阅读说明：本技术 一种高纯度粉末状的过氧化二(2,4-二氯苯甲酰)的制备方法 (Preparation method of high-purity powdery di (2, 4-dichlorobenzoyl) peroxide ) 是由 于磊 黄存影 杜孟成 李元杰 马振宇 王博玉 于 2021-08-20 设计创作，主要内容包括：本申请提供了一种高纯度粉末状的过氧化二(2,4-二氯苯甲酰)的制备方法,将2,4-二氯苯甲酰氯溶解至有机溶剂中得到2,4-二氯苯甲酰氯与有机溶剂的混合溶液,然后与过氧化钠溶液反应,然后通过分液、降温结晶与溶析结晶相结合的重结晶方式,得到过氧化二(2,4-二氯苯甲酰),有机溶剂为三氯甲烷、二氯甲烷或苯；降低了2,4-二氯苯甲酰氯的水解,减少了副反应的发生,降低了反应浓度,提高了反应体系分散性,加快了反应速率,缩短了反应时间,使反应更加充分彻底；提高了产品的纯度,产品的纯度≥99.70wt％；得到的产品的粒径≤100μm；反应温度不高,操作条件温和,收率为80.0％～90.0％,易于工业化生产。(The application provides a preparation method of high-purity powdery di (2, 4-dichlorobenzoyl) peroxide, which comprises the steps of dissolving 2, 4-dichlorobenzoyl chloride in an organic solvent to obtain a mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent, then reacting the mixed solution with a sodium peroxide solution, and then obtaining the di (2, 4-dichlorobenzoyl) peroxide in a recrystallization mode of combining liquid separation, cooling crystallization and elution crystallization, wherein the organic solvent is trichloromethane, dichloromethane or benzene; the hydrolysis of the 2, 4-dichlorobenzoyl chloride is reduced, the occurrence of side reactions is reduced, the reaction concentration is reduced, the dispersibility of a reaction system is improved, the reaction rate is accelerated, the reaction time is shortened, and the reaction is more complete; the purity of the product is improved, and is more than or equal to 99.70 wt%; the grain diameter of the obtained product is less than or equal to 100 mu m; the reaction temperature is not high, the operation condition is mild, the yield is 80.0-90.0 percent, and the industrial production is easy to realize.)

1. A method for preparing high-purity powdery bis (2, 4-dichlorobenzoyl) peroxide, which is characterized by comprising the following steps of sequentially carrying out:

1) adding a sodium hydroxide solution into a first reaction kettle, and stirring and cooling;

2) under the conditions of cooling and stirring, dropwise adding a hydrogen peroxide solution into the sodium hydroxide solution obtained in the step 1), mixing the sodium hydroxide and the hydrogen peroxide, carrying out a chemical reaction to generate sodium peroxide, and obtaining an intermediate liquid A after the reaction is finished;

3) adding a phase transfer catalyst into the intermediate liquid A prepared in the step 2), and uniformly mixing to obtain an intermediate liquid B;

4) dissolving 2, 4-dichlorobenzoyl chloride in an organic solvent to obtain a mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent;

5) under the conditions of cooling and increasing the stirring speed, dropwise adding the uniformly mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent prepared in the step 4) into the intermediate liquid B prepared in the step 3), and carrying out a chemical reaction on sodium peroxide and the 2, 4-dichlorobenzoyl chloride in the presence of a phase transfer catalyst to generate bis (2, 4-dichlorobenzoyl) peroxide to obtain an intermediate liquid C;

6) adding water into the intermediate liquid C prepared in the step 5), then sequentially stirring and separating by using a separating funnel, wherein the upper layer is an aqueous solution and the lower layer is an organic liquid after the separation is finished;

7) adding the organic liquid obtained in the step 6) into an inert solvent in a second reaction kettle, using the inert solvent as a dissolving-out agent to perform dissolving-out crystallization, using an ice maker to perform quenching operation on the liquid in the second reaction kettle, and continuously stirring at a low temperature to perform cooling crystallization to obtain an intermediate liquid D;

8) filtering the intermediate liquid D prepared in the step 7), and obtaining filter residue and filtrate after filtering;

9) drying the filter residue obtained in the step 8) at a low temperature to obtain powdery di (2, 4-dichlorobenzoyl) peroxide after drying.

2. The method for preparing high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein the sodium hydroxide solution in step 1) is a 32% sodium hydroxide aqueous solution.

3. The method for preparing high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein in the step 2), the amount of hydrogen peroxide is 1 (2-2.5);

and (3) dropwise adding a hydrogen peroxide solution when the temperature of the sodium hydroxide solution in the first reaction kettle is controlled to be 5-10 ℃.

