, heating evaporation is performed by using a rotary evaporator, the pressure in the rotary evaporator is less than -0.09 MPa, the water bath temperature is 40-90° C., preferably 58-75° C., and the rotary evaporation time is 1-3 min.

[0027] The beneficial effects of the present invention are: 1. The method for preparing sodium formate provided by the present invention changes the sodium formate production method into a one-step production method for the first time. After the raw materials are added at one time, the reaction pH can be controlled by sulfur dioxide liquid in the later stage. The present invention provides a simple and easy-to-control production method, which can stably prepare high-quality sodium formate.

[0028] 2. The method for preparing the hydrosulfur powder provided by the present invention innovatively improves the traditional production process and avoids the use of ethylene oxide, which is seriously harmful to the human body and the environment and is flammable and explosive, during the reaction process.

[0029] 3. The method for preparing sodium hydrosulfite provided by the present invention greatly simplifies the operation process in industrial production, improves the safety of the production process, can be better applied to the automation system, reduces human operation errors, improves production efficiency, and has significant industrial application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 The present invention is a flowchart of the method for preparing the hydrosulfur powder. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe 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.

[0033] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0034] like Figure 1 As shown, the method for preparing hydrosulfur powder of the present application comprises the following steps: S1. Weigh the raw materials sodium formate, sodium metabisulfite, water and methanol according to a certain ratio, mix the above raw materials and prepare a mixed solution.

[0035] The advantages of the mixed liquid prepared in step S1 are: in industrial production, it is suitable for preparing the mixed liquid in advance as a reserve. When a reaction is required, the pre-prepared mixed liquid is directly added to the insurance powder reactor through pipeline transportation, and then the sulfur dioxide methanol absorption liquid is added to start the next step of the reaction, which greatly simplifies the production process and improves production efficiency; the process method can be better applied to automation systems, reduce human operating errors, improve production efficiency, and has significant industrial application potential.

[0036] S2. Add sulfur dioxide methanol absorption liquid to the mixed solution prepared in step S1 to prepare a reaction stock solution.

[0037] Since a large amount of sodium formate exists in the initial reaction stock solution, sodium formate can be used as a buffer to stabilize the pH value. In this step S2, when preparing the reaction stock solution, a large amount of sulfur dioxide methanol absorption liquid is added to quickly start the reaction, and the addition of sulfur dioxide methanol absorption liquid has a warming effect, which can reduce heating energy consumption.

[0038] S3. Add the reaction stock solution into the hydrosulfur powder reactor for reaction. During the reaction, the reaction pH value is controlled by slowly adding sulfur dioxide methanol absorption solution into the hydrosulfur powder reactor to obtain a product solution.

[0039] In this step S3, the reaction stock solution prepared in step S2 is added to the hydrosulfite reactor and the reactor is sealed, and the temperature and pressure in the hydrosulfite reactor are controlled to be stable, so that the reaction stock solution undergoes reaction crystallization. During the reaction, samples are taken regularly through the material taking tube to detect the content and pH value of the solution so as to monitor the reaction changes in real time, and the pH value of the reaction is controlled by slowly adding sulfur dioxide methanol absorption liquid to the hydrosulfite reactor according to the changes in the pH value, thereby controlling the progress of the entire reaction; specifically, the pH value of the solution is tested once every 10-20 minutes with a precision pH test paper. After a period of reaction, a product solution is obtained.

[0040] In this step S3, since the sodium formate has begun to be generated during the reaction process, the sodium formate as a raw material is gradually consumed during the reaction process. If a large amount of sulfur dioxide methanol absorption liquid is added again, the pH stabilization system may be broken, and the sodium formate will decompose and produce a large number of by-products under the condition of superacidity; at this time, it is necessary to add ethylene oxide for control, and at the same time, replenish sodium formate as soon as possible during the reaction process, otherwise the product will be further decomposed due to the production of by-products, resulting in a sharp drop in product content. In this step, the addition speed of the sulfur dioxide methanol absorption liquid is stably controlled to avoid the occurrence of side reactions caused by excessive addition of sulfur dioxide, so that it is no longer necessary to add ethylene oxide, a toxic and harmful inhibitor, to inhibit the progress of side reactions during the reaction process, and the use of the raw material sulfur dioxide methanol absorption liquid can also be effectively saved.

[0041] S4. The product liquid is filtered, washed with methanol, and dried to obtain a dry product of the hydrosulfite.

