阅读说明：本技术 一种甲基丙烯磺酸钠的合成和精制方法 (Synthesis and refining method of sodium methallyl sulfonate ) 是由 赵炯峰 金一丰 贺丽丹 王胜利 秦飞 于 2021-01-18 设计创作，主要内容包括：本发明提供一种甲基丙烯磺酸钠的合成和精制方法,以亚硫酸钠和甲基烯丙基氯为原料,经过包括(1)亚硫酸钠和甲基烯丙基氯经过两步磺化反应,得到磺化反应液；(2)磺化反应液经过脱水、热过滤或保温离心,除去析出的氯化钠,得到浓缩液；(3)浓缩液经过梯度降温结晶、离心,得到甲基丙烯磺酸钠粗品和结晶母液,结晶母液返回脱水步骤,继续进行脱水等操作；(4)甲基丙烯磺酸钠经过洗涤、干燥,得到精制的甲基丙烯磺酸钠。本发明不仅生产效率高,产品的质量好(纯度大于99.8％)、收率高(＞98％),而且操作简单、批次间稳定性好。(The invention provides a method for synthesizing and refining sodium methallyl sulfonate, which takes sodium sulfite and methallyl chloride as raw materials, and obtains sulfonation reaction liquid through two-step sulfonation reaction of (1) the sodium sulfite and the methallyl chloride; (2) dehydrating, filtering or centrifuging the sulfonation reaction solution at a constant temperature, and removing precipitated sodium chloride to obtain a concentrated solution; (3) performing gradient cooling crystallization and centrifugation on the concentrated solution to obtain a sodium methallyl sulfonate crude product and a crystallization mother solution, returning the crystallization mother solution to the dehydration step, and continuing to perform dehydration and other operations; (4) and washing and drying the sodium methallyl sulfonate to obtain the refined sodium methallyl sulfonate. The invention has the advantages of high production efficiency, good product quality (the purity is more than 99.8%), high yield (more than 98%), simple operation and good stability among batches.)

1. A method for synthesizing and refining sodium methallyl sulfonate is characterized by comprising the following steps:

s1, performing two-step sulfonation reaction on sodium sulfite and methyl allyl chloride to obtain a sulfonation reaction solution;

s2, dehydrating, carrying out thermal filtration or carrying out heat preservation centrifugation on the sulfonation reaction solution, and removing precipitated sodium chloride to obtain a concentrated solution;

s3, carrying out gradient cooling crystallization and centrifugation on the concentrated solution to obtain a sodium methallyl sulfonate crude product and a crystallization mother solution, returning the crystallization mother solution to the dehydration step, and continuing to carry out dehydration and other operations;

and S4, washing and drying the sodium methallyl sulfonate crude product to obtain the refined sodium methallyl sulfonate.

2. The method for synthesizing and refining sodium methallyl sulfonate as claimed in claim 1, wherein the first step of the two-step sulfonation reaction of S1 is: adding a certain amount of sodium sulfite solution into a closed reaction kettle, replacing with nitrogen, heating to 45 ℃, and beginning to dropwise add methyl allyl chloride; the temperature is raised to 60-70 ℃ by means of the self-heat release of the reaction, and the temperature is reduced to 40 ℃ after the heat preservation reaction.

3. The method for synthesizing and refining sodium methallyl sulfonate as claimed in claim 2, wherein in the first reaction step of S1, the concentration of sodium sulfite is 20 wt% to 25 wt%, and the molar ratio of methallyl chloride to sodium sulfite is 0.95-0.98: 1.

4. The method for synthesizing and refining sodium methallyl sulfonate according to claim 3, wherein the second step in the two-step sulfonation reaction of S1 is: after the first-step reaction is finished and the temperature is reduced to 40 ℃, adding sodium sulfate solid into a reaction kettle, replacing with nitrogen, stirring and dissolving, heating to 45 ℃, dropwise adding methallyl chloride, releasing heat by the reaction, or heating to 60-70 ℃ with heat transfer oil, keeping the temperature, reacting, and removing unreacted methallyl chloride under the pressure of-0.95 MPa.

5. The method of claim 4, wherein in the second reaction step of S1, the amount of sodium sulfite solid added is 5 to 10 wt% of the total amount of the sulfonation reaction solution produced in the first reaction step, and the molar ratio of the dropwise added methallyl chloride to the added sodium sulfite solid is 1.0 to 1.1.

