Method for improving sulfonation reaction efficiency and production method of dispersing agent MF
Through emulsification and dispersion method and chemical modification technology, combined with composite sulfonating agent and ultrasonic equipment, the acid concentration and heat are dynamically monitored, which solves the problems of low reaction rate and unstable product quality in the traditional sulfonating reaction process, and achieves efficient and stable sulfonating reaction and the production of high-quality dispersant MF.
Patent Information
- Application Number
- CN202411920423.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-03-18
AI Technical Summary
The traditional sulfonation reaction process has problems such as low reaction rate, uneven heat distribution, frequent side reactions, unstable product quality and high sodium sulfate content, which affects production efficiency and product consistency.
The emulsification dispersion method is used to mix methyl naphthalene and sodium dodecylbenzene sulfonate to form a stable emulsion system; succinic anhydride and dimethyl sulfoxide are added during the reaction process for chemical modification, and a composite sulfonating agent is used to cooperate with ultrasonic equipment to dynamically monitor and regulate the acid concentration, and heat is managed through a multi-layer stirring reactor and an internally cooled reactor.
The efficiency and product quality of the sulfonation reaction are significantly improved, the reaction time is shortened, and the generation of side reactions is reduced. The sodium sulfate content in the product is significantly reduced, and the heat resistance and dispersion are also improved.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical production, and in particular to a method for improving sulfonation reaction efficiency and a method for producing a dispersant MF. Background Art
[0002] Sulfonation reaction plays an important role in the field of fine chemicals and is a key step in the synthesis of many products such as dispersant MF. The traditional sulfonation process has many disadvantages. The mixing effect of raw materials and sulfonating agents is poor, and the reactive sites cannot fully play their role, resulting in low reaction rate; the heat distribution during the reaction is uneven, and local overheating or overcooling is frequent, which triggers a large number of side reactions and seriously affects product quality; the reaction system has poor stability and it is difficult to maintain ideal reaction conditions for a long time, making it difficult to ensure production efficiency and product consistency.
[0003] In addition, the traditional process has insufficient control over some key factors during the reaction. For example, it fails to effectively solve the problem of dilution of sulfuric acid concentration by reaction-generated water, resulting in the need to use excessive sulfuric acid to promote the reaction. This not only increases production costs, but also brings serious environmental pressure. In addition, the sodium sulfate content in the product is relatively high, and the product quality and production efficiency need to be improved. Summary of the invention
[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for improving the efficiency of sulfonation reaction and a method for producing dispersant MF.
[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for improving sulfonation reaction efficiency comprises the following steps: S1, emulsification dispersion, sodium dodecylbenzene sulfonate is selected as the emulsifier, and the amount of the emulsifier is 1%-3% of the mass of methylnaphthalene. The methylnaphthalene raw material and the emulsifier are emulsified and dispersed under the action of a high-speed stirrer to form a stable emulsion system, so that the methylnaphthalene exists in the form of tiny droplets. Compared with the unemulsified liquid state, this tiny droplet state greatly increases the contact area between the methylnaphthalene and the sulfonating agent; S2, chemical modification, transferring the raw materials after emulsification and dispersion in step S1 to a reactor, adding succinic anhydride at a mass ratio of 0.2%-0.4% of the mass of methylnaphthalene and dimethyl sulfoxide at a mass ratio of 4%-6% of the mass of methylnaphthalene, stirring and reacting at 40-50° C. for 1-2 hours, acylation reaction of succinic anhydride and methylnaphthalene molecules, introducing active functional groups and increasing their reactivity, and dimethyl sulfoxide helps the reaction to proceed uniformly and improve the reactivity of the raw materials; S3, deploying sulfonating agent, using concentrated sulfuric acid, oleum and potassium pyrosulfate in a mass ratio of 3.5:2.5:1 to form a composite sulfonating agent; S4, sulfonation reaction, the raw materials and the composite sulfonating agent are put into a multi-layer stirred reactor for mixing to produce a sulfonation reaction to generate the product sulfonated methylnaphthalene, and the ultrasonic device is turned on during the reaction, the acid concentration is regulated by the online acidity monitor, the internal cooling reactor and the heat exchange system manage the heat, and the tail gas is processed through a spray tower and a condenser to recover the organic matter.