[0042] In this step S4, the product liquid obtained in step S3 is put into a Buchner funnel for suction filtration as soon as possible. When it is almost completely dry, methanol with an amount of about twice the volume of the sodium hypochlorite is added for washing. After washing, the sodium hypochlorite layer on the surface of the Buchner funnel is scraped off, and the sodium hypochlorite in the middle layer of the filter cake is quickly extracted for drying. After drying, the sodium hypochlorite dry product is obtained and tested using the national standard HG / T2074-2011 method. Specifically, the drying treatment method is: after alcohol washing, dry or dry or rotary evaporation is used; wherein, the alcohol washing step is to wash the extracted sodium hypochlorite product with methanol, and then directly detect the content; the frying and drying step is to heat the surface dish to 55-70°C, and then put the sodium hypochlorite product after alcohol washing into the surface dish for frying and drying; the drying step is to use an oven to dry the sodium hypochlorite product after alcohol washing at a temperature of 55-70°C; the rotary evaporation is to use a rotary evaporator to rotary evaporate the sodium hypochlorite product after alcohol washing for 1-3 minutes under the conditions of pressure less than -0.09Mpa and water bath temperature of 40-90°C, preferably 58-75°C. At the same time, the reaction product liquid can be washed with a prepared alkaline salt solution between the two steps of suction filtration and alcohol washing. To further improve the shelf life of the product.

[0043] Preferably, in step S1, the molar mass ratio of sodium formate, methanol, water and sodium metabisulfite is 1: 2.5-5: 1.5-4: 0.1-0.9, preferably 1: 3-4: 2-3: 0.25-0.5.

[0044] Preferably, step S1 also includes the step of grinding the raw material or the mixed solution. Grinding can accelerate the reaction speed to a certain extent and is beneficial to the transportation of materials, but does not have a significant impact on the quality of the hydrosulfite product, and does not affect the preparation of superior products by this preparation method. Optionally, the particle size of the particles in the mixed solution prepared in step S1 is ground to 80-200 mesh. In this step, sodium formate, sodium metabisulfite, water and methanol can be selectively prepared into a mixed solution, and then ground using a grinder; it can also be selected to first mix sodium formate or sodium metabisulfite with water and / or methanol respectively and then grind, and then prepare a mixed solution. After sufficient grinding, the particle size of the particles in the mixed liquid is reduced to 80-200 mesh, which is conducive to the rapid reaction. The principle is: during the reaction, sodium formate will be completely dissolved at normal reaction temperature, but sodium metabisulfite cannot be completely dissolved; and the insurance powder usually grows on the surface of sodium metabisulfite during the reaction crystallization process. In traditional industrial production methods, sodium metabisulfite is usually not ground, resulting in large particles of sodium metabisulfite being wrapped in the generated insurance powder, resulting in insufficient raw material reaction, and reducing the actual production of insurance powder content; at the same time, the insurance powder particles grown on the uneven metabisulfite particles are also uneven, resulting in poor shape and poor particle uniformity of the insurance powder product; and the insurance powder product is unstable and easily broken to produce a large amount of fine insurance powder and dust, which will have an adverse effect on the packaging and use of the product. Therefore, in this step, by using a grinder to fully grind the raw materials or the mixed liquid, the content of sodium pyrosulfite contained in the sodium hydrosulfite powder can be reduced, so as to further prepare sodium hydrosulfite with higher content and purity; at the same time, grinding is conducive to the sodium pyrosulfite dissolving in the reaction liquid as quickly as possible, so as to increase the reaction speed.

[0045] Preferably, step S1 further comprises the step of removing dissolved oxygen from the mixed solution, and the method for removing dissolved oxygen comprises: any one or more of ultrasonic treatment, grinding treatment under nitrogen protection and grinding treatment under negative pressure protection.

[0046] The preparation method of the present application selects to use ultrasonic treatment after the mixed solution is ground. This step is not necessary for the present method. Even if this step is not used, the present embodiment can still achieve the expected technical effect; but after adding this step, the reaction effect can be further optimized. The principle is: since the generated product has extremely strong reducibility, it will decompose rapidly in the presence of water and oxygen, and the by-products produced by the decomposition will further promote the decomposition of the hydrosulfite, so the possibility of oxygen entering any industrial link should be reduced as much as possible to increase the yield; specifically, by subjecting the mixed solution to ultrasonic treatment for 1-5 minutes, the dissolved oxygen in the liquid can be reduced, the oxidative decomposition of the hydrosulfite can be reduced, and the efficiency of the reaction and the purity of the product can be improved. In industrial production, the ultrasonic treatment can also be replaced by grinding treatment under negative pressure or nitrogen protection.

[0047] Preferably, in step S2, the molar mass ratio of sodium formate to sulfur dioxide in the reaction stock solution is 1: 0.1-0.9, preferably 1: 0.4-0.65.

[0048] Preferably, in step S3, the reaction temperature in the hydrosulfur powder reactor is set to 60-85°C, preferably 78-83°C; and the pressure is 0.15-0.25Mpa.

[0049] Preferably, in step S3, since the pH value of the reaction gradually increases during the reaction, the pH value of the reaction in the sodium hypochlorite reactor is controlled to be 4.1-4.9, preferably 4.5-4.8, by slowly pressing sulfur dioxide methanol absorption liquid into the sodium hypochlorite reactor.

