CN110229084B - Preparation method of guaiacol potassium sulfonate - Google Patents

Abstract

The invention discloses a preparation method of guaiacol potassium sulfonate, which takes guaiacol as a raw material and prepares a crude guaiacol potassium sulfonate product through sulfonation, calcification and potassium reaction.

Description

Preparation method of guaiacol potassium sulfonate

Technical Field

The invention relates to the technical field of compound synthesis, in particular to a preparation method of guaiacol potassium sulfonate.

Background

The potassium guaiacolsulfonate is a pungent expectorant, makes sputum thin and easy to cough out by stimulating secretion of bronchial mucosa glands, and is often used as one of main components of compound expectorant and antitussive oral liquids. The finished product of the potassium guaiacolsulfonate sold in the market at home at present is a mixture of potassium 4-hydroxy-3-methoxybenzenesulfonate and potassium 3-hydroxy-4-methoxybenzenesulfonate (the name of the English is potassium 4-hydroxy-3-methoxy-4-methoxy-zenesulfonate/potassium 3-hydroxy-4-methoxy-zenesulfonate). Potassium guaiacolsulfonate is approved in the united states pharmacopeia USP 33. At present, the method for synthesizing the guaiacol potassium sulfonate is mainly prepared by sulfonating guaiacol (o-methoxyphenol) and derivatives thereof.

The sulfonation reaction is a conventional organic chemical reaction, and is a reaction in which a sulfonating agent directly substitutes a sulfonic acid group for a hydrogen atom. Common sulfonating agents are concentrated sulfuric acid, sulfur trioxide dissolved in chlorinated hydrocarbons, liquid sulfur dioxide, dioxane, pyridine and other solvents, chlorosulfonic acid, mixtures of sulfur dioxide and chlorine, sulfuryl chloride and the like. Sulfuric acid is a milder sulfonating agent used for the sulfonation of most aromatic compounds; sulfur trioxide is a relatively aggressive sulfonating agent and is generally used in solution in a solvent due to the production of by-products. In addition, it is important to control the temperature of the sulfonation reaction, and when the temperature is low, the sulfonic acid group is likely to enter the ortho position of the substituent, and when the temperature is high, the sulfonic acid group is likely to enter the para position of the substituent.

Patent CN 104292136 a discloses a preparation method of guaiacol potassium sulfonate. Taking o-dimethyl ether which is a byproduct in the guaiacol production as a raw material, taking sulfuric acid as a solvent and a sulfonating agent, cooling to-5-10 ℃, adding the o-dimethyl ether, heating while stirring, reacting, and adding calcium oxide or calcium carbonate to adjust the pH value; and filtering the reaction liquid to obtain 3, 4-dimethoxy calcium benzenesulfonate, adding Lewis acid into the 3, 4-dimethoxy calcium benzenesulfonate, heating to 60-100 ℃, reacting for 2-5 hours, and cooling to 20-30 ℃ to obtain a mixture of the 3-hydroxy-4-methoxy calcium benzenesulfonate and the 4-hydroxy-3-methoxy calcium benzenesulfonate. Adding potassium carbonate, potassium bicarbonate or potassium hydroxide into a mixture of the calcium 3-hydroxy-4-methoxybenzenesulfonate and the calcium 4-hydroxy-3-methoxybenzenesulfonate, heating to 50-100 ℃, reacting for 2-10 hours, cooling to-10-0 ℃, and filtering to remove insoluble substances to obtain the potassium guaiacolsulfonate. The method takes the by-product of the guaiacol production, namely the o-dimethyl ether, as a raw material, has the advantages of low price, mild reaction conditions and environmental friendliness, and can be used for industrial mass production. However, the product obtained by the method is a crude product of the guaiacol potassium sulfonate, the purity is low, the used catalysts are more, the controlled temperature difference is large, the reaction time is long, the product is unstable and is not suitable for industrial large-scale production, the embodiment of the method is a small-batch production method, and the yield is high but cannot be achieved when large-batch production is carried out.

