Preparation method of m-chloroperoxybenzoic acid

Abstract

The invention discloses a preparation method of m-chloroperoxybenzoic acid, which belongs to the technical field of chemical material preparation and comprises the following steps: dissolving m-chlorobenzoic acid in an alkaline environment; controlling the temperature and dropwise adding hydrogen peroxide for reaction; acidizing the reaction product; standing for liquid separation, and collecting an organic phase; washing the organic phase with water; distilling the organic phase after water washing; and carrying out suction filtration on the distilled product to obtain a metachloroperbenzoic acid wet product. According to the preparation method of the m-chloroperoxybenzoic acid, the required raw materials are cheap and easy to obtain, the production cost is reduced, the reaction is performed under the alkaline condition, the potential harm to the environment and equipment is reduced, the yield of a finished product is high, the requirements of industrial production are met, generated wastewater, waste gas and the like are easy to treat, and the requirements of environmental protection are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical material preparation, and particularly relates to a preparation method of meta-chloroperoxybenzoic acid. BACKGROUND

[0002] As a high-efficiency oxidant, meta-chloroperoxybenzoic acid plays an irreplaceable role in the synthesis of medicines and pesticides. At present, the mainstream production process adopts a meta-chlorobenzoic acid catalytic oxidation method: concentrated sulfuric acid is used as a catalyst to react meta-chlorobenzoic acid with hydrogen peroxide at low temperature (0-10 DEG C). The method has the following technical defects: The concentrated sulfuric acid as a catalyst has a very high requirement for the corrosion resistance of the reaction equipment, thereby increasing the equipment maintenance cost; a large amount of acidic wastewater is generated after the reaction, and a large amount of alkali needs to be consumed for neutralization in the treatment process, and residual organic pollutants increase the difficulty of sewage treatment; hydrogen peroxide is easy to decompose and release heat in an acidic environment, which may cause an explosion accident and restrict the industrialized scale-up production; a large amount of acidic wastewater is generated in the post-reaction treatment process, and the environmental pollution is large.

[0003] Therefore, it is a long-term unsolved technical problem in the field to develop a green, safe and efficient preparation process of meta-chloroperoxybenzoic acid. SUMMARY

[0004] The present application aims to provide a preparation method of meta-chloroperoxybenzoic acid to solve the above problems.

[0005] The present application provides a preparation method of meta-chloroperoxybenzoic acid, comprising the following steps: Step one, alkaline dissolution: meta-chlorobenzoic acid is added into a mixed system of an alkaline solution and an organic solvent to generate sodium meta-chlorobenzoate; Step two, oxidation reaction: hydrogen peroxide is added dropwise into the system of step one under the condition that the temperature is lower than 15±5 DEG C to generate sodium meta-chloroperoxybenzoate; Step three, acidification: an acid solution is added into the reaction system to adjust the pH to 3-5, so that the sodium meta-chloroperoxybenzoate is converted into meta-chloroperoxybenzoic acid; Step four, liquid separation: the organic phase containing meta-chloroperoxybenzoic acid is separated after being left to stand and stratified; Step five, water washing: the organic phase is mixed with distilled water and stirred to separate the water phase; Step six, distillation: the organic phase is distilled at 40±5 DEG C to recover the solvent; Step seven, suction filtration: the temperature is lowered to 20±5 DEG C, and suction filtration is performed to obtain meta-chloroperoxybenzoic acid wet product.

[0006] Preferably, in the above preparation method of meta-chloroperoxybenzoic acid, in step one, the alkaline solution is a sodium hydroxide solution with a mass concentration of 30%, and the organic solvent is dichloromethane.

[0007] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, in step two, the temperature is controlled to be ≤20℃ when adding hydrogen peroxide, and if the temperature exceeds 20±2℃, the adding is stopped.

[0008] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, in step three, the acid used for acidification is a 30% mass concentration hydrochloric acid solution, and the pH is adjusted to 4±1.

[0009] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, after the separation in step four, sodium sulfite is added to the separated aqueous phase to treat the residual m-chloroperoxybenzoic acid, and then the aqueous phase is discharged to a sewage treatment unit.

[0010] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, the water washing operation in step five is repeated twice.

[0011] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, the solvent recovered by distillation in step six is dichloromethane, which is recycled for step one.

[0012] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, the purity of the wet product obtained in step seven is 93%-95%, and the mother liquor is discharged after sewage treatment.

[0013] Preferably, in the preparation method of the above m-chloroperoxybenzoic acid, the preparation method is carried out in a PTFE-lined reaction kettle.