[0050] Preferably, in step S3, in order to control the addition rate of sulfur dioxide methanol absorption liquid as slow as possible, the addition flow rate of sulfur dioxide methanol absorption liquid should be less than 2.5% of the total volume of reaction stock solution per minute. Although the addition rate limit range of sulfur dioxide absorption liquid is clearly defined in this application, this limit range is not a key factor affecting the reaction. The main reason for setting this restriction condition for the reaction is to control the concentration of local sulfur dioxide absorption liquid and avoid the occurrence of side reactions due to the local too low pH value, thereby reducing the product content. In actual operation, if the addition method is changed, such as increasing the number of addition tubes, or reducing the opening of the addition port to allow the logistics to be added to the entire reaction system in a more dispersed manner, or increasing the rotation speed of the reaction device and optimizing the mixing method of the materials in the reactor to enhance the mixing efficiency of the device, and prevent the occurrence of local pH values ​​that are too low, the occurrence of side reactions can be effectively suppressed, and it is consistent with the purpose of this restriction condition to control the flow rate.

[0051] Preferably, step S3 further includes the step of stirring the solution in the hydrosulfur powder reactor, with a stirring speed of 40-360 rpm and a linear speed of 0.8-4 m / s.

[0052] Preferably, the sulfur dioxide content of the sulfur dioxide methanol absorption liquid is 350-500 g / L, preferably 380-430 g / L.

[0053] Preferably, in step S4, heating evaporation is performed by using a rotary evaporator, the pressure in the rotary evaporator is less than -0.09 MPa, the water bath temperature is 40-90° C., preferably 58-75° C.; and the rotary evaporation time is 1-3 min.

[0054] Compared with the prior art, the present invention has the following beneficial effects: 1. The method for preparing sodium formate provided by the present invention changes the sodium formate production method into a one-step production method for the first time. After the raw materials are added at one time, the reaction pH can be controlled by sulfur dioxide liquid in the later stage. The present invention provides a simple and easy-to-control production method, which can stably prepare high-quality sodium formate.

[0055] 2. The method for preparing the hydrosulfur powder provided by the present invention innovatively improves the traditional production process and avoids the use of ethylene oxide, which is seriously harmful to the human body and the environment and is flammable and explosive, during the reaction process.

[0056] 3. The method for preparing sodium hydrosulfite provided by the present invention greatly simplifies the operation process in industrial production, improves the safety of the production process, can be better applied to the automation system, reduces human operation errors, improves production efficiency, and has significant industrial application potential.

[0057] Based on the inventive concept of the method for preparing sodium hydrosulfite of the present application, the present application also provides the following Examples 1 to 18 and Comparative Examples 1 to 8: Example

[0058] 1.1 Weigh 175.85 g of sodium formate, and weigh methanol, water and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; ultrasonic vibration for 1 minute.

[0059] 1.2 According to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571, weigh the sulfur dioxide methanol absorption liquid and add it to the mixed liquid to prepare the reaction stock solution. During the weighing process, the sampling amount is controlled within the error range of 1%.

[0060] 1.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 273min to obtain the product liquid.

[0061] 1.4 After filtering the product liquid, it was washed with methanol and the product content was detected to be 82.1%; The product liquid after alcohol washing was fried to dryness, and the product content was detected to be 88.3%; The product liquid after alcohol washing was dried, and the product content was detected to be 87.8%; The product liquid after alcohol washing was subjected to rotary evaporation, and the product content was detected to be 92.3%; After washing with alkaline salt solution and then with alcohol, the product content was detected to be 91.4% after rotary evaporation.

[0062] Experimental results: The product content was tested after being stored for one day. The content after alcohol washing was 48.2%; the content after alcohol washing and frying was 70.1%; the content after alcohol washing and drying was 73.1%; the content after alcohol washing and rotary evaporation was 90.1%; the content after washing with alkaline salt solution and then alcohol washing and rotary evaporation was 91.0%.

[0063] Embodiment 2: The main difference between this embodiment and embodiment 1 is that the nitrogen replacement step is omitted.

[0064] 2.1 Weigh 175.85 g of sodium formate, and weigh methanol, water and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; ultrasonic vibration for 1 minute.

[0065] 2.2 According to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571, weigh the sulfur dioxide methanol absorption liquid and add it to the mixed liquid to prepare the reaction stock solution. During the weighing process, the sampling amount is controlled within the error range of 1%.

[0066] 2.3 Add the reaction stock solution into the hydrosulfur powder reactor, fill with nitrogen until the pressure is 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add the sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 275min to obtain the product liquid.

[0067] 2.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 91.5%.

[0068] Embodiment 3: The main difference between this embodiment and embodiment 1 is that only the solution obtained by mixing sodium pyrosulfite and a certain amount of methanol is ground.