Disclosure of Invention

The invention aims to provide a preparation method of guaiacol potassium sulfonate, which solves the problem that hydroxyl is easily oxidized by the oxidability of a sulfonating agent, has the advantages of simple preparation method, short time consumption, high purity and good yield of the guaiacol potassium sulfonate, and is suitable for industrial mass production.

A method for preparing potassium guaiacolsulfonate comprises the following steps of introducing nitrogen during sulfonation to prevent oxidation and polymerization of guaiacol, filtering intermediate calcium guaiacolsulfonate solution, crude guaiacolsulfonate and fine guaiacolsulfonate solution by using a 0.22-0.65 mu m filter membrane for precise filtration, reducing concentration temperature and heating time by using a heat pump recompression, reduced pressure, concentration and continuous crystallization technology, and reducing by-products generated during high-temperature concentration to improve the purity and yield of the potassium guaiacolsulfonate, wherein the specific steps are as follows:

(1) adding guaiacol into a reactor, introducing nitrogen for 10 minutes while stirring, removing air in the reactor and the guaiacol by replacement, slowly dripping sulfuric acid for 2-3 hours, continuously introducing nitrogen after dripping sulfuric acid is finished, reacting for 15-25 minutes while stirring, heating to 70-80 ℃, and preserving heat for 5-6 hours; checking the sulfonation end point, stopping the reaction after reaching the end point, and stopping introducing nitrogen.

(2) Slowly pumping the sulfonated liquid obtained in the step (1) into purified water at the temperature of 70-80 ℃, wherein the consumption of the purified water is 1.60-1.64 times of that of the sulfonated liquid, slowly adding calcium carbonate for multiple times under stirring until the pH value is 5.0-5.5, and performing calcification end point inspection;

(3) after the calcification end point is reached, carrying out heat preservation reaction at the temperature of 80-85 ℃ for 20-30 minutes, stopping heating, and standing for 15-20 minutes; filtering with a centrifuge, and performing precision filtration with a 0.22-0.65 μm filter membrane to obtain the calcification liquid.

(4) Weighing potassium carbonate, adding purified water with the same amount, stirring, and heating until the potassium carbonate is completely dissolved for later use; heating the calcified liquid to 70-80 ℃ under stirring, slowly dripping the potassium carbonate solution for 1-1.5 hours, and performing potassium end point inspection when the pH value is slightly alkaline by using a precision test paper.

(5) And after the end point of the potassium making is reached, heating the potassium making liquid to slight boiling, keeping for 10-15 minutes, cooling to 70-80 ℃ under stirring, carrying out precision filtration, carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the filtrate, controlling the vacuum degree to be-0.065-0.08 MPa and the temperature to be 75-85 ℃, and continuously sending the crystals to a crystallization cooling tank.

(6) And cooling the crystals to 15-20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystals with purified water, checking the pH value of washing liquid to be 7.5-8.0, carrying out spin-drying to obtain a wet crude product of the potassium guaiacolsulfonate, and sending the wet crude product to a refining process.

(7) And (4) refining the wet crude product of the potassium guaiacolsulfonate obtained in the step (6), pumping purified water into the wet crude product of the potassium guaiacolsulfonate, wherein the amount of the purified water is 2-2.4 times of that of the wet crude product of the potassium guaiacolsulfonate, heating the mixture to completely dissolve the mixture to be clear under stirring, and then performing precise filtration by using a 0.22-0.65 mu m filter membrane.

(8) And (4) carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the fine filtrate obtained by membrane filtration in the step (7), controlling the vacuum degree to be-0.065-0.08 MPa and the temperature to be 75-85 ℃, and continuously conveying the crystals to a crystallization cooling tank.

(9) And cooling the crystals to 15-20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystals with purified water, checking the pH value of a washing solution to be 7.0-7.5 by using precision test paper, drying a filter cake to obtain a fine wet product of the potassium guaiacolsulfonate, and sending the wet product to a drying process.

(10) Drying the wet fine guaiacol potassium sulfonate product in an oven at 85-90 ℃ for 8-10 hours, crushing, screening and inspecting to obtain the fine guaiacol potassium sulfonate product.