[0006] The present invention also proposes a method for producing a dispersant MF based on the above-mentioned method for improving the efficiency of the sulfonation reaction, comprising the following steps: Step 1, neutralizing the sulfonated methylnaphthalene reaction solution obtained in step S4 with 20%-25% sodium hydroxide solution in a neutralization kettle; Step 2: Filter the neutralized solution obtained in step 1 through a fine filter membrane to remove possible impurity particles therein, put the filtered solution into a condensation reactor, add formaldehyde, and stir and condense at 100-150° C., 50-200 mmHg, and 300-400 rpm for 2-5 hours; Step 3: After the condensation reaction is completed, the condensation product is neutralized with 20-50% liquid alkali, the pH is adjusted to 7-9, and MF solution is obtained. A macroporous resin or other adsorbent is used to adsorb possible trace impurities or unreacted substances, and finally a spray dryer is used to dry the solution to obtain a dispersant MF product.
[0007] Preferably, in step S4, the multi-layer stirred reactor is specifically a reactor with an upper frame type, a middle turbine type, and a lower anchor type composite structure, wherein the stirring speed of the upper frame type is 200-300 rpm, the stirring speed of the middle turbine type is 300-400 rpm, and the stirring speed of the lower anchor type is 400-500 rpm.
[0008] Preferably, in the step 1, the stirring speed of the neutralization kettle is 200-300 rpm, the temperature in the kettle is controlled at 40-50° C., and the pH is controlled at 7-8.
[0009] Preferably, in step 2, the molar ratio of added formaldehyde to sodium methylnaphthalene sulfonate is 0.7:1.
[0010] Preferably, the concentrated sulfuric acid concentration in the composite sulfonating agent is 98%, and the oleum is oleum with 20%-25% free SO3. When the composite sulfonating agent is added to the multi-layer stirred reactor, the concentrated sulfuric acid is added first, and then the oleum is added dropwise at a rate of 0.5-1 ml / sec and potassium pyrosulfate is added dropwise at a rate of 0.2-0.5 g / sec, respectively, and the mixture is stirred for 20-30 minutes after the addition.
[0011] Preferably, in step S2, the methylnaphthalene raw material and the emulsifier are stirred in a high-speed stirrer at a speed of 1000-1500 rpm.
[0012] The present invention has the following beneficial effects: 1. Methylnaphthalene forms tiny droplets after emulsification and dispersion. Compared with the unemulsified liquid state, this tiny droplet state greatly increases the contact area between methylnaphthalene and the sulfonating agent. At the same time, the stable emulsion system formed by emulsification and dispersion can ensure that methylnaphthalene is evenly distributed in the entire reaction system; 2. The activity of methylnaphthalene can be improved by adding succinic anhydride and dimethyl sulfoxide, and the reaction rate is greatly improved by fully contacting the optimized composite sulfonating agent under multi-layer stirring and ultrasound assistance; 2. Dynamic monitoring and control of acid concentration during the reaction ensures that the reaction is always carried out under the optimal acidity conditions, avoiding the decrease in reaction rate due to acid concentration fluctuations, allowing the sulfonation reaction to proceed efficiently, shortening the reaction time and improving production efficiency; 3. Fine raw material pretreatment and precise reaction condition control, including temperature, acidity, and other optimizations, reduce the occurrence of side reactions, thereby reducing the content of impurities in the product. The sodium sulfate content in the product is significantly reduced (<3%), the heat resistance is improved (heat resistance 150°C stable), the dispersibility is more excellent, and the quality of dispersant MF is improved. DETAILED DESCRIPTION
[0013] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.