[0069] 3.1 Weigh 175.85g of sodium formate, and weigh methanol, water and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. First, mix the sodium pyrosulfite with a certain amount of methanol, and then use a grinder to fully grind and break the particles in the mixed solution to 80-200 mesh; then mix with other raw materials to prepare a mixed solution, and ultrasonically vibrate for 1 minute.

[0070] 3.2 According to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571, weigh the sulfur dioxide methanol absorption liquid and add it to the mixed liquid to prepare the reaction stock solution. During the weighing process, the sampling amount is controlled within the error range of 1%.

[0071] 3.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 273min to obtain the product liquid.

[0072] 3.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 92.0%.

[0073] Embodiment 4: The main difference between this embodiment and embodiment 1 is that only the solution of sodium formate mixed with water and a certain amount of methanol is ground.

[0074] 4.1 Weigh 175.85g of sodium formate, and weigh methanol, water and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. First, mix the sodium formate with all the water and a certain amount of methanol, and then use a grinder to fully grind and break the particles in the mixed solution to 80-200 mesh; then mix with other raw materials to prepare a mixed solution, and ultrasonically vibrate for 1 minute.

[0075] 4.2 According to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571, weigh the sulfur dioxide methanol absorption liquid and add it to the mixed liquid to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0076] 4.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 284min to obtain the product liquid.

[0077] 4.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 88.2%.

[0078] Embodiment 5: The main difference between this embodiment and the embodiment 1 is that the grinding process step is omitted.

[0079] 5.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, ultrasonic vibration is applied for 1 min.

[0080] 5.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0081] 5.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 273min to obtain the product liquid.

[0082] 5.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 89.5%.

[0083] Embodiment 6: The main difference between this embodiment and embodiment 1 is that the ultrasonic treatment step is omitted.

[0084] 6.1 Weigh 175.85 g of sodium formate, and weigh methanol, water and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh.

[0085] 6.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0086] 6.3 Add the reaction stock solution to the hydrosulfur powder reactor, replace it with nitrogen three times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 270min to obtain the product liquid.

[0087] 6.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 89.8%.

[0088] Embodiment 7: The main difference between this embodiment and embodiment 1 is that the ultrasonic treatment step is prolonged.

[0089] 7.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh, and ultrasonically vibrate for 3 minutes.

[0090] 7.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0091] 7.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 270min to obtain the product liquid.

[0092] 7.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 92.1%.

[0093] Embodiment 8: The main difference between this embodiment and embodiment 1 is that the molar mass ratio of sulfur dioxide in the reaction stock solution is reduced.

[0094] 8.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; ultrasonically vibrate for 1 min.

[0095] 8.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.1 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0096] 8.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 356min to obtain the product liquid.

[0097] 8.4 After filtering the product liquid, it was washed with methanol and then subjected to rotary evaporation. The product content was detected to be 87.8%.

[0098] Embodiment 9: The main difference between this embodiment and embodiment 1 is that the molar mass ratio of sulfur dioxide in the reaction stock solution is increased.

[0099] 9.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0100] 9.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.9 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0101] 9.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 250min to obtain the product liquid.

[0102] 9.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 85.8%.

[0103] Embodiment 10: The main difference between this embodiment and embodiment 1 is that the stirring speed of the hydrosulfur powder reactor is reduced.

[0104] 10.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0105] 10.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0106] 10.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 60r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 295min to obtain the product liquid.

[0107] 10.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 89.2%.

[0108] Embodiment 11: The main difference between this embodiment and embodiment 1 is that the stirring speed of the hydrosulfur powder reactor is increased.

[0109] 11.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0110] 11.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0111] 11.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 360r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 310min to obtain the product liquid.

[0112] 11.4 After filtering the product liquid, it was washed with methanol and then subjected to rotary evaporation. The product content was detected to be 90.1%.

[0113] Embodiment 12: The main difference between this embodiment and embodiment 1 is that the reaction temperature of the hydrosulfur powder reactor is increased.

[0114] 12.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0115] 12.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0116] 12.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 85°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 260min to obtain the product liquid.

[0117] 12.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 88.5%.

[0118] Embodiment 13: The main difference between this embodiment and embodiment 1 is that the reaction temperature of the hydrosulfur powder reactor is lowered.

[0119] 13.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0120] 13.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0121] 13.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 78°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 323min to obtain the product liquid.

[0122] 13.4 After filtering the product liquid, it was washed with methanol and then subjected to rotary evaporation. The product content was detected to be 92.4%.

[0123] Embodiment 14: The main difference between this embodiment and embodiment 1 is that the reaction temperature of the hydrosulfur powder reactor is lowered.

[0124] 14.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0125] 14.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0126] 14.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 60°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 411min to obtain the product liquid.

[0127] 14.4 After filtering the product liquid, it was washed with methanol and then subjected to rotary evaporation. The product content was detected to be 91.1%.

[0128] Embodiment 15: The main difference between this embodiment and embodiment 1 is that the water content in the raw material is reduced.