The method for checking the sulfonation end point in the step (1) is to uniformly mix purified water and sulfonated liquid obtained by reaction in a volume ratio of 9:1, and the sulfonation end point is reached when no oil is precipitated.

The method for checking the calcification end point in the step (2) comprises the following two methods: 1) taking a small amount of calcification liquid, and checking the pH of the calcification liquid by using pH precision test paper, wherein the end point of calcification is reached when the pH is within a range of 5.0-5.5; 2) and (3) taking a small amount of calcification liquid, adding a small amount of calcium carbonate, and stirring to obtain the final calcification point without generating bubbles.

The method for checking the potassium end point in the step (4) comprises the following steps:

1) adding purified water into ammonium oxalate to dissolve the ammonium oxalate to prepare an ammonium oxalate test solution with the concentration of 35 mg/mL;

2) taking 2mL of potassium solution, adding 10mL of purified water, and shaking up;

3) taking 2mL of potassium solution, adding 8mL of purified water, adding 2mL of ammonium oxalate test solution, and shaking up;

4) within one minute, the solution of 2) compared to the solution of 3), the solution of 3) should be as substantially clear as the solution of 2), i.e., indicating the endpoint is reached.

The invention has the beneficial effects that:

the invention takes guaiacol as raw material, and obtains wet crude product of guaiacol potassium sulfonate through sulfuric acid sulfonation, calcium carbonate calcification and potassium carbonate potassification, and the crude product and the refined product solution of the guaiacol potassium sulfonate both adopt the technology of heat pump recompression, decompression, concentration and continuous crystallization to reduce concentrationThe temperature and the heating time are shortened, and the by-products generated during high-temperature concentration are reduced, so that the purity and the yield of the guaiacol potassium sulfonate are improved. According to the invention, nitrogen is filled during sulfonation to protect the sulfonation process, so that guaiacol is prevented from being oxidized and polymerized, the color of the product is white, activated carbon is not needed for decolorization, polymerized jelly is greatly reduced, subsequent filtration is facilitated, and the yield is greatly improved. The invention carries out the reaction end point check after the sulfonation, calcification and kalification reactions, and the next operation is carried out after the raw materials are completely reacted after the end point is determined, thereby ensuring that most of the raw materials are changed into products and the yield of the products is high. The invention adopts the heat pump recompression decompression concentration continuous crystallization technology to carry out decompression concentration continuous crystallization on the potassium guaiacolsulfonate wet crude product solution and the fine product solution, thereby greatly reducing the generation of impurities in the high-temperature concentration process, improving the purity of the potassium guaiacolsulfonate and simultaneously improving the yield of the potassium guaiacolsulfonate, and the obtained final product reaches the standard of the quality enterprise of the potassium guaiacolsulfonate and contains C₇H₇KO₅98.5 to 101.0 percent of S, 3.0 to 6.0 percent of water and the yield of mass production can reach more than 82 percent.

Drawings

Fig. 1 is a heat pump recompression decompression concentration continuous crystallizer for potassium guaiacolsulfonate, which has a composition structure as follows: 01 tubular heat exchanger, 02 evaporating pot, 03 vapor-liquid separator, 04 heat pump, 05 heat circulating pump, 06 hot water recovering pot, 07 electric continuous discharging valve, 08 crystallizing cooling pot.

Detailed Description

In order to describe the present invention in more detail, the present invention will be further described with reference to the following examples.

Example 1

A method for preparing guaiacol potassium sulfonate comprises the following steps of introducing nitrogen during sulfonation to prevent oxidation and polymerization of guaiacol, and improving the yield and purity of the guaiacol potassium sulfonate by adopting a heat pump recompression, reduced pressure concentration and continuous crystallization technology:

(1) adding guaiacol into a reactor, introducing nitrogen for 10 minutes while stirring, removing air in the reactor and the guaiacol by replacement, slowly dripping sulfuric acid for 2 hours, continuously introducing nitrogen after dripping sulfuric acid is finished, reacting for 15 minutes while stirring, heating to 70 ℃, and keeping the temperature for 6 hours; checking the sulfonation end point, stopping the reaction after reaching the end point, and stopping introducing nitrogen.

