Method for synthesizing m-chloroperoxybenzoic acid from m-chlorobenzoyl chloride

Abstract

The invention relates to the technical field of chemical engineering, and particularly discloses a method for synthesizing m-chloroperoxybenzoic acid from m-chlorobenzoyl chloride, which comprises the following steps: adding an aqueous solution of alkali into a reaction system, adding inorganic salt, then dropwise adding hydrogen peroxide, controlling the reaction temperature to be-2-10 DEG C, adding an organic solvent and a two-phase interface optimizer into the system in the step S1, and reacting for 1-2 hours at the temperature of-2-10 DEG C to obtain the m-chloroperoxybenzoic acid. Then adding m-chlorobenzoyl chloride, keeping the reaction temperature to be less than or equal to 25 DEG C and the reaction time to be less than or equal to 3 hours, cooling reaction liquid to be below 0 DEG C, adding dilute acid to neutralize until the pH is less than 4, standing for layering, then collecting an organic phase, carrying out vacuum low-temperature distillation or freezing on the organic phase to separate out a solid, and carrying out solid-liquid separation to obtain m-chloroperoxybenzoic acid; according to the method, the inorganic salt is added under the low-temperature reaction system, and then the two-phase interface optimizer and the stabilizer are added, so that decomposition of peroxide bonds and generation of side reactions are effectively inhibited, the reaction time is shortened, the method does not need high temperature and high pressure, the operation safety is high, and the emission of three wastes is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride. Background Art

[0002] As an important organic peroxide, m-chloroperbenzoic acid is used in cyclization reactions, Baeyer-Villiger reactions, N-oxidation reactions, S-oxidation reactions, etc., and is widely used in the fields of chemical engineering, medicine, agrochemicals, etc. 1,4-dioxane, as a commonly used solvent, can be miscible with water and most organic solvents, and has strong dissolving ability. However, at the same time, 1,4-dioxane is a kind of organic pollutant that is difficult to degrade. After entering the environment, it will remain in the soil and water for a long time, which may damage the balance of the aquatic ecosystem, affect soil fertility and vegetation growth, and cause serious environmental pollution. In addition, 1,4-dioxane can form an explosive mixture with vapor and air, and can cause combustion and explosion when encountering open fire and high heat energy. Therefore, strict safety regulations need to be observed during storage and use, so safety accidents are extremely likely to occur. Pipeline production is a continuous and automated production method. The raw materials pass through a closed pipeline system and complete chemical reactions in a continuous flow state. Then, the crude product is separated, purified and other processes, and finally the product is produced, with high production safety.

[0003] Traditional synthesis methods are mostly based on the reaction of m-chlorobenzoyl chloride and hydrogen peroxide under alkaline conditions. For example, phase transfer inorganic salts are used to promote the two-phase reaction, the reaction temperature range is relatively wide, and organic solvents are used as reaction media. Although the traditional method can achieve the synthesis of the target product, there are obvious limitations in terms of reaction efficiency, product purity and process controllability. There are the following problems: (1) m-chlorobenzoyl chloride and hydrogen peroxide are extremely easy to decompose and are unstable; (2) the reaction process temperature is difficult to control, easy to release heat, and the controllability is poor; (3) the use of high-concentration liquid alkali and a large amount of acid generates a large amount of wastewater; (4) the solvent is difficult to recover after the reaction. And in the prior art, 1,4-dioxane is mostly used as the reaction solvent. However, when 1,4-dioxane is used as the reaction solvent, there are problems such as high solvent recovery temperature and difficult product separation, resulting in low yield of m-chloroperbenzoic acid, which is not suitable for large-scale industrial production. Therefore, it is urgent to propose a method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride to solve the problems of difficult reaction temperature control, easy decomposition of raw materials, many by-products and high production safety risks in the traditional process. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride to solve the problems mentioned in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride, comprising:

[0007] S1. Add an aqueous solution of a base to the reaction system, add an inorganic salt, and then dropwise add hydrogen peroxide, controlling the reaction temperature at -2 to 10 °C;

[0008] S2. Add an organic solvent and a two-phase interface optimizer to the system of step S1, and then add m-chlorobenzoyl chloride, maintaining the reaction temperature ≤ 25 °C and the reaction time ≤ 3 hours;

[0009] S3. Cool the reaction solution to below 0 °C, add dilute acid to neutralize to pH < 4, and collect the organic phase after standing and separating the layers;

[0010] S4. Perform vacuum low-temperature distillation or freeze out solids on the organic phase, and obtain m-chloroperbenzoic acid after solid-liquid separation.