[0014] A method for improving sulfonation reaction efficiency comprises the following steps: S1, emulsification dispersion, sodium dodecylbenzene sulfonate is selected as the emulsifier, and the amount of the emulsifier is 1%-3% of the mass of methylnaphthalene. The methylnaphthalene raw material and the emulsifier are emulsified and dispersed under the action of a high-speed stirrer to form a stable emulsion system, so that the methylnaphthalene exists in the form of tiny droplets. Compared with the unemulsified liquid state, this tiny droplet state greatly increases the contact area between the methylnaphthalene and the sulfonating agent; S2, chemical modification, the raw material after emulsification and dispersion in step S1 is transferred to a reactor, succinic anhydride with a mass ratio of 0.2%-0.4% of methylnaphthalene and dimethyl sulfoxide with a mass ratio of 4%-6% of methylnaphthalene are added, and the mixture is stirred and reacted at 40-50° C. for 1-2 hours, succinic anhydride and methylnaphthalene molecules undergo acylation reaction, active functional groups are introduced, and their reactivity is increased, and dimethyl sulfoxide helps the reaction to proceed uniformly and improves the reactivity of the raw material, and the methylnaphthalene raw material and the emulsifier are stirred in a high-speed stirrer at a speed of 1000-1500 rpm.
[0015] S3. Prepare a sulfonating agent, using concentrated sulfuric acid, oleum and potassium pyrosulfate in a mass ratio of 3.5:2.5:1 to form a composite sulfonating agent; it should be noted that the addition of potassium pyrosulfate can adjust the acidity and activity of the sulfonating agent, synergize with concentrated sulfuric acid and oleum, broaden the activity window of the sulfonation reaction, improve the selectivity and efficiency of the sulfonation reaction, and change the performance limitations of traditional single sulfonating agents or simple composite sulfonating agents.
[0016] S4, sulfonation reaction, the raw materials and the composite sulfonating agent are put into a multi-layer stirred reactor for mixing and sulfonation reaction to generate the product sulfonated methylnaphthalene, and the ultrasonic device is turned on during the reaction, the acid concentration is regulated by the online acidity monitor, the internal cooling reactor and the heat exchange system manage the heat, and the tail gas is processed by the spray tower and condenser to recover the organic matter. Among them, the multi-layer stirred reactor is specifically a reactor with an upper frame type, a middle turbine type, and a lower anchor type composite structure, wherein the stirring speed of the upper frame type is 200-300 rpm, the stirring speed of the middle turbine type is 300-400 rpm, and the stirring speed of the lower anchor type is 400-500 rpm.
[0017] In addition, when the composite sulfonating agent is put into the multi-layer stirred reactor, the concentrated sulfuric acid is added first, and then the fuming sulfuric acid is added dropwise at a rate of 0.5-1 ml / sec and potassium pyrosulfate is added dropwise at a rate of 0.2-0.5 g / sec, and the mixture is stirred for 20-30 minutes after the addition.
[0018] The present invention also proposes a method for producing a dispersant MF based on the above-mentioned method for improving the efficiency of the sulfonation reaction, comprising the following steps: Step 1: neutralize the sulfonated methylnaphthalene reaction solution obtained in step S4 with 20%-25% sodium hydroxide solution in a neutralization kettle; the stirring speed of the neutralization kettle is 200-300 rpm, the temperature in the kettle is controlled at 40-50° C., and the pH is controlled at 7-8.
[0019] Step 2: Filter the neutralized solution obtained in step 1 through a fine filter membrane to remove possible impurity particles therein, add formaldehyde to a condensation reactor, and add formaldehyde in a molar ratio of 0.7:1 to sodium methylnaphthalene sulfonate. Stir and condense at 300-400 rpm for 2-5 hours at 100-150° C. and 50-200 mmHg.