[0014] Therefore, the present application adopts the above preparation method of m-chloroperoxybenzoic acid, which has the following beneficial effects: the raw materials used, such as m-chlorobenzoic acid, sodium hydroxide, and hydrogen peroxide, are inexpensive and easy to obtain, reducing the cost of raw materials. The use of alkaline conditions instead of concentrated sulfuric acid catalysis avoids the investment in high-cost corrosion-resistant equipment, reducing the production hardware cost. The reaction is carried out in an alkaline environment, avoiding contact with strong acid, reducing the risk of equipment corrosion and operation safety. The temperature control condition is clear, reducing the abnormal reaction caused by temperature loss of control. Through precise control of the reaction steps, the yield of the finished product can reach 89%-91%, and the purity reaches 93%-95%, meeting the needs of industrial large-scale production. The process steps are highly standardized and have strong repeatability, making it easy to scale up. The use of concentrated sulfuric acid is avoided, reducing the generation of acidic wastewater; the aqueous phase is discharged after sodium sulfite treatment, reducing the pollutant concentration. Dichloromethane is recovered by distillation, reducing solvent waste and exhaust gas emission, meeting the requirements of green chemical industry. The operation process of steps such as water washing, liquid separation, and distillation is clear, and no complex equipment is needed, reducing the difficulty and energy consumption of post-processing. The waste treatment process is clear, such as unified treatment of the aqueous phase and recovery of the mother liquor, meeting the environmental protection specifications and reducing the treatment cost.

[0015] The technical solutions of the present application will be further described in detail through examples. DETAILED DESCRIPTION

[0016] In order to make the above-mentioned technical solutions better understood, the above-mentioned technical solutions will be described in detail below in combination with specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0017] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0018] It should also be noted that the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the goods or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or include elements inherent to such goods or devices. Without more limitation, the element defined by the statement "including a" does not exclude the presence of other identical elements in the goods or devices including the element.

[0019] The present application provides a preparation method of meta-chloroperoxybenzoic acid, comprising the following steps: Step one, alkaline dissolution: adding meta-chlorobenzoic acid into a mixed system of alkaline solution and organic solvent to generate sodium meta-chloroperoxybenzoate; the alkaline solution is sodium hydroxide solution with a mass concentration of 30%, and the organic solvent is dichloromethane.

[0020] Step two, oxidation reaction: under the condition that the temperature is lower than 15±5℃, adding hydrogen peroxide to the system of step one to generate sodium meta-chloroperoxybenzoate; when adding hydrogen peroxide, the reaction temperature is controlled to be ≤20℃, and if the temperature exceeds 20±2℃, the adding of hydrogen peroxide is stopped.

[0021] Step three, acidification: adding acid solution to the reaction system to adjust the pH to 3-5, so that sodium meta-chloroperoxybenzoate is converted into meta-chloroperoxybenzoic acid; the acid used for acidification is hydrochloric acid solution with a mass concentration of 30%, and the pH is adjusted to 4±1.

[0022] Step four, liquid separation: standing and separating, and separating the organic phase containing meta-chloroperoxybenzoic acid; after liquid separation, sodium sulfite is added to the separated aqueous phase to treat residual meta-chloroperoxybenzoic acid, and then discharged to a sewage treatment unit.

[0023] Step five, water washing: mixing and stirring the organic phase with distilled water to separate the aqueous phase; the water washing operation is repeated twice.

[0024] Step six, distillation: distill the organic phase at 40±5℃ to recover the solvent; the distillated recovered solvent is dichloromethane, which is recycled for use in step one.

[0025] Step seven, suction filtration: after cooling to 20±5℃, suction filtration is performed to obtain the wet m-chloroperoxybenzoic acid; the purity of the obtained wet product is 93%-95%, and the mother liquor is discharged after sewage treatment. The preparation method is performed in a PTFE-lined reaction kettle.

[0026] In order to more clearly and specifically introduce the preparation method of m-chloroperoxybenzoic acid provided by the embodiments of the present application, the following will be described in combination with specific embodiments.

[0027] Embodiment 1 In a PTFE-lined reaction kettle, 125 kg of 30% sodium hydroxide solution was added, and 460 L of dichloromethane solvent was pumped in under stirring conditions, followed by the addition of 38 kg of m-chlorobenzoic acid, and stirring until the reaction was completed to form sodium m-chlorobenzoate.