[0011] Preferably, the reaction system is selected from a batch reaction vessel or a continuous microreactor.

[0012] Preferably, the organic solvent is selected from at least one of dichloromethane, chloroform, dichloroethane, and carbon tetrachloride; the two-phase interface optimizer is at least one of methanol, ethanol, and isopropanol.

[0013] Preferably, the mass fraction of the aqueous solution of the base is 8% to 30%, and the base is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate; the mass fraction of hydrogen peroxide is 8% to 40%.

[0014] Preferably, the two-phase interface transfer agent is at least one of alcohols, water-soluble phosphine ligands, and quaternary ammonium salts.

[0015] Preferably, in step S4, a stabilizer is added during vacuum low-temperature distillation, and the stabilizer is an antioxidant or an inorganic porous material.

[0016] Preferably, in step S3, the aqueous phase after neutralization is extracted with an organic solvent to recover the residual product, and the extract is incorporated into the organic phase for treatment.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) The present invention adopts a pipeline automated production method, which reduces the liquid holdup, promotes the mass transfer process of the oxidant in the aqueous phase into the organic phase, the reaction process temperature is stable and controllable, shortens the reaction time, reduces the decomposition of hydrogen peroxide and m-chlorobenzoyl chloride, and greatly improves the production safety factor.

[0019] (2) Under a low-temperature reaction system, by adding inorganic salts, two-phase interface optimizers, and stabilizers, and conducting pipelined production with automatic temperature control, a large amount of heat released during the reaction is effectively avoided. The low-temperature reaction inhibits the decomposition of peroxy bonds and the generation of side reactions. Using alkaline substances and hydrogen peroxide for low-temperature feeding, with automatic feeding and temperature control, the disadvantages of low yield of the target product, heavy pollution, and difficult recovery in the original traditional production process are overcome, and the yield of m-chloroperbenzoic acid is increased. Using dichloromethane to replace 1,4-dioxane as the reaction solvent overcomes the disadvantage of a large discharge of organic substances in the wastewater in the traditional process and effectively solves the environmental pollution problem. The raw materials are easy to obtain and have obvious cost advantages, making it suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the process flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] Example 1:

[0023] Please refer to Figure 1 As shown, a method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride, the specific steps are as follows:

[0024] Add 360 mL of 10% sodium hydroxide aqueous solution, 1.5 g of magnesium sulfate, and 0.8 g of benzyltriethylammonium chloride into an intermittent reaction vessel. Cool the reaction system to 0 °C, slowly dropwise add 90 mL of 30% hydrogen peroxide, control the temperature not to exceed 8 °C. After keeping the temperature for 15 minutes, add 400 mL of dichloromethane organic solvent and 20 ml of methanol as the two-phase interface optimizer to the above system, and then add 49.5 g of m-chlorobenzoyl chloride. Keep the reaction temperature below 25 °C and stir the reaction for 2.5 hours;

[0025] Cool the reaction solution to -3 °C, slowly add dilute sulfuric acid (mass fraction 20%) to neutralize to pH = 3, with the temperature not higher than 10 °C, and let it stand for stratification. Separate the organic phase, extract the aqueous phase twice with 20 mL of dichloromethane, combine the organic phases, and conduct vacuum low-temperature distillation (30 °C, -0.09 MPa) to remove the solvent. Crystals precipitate, and after suction filtration and washing with water, 45 g of white solid m-chloroperbenzoic acid is obtained, with a yield of 92%, a content of 93.5% measured by titration method, and an HPLC purity of 90.8%.

[0026] Example 2:

[0027] Please refer to Figure 1 as shown below. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride, the specific steps are as follows:

[0028] Add 550 kg of 10% sodium hydroxide aqueous solution, 2.7 kg of magnesium sulfate, and 1.76 kg of tetrabutylammonium chloride into a 2000 L enamel reactor, cool down to 0 °C, slowly add 185 kg of 27.5% hydrogen peroxide dropwise, control the temperature not to exceed 8 °C, after keeping warm for 15 minutes, add 600 kg of dichloromethane and 50 kg of methanol to the above system, quickly add 75 kg of m-chlorobenzoyl chloride dropwise, keep the reaction temperature below 25 °C, and stir the reaction for 2.5 hours;

[0029] Cool the reaction solution to -3 °C, slowly add dilute sulfuric acid (mass fraction 20%) to neutralize to pH = 3, keep the temperature not higher than 10 °C, and let it stand for liquid separation. Separate the organic phase, extract the aqueous phase twice with 40 kg of dichloromethane, combine the organic phases, and perform vacuum low-temperature distillation (30 °C, -0.09 MPa) to remove the solvent, precipitate crystals, and obtain 68 kg of white solid m-chloroperbenzoic acid after centrifugal washing with water. The yield is 91.8%, the content measured by titration method is 93.2%, and the HPLC purity is 90.4%.