(2) Slowly pumping the sulfonated liquid obtained in the step (1) into purified water at the temperature of 70-80 ℃, slowly adding calcium carbonate for multiple times under stirring until the pH value is 5.5, and performing calcification end point inspection.

(3) After the calcification end point is reached, keeping the temperature at 85 ℃ for reaction for 30 minutes, stopping heating, and standing for 15 minutes; filtering with a centrifuge, and performing precision filtration with a 0.22-0.65 μm filter membrane to obtain the calcification liquid.

(4) Weighing potassium carbonate, adding equivalent purified water, stirring, and heating to 50-60 ℃ to completely dissolve the potassium carbonate for later use; heating the calcified liquid to 70 ℃ under stirring, slowly dripping the potassium carbonate solution for 1.5 hours, and checking the potassium end point when the pH value is slightly alkaline by using a precision test paper.

(5) And after the end point of the potassium treatment is reached, heating the potassium solution to slight boiling, keeping for 15 minutes, cooling to 70-80 ℃ under stirring, carrying out precision filtration through a filter membrane of 0.22-0.65 mu m, carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the filtrate, controlling the vacuum degree to be-0.065 MPa and the temperature to be 85 ℃, and continuously sending the crystals to a crystallization cooling tank.

(6) Cooling the crystal to 15 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystal with purified water, checking the pH value of the washing liquid to be 7.5, carrying out spin-drying to obtain a wet crude product of the guaiacol potassium sulfonate, and sending the wet crude product to a refining process.

(7) And (4) refining the wet crude product of the potassium guaiacolsulfonate obtained in the step (6), pumping purified water into the wet crude product of the potassium guaiacolsulfonate, wherein the amount of the purified water is 2 times of that of the wet crude product of the potassium guaiacolsulfonate, heating the mixture to be completely dissolved to be clear under stirring, and then performing precise filtration by using a 0.22-0.65 mu m filter membrane.

(8) And (4) carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the fine filtrate obtained by membrane filtration in the step (7), controlling the vacuum degree to be 0.08MPa and the temperature to be 75 ℃, and continuously conveying the crystals to a crystallization cooling tank.

(9) Cooling the crystal to 20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystal with purified water, checking the pH value of washing liquid to be 7.0 by using precision test paper, drying a filter cake to obtain a fine wet product of the potassium guaiacolsulfonate, and sending the wet product to a drying process.

(10) Drying the wet fine guaiacol potassium sulfonate product in an oven at 85-90 ℃ for 8 hours, crushing, screening and inspecting to obtain the fine guaiacol potassium sulfonate product, wherein the yield of the fine guaiacol potassium sulfonate product is 84.93%.

The method for checking the sulfonation end point in the step (1) is to uniformly mix purified water and sulfonated liquid obtained by reaction in a volume ratio of 9:1, and the sulfonation end point is reached when no oil is precipitated.

The method for checking the calcification end point in the step (2) comprises the following steps: and (3) taking a small amount of calcification liquid, and checking the pH of the calcification liquid by using pH precision test paper, wherein the end point of calcification is reached when the pH is within a range of 5.0-5.5.

The method for checking the potassium end point in the step (4) comprises the following steps:

1) adding purified water into ammonium oxalate to dissolve the ammonium oxalate to prepare an ammonium oxalate test solution with the concentration of 35 mg/mL;

2) taking 2mL of potassium solution, adding 10mL of purified water, and shaking up;

3) taking 2mL of potassium solution, adding 8mL of purified water, adding 2mL of ammonium oxalate test solution, and shaking up;

4) within one minute, the solution of 2) compared to the solution of 3), the solution of 3) should be as substantially clear as the solution of 2), i.e., indicating the endpoint is reached.