6. The method for synthesizing and refining sodium methallyl sulfonate as claimed in claim 5, wherein in S2, the dehydration temperature is 80-90 ℃, the vacuum degree is-0.95 MPa, and the removed water amount is 30-35 wt% of the total sulfonation reaction liquid obtained by the S1 two-step sulfonation reaction.

7. The method for synthesizing and refining sodium methallyl sulfonate as claimed in claim 1, wherein the gradient temperature-reducing crystallization process in S3 is as follows: cooling to 76-78 deg.C for 0.5-1 hr, and slowly cooling to 25-30 deg.C for a while.

8. The method for synthesizing and refining sodium methallyl sulfonate as defined in claim 1, wherein in the centrifugation step of S3, the rotation speed of the centrifuge is 1500-2000rpm, and the centrifugation time is 10-20 minutes.

9. The method for synthesizing and refining sodium methallyl sulfonate according to claim 1, wherein the specific operation method of washing in S4 is as follows: uniformly spraying deionized water on the surface of the crude methallyl chloride product obtained by centrifugation for 3-5 times, wherein the amount of the deionized water sprayed each time is 4-8 wt% of the total amount of the crude methallyl chloride product, and after each spraying, performing centrifugation.

10. The method for synthesizing and purifying sodium methallyl sulfonate as defined in claim 1, wherein the drying temperature in S4 is 110-120 ℃, and the drying time is 1-2 h.

Technical Field

The invention belongs to the technical field of aliphatic sulfonate, and particularly relates to a method for synthesizing sodium methallyl sulfonate by using methallyl chloride and sodium sulfite as raw materials.

Background

The sodium methallyl sulfonate can be used for a polycarboxylic acid high-performance water reducing agent, and has high water reducing rate and good retardation. Meanwhile, in the ternary polymerization acrylic fibers taking acrylonitrile as a main component, trace sodium methallyl sulfonate can improve the dyeing property of the fibers, so that the fibers have the advantages of fast color absorption, strong fastness and bright color, and the heat resistance and elasticity of the fibers can be improved. Besides, it can be used as monomer of water treatment corrosion and scale inhibitor, coating adjuvant, drying strength agent in paper-making adjuvant, etc.

Sodium methallyl sulfonate is mainly synthesized by the reaction of methallyl chloride and sodium sulfite. Chinese patent with publication number CN101492399A entitled "preparation method of sodium methallyl sulfonate" discloses a specific production method of sodium methallyl sulfonate, which takes methallyl chloride and sodium sulfite as raw materials and obtains the sodium methallyl sulfonate through the steps of reaction, dehydration, crystallization, solid-liquid separation, washing and the like. The sodium sulfite used in the method has low solubility, which results in low production efficiency. Meanwhile, the washing process is carried out in a washing kettle, the solid material with low moisture content is difficult to transfer in a reaction kettle, and a solvent used for washing is a methanol-water solution, so that the solution has a great problem in the aspect of safety. Chinese patent No. CN 101805275a, entitled "method for synthesizing sodium methallyl sulfonate", discloses a method for synthesizing sodium methallyl sulfonate by using sodium metabisulfite and methallyl chloride as raw materials, which uses sodium metabisulfite with higher solubility to replace sodium sulfite for reaction to obtain the product. However, sodium metabisulfite is easy to generate oxidation reaction in the using process, so that the color of reaction liquid is deepened, and the quality of a final product is influenced. Chinese patent CN 1172800a, entitled "sodium methallyl sulfonate production process and equipment", discloses a process flow for producing sodium methallyl sulfonate by using sodium sulfite and methallyl chloride as raw materials, and adopts centrifugal water washing and other processes to solve the problem of transfer of solid materials in the washing process. However, the amount of water used for washing in the process is large, and a large amount of washing water is returned to the dehydration process, so that the energy consumption is increased, and the production efficiency is reduced. Chinese patent with publication No. CN1462741A and patent name "a method for producing sodium methallyl sulfonate" discloses a method for synthesizing sodium methallyl sulfonate by using sodium sulfite and methallyl chloride as raw materials, and in the method, EDTA is used as an auxiliary agent, so that the content of iron ions in the product is reduced. However, the process also has the problem that solid materials are difficult to transfer in the reaction kettle.