[0028] The system was cooled to 15℃, and 40 L of 30% hydrogen peroxide was slowly added dropwise from the top of the kettle, and the temperature rise was controlled to be no more than 20℃; if the temperature exceeds 20±2℃, the dropwise addition is temporarily suspended. After the dropwise addition is completed, continue to stir, and monitor the reaction progress by liquid chromatography.

[0029] After the reaction is completed, 30% hydrochloric acid solution is added to the system to adjust the pH to 4, so that the sodium m-chloroperoxybenzoate is converted into m-chloroperoxybenzoic acid.

[0030] The system is allowed to stand, and the organic phase is separated into a temporary storage kettle; the aqueous phase is discharged into a storage kettle, and sodium sulfite is added to reduce the residual m-chloroperoxybenzoic acid, and then discharged into a sewage treatment unit.

[0031] The organic phase is transferred to the reaction kettle, 190 L of distilled water is added and stirred for 30 minutes, and then allowed to stand and separate; the water washing operation is repeated twice, and the organic phase is collected.

[0032] The organic phase is transferred to a distillation kettle, distilled water is added, and the temperature is raised to 40℃ to distill dichloromethane.

[0033] After distillation, the system is cooled to 205℃, and after uniform stirring, it is flowed into a suction filtration bag for suction filtration to obtain wet m-chloroperoxybenzoic acid with a purity of about 80%, and the mother liquor is discharged into a sewage treatment unit.

[0034] It can be detected that the yield of the obtained wet m-chloroperoxybenzoic acid is 90.5%, and the purity of the product is 94%; after sodium sulfite treatment, the COD value of the aqueous phase is reduced to below 500 mg / L, which meets the discharge standard.

[0035] Embodiment 2 Into a PTFE-lined reaction vessel was added 150 kg of 25% sodium hydroxide solution, after stirring, 460 L of dichloromethane was pumped in, and 38 kg of m-chlorobenzoic acid was added to form sodium m-chlorobenzoate.

[0036] The temperature was lowered to 10°C, 40 L of 30% hydrogen peroxide was added dropwise, and the reaction temperature was controlled to be ≤20°C. If the temperature exceeded 22°C, the dropwise addition was paused.

[0037] The pH was adjusted to 4 using 30% hydrochloric acid, and after standing and separating, the organic phase was washed with 190 L of distilled water twice, and the distillation temperature was controlled at 35°C. The temperature was lowered to 20°C before filtration.

[0038] The obtained m-chloroperoxybenzoic acid wet product was detected, and the wet product yield was 90%, and the product purity was 93.5%. After the concentration of sodium hydroxide was reduced, the alkalinity of the reaction system was weakened, but it could still ensure that the m-chlorobenzoic acid was completely dissolved, and the yield and purity were close to those of Example 1, which was suitable for raw material cost-sensitive scenarios.

[0039] Example 3 According to the operations of steps 1-4 of Example 1, 125 kg of 30% sodium hydroxide solution, 460 L of dichloromethane, 38 kg of m-chlorobenzoic acid, and 40 L of hydrogen peroxide were used.

[0040] After separation, the organic phase was washed with 190 L of distilled water three times, each time for 30 minutes, and the remaining steps were the same as in Example 1.

[0041] The obtained m-chloroperoxybenzoic acid wet product was detected, and the wet product yield was 89.2%, and the product purity was 95% (HPLC). Increasing the number of water washes could further remove inorganic salt impurities in the organic phase, improving the purity, which was suitable for scenarios requiring higher product purity (such as pharmaceutical intermediates), but the water washing energy consumption increased slightly.

[0042] Comparative Example 1 The m-chlorobenzoic acid was dissolved in dichloromethane solvent, and concentrated sulfuric acid was added as a catalyst, with a dosage of 10% of the mass of m-chlorobenzoic acid.

[0043] Under stirring conditions at 0-10°C, hydrogen peroxide solution was slowly added dropwise, and the reaction temperature was controlled to be no more than 10°C.

[0044] After the reaction was completed, the product was obtained through steps such as separation, water washing, and drying.

[0045] The obtained product had a wet product yield of about 72% and a purity of 88%, which was lower than that of Example 1. After the reaction, there were obvious acid corrosion marks on the inner wall of the equipment, which required regular replacement of corrosion-resistant parts. Acidic wastewater was generated, which required additional investment in neutralizing agents for treatment, and the treatment cost was 2.5 times that of Example 1. During the reaction, due to the strong corrosiveness of concentrated sulfuric acid, there was a risk of leakage of the dropwise addition device, which posed a safety hazard.