[0020] Step 3: After the condensation reaction is completed, the condensation product is neutralized with 20-50% liquid alkali, the pH is adjusted to 7-9, and MF solution is obtained. A macroporous resin or other adsorbent is used to adsorb possible trace impurities or unreacted substances, and finally a spray dryer is used to dry the solution to obtain a dispersant MF product.
[0021] Embodiment 1: Take 100 kg of methylnaphthalene and 2 kg of sodium dodecylbenzene sulfonate and emulsify and disperse them in a high-speed stirrer (1200 rpm) to form an emulsion. The particle size of the methylnaphthalene droplets in the emulsion is about 8 microns. Transfer the emulsion to a reactor, add 0.3 kg of succinic anhydride and 5 kg of dimethyl sulfoxide, and stir the reaction at 45°C for 1.5 hours.
[0022] Preparation and activation of sulfonating agent: In a cooling jacketed container, first add 45 kg of concentrated sulfuric acid (stirring at 120 rpm, 12°C), then drop 30 kg of fuming sulfuric acid and 10 kg of potassium pyrosulfate at a rate of 0.8 ml / s and 0.3 g / s respectively, and stir for 25 minutes after dropping.
[0023] Reaction process: raw materials and sulfonating agent are put into a multi-layer stirred reactor, ultrasound (28kHz, 650W) is turned on, acid concentration is regulated by acidity monitoring, internal cooling reactor and heat exchange system manage heat, and tail gas is processed through a spray tower and condenser to recycle resources.
[0024] Post-treatment of dispersant MF: neutralization, filtration, condensation and spray drying of the sulfonated liquid to obtain the product.
[0025] Example 2: 80 kg of methylnaphthalene and 1.5 kg of sodium dodecylbenzene sulfonate were emulsified and dispersed (stirred at 1000 rpm), transferred to a reaction kettle, 0.25 kg of succinic anhydride and 4 kg of dimethyl sulfoxide were added, and stirred at 42°C for 1.2 hours.
[0026] Preparation and activation of sulfonating agent: In a cooling jacketed container, first add 50 kg of concentrated sulfuric acid (stirring at 130 rpm, 13°C), then drop 35 kg of fuming sulfuric acid and 12 kg of potassium pyrosulfate at a rate of 0.9 ml / s and 0.4 g / s respectively, and stir for 30 minutes after the dropwise addition.
[0027] Reaction process: raw materials and sulfonating agent are put into a multi-layer stirred reactor, ultrasound (29kHz, 700W) is turned on, acid concentration is regulated by acidity monitoring, heat is managed by the internal cooling reactor and heat exchange system, tail gas is processed by the spray tower and condenser to recycle resources, the reaction is efficient and stable, and the product quality is excellent. After the reaction is completed, the conversion rate of the sulfonation reaction is measured to be 96% (the analysis method is the same as in Example 1).
[0028] Post-treatment of dispersant MF: neutralization, filtration, condensation and spray drying of the sulfonated liquid to obtain the product.
[0029] Embodiment three: Raw material pretreatment: 150 kg of methylnaphthalene and 3 kg of sodium dodecylbenzene sulfonate were emulsified and dispersed (stirred at 1500 rpm), transferred to the reactor, 0.4 kg of succinic anhydride and 7 kg of dimethyl sulfoxide were added, and the mixture was stirred at 48°C for 1.8 hours.
[0030] Preparation and activation of sulfonating agent: In a cooling jacketed container, first add 55 kg of concentrated sulfuric acid (stirring at 140 rpm, 14°C), then drop 35 kg of fuming sulfuric acid and 12 kg of potassium pyrosulfate at a rate of 0.9 ml / s and 0.35 g / s respectively, and stir for 28 minutes after the dropwise addition.