In conclusion, the existing preparation process of sodium methallyl sulfonate has the problems of low production efficiency, difficult solid material transfer in the washing process, low washing efficiency and the like. In addition, in the crystallization process, the crystallization is too fast due to the too fast cooling speed, so that the crystal precipitation is too fast, the material entrainment is high, and the product quality and the stability among batches are influenced.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a method for synthesizing and refining sodium methallyl sulfonate, the method obtains high-quality sodium methallyl sulfonate through the steps of two-step reaction, dehydration for removing sodium chloride, gradient cooling crystallization, centrifugation, washing, drying and the like, and the whole process has high production efficiency, simple operation and good stability among product batches.

The technical scheme adopted by the invention is as follows:

a method for synthesizing and refining sodium methallyl sulfonate is characterized in that:

s1, performing two-step sulfonation reaction on sodium sulfite and methyl allyl chloride to obtain a sulfonation reaction solution;

s2, dehydrating, carrying out thermal filtration or carrying out heat preservation centrifugation on the sulfonation reaction solution, and removing precipitated sodium chloride to obtain a concentrated solution;

s3, carrying out gradient cooling crystallization and centrifugation on the concentrated solution to obtain a sodium methallyl sulfonate crude product and a crystallization mother solution, returning the crystallization mother solution to the dehydration step, and continuing to carry out dehydration and other operations;

and S4, washing and drying the sodium methallyl sulfonate to obtain the refined sodium methallyl sulfonate.

Preferably, the first step of the S1 two-step sulfonation reaction comprises: adding a certain amount of sodium sulfite solution into a 2.5L reaction kettle, heating to 45 ℃ after nitrogen replacement, beginning to dropwise add methyl allyl chloride, heating to 60-70 ℃ depending on the self heat release of the reaction, keeping the temperature for reaction for 3 hours, and then cooling to 40 ℃. This is due to: the reaction temperature is too low, the reaction speed is slow, and the production efficiency is reduced; the reaction temperature is too high, side reaction is easy to cause, and the product yield is reduced. Further preferably, the reaction temperature is 63 to 66 ℃.

The concentration of the sodium sulfite solution is 20-25 wt%. This is due to: the concentration of sodium sulfite is too low, and the production efficiency is low; the sodium sulfite concentration is too high, which easily causes incomplete dissolution. Further preferably, the concentration of the sodium sulfite solution is 23 wt% to 24 wt%. The molar ratio of methallyl chloride to sodium sulfite is from 0.90 to 1.1, more preferably, the molar ratio of methallyl chloride to sodium sulfite is from 0.95 to 0.98. The dropping time of the methallyl chloride is 1 h.

The second step of the S1 two-step sulfonation reaction comprises the following specific steps: after the first-step reaction is finished, adding a certain amount of sodium sulfite solid into a reaction kettle, stirring and dissolving after nitrogen replacement, heating to 45 ℃, and beginning to dropwise add a second part of methallyl chloride. The temperature is raised to 60-70 ℃ by means of self heat release of the reaction and heating of heat conducting oil, and after the reaction is carried out for 2 hours under the heat preservation, unreacted methallyl chloride is removed under the pressure of-0.095 MPa.

The adding amount of the solid sodium sulfite is 2-15 wt% of the total amount of the first-step reaction liquid. The sodium sulfite addition is too low, the production efficiency is not obviously improved, the sodium sulfite addition is too high, and insoluble substances are increased. Further preferably, the amount of the solid sodium sulfite added is 5 wt% to 10 wt% of the total amount of the first-step reaction liquid. The mol ratio of the methallyl chloride to the sodium sulfite is 1.0-1.1, and the dropping time of the methallyl chloride is 0.5 h.

Preferably, S2 specifically includes:

the dehydration of the reaction liquid is carried out under the vacuum condition, the vacuum degree is-0.095 MPa, the dehydration temperature is 80-90 ℃, the removed water amount accounts for 25-40 wt% of the total amount of the reaction liquid in the two steps, and more preferably, the removed water amount accounts for 30-35 wt% of the total amount of the reaction liquid in the two steps. And (3) carrying out thermal filtration on the dehydrated reaction liquid to remove precipitated sodium chloride, and then carrying out a cooling crystallization process.