4. The method for preparing high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein in the step 3), the phase transfer catalyst is sodium dodecyl sulfate, sodium dodecyl sulfate or sodium dodecyl benzene sulfonate;

the mass of the phase transfer catalyst is that the mass of 2, 4-dichlorobenzoyl chloride (0.2-0.5%) is 1.

5. The method for preparing high purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein in the step 4), the organic solvent is chloroform, dichloromethane or benzene; the amount of 2, 4-dichlorobenzoyl chloride (2-2.3) of hydrogen peroxide is 1; the mass of the organic solvent is (3-6) and the mass of the 2, 4-dichlorobenzoyl chloride is 1.

6. The method for preparing high-purity bis (2, 4-dichlorobenzoyl) peroxide in powder form according to claim 1, wherein in the step 5), a mixed solution of 2, 4-dichlorobenzoyl chloride and an organic solvent is added dropwise while controlling the temperature of the intermediate liquid B in the first reaction tank to be 5 ℃ to 10 ℃.

7. The method for producing high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein in the step 6), the mass of water is 32% by mass of an aqueous solution of sodium hydroxide (0.5 to 2):1, and the stirring time is 5 to 15 minutes.

8. The method for preparing high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein in the step 7), the liquid in the second reaction kettle is subjected to a quenching operation until the temperature of the liquid in the second reaction kettle is reduced to-15 ℃ to-5 ℃;

the inert solvent is methanol or acetone;

continuously stirring for 20min to 30min at the temperature of between 15 ℃ below zero and 5 ℃ below zero.

9. The method for preparing high purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to claim 1, wherein the low temperature drying temperature in the step 9) is 45 ℃ to 50 ℃.

Technical Field

The invention relates to the technical field of synthesis and preparation of di (2, 4-dichlorobenzoyl) peroxide, in particular to a preparation method of high-purity powdery di (2, 4-dichlorobenzoyl) peroxide.

Background

Bis (2, 4-dichlorobenzoyl) peroxide, also known as 2, 4-dichlorobenzoyl peroxide (DCBP for short), is a diacyl organic peroxide. The di (2, 4-dichlorobenzoyl) peroxide can be used as a normal-temperature curing initiator of unsaturated polyester resin, is usually matched with an accelerator for use, is widely applied to the fields of glass fiber reinforced plastic products, artificial marble, Baoli plates, automobile enclosure, polyester furniture, process casting, paint and the like, is particularly used for resin anchor rods which are rapidly cured at low temperature, and can shorten the resin gel time by more than 85 percent compared with dibenzoyl peroxide (BPO) which is also used as an initiator. In addition, DCBP is widely used as a good vulcanizing agent for silicon rubber, and can be used for preparing low-voltage power cable rubber materials, high-performance fluororubber composite materials, oil-resistant flame-retardant cables special for oil platforms and the like.

At present, the method for synthesizing the di (2, 4-dichlorobenzoyl) peroxide at home and abroad mainly comprises the following steps:

the first method comprises the following steps: adding hydrogen peroxide into a sodium hydroxide solution under a cooling condition to generate a sodium peroxide solution; then, 2, 4-dichlorobenzoyl chloride is added dropwise under stirring to produce bis (2, 4-dichlorobenzoyl) peroxide. Then cooling, filtering and washing to obtain the bis (2, 4-dichlorobenzoyl) peroxide product. Since 2, 4-dichlorobenzoyl chloride is very easy to hydrolyze, a large amount of 2, 4-dichlorobenzoic acid by-products are generated in the process of dripping 2, 4-dichlorobenzoyl chloride, so that the purity and yield of the final product are reduced. In addition, the method generates a large amount of synthetic mother liquor and washing water, and the waste water contains water-soluble sodium hydroxide, sodium chloride and 2, 4-sodium dichlorobenzoate, thereby causing serious environmental pollution. Meanwhile, the DCBP product synthesized by the method is granular and has larger grain size.

The second method comprises the following steps: the method adopts ammonium bicarbonate or sodium bicarbonate to replace sodium hydroxide and is matched with a surfactant to produce the bis (2, 4-dichlorobenzoyl) peroxide. The method does not solve the problems of hydrolysis of 2, 4-dichlorobenzoyl chloride and large wastewater amount, and simultaneously, when ammonium bicarbonate or sodium bicarbonate is used as an alkaline medium, the reaction completion time is long and reaches more than 6 hours, materials are easy to agglomerate in the reaction, the stirring is difficult, the particle size of a final product is larger, and the purity and the yield are lower.