[0031] Reaction process: raw materials and sulfonating agent are put into a multi-layer stirred reactor, ultrasound (29kHz, 700W) is turned on, acid concentration is regulated by acidity monitoring, heat is managed by the internal cooling reactor and the heat exchange system, and tail gas is processed by the spray tower and condenser to recycle resources. The reaction is efficient and stable, and the product quality is excellent. After the reaction is completed, the conversion rate of the sulfonation reaction is measured to be 96.5% (the analysis method is the same as in Example 1).
[0032] Post-treatment of dispersant MF: neutralization, filtration, condensation and spray drying of the sulfonated liquid to obtain the product.
[0033] Embodiment 4: Raw material pretreatment: 120 kg of methylnaphthalene and 2.5 kg of sodium dodecylbenzene sulfonate were emulsified and dispersed (stirred at 1300 rpm), transferred to the reactor, 0.35 kg of succinic anhydride and 6 kg of dimethyl sulfoxide were added, and the mixture was stirred at 46°C for 1.6 hours.
[0034] Preparation and activation of sulfonating agent: In a cooling jacketed container, first add 48 kg of concentrated sulfuric acid (stirring at 130 rpm, 13°C), then drop 32 kg of fuming sulfuric acid and 10 kg of potassium pyrosulfate at a rate of 0.7 ml / s and 0.3 g / s respectively, and stir for 26 minutes after the dropwise addition.
[0035] Reaction process: raw materials and sulfonating agent are put into a multi-layer stirred reactor, ultrasound (27kHz, 680W) is turned on, acid concentration is regulated by acidity monitoring, heat is managed by the internal cooling reactor and heat exchange system, tail gas is processed by the spray tower and condenser to recycle resources, the reaction is efficient and stable, and the product quality is excellent. After the reaction is completed, the conversion rate of the sulfonation reaction is measured to be 95.5% (the analysis method is the same as in Example 1).
[0036] Post-treatment of dispersant MF: neutralization, filtration, condensation and spray drying of the sulfonated liquid to obtain the product.
[0037] And add a set of comparison ratios: The traditional process uses methylnaphthalene and concentrated sulfuric acid (98%) to react, without raw material pretreatment, composite sulfonating agent preactivation, multi-layer stirring ultrasonic mixing and dynamic acid concentration control, etc. The product is obtained by neutralization, condensation and drying.
[0038] The concentrations of raw materials and products were analyzed by high performance liquid chromatography, and the conversion rates of the sulfonation reactions of the various examples and comparative examples were calculated; The solid content of the dispersant MF of each group of examples and comparative examples was determined by a heating drying method; The calcium soap dispersion method was used to test the V value (the critical amount of the dispersant solution at which the dispersant can prevent sodium oleate (or solid transparent soap solution) from reacting with the calcium chloride solution to produce precipitation) of the dispersant MF of each group of embodiments and comparative examples; The viscosity of the dispersant MF of each group of embodiments and comparative examples was measured by a rotational viscometer at a specific shear rate; The sodium sulfate content in the dispersant MF of each group of examples and comparative examples was determined by ion chromatography. The above measured values are statistically shown in the following table: Table 1: Sulfonation reaction rate and performance parameters of dispersant MF of Examples 1 to 4 and Comparative Examples Project Name Conversion rate of sulfonation reaction (%) Solid content (%) V value (ml) Viscosity (mPa・s) Sodium sulfate content (%) Embodiment 1 95 95 1.5 50 2.8 Embodiment 2 94 94 1.8 58 3.2 Embodiment 3 96.5 96 1.3 45 2.5 Embodiment 4 95.5 95.5 1.4 48 2.7 Comparative Example 75 90 3 80 8 In summary, the method for improving the efficiency of sulfonation reaction and the method for producing dispersant MF proposed in the present invention have the following advantages: 1. The efficiency of sulfonation reaction is significantly improved In Examples 1 to 4, the conversion rates of the sulfonation reaction all reached a relatively high level, which were 95%, 94%, 96.5% and 95.5%, respectively, which were significantly higher than the traditional process in the comparative example. This shows that the method of the present invention effectively improves the reactivity between methylnaphthalene and the sulfonating agent through a series of measures such as raw material pretreatment, the deployment and activation of the composite sulfonating agent, the construction and strengthening of the reaction system, and the dynamic monitoring and regulation of the acid concentration during the reaction, so that more methylnaphthalene molecules can participate in the sulfonation reaction, thereby significantly improving the efficiency of the sulfonation reaction.