[0030] Example 3:

[0031] Please refer to Figure 1 as shown below. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride, the specific steps are as follows:

[0032] A sodium hydroxide aqueous solution with a mass fraction of 10% (containing 0.49% magnesium sulfate and 0.31% tetrabutylammonium chloride) and hydrogen peroxide with a mass fraction of 27.5% are cooled to below 0 °C. The 10% sodium hydroxide solution is controlled to flow into a rotary cutting pipe reactor (abbreviated as rotary cutting pipe reactor) at a flow rate of 504 kg / h. At the same time, the 27.5% hydrogen peroxide aqueous solution is controlled to flow at a rate of 180 kg / h and is added through 2 feed inlets, with the temperature controlled below 8 °C. The effluent enters another rotary cutting pipe reactor, and at the same time, a mixture of dichloromethane and methanol (dichloromethane:methanol = 6:1 by mass) is injected at a flow rate of 350 kg / h, and a mixture of dichloromethane + m-chlorobenzoyl chloride (dichloromethane:m-chlorobenzoyl chloride = 4:1 by mass) is injected at a flow rate of 375 kg / h. The reaction temperature is maintained below 25 °C. The effluent is collected in a 2000 L reaction kettle. When about 1200 L is collected, the reaction solution is cooled to -3 °C, and dilute sulfuric acid (mass fraction 25%) is slowly added to neutralize to pH = 3, with the temperature not exceeding 10 °C, and then left to stand for liquid separation. The organic phase is separated, and the aqueous phase is extracted twice with 30 kg of dichloromethane. The organic phases are combined, and the solvent is removed by vacuum low-temperature distillation (30 °C, -0.09 MPa) to precipitate crystals, which are centrifuged, washed with water, and dried to obtain white solid m-chloroperoxybenzoic acid with a yield of 92%. The content measured by titration is 93.8%, and the HPLC purity is 91.3%.

[0033] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride, characterized in that, Comprising: S1. Add an aqueous solution of alkali to the reaction system, add inorganic salts, and then dropwise add hydrogen peroxide, controlling the reaction temperature at -2 to 10 °C; S2. Add an organic solvent and a two-phase interface optimizer to the system of step S1, and then add m-chlorobenzoyl chloride, maintaining the reaction temperature ≤ 25 °C and the reaction time ≤ 3 hours; S3. Cool the reaction solution to below 0 °C, add dilute acid to neutralize to pH < 4, let it stand for layering, and collect the organic phase; S4. Perform vacuum low-temperature distillation or freeze out solids on the organic phase, and obtain m-chloroperbenzoic acid after solid-liquid separation.

2. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride according to claim 1, characterized in that: The reaction system is selected from a batch reaction vessel or a continuous microreactor.

3. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride according to claim 1, characterized in that: The organic solvent is selected from at least one of dichloromethane, chloroform, dichloroethane, and carbon tetrachloride; the two-phase interface optimizer is at least one of methanol, ethanol, and isopropanol.

4. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride according to claim 1, characterized in that: The mass fraction of the aqueous solution of alkali is 8% - 30%, and the alkali is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate; the mass fraction of hydrogen peroxide is 8% - 40%.

5. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride according to claim 1, characterized in that: The two-phase interface transfer agent is at least one of alcohols, water-soluble phosphine ligands, and quaternary ammonium salts.

6. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride according to claim 1, characterized in that: In step S4, a stabilizer is added during vacuum low-temperature distillation, and the stabilizer is an antioxidant or an inorganic porous material.

7. A method for synthesizing m-chloroperbenzoic acid from m-chlorobenzoyl chloride according to claim 1, characterized in that: In step S3, the aqueous phase after neutralization is extracted with an organic solvent to recover the residual product, and the extraction solution is incorporated into the organic phase for treatment.

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