Example 2

A method for preparing guaiacol potassium sulfonate comprises the following steps of introducing nitrogen during sulfonation to prevent oxidation and polymerization of guaiacol, and improving the yield and purity of the guaiacol potassium sulfonate by adopting a vacuum continuous crystallization and concentration technology at normal temperature:

(1) adding guaiacol into a reactor, introducing nitrogen for 10 minutes while stirring, removing air in the reactor and the guaiacol by replacement, slowly dripping sulfuric acid for 2.5 hours, continuously introducing nitrogen after dripping sulfuric acid is finished, reacting for 20 minutes while stirring, heating to 75 ℃, and keeping the temperature for 5.5 hours; checking the sulfonation end point, stopping the reaction after reaching the end point, and stopping introducing nitrogen.

(2) Slowly pumping the sulfonated liquid obtained in the step (1) into purified water at the temperature of 70-80 ℃, slowly adding calcium carbonate for 3 times under stirring until the pH value is 5.2, and performing calcification end point inspection.

(3) After the calcification end point is reached, keeping the temperature of 80-85 ℃ for reaction for 25 minutes, stopping heating, and standing for 18 minutes; filtering with a centrifuge, and performing precision filtration with a 0.22-0.65 μm filter membrane to obtain the calcification liquid.

(4) Weighing potassium carbonate, adding equivalent purified water, stirring, and heating to 50-60 ℃ to completely dissolve the potassium carbonate for later use; heating the calcified liquid to 70-80 ℃ under stirring, slowly dripping the potassium carbonate solution for 1.2 hours, and checking the potassium end point when the pH value is slightly alkaline by using a precision test paper.

(5) And after the end point of the potassium treatment is reached, heating the potassium solution to slight boiling, keeping for 12 minutes, cooling to 70-80 ℃ under stirring, carrying out precision filtration through a filter membrane of 0.22-0.65 mu m, carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the filtrate, controlling the vacuum degree to be-0.07 MPa and the temperature to be 82 ℃, and continuously feeding the crystals to a crystallization cooling tank.

(6) Cooling the crystal to 18 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystal with purified water, checking the pH value of the washing liquid to be 7.8, carrying out spin-drying to obtain a wet crude product of the guaiacol potassium sulfonate, and sending the wet crude product to a refining process.

(7) And (4) refining the wet crude product of the potassium guaiacolsulfonate obtained in the step (6), pumping purified water into the wet crude product of the potassium guaiacolsulfonate, wherein the amount of the purified water is 2.2 times of that of the wet crude product of the potassium guaiacolsulfonate, heating the mixture to completely dissolve the mixture to be clear under stirring, and then performing precise filtration by using a 0.22-0.65 mu m filter membrane.

(8) And (4) carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the fine filtrate obtained by membrane filtration in the step (7), controlling the vacuum degree to be-0.075 MPa and the temperature to be 78 ℃, and continuously conveying the crystals to a crystallization cooling tank.

(9) Cooling the crystal to 18 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystal with purified water, checking the pH value of washing liquid to be 7.2 by using precision test paper, drying a filter cake to obtain a fine wet product of the potassium guaiacolsulfonate, and sending the wet product to a drying process.

(10) Drying the fine wet guaiacol potassium sulfonate product in an oven at 85-90 ℃ for 9 hours, crushing, screening and inspecting to obtain the fine guaiacol potassium sulfonate product, wherein the yield of the fine guaiacol potassium sulfonate product is 92.94%.

The method for checking the sulfonation end point in the step (1) is to uniformly mix purified water and sulfonated liquid obtained by reaction in a volume ratio of 9:1, and the sulfonation end point is reached when no oil is precipitated.

The method for checking the calcification end point in the step (2) comprises the following steps: and (3) taking a small amount of calcification liquid, adding a small amount of calcium carbonate, and stirring to obtain the final calcification point without generating bubbles.

The method for checking the potassium end point in the step (4) comprises the following steps:

1) adding purified water into ammonium oxalate to dissolve the ammonium oxalate to prepare an ammonium oxalate test solution with the concentration of 35 mg/mL;

2) taking 2mL of potassium solution, adding 10mL of purified water, and shaking up;

3) taking 2mL of potassium solution, adding 8mL of purified water, adding 2mL of ammonium oxalate test solution, and shaking up;

4) within one minute, the solution of 2) compared to the solution of 3), the solution of 3) should be as substantially clear as the solution of 2), i.e., indicating the endpoint is reached.