Preferably, S3 specifically includes:

the temperature reduction and crystallization process of the concentrated solution is step-by-step temperature reduction, wherein the temperature is reduced from 85-90 ℃ to 76-78 ℃, the temperature is kept for 1h, and then the temperature is continuously and slowly reduced to 25 ℃ and kept for 1 h. The centrifugal stage, the rotating speed of the centrifugal machine is 1500-.

Preferably, S4 specifically includes:

and uniformly spraying deionized water on the surface of the coarse sodium methallyl sulfonate obtained by centrifugation, and centrifuging to obtain the refined sodium methallyl sulfonate, wherein the deionized water spraying frequency is 3-5 times, the amount of the deionized water sprayed each time is 3-10 wt% of the total amount of the coarse crystallized product, and the amount of the deionized water sprayed each time is 4-8 wt% of the total amount of the coarse crystallized product. More preferably, the amount of deionized water sprayed in each time is 5 wt% to 6 wt% of the total amount of the crude crystals. In the centrifugation process, the rotation speed of the centrifuge is 1500-. And drying the centrifuged product to obtain a finished product.

Compared with the prior art, the invention has the beneficial effects that:

(1) the method prepares the sodium methallyl sulfonate through two-step reaction, and obviously improves the concentration of products in reaction liquid, thereby reducing the water amount removed in a dehydration stage, reducing energy consumption and improving production efficiency;

(2) the cooling crystallization process is carried out in two steps, more crystal nuclei are formed by preserving heat for a certain time in a supersaturated state in the first cooling process, so that the growth of crystals is more uniform in the second cooling crystallization process, the phenomenon of 'wrapping' is avoided, and the product production quality and the batch stability are improved;

(3) the invention solves the problem of difficult transfer of the sodium methallyl sulfonate solid in the washing process by a centrifugation and water washing method, has little washing water amount and obvious washing effect, and the final purity of the product is more than 99.5 percent.

The specific implementation mode is as follows:

the following description will explain specific embodiments of the present invention, but is not limited to these examples.

Example 1

According to this example, sodium methallyl sulfonate is prepared by the following steps:

(1) and (3) sulfonation reaction: adding 1.5kg of sodium sulfite solution with the mass fraction of 25% into a 2.5L reaction kettle, heating to 45 ℃ after nitrogen replacement, starting to dropwise add 264g of methallyl chloride, continuing the whole dropwise adding process for 1h, heating to 60-70 ℃ depending on the self-heat release of the reaction, and carrying out heat preservation reaction for 3 h; and after the reaction is finished, cooling to 40 ℃, adding 88g of solid sodium sulfite, stirring to dissolve, heating to 45 ℃, dripping 65g of methyl allyl chloride, continuing the whole dripping process for 0.5h, heating to 60-70 ℃ by virtue of self-heat release of the reaction and heat transfer oil, keeping the temperature, reacting for 2h, and removing unreacted methyl allyl chloride under the pressure of-0.95 MPa to obtain a sulfonation reaction solution. The conversion rate is more than 99 percent in the whole reaction process calculated by sodium sulfite.

(2) And a dehydration stage: the sulfonation reaction solution obtained above is dehydrated to 576g of water under the conditions that the vacuum degree is minus 0.95MPa and the temperature is 80-90 ℃; removing the precipitated sodium chloride by thermal filtration, and allowing the filtrate to enter a cooling crystallization stage.

(3) And a cooling crystallization stage: cooling the filtrate obtained in the dehydration stage to 76-78 deg.C, maintaining the temperature for 1h, cooling to 25 deg.C at a speed of 1 deg.C/2 min, and maintaining the temperature for 1 h; and carrying out centrifugal separation on the obtained solid-liquid mixture, wherein the rotating speed of a centrifugal machine is 2000rpm, and the centrifugal time is 10 minutes, so as to obtain a sodium methallyl sulfonate crude product.

(4) And (3) washing and drying: uniformly spraying 5 wt% of deionized water 4 times on the surface of the sodium methallyl sulfonate crude product and centrifuging, wherein the rotating speed of a centrifuge is 2000rpm, and the centrifuging time is 10 minutes each time. The washed product was dried to obtain 290g of refined sodium methallyl sulfonate.

The quality test results of the obtained sodium methallyl sulfonate finished product are shown in table 1.