[0129] 15.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite at a molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0130] 15.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0131] 15.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 311min to obtain the product liquid.

[0132] 15.4 After filtering the product liquid, it was washed with methanol and then subjected to rotary evaporation. The product content was detected to be 90.8%.

[0133] Embodiment 16: The main difference between this embodiment and embodiment 1 is that the water content in the raw material is increased.

[0134] 16.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 3: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0135] 16.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0136] 16.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 311min to obtain the product liquid.

[0137] 16.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 85.7%.

[0138] Embodiment 17: The main difference between this embodiment and embodiment 1 is that the pH control conditions are changed.

[0139] 17.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0140] 17.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0141] 17.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. Add sulfur dioxide methanol absorption liquid, and control the pH between 4.1-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 251min to obtain the product liquid.

[0142] 17.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was found to be 85.1%.

[0143] Embodiment 18: The main difference between this embodiment and embodiment 1 is that the speed of adding sulfur dioxide methanol absorption liquid is increased.

[0144] 18.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0145] 18.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0146] 18.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition effect of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 2.5% of the total volume of the reaction stock solution per minute, and the reaction time is 261min to obtain the product liquid.

[0147] 18.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 88.0%.

[0148] Comparative Example 1: The main difference between this comparative example and Example 1 is that the reaction temperature of the hydrosulfur powder reactor is increased.

[0149] D1.1 Weigh 175.85g of sodium formate, and weigh methanol, water and sodium pyrosulfite respectively according to the molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed liquid, use a grinder to fully grind and break the particles in the mixed liquid to a particle size of 80-200 mesh; ultrasonic vibration for 1 minute.

[0150] D1.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0151] D1.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 90℃. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 220min to obtain the product liquid.

[0152] D1.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 61.2%.

[0153] Comparative Example 2: The main difference between this comparative example and Example 1 is that the reaction temperature of the hydrosulfur powder reactor is lowered.

[0154] D2.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite in a molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; ultrasonically vibrate for 1 min.

[0155] D2.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0156] D2.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 55°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 447min to obtain the product liquid.

[0157] D2.4 Filter the product liquid, and perform rotary evaporation on the product liquid after alcohol washing. The product content is detected to be 80%.

[0158] Comparative Example 3: The main difference between this comparative example and Example 1 is that the water content in the raw material is reduced.

[0159] D3.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite in a molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 1: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0160] D3.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0161] D3.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 370min to obtain the product liquid.

[0162] D3.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 81.8%.

[0163] Comparative Example 4: The main difference between this comparative example and Example 1 is that the water content in the raw material is increased.

[0164] D4.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite in a molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 4.5: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0165] D4.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0166] D4.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83°C. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 1.00% of the total volume of the reaction stock solution per minute, and the reaction time is 248min to obtain the product liquid.

[0167] D4.4 After filtering the product liquid, it was washed with methanol and subjected to rotary evaporation. The product content was detected to be 61.8%.

[0168] Comparative Example 5: The main difference between this comparative example and Example 1 is that the addition rate of the sulfur dioxide methanol absorption liquid is increased.

[0169] D5.1 Weigh 175.85 g of sodium formate, and weigh methanol, water, and sodium pyrosulfite in a molar mass ratio of n(sodium formate): n(methanol): n(water): n(sodium pyrosulfite) = 1: 3.67: 2.46: 0.3. After the above raw materials are fully mixed to prepare a mixed solution, use a grinder to fully grind and break the particles in the mixed solution to a particle size of 80-200 mesh; and ultrasonically vibrate for 1 min.

[0170] D5.2 Weigh sulfur dioxide methanol absorption liquid according to the molar mass ratio of n(sodium formate) : n(sulfur dioxide) = 1 : 0.571 and add it to the mixed solution to prepare the reaction stock solution. During the weighing process, control the sampling amount within the error range of 1%.

[0171] D5.3 Add the reaction stock solution to the hydrosulfur powder reactor, use nitrogen to replace it 3 times, fully replace the oxygen in the reaction system, reduce the oxidative decomposition of oxygen on the product, fill with nitrogen to a pressure of 0.2-0.22Mpa, set the stirring speed to 180r / min, and set the reaction temperature to 83℃. When the pH is 4.9, add sulfur dioxide methanol absorption liquid, and stop adding after the pH is controlled between 4.5-4.8. The sulfur dioxide methanol absorption liquid is added to the reaction stock solution at a flow rate of 4.00% of the total volume of the reaction stock solution per minute, and the reaction time is 265min to obtain the product liquid.

[0172] D5.4 After filtering the product liquid, it was washed with methanol and then subjected to rotary evaporation. The product content was detected to be 85.9%.

[0173] Comparative Example 6: This comparative example adopts a preparation method with patent application number CN201611155475.3 and patent name “Continuous production method for synthesis of hydrosulfur powder”.