[0039] Compared with the traditional process, the process of the present invention can better control the reaction conditions, such as temperature, acidity, etc., during the reaction process, provide a more favorable environment for the sulfonation reaction, reduce the incomplete reaction caused by poor reaction conditions, and enable the sulfonation reaction to proceed more fully, thereby improving the conversion rate.
[0040] 2. The quality of dispersant MF products has been greatly improved Dispersibility: From the V value of the calcium soap dispersion method test, the V values of the products of Examples 1 to 4 are 1.5 ml, 1.8 ml, 1.3 ml and 1.4 ml, respectively, which are much smaller than 3.0 ml in the comparative example. This means that the dispersant MF produced by the present invention has a better dispersibility and can better disperse particles such as pigments in the medium to prevent particle agglomeration, thereby improving the stability and use effect of the product.
[0041] Solid content and chemical composition: The solid content of the products in the examples is above 94%, and the chemical composition is consistent with the expected structure after infrared spectrum analysis, indicating that the products have a high content of active ingredients and a stable chemical structure, ensuring the consistency of product quality and performance. The solid content of the comparative example is only 90%, which is significantly lower than the product of the present invention in quality.
[0042] Rheological properties: At a specific shear rate, the viscosity of the example product is moderate and stable, such as the viscosity of Example 1 is 50mPa・s, which helps to maintain good fluidity and processing performance in practical applications, ensuring that the dispersant can be evenly dispersed in the system and exert its dispersing effect. The higher viscosity (80mPa・s) in the comparative example may cause problems such as poor fluidity and difficulty in dispersion during use.
[0043] 3. Sodium sulfate content is significantly reduced The sodium sulfate content of the products in Examples 1 to 4 is 2.8%, 3.2%, 2.5% and 2.7%, respectively, which are all much lower than 8% in the comparative example. The lower sodium sulfate content helps to improve the purity of the dispersant MF and reduce the impact of impurities on product performance. It also meets environmental protection requirements and reduces the cost and environmental pressure of subsequent treatment of sodium sulfate impurities.
[0044] 4. High process stability and reliability Through the verification of multiple examples, under different raw material dosages and reaction condition parameter settings, the process of the present invention can stably produce high-quality dispersant MF products, and the fluctuation of various performance indicators is small, indicating that the process has good repeatability and reliability. This provides a strong guarantee for industrial large-scale production, and enterprises can flexibly adjust process parameters within a certain range according to actual production needs without worrying about large fluctuations in product quality.
[0045] 5. Obvious overall performance advantages Based on the above data comparison, the method of the present invention shows significantly better performance than the traditional process in terms of sulfonation reaction efficiency, dispersant MF product quality, sodium sulfate content control and process stability. These advantages make the dispersant MF product of the present invention more competitive in the market, can better meet the needs of various industries for high-quality dispersants, and also provide valuable reference and reference for the improvement and innovation of sulfonation reaction related processes in the chemical industry.
[0046] 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.