Example 2

According to this example, sodium methallyl sulfonate is prepared by the following steps:

(1) and (3) sulfonation reaction: adding 1.5kg of 20% sodium sulfite solution into a 2.5L reaction kettle, heating to 45 ℃ after nitrogen replacement, starting to dropwise add 211g of methyl allyl chloride, continuing the whole dropwise adding process for 1h, heating to 60-70 ℃ depending on the self-heat release of the reaction, and carrying out heat preservation reaction for 3 h; after the reaction is finished, cooling to 40 ℃, adding 171g of solid sodium sulfite, heating to 45 ℃ after stirring and dissolving, dripping 127g of methyl allyl chloride, continuing the whole dripping process for 0.5h, heating to 60-70 ℃ by means of self-heat release of the reaction and heat transfer oil, keeping the temperature, reacting for 2h, and removing unreacted methyl allyl chloride under the pressure of-0.95 MPa to obtain a sulfonation reaction solution. The conversion rate is more than 98.7 percent in the whole reaction process calculated by sodium sulfite.

(2) And a dehydration stage: 660g of water is removed from the obtained sulfonation reaction solution under the conditions that the vacuum degree is-0.95 MPa and the temperature is 80-90 ℃; removing the precipitated sodium chloride by thermal filtration, and allowing the filtrate to enter a cooling crystallization stage.

(3) And a cooling crystallization stage: cooling the filtrate obtained in the dehydration stage to 76-78 deg.C, maintaining the temperature for 1h, cooling to 25 deg.C at a speed of 1 deg.C/2 min, and maintaining the temperature for 1 h; and carrying out centrifugal separation on the obtained solid-liquid mixture, wherein the rotating speed of a centrifugal machine is 2000rpm, and the centrifugal time is 10 minutes, so as to obtain a sodium methallyl sulfonate crude product.

(4) And (3) washing and drying: uniformly spraying deionized water (the amount of the deionized water accounts for 6% of the amount of the crude product) on the surface of the crude product of the sodium methallylsulfonate for 3 times, and centrifuging at the rotating speed of a centrifuge of 2000rpm for 10 minutes. The washed product was dried to obtain 295g of refined sodium methallyl sulfonate.

Comparative example

According to this comparative example, sodium methallyl sulfonate was prepared by the following steps:

(1) and (3) sulfonation reaction: adding 1.5kg of sodium sulfite solution with the mass fraction of 25% into a 2.5L reaction kettle, heating to 45 ℃ after nitrogen replacement, starting to dropwise add 264g of methallyl chloride, continuing the whole dropwise adding process for 1h, heating to 60-70 ℃ depending on the self-heat release of the reaction, and carrying out heat preservation reaction for 3 h; after the reaction is finished, removing unreacted methallyl chloride under the pressure of-0.95 MPa to obtain a sulfonation reaction solution. The conversion rate is more than 98.8 percent in the whole reaction process calculated by sodium sulfite.

(2) And a dehydration stage: 610g of water is removed from the obtained sulfonation reaction solution under the conditions that the vacuum degree is-0.95 MPa and the temperature is 80-90 ℃; removing the precipitated sodium chloride by thermal filtration, and allowing the filtrate to enter a cooling crystallization stage.

(3) And a cooling crystallization stage: cooling the filtrate obtained in the dehydration stage to 25 ℃ at the speed of 1 ℃/2min, and preserving the heat for 1 h; and carrying out centrifugal separation on the obtained solid-liquid mixture, wherein the rotating speed of a centrifugal machine is 2000rpm, and the centrifugal time is 10 minutes, so as to obtain a sodium methallyl sulfonate crude product.

(4) And (3) washing and drying: uniformly spraying 5 wt% of deionized water 4 times on the surface of the sodium methallyl sulfonate crude product and centrifuging, wherein the rotating speed of a centrifuge is 2000rpm, and the centrifuging time is 10 minutes each time. The washed product was dried to obtain 235g of refined sodium methallyl sulfonate.

The improvement in the production efficiency of the present invention is demonstrated by the comparison of the amount of the product obtained in examples 1 and 2 with that obtained in the comparative example.

The results of quality inspection of the sodium methallyl sulfonate finished products obtained in examples 1 and 2 and comparative example are shown in Table 1.

TABLE 1 quality test results of sodium methallylsulfonate finished products

As can be seen from the above table, the product quality is slightly reduced because the comparative example does not undergo stepwise cooling.