Example 3

A method for preparing guaiacol potassium sulfonate comprises the following steps of introducing nitrogen during sulfonation to prevent oxidation and polymerization of guaiacol, and improving the yield and purity of the guaiacol potassium sulfonate by adopting a vacuum continuous crystallization and concentration technology at normal temperature:

(1) adding guaiacol into a reactor, introducing nitrogen for 10 minutes while stirring, removing air in the reactor and the guaiacol by replacement, slowly dripping sulfuric acid for 3 hours, continuously introducing nitrogen after dripping sulfuric acid is finished, reacting for 25 minutes while stirring, heating to 80 ℃, and preserving heat for 5 hours; checking the sulfonation end point, stopping the reaction after reaching the end point, and stopping introducing nitrogen.

(2) Slowly pumping the sulfonated liquid obtained in the step (1) into purified water at the temperature of 70-80 ℃, slowly adding calcium carbonate for multiple times under stirring until the pH value is 5.0, and performing calcification end point inspection.

(3) After the calcification end point is reached, keeping the temperature at 85 ℃ for reacting for 20 minutes, stopping heating, and standing for 20 minutes; filtering with a centrifuge, and performing precision filtration with a 0.22-0.65 μm filter membrane to obtain the calcification liquid.

(4) Weighing potassium carbonate, adding purified water with the same amount, stirring, and heating until the potassium carbonate is completely dissolved for later use; heating the calcified liquid to 75 ℃ under stirring, slowly dripping the potassium carbonate solution for 1.0 hour, and checking the potassium end point when the pH value is slightly alkaline by using a precision test paper.

(5) And after the end point of the potassium treatment is reached, heating the potassium solution to slight boiling, keeping for 10 minutes, cooling to 70-80 ℃ under stirring, carrying out precision filtration through a filter membrane of 0.22-0.65 mu m, carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the filtrate, controlling the vacuum degree to be-0.075 MPa and the temperature to be 75 ℃, and continuously sending the crystals to a crystallization cooling tank.

(6) Cooling the crystal to 20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystal with purified water, checking the pH value of the washing liquid to be 8.0, carrying out spin-drying to obtain a wet crude product of the guaiacol potassium sulfonate, and sending the wet crude product to a refining process.

(7) And (4) refining the wet crude product of the potassium guaiacolsulfonate obtained in the step (6), pumping purified water into the wet crude product of the potassium guaiacolsulfonate, wherein the amount of the purified water is 2.4 times of that of the wet crude product of the potassium guaiacolsulfonate, heating the mixture to completely dissolve the mixture to be clear under stirring, and then performing precise filtration by using a 0.22-0.65 mu m filter membrane.

(8) And (4) carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the fine filtrate obtained by membrane filtration in the step (7), controlling the vacuum degree to be-0.065 MPa and the temperature to be 85 ℃, and continuously conveying the crystals to a crystallization cooling tank.

(9) Cooling the crystal to 20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystal with purified water, checking the pH value of washing liquid to be 7.5 by using precision test paper, drying a filter cake to obtain a fine wet product of the potassium guaiacolsulfonate, and sending the wet product to a drying process.

(10) Drying the wet fine guaiacol potassium sulfonate product in an oven at 85-90 ℃ for 10 hours, crushing, screening and inspecting to obtain the fine guaiacol potassium sulfonate product, wherein the yield of the fine guaiacol potassium sulfonate product is 83.81%.

The method for checking the sulfonation end point in the step (1) is to uniformly mix purified water and sulfonated liquid obtained by reaction in a volume ratio of 9:1, and the sulfonation end point is reached when no oil is precipitated.

The method for checking the calcification end point in the step (2) comprises the following two methods: 1) taking a small amount of calcification liquid, and checking the pH of the calcification liquid by using pH precision test paper, wherein the end point of calcification is reached when the pH is within a range of 5.0-5.5; 2) and (3) taking a small amount of calcification liquid, adding a small amount of calcium carbonate, and stirring to obtain the final calcification point without generating bubbles.