[0174] Preparation: Prepare 98% HCOONa by mass, 62% sodium metabisulfite by mass, SO2-CH3OH, SO2 concentration ≥ 370g / L, and 78% by mass of carrier methanol; Feed the base material: pressurize the storage tank with inert gas, open the flow meter to feed about 1.8m3 of AE into the synthesis large dropping pot, and start heating; Adjustment: Turn on the steam and when the temperature rises to 76℃ and the pressure is 0.1MPa, open the flow meter valve at the same time and add 25L of SO2-CH3OH solution and a certain amount of ethylene oxide to the large dropping pot, and adjust the pH to 4.3; Large dropping: After adjusting for 10min~20min, when the temperature rises to 81℃~83℃, start adding AE and ME to stabilize the PH at 4.4~4.5 and the pressure at 0.2MPa~0.25MPa. When the synthesis large dropping pot reaches 80% (a batch of materials) visually, the bottom tube in the pot is automatically opened to continuously transfer materials to the four small dropping pots A#~D#. During the material transfer process, raw materials AE and ME continue to be added to the synthesis large pot. When the synthesis small dropping pot receives a batch of materials, the second small dropping pot starts to receive materials from the synthesis large dropping pot, and so on; always maintain the time required for the reaction of the four small dropping pots to reach the end point.

[0175] Small drop addition: Control the temperature at 83℃~83℃, the pressure at 0.2MPa~0.25MPa, and continuously add 100L of SO2-CH3OH solution at a fast and then slow rhythm, and control the pH at 4.5~4.6 to continuously generate the hydrosulfite to increase the content of the hydrosulfite. Visually observe that the synthetic liquid is clear or analyze the content of sodium bisulfite in the clear liquid. When NaHSO3≤10g / L, the small drop addition is completed and the heat preservation operation is started; Insulation: After 10 minutes of insulation, take samples for analysis. When the pH value is ≥4.9 and the sanitary powder in the sample is ≥85%, the insulation ends. Cooling and discharging: Discharge when the temperature is 68℃~75℃, PH value ≥4.9, and Na2S203 ≤10g / L.

[0176] Comparative Example 7: This comparative example adopts a preparation method with patent application number CN201110382305.X and patent name “A method for synthesizing hydrosulfur powder”.

[0177] A method for synthesizing sodium hydrosulfite. The method for synthesizing sodium hydrosulfite by adding AE liquid and AME liquid materials into a synthesis reactor using an automatic control system is implemented in the following steps: Preparation of synthetic base material: At normal temperature and pressure, set the flow rate of AE liquid material to 60L / s, add 1200L of AE liquid material to the synthesis reactor through the AE liquid automatic regulating valve, start the synthesis reactor stirring, and then introduce steam into the jacket of the synthesis reactor for automatic slow heating; wherein the AE liquid material is a dispersed material prepared in advance in the AE batching pot with qualified washing methanol or refined methanol, sodium formate and water. The preparation process is: add 7000L of qualified washing methanol or refined methanol to the AE batching pot, start stirring, then open the AE batching pot quick opening hand hole, put in 2500Kg of solid sodium formate, close the quick opening hand hole, and then add 500L of water, and then use the steam in the synthesis reactor jacket to slowly heat up to 60℃ 70℃ in the synthesis reactor, so that the solid sodium formate is dissolved and dispersed evenly, and set aside.

[0178] Neutralization and adjustment: When the temperature in the synthesis reactor automatically rises to 75℃~80℃, control the pressure in the synthesis reactor to 0.10Mpa, set the flow rate of AME liquid material to 30L / s, add AME liquid material to the synthesis pot through the AME liquid automatic regulating valve, and adjust the pH value of the material in the synthesis pot to 4.4; the AME liquid material is the acidified material prepared in advance in the AME batching pot with refined methanol or qualified washing methanol, sodium pyrosulfite, and liquid sulfur dioxide. The preparation process is: open the tail gas vacuum valve of the AME batching pot, vacuum for several minutes, add qualified washing methanol or refined methanol 3500L to the AE batching pot, start stirring, open the quick-opening hand hole on the AE batching pot under the slight negative pressure in the AME batching pot, add 2500Kg of sodium pyrosulfite and immediately close the quick-opening hand hole, close the tail gas vacuum valve, and then add 2500L of liquid sulfur dioxide, beat and acidify evenly, and set aside.

[0179] Large dropwise addition: After neutralization and adjustment, when the temperature in the synthesis reactor automatically rises to 80°C~85°C, large dropwise addition is started, and the AE liquid material flow rate is set to 80L / s, and the AME liquid material flow rate is set to 60L / s. Within 70 minutes, the remaining materials of AE liquid and AME liquid are added evenly at the same time through the AE liquid automatic regulating valve and the AME liquid automatic regulating valve; After the large drop addition, the material in the synthesis reactor is kept warm for 10 minutes, and then the small drop addition is started, that is, liquid sulfur dioxide is added evenly in a thin stream within 160 minutes until the content of sodium hypochlorite in the synthetic material is ≥88.5%, and the synthesis small drop addition is completed. Keep warm, cool and discharge the material, and put the synthesized sodium hypochlorite material in the synthesis reactor into a four-in-one dryer for filter pressing, washing, drying, cooling, blending, discharging and packaging to obtain a qualified sodium hypochlorite product.