The third method comprises the following steps: sodium carbonate is used as the alkaline medium for the synthesis reaction. This method still does not improve the problems of hydrolysis of 2, 4-dichlorobenzoyl chloride and the amount of waste water. Meanwhile, the sodium carbonate is very easy to react with the 2, 4-dichlorobenzoic acid generated by hydrolysis of the 2, 4-dichlorobenzoyl chloride to generate carbon dioxide gas, namely a large amount of bubbles are found in the synthesis reaction process, so that the yield and the purity of the product are reduced.

Disclosure of Invention

The invention aims to provide a preparation method of high-purity powdery bis (2, 4-dichlorobenzoyl) peroxide, which is characterized in that 2, 4-dichlorobenzoyl chloride is dissolved into an organic solvent to obtain a uniform and stable organic solution of the 2, 4-dichlorobenzoyl chloride, a mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent is reacted with a sodium peroxide solution, and then the high-purity powdery bis (2, 4-dichlorobenzoyl) peroxide is obtained through a recrystallization mode combining liquid separation, temperature reduction crystallization and elution crystallization.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a method for preparing high purity powdered bis (2, 4-dichlorobenzoyl) peroxide comprising the following sequential steps:

1) adding a sodium hydroxide solution into a first reaction kettle, and stirring and cooling;

2) under the conditions of cooling and stirring, dropwise adding a hydrogen peroxide solution into the sodium hydroxide solution obtained in the step 1), mixing the sodium hydroxide and the hydrogen peroxide, carrying out a chemical reaction to generate sodium peroxide, and obtaining an intermediate liquid A after the reaction is finished;

3) adding a phase transfer catalyst into the intermediate liquid A prepared in the step 2), and uniformly mixing to obtain an intermediate liquid B;

4) dissolving 2, 4-dichlorobenzoyl chloride in an organic solvent to obtain a mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent;

5) under the conditions of cooling and increasing the stirring speed, dropwise adding the uniformly mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent prepared in the step 4) into the intermediate liquid B prepared in the step 3), and carrying out a chemical reaction on sodium peroxide and the 2, 4-dichlorobenzoyl chloride in the presence of a phase transfer catalyst to generate bis (2, 4-dichlorobenzoyl) peroxide to obtain an intermediate liquid C;

6) adding water into the intermediate liquid C prepared in the step 5), then sequentially stirring and separating by using a separating funnel, wherein the upper layer is an aqueous solution and the lower layer is an organic liquid after the separation is finished;

7) adding the organic liquid obtained in the step 6) into an inert solvent in a second reaction kettle, using the inert solvent as a dissolving-out agent to perform dissolving-out crystallization, using an ice maker to perform quenching operation on the liquid in the second reaction kettle, and continuously stirring at a low temperature to perform cooling crystallization to obtain an intermediate liquid D;

8) filtering the intermediate liquid D prepared in the step 7), and obtaining filter residue and filtrate after filtering;

9) drying the filter residue obtained in the step 8) at a low temperature to obtain powdery di (2, 4-dichlorobenzoyl) peroxide after drying.

Preferably, in step 1), the sodium hydroxide solution is 32% sodium hydroxide aqueous solution by mass fraction.

Preferably, in the step 2), the amount of the hydrogen peroxide is 1 (2 to 2.5);

and (3) dropwise adding a hydrogen peroxide solution when the temperature of the sodium hydroxide solution in the first reaction kettle is controlled to be 5-10 ℃.

Preferably, in step 3), the phase transfer catalyst is sodium dodecyl sulfate, sodium dodecyl sulfate or sodium dodecyl benzene sulfonate;

the mass of the phase transfer catalyst is that the mass of 2, 4-dichlorobenzoyl chloride (0.2-0.5%) is 1.

Preferably, in step 4), the organic solvent is chloroform, dichloromethane or benzene; the amount of 2, 4-dichlorobenzoyl chloride (2-2.3) of hydrogen peroxide is 1; the mass of the organic solvent is (3-6) and the mass of the 2, 4-dichlorobenzoyl chloride is 1.

Preferably, in the step 5), when the temperature of the intermediate liquid B in the first reaction kettle is controlled to be 5-10 ℃, a mixed solution of 2, 4-dichlorobenzoyl chloride and an organic solvent is dropwise added.

Preferably, in step 6), the stirring time is 5 to 15min, where the mass of water is 32% and the mass of the aqueous solution of sodium hydroxide is 1 (0.5 to 2).

Preferably, in the step 7), the liquid in the second reaction kettle is subjected to quenching operation until the temperature of the liquid in the second reaction kettle is reduced to-15 ℃ to-5 ℃;

the inert solvent is methanol or acetone;

continuously stirring for 20min to 30min at the temperature of between 15 ℃ below zero and 5 ℃ below zero.