The method for checking the potassium end point in the step (4) comprises the following steps:

1) adding purified water into ammonium oxalate to dissolve the ammonium oxalate to prepare an ammonium oxalate test solution with the concentration of 35 mg/mL;

2) taking 2mL of potassium solution, adding 10mL of purified water, and shaking up;

3) taking 2mL of potassium solution, adding 8mL of purified water, adding 2mL of ammonium oxalate test solution, and shaking up;

4) within one minute, the solution of 2) compared to the solution of 3), the solution of 3) should be as substantially clear as the solution of 2), i.e., indicating the endpoint is reached.

In the above embodiment, the heat pump recompression, reduced pressure concentration and continuous crystallization are performed in the steps (5) and (8), the composition structure diagram of the potassium guaiacolsulfonate heat pump recompression, reduced pressure concentration and continuous crystallizer is shown in fig. 1, and the working principle is as follows:

pumping a solution of potassium guaiacolsulfonate to be concentrated into atube heat exchanger 01, starting aheat circulating pump 05 to enable the solution to circulate through thetube heat exchanger 01, then opening an auxiliary steam tube valve to start circulating heating and temperature rising, closing the auxiliary steam tube valve when the temperature of the solution rises to 75-85 ℃, starting aheat pump 04 to start decompression concentration, directly feeding steam evaporated by anevaporation tank 02 into theheat pump 04, directly feeding high-temperature steam compressed by theheat pump 04 into thetube heat exchanger 01 to heat the potassium guaiacolsulfonate solution, paying attention to the fact that crystallization begins to separate out from a concentrated solution in an observation device, starting an electriccontinuous discharge valve 07 continuous discharge valve after a large amount of crystallization is separated out, feeding the crystallization into acrystallization cooling tank 08 to be properly cooled, and then carrying out centrifugal filtration, washing and drying to obtain a fine product of potassium guaiacolsulfonate.

Claims (1)

1. A preparation method of guaiacol potassium sulfonate is characterized by comprising the following specific steps:

(1) adding guaiacol into a reactor, introducing nitrogen for 10 minutes while stirring, removing air in the reactor and the guaiacol by replacement, slowly dripping sulfuric acid for 2-3 hours, continuously introducing nitrogen after dripping sulfuric acid is finished, reacting for 15-25 minutes while stirring, heating to 70-80 ℃, and preserving heat for 5-6 hours; checking the sulfonation end point, stopping the reaction after the sulfonation end point is reached, and stopping introducing nitrogen;

(2) slowly pumping the sulfonated liquid obtained in the step (1) into purified water at the temperature of 70-80 ℃, wherein the consumption of the purified water is 1.60-1.64 times of that of the sulfonated liquid, slowly adding calcium carbonate for multiple times under stirring until the pH value is 5.0-5.5, and performing calcification end point inspection;

(3) after the calcification end point is reached, carrying out heat preservation reaction at the temperature of 80-85 ℃ for 20-30 minutes, stopping heating, and standing for 15-20 minutes; filtering by a centrifugal machine, and performing precise filtration by a filter membrane of 0.22-0.65 mu m to obtain a calcification liquid;

(4) weighing potassium carbonate, adding purified water with the same amount, stirring, and heating until the potassium carbonate is completely dissolved for later use; heating the calcified liquid to 70-80 ℃ under stirring, slowly dripping the potassium carbonate solution for 1-1.5 hours, and performing potassium end point inspection when the pH value is slightly alkaline by using a precision test paper;

(5) after the potassium end point is reached, heating the potassium solution to slight boiling, keeping for 10-15 minutes, cooling to 70-80 ℃ under stirring, carrying out precision filtration through a filter membrane of 0.22-0.65 mu m, carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the filtrate, controlling the vacuum degree to be-0.065-0.08 MPa and the temperature to be 75-85 ℃, and continuously sending the crystals to a crystallization cooling tank;