Claims
1. A method for improving sulfonation reaction efficiency, characterized in that: The following steps are involved: S1, emulsification dispersion, select sodium dodecylbenzene sulfonate as emulsifier, and the amount of emulsifier is 1%-3% of the mass of methylnaphthalene, the methylnaphthalene raw material and the emulsifier are emulsified and dispersed under the action of a high-speed stirrer to form a stable emulsion system, so that the methylnaphthalene exists in the form of tiny droplets. Compared with the unemulsified liquid state, this tiny droplet state greatly increases the contact area between the methylnaphthalene and the sulfonating agent; S2, chemical modification, transferring the raw materials after emulsification and dispersion in step S1 to a reactor, adding succinic anhydride at a mass ratio of 0.2%-0.4% of the mass of methylnaphthalene and dimethyl sulfoxide at a mass ratio of 4%-6% of the mass of methylnaphthalene, stirring and reacting at 40-50° C. for 1-2 hours, acylation reaction of succinic anhydride and methylnaphthalene molecules, introducing active functional groups and increasing their reactivity, and dimethyl sulfoxide helps the reaction to proceed uniformly and improve the reactivity of the raw materials; S3, deploying sulfonating agent, using concentrated sulfuric acid, oleum and potassium pyrosulfate in a mass ratio of 3.5:2.5:1 to form a composite sulfonating agent; S4, sulfonation reaction, the raw materials and the composite sulfonating agent are put into a multi-layer stirred reactor for mixing to produce a sulfonation reaction to generate the product sulfonated methylnaphthalene, and the ultrasonic device is turned on during the reaction, the acid concentration is regulated by the online acidity monitor, the internal cooling reactor and the heat exchange system manage the heat, and the tail gas is processed through a spray tower and a condenser to recover the organic matter.
2. A method for producing a dispersant MF, based on the method for improving the efficiency of sulfonation reaction according to claim 1, characterized in that: The following steps are involved: Step 1, neutralizing the sulfonated methylnaphthalene reaction solution obtained in step S4 with 20%-25% sodium hydroxide solution in a neutralization kettle; Step 2: Filter the neutralized solution obtained in step 1 through a fine filter membrane to remove possible impurity particles therein, put the filtered solution into a condensation reactor, add formaldehyde, and stir and condense at 100-150° C., 50-200 mmHg, and 300-400 rpm for 2-5 hours; Step 3: After the condensation reaction is completed, the condensation product is neutralized with 20-50% liquid alkali, the pH is adjusted to 7-9, and MF solution is obtained. A macroporous resin or other adsorbent is used to adsorb possible trace impurities or unreacted substances, and finally a spray dryer is used to dry the solution to obtain a dispersant MF product.
3. A method for improving sulfonation reaction efficiency according to claim 1, characterized in that: In step S4, the multi-layer stirred reactor is specifically a reactor with an upper frame type, a middle turbine type, and a lower anchor type composite structure, wherein the stirring speed of the upper frame type is 200-300 rpm, the stirring speed of the middle turbine type is 300-400 rpm, and the stirring speed of the lower anchor type is 400-500 rpm.
4. The method for producing a dispersant MF according to claim 2, characterized in that: In the step 1, the stirring speed of the neutralization kettle is 200-300 rpm, the temperature in the kettle is controlled at 40-50° C., and the pH is controlled at 7-8.
5. The method for producing a dispersant MF according to claim 2, characterized in that: In the step 2, the molar ratio of the added formaldehyde to the sodium methylnaphthalene sulfonate is 0.7:
1.
6. A method for improving sulfonation reaction efficiency according to claim 1, characterized in that: The concentration of concentrated sulfuric acid in the composite sulfonating agent is 98%, and the concentration of fuming sulfuric acid is fuming sulfuric acid with 20%-25% free SO3. When the composite sulfonating agent is put into the multi-layer stirred reactor, concentrated sulfuric acid is added first, and then fuming sulfuric acid is added dropwise at a rate of 0.5-1 ml / sec, and potassium pyrosulfate is added dropwise at a rate of 0.2-0.5 g / sec, and stirring is carried out for 20-30 minutes after the addition is completed.
7. A method for improving sulfonation reaction efficiency according to claim 1, characterized in that: In the step S2, the methylnaphthalene raw material and the emulsifier are stirred in a high-speed stirrer at a speed of 1000-1500 rpm.