[0046] It can be seen that the embodiment 1 of the present application has significant advantages over the existing concentrated sulfuric acid catalysis method of comparative example 1 in many key technical indicators: the embodiment replaces concentrated sulfuric acid catalysis with alkaline conditions, the wet product yield is increased to about 90%, the product purity is above 93%-95%, and the strong corrosiveness of concentrated sulfuric acid to equipment is completely avoided, the equipment maintenance cost is greatly reduced; in terms of wastewater treatment, the COD value of the aqueous phase after treatment is ≤500 mg / L, the treatment difficulty and cost are significantly reduced; the raw material cost is reduced due to the use of cheap reagents such as sodium hydroxide, and the strong acid leakage risk is eliminated in the alkaline environment operation, the safety is greatly improved, fully embodying the comprehensive technical advantages of the present application in yield, purity, equipment protection, environmental protection and safety, etc.

[0047] Therefore, the present application adopts the above-mentioned preparation method of meta-chloroperoxybenzoic acid, which has the following beneficial effects: the raw materials used, such as meta-chlorobenzoic acid, sodium hydroxide and hydrogen peroxide, are low in price and easy to obtain, reducing the cost of raw materials. Alkaline conditions are used instead of concentrated sulfuric acid catalysis, avoiding the investment in high-cost corrosion-resistant equipment and reducing the production hardware cost. The reaction is carried out in an alkaline environment, avoiding strong acid contact and reducing equipment corrosion and operation safety risk. The temperature control condition is clear, reducing the abnormal reaction caused by temperature out of control. By precisely controlling the reaction steps, the finished product yield can reach about 80% wet product, meeting the needs of industrial large-scale production. The process steps are highly standardized and have strong repeatability, facilitating large-scale promotion. The use of concentrated sulfuric acid is avoided, reducing the generation of acidic wastewater; the aqueous phase is discharged after sodium sulfite treatment, reducing the pollutant concentration. Dichloromethane is recovered by distillation, reducing solvent waste and exhaust gas emission, meeting the requirements of green chemical industry. The operation process of steps such as water washing, liquid separation and distillation is clear, without the need for complex equipment, reducing the difficulty and energy consumption of post-treatment. The waste treatment process is clear, such as unified treatment of aqueous phase and recovery of mother liquor, meeting the environmental protection specifications and reducing the treatment cost.

[0048] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing meta-chloroperbenzoic acid, characterized in that: The following steps are involved: Step 1, alkaline dissolution: adding m-chlorobenzoic acid to a mixture of an alkaline solution and an organic solvent to react and generate sodium m-chlorobenzoate; Step 2, oxidation reaction: under the condition of temperature below 15±5°C, hydrogen peroxide is added dropwise to the system of step 1 for oxidation reaction to generate sodium meta-chloroperbenzoate; Step 3, acidification: adding an acid solution to the reaction system to adjust the pH to 3-5 to convert sodium meta-chloroperbenzoate into meta-chloroperbenzoic acid; Step 4, separation: standing and separating the layers to separate the organic phase containing meta-chloroperbenzoic acid; Step 5, water washing: mixing the organic phase with distilled water and stirring, and separating the aqueous phase; Step 6, distillation: distill the organic phase at 40±5°C to recover the solvent; Step 7, filtration: Cool to 20±5°C and filter to obtain a wet product of meta-chloroperbenzoic acid.

2. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein In step 1, the alkaline solution is a sodium hydroxide solution with a mass concentration of 30%, and the organic solvent is dichloromethane.

3. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein In step 2, the reaction temperature is controlled to be ≤20°C when hydrogen peroxide is added dropwise. If the temperature exceeds 20±2°C, the addition is stopped.

4. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein In step 3, the acid used for acidification is a hydrochloric acid solution with a mass concentration of 30%, and the pH is adjusted to 4±1.

5. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein After the liquid separation in step 4, sodium sulfite is added to the separated aqueous phase to treat the residual meta-chloroperbenzoic acid, and then discharged to the sewage treatment unit.

6. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein The water washing operation in step 5 was repeated twice.

7. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein The solvent recovered by distillation in step 6 is dichloromethane, which is recycled for step 1.

8. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein The purity of the wet product obtained in step 7 is 93%-95%, and the mother liquor is discharged after sewage treatment.

9. The method for preparing meta-chloroperbenzoic acid according to claim 1, wherein The preparation method is carried out in a PTFE-lined reactor.