(6) cooling the crystals to 15-20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystals with purified water, checking the pH value of washing liquid to be 7.5-8.0, carrying out spin-drying to obtain a wet crude product of the potassium guaiacolsulfonate, and sending the wet crude product to a refining process;

(7) refining the wet crude product of the potassium guaiacol sulfonate in the step (6), pumping purified water into the wet crude product of the potassium guaiacol sulfonate, wherein the amount of the purified water is 2-2.4 times of that of the wet crude product of the potassium guaiacol sulfonate, heating the solution to be completely dissolved to be clear under stirring, and then performing precise filtration by using a 0.22-0.65 mu m filter membrane;

(8) carrying out heat pump recompression, reduced pressure concentration and continuous crystallization on the fine filtrate obtained by membrane filtration in the step (7), controlling the vacuum degree to be-0.065-0.08 MPa and the temperature to be 75-85 ℃, and continuously sending the crystals to a crystallization cooling tank;

(9) cooling the crystals to 15-20 ℃, then carrying out centrifugal filtration to remove mother liquor, washing the crystals with purified water, checking the pH value of a washing solution to be 7.0-7.5 by using precision test paper, drying a filter cake to obtain a fine wet product of the potassium guaiacolsulfonate, and sending the wet product to a drying process;

(10) drying the wet guaiacol potassium sulfonate refined product in an oven at 85-90 ℃ for 8-10 hours, crushing, screening and inspecting to obtain the guaiacol potassium sulfonate refined product;

the method for checking the sulfonation end point in the step (1) is to uniformly mix purified water and sulfonated liquid obtained by reaction in a volume ratio of 9:1, wherein the sulfonation end point is reached when no oil is separated out;

the method for checking the calcification end point in the step (2) comprises the following two methods: 1) taking a small amount of calcification liquid, and checking the pH of the calcification liquid by using pH precision test paper, wherein the end point of calcification is reached when the pH is within a range of 5.0-5.5; 2) taking a small amount of calcification liquid, adding a small amount of calcium carbonate, and stirring to obtain a calcification end point without generating bubbles;

the method for checking the potassium end point in the step (4) comprises the following steps:

1) adding purified water into ammonium oxalate to dissolve the ammonium oxalate to prepare an ammonium oxalate test solution with the concentration of 35 mg/mL;

2) taking 2mL of potassium solution, adding 10mL of purified water, and shaking up;

3) taking 2mL of potassium solution, adding 8mL of purified water, adding 2mL of ammonium oxalate test solution, and shaking up;

4) within one minute, 2) compare the solution of 3), the solution of 3) should be as clear as the solution of 2), i.e., indicating the endpoint is reached;

the heat pump recompression, reduced pressure concentration and continuous crystallization of the filtrate in the steps (5) and (8) is carried out by adopting a potassium guaiacolsulfonate heat pump recompression, reduced pressure concentration and continuous crystallizer, and the crystallizer comprises the following components: the device comprises a tubular heat exchanger (01), an evaporation tank (02), a vapor-liquid separator (03), a heat pump (04), a heat circulating pump (05), a hot water recovery tank (06), an electric continuous discharge valve (07) and a crystallization cooling tank (08); when the device works specifically, a potassium guaiacolsulfonate solution to be concentrated is pumped into a tubular heat exchanger (01), a heat circulating pump (05) is started to enable the solution to circulate through the tubular heat exchanger (01), then an auxiliary steam tube valve is opened to start circulating heating and temperature rising, the auxiliary steam tube valve is closed when the temperature of the solution rises to 75-85 ℃, a heat pump (04) is started to start decompression and concentration, steam evaporated by an evaporation tank (02) directly enters a heat pump (04), high-temperature steam compressed by the heat pump (04) directly enters the tubular heat exchanger (01) to heat the potassium guaiacolsulfonate solution, attention is paid to the fact that crystallization begins to separate out from a concentrated solution in an observation device, an electric continuous discharge valve (07) continuous discharge valve is started after a large amount of crystallization is separated out, and the crystallization is sent into a crystallization cooling tank (08).

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