[0180] Comparative Example 8: This comparative example adopts a preparation method with patent application number CN201110418469.3 and patent name “A method for synthesizing hydrosulfur powder”.

[0181] At normal temperature and pressure, add 1000L of AE liquid into the synthesis reactor, stir evenly, and then introduce steam into the jacket of the synthesis reactor to increase the temperature: When the temperature in the synthesis reactor rises to 75°C, control the pressure in the synthesis reactor to 0.05MP, and add AME liquid into the synthesis reactor to adjust the pH value of the material in the synthesis reactor to 4.2; After the pH is adjusted and the temperature in the synthesis reactor automatically rises to 80°C, start adding dropwise, that is, add the remaining materials of AE liquid and AME liquid evenly within 50 minutes; After the large drop addition is completed, the material in the synthesis reactor is kept warm for 5 minutes, and small drop addition is started, that is: the liquid sulfur dioxide flow rate is set at 2L / s, and liquid sulfur dioxide is added evenly within 100 minutes through the liquid sulfur dioxide automatic control drop addition system until the mass fraction of Na2S2O3 in the synthesis reactor is ≥88.5%; After the small drop addition is completed, the temperature is kept warm for 30 minutes. During the insulation process, the pressure in the synthesis reactor is controlled to be 0.10 MPa and the temperature is 80°C. The pH at the end of the insulation is ≥4.9, and then the material is cooled and discharged.

[0182] The AE liquid is prepared in advance by the following method: add 5000L of refined methanol to the AE batching pot, then add 2000kg of solid sodium formate, stir evenly, then add 300L of water, and then slowly heat to 60°C to dissolve and disperse the solid sodium formate evenly for use.

[0183] The AME solution is prepared in advance by the following method: under vacuum conditions, add 2500L of qualified washing methanol, 2000kg of sodium pyrosulfite, and 1500L of sulfur dioxide to the AE batching pot, and beat and acidify evenly for use. The qualified washing methanol used is the recovered methanol obtained by filter pressing of the previous batch of reaction liquid, and the Na2S2O3 concentration in the qualified washing methanol is less than 5g / L; the main components of the recovered methanol are: 90% methanol, 8% water, and the rest are inorganic salts containing sodium atoms.

[0184] Experimental results: 1. Comparative analysis of experimental results: 1. Through comparative analysis of the experimental results of the embodiments and the comparative examples, it can be seen that the method for preparing the insurance powder of the present application has a simpler operating process and is highly feasible in industrial automation applications; at the same time, the preparation method significantly reduces the need for manual judgment; and without adding ethylene oxide during the production process, it can still efficiently generate high-content insurance powder, ensure the content of synthetic insurance powder, and improve the problems of poor safety and environmental pollution of traditional production processes.

[0185] 2. By comparing the results of Comparative Example 2 with those of other embodiments, it can be seen that although low temperature can increase the content of the product to a certain extent, it will also lead to a longer reaction time of the experiment, and side reactions are more likely to occur under long-term reactions. Appropriate temperature can obtain a high content of sodium hydrosulfite product within a faster reaction time. However, too high a temperature will directly cause the entire reaction system to be destroyed and the content to drop sharply, so the reaction temperature must be controlled as stably as possible to be stable in a suitable range during the experiment.

[0186] 3. By comparing the results of Comparative Example 5 with those of other embodiments, it can be seen that the addition speed of the sulfur dioxide absorption liquid is too fast, which will cause the pH of the part where the solution is added to decrease rapidly, resulting in the occurrence of side reactions. Finally, the side reactions in the entire reaction system continue to occur, and the content of the obtained product is significantly reduced.

[0187] (II) Further comparative analysis between the embodiments: 1. By comparing Example 1 with Examples 12 to 14, the effect of reaction temperature on product quality was analyzed: In Example 1, the reaction temperature is 83°C, and the product is washed with alcohol and then subjected to rotary evaporation, and the product content is 92.3%.

[0188] In Example 12, the reaction temperature was increased to 85°C, the reaction time was 260 min, and the product content was 88.5%.

[0189] In Example 13, the reaction temperature was lowered to 78°C, the reaction time was 323 min, and the product content was 92.4%.

[0190] In Example 14, the reaction temperature was lowered to 60°C, the reaction time was 411 min, and the product content was 91.1%.

[0191] Conclusion: Within a certain range, lowering the reaction temperature may help to increase the product content, but too low a reaction temperature will prolong the reaction time.

[0192] 2. By comparing Example 1 with Example 8 and Example 9, the effect of the sulfur dioxide methanol absorption liquid content on the reaction was analyzed: In Example 1, the molar ratio of sulfur dioxide to methanol absorption liquid is 0.571, and the product content is 92.3%.

[0193] In Example 8, the molar ratio of sulfur dioxide to methanol absorption liquid was reduced to 0.1, and the product content was 87.8%.

[0194] In Example 9, the molar ratio of sulfur dioxide to methanol absorption liquid was increased to 0.9, and the product content was 85.8%.

[0195] Conclusion: The molar ratio of sulfur dioxide to methanol absorption liquid has a significant effect on the product content. A too high molar ratio will cause the overall solution to be acidic, which is not conducive to the synthesis of insurance powder. A too low molar ratio will lead to a slow reaction rate in the early stage, which is not conducive to increasing the product content. Too long a reaction time will make side reactions more likely to occur, which will ultimately affect the product content.

[0196] 3. By comparing Example 1 with Example 17, the effect of pH control on product quality was analyzed: In Example 1, standard pH control was performed and the product content was 92.3%.

[0197] In Example 17, the pH control conditions were changed and the product content was 85.1%.

[0198] Conclusion: Accurate pH control is critical to product quality, and inappropriate pH control may reduce product content.

[0199] 4. By comparing Example 1 with Example 15 and Comparative Example 3, the influence of raw material ratio on product quality is analyzed: In Example 1, the molar ratio of water in the raw material is 2.46, and the content of the product is 92.3%.

[0200] In Example 15, the molar ratio of water in the raw material was reduced to 2, and the product content was 90.8%.

[0201] In Comparative Example 3, the molar ratio of water in the raw material was further reduced to 1, and the product content was 81.8%.

[0202] Conclusion: Reducing the amount of water will increase the reaction time, thereby increasing the existence time of side reactions and affecting the progress of the reaction and the purity of the product.

[0203] Regarding the embodiments of the present invention, it should also be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0204] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. The protection scope of the present invention shall be subject to the protection scope of the claims. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing hydrosulfur powder, characterized in that: The following steps are involved: S1. The raw materials sodium formate, sodium metabisulfite, water and methanol are prepared into a mixed solution in a certain proportion; S2. adding sulfur dioxide methanol absorption liquid to the mixed solution to prepare a reaction stock solution; S3. The reaction solution is added to the insurance powder reactor for reaction, and during the reaction, sulfur dioxide methanol absorption liquid is slowly added to the insurance powder reactor to control the reaction pH value to obtain a product liquid; S4. The product liquid is filtered, washed with methanol, and dried to obtain a dry product of the hydrosulfite.

2. The method for preparing hydrosulfur powder according to claim 1, characterized in that: In step S1, the molar mass ratio of sodium formate, methanol, water and sodium metabisulfite is 1: 2.5-5: 1.5-4: 0.1-0.9, preferably 1: 3-4: 2-3: 0.25-0.

5.

3. The method for preparing hydrosulfur powder according to claim 1, characterized in that: The step S1 further includes grinding the raw material or the mixed solution to reduce the particle size of particles in the mixed solution to 80-200 meshes.

4. The method for preparing hydrosulfur powder according to claim 1, characterized in that: The step S1 further includes a step of removing dissolved oxygen from the mixed solution, wherein the method for removing dissolved oxygen includes any one or more of ultrasonic treatment, grinding treatment under nitrogen protection, and grinding treatment under negative pressure protection.

5. The method for preparing hydrosulfur powder according to claim 1, characterized in that: In step S2, the molar mass ratio of sodium formate to sulfur dioxide in the reaction stock solution is 1: 0.1-0.9, preferably 1: 0.4-0.

65.

6. The method for preparing hydrosulfur powder according to claim 1, characterized in that: In step S3, the reaction temperature in the hydrosulfur powder reactor is set to 60-85°C, preferably 78-83°C; and the pressure is 0.15-0.25Mpa.

7. The method for preparing hydrosulfur powder according to claim 1, characterized in that: In the step S3, the pH value of the reaction in the hydrosulfur powder reactor is controlled to be 4.1-4.9, preferably 4.5-4.

8.

8. The method for preparing hydrosulfur powder according to claim 1, characterized in that: In step S3, the addition flow rate of the sulfur dioxide methanol absorption liquid is less than 2.5% of the total volume of the reaction stock solution per minute.

9. The method for preparing hydrosulfur powder according to claim 1, characterized in that: The sulfur dioxide content of the sulfur dioxide methanol absorption liquid is 350-500 g / L, preferably 380-430 g / L.

10. The method for preparing hydrosulfur powder according to claim 1, characterized in that: In the step S4, heating evaporation is performed by using a rotary evaporator, the pressure in the rotary evaporator is less than -0.09 MPa, the water bath temperature is 40-90° C., preferably 58-75° C., and the rotary evaporation time is 1-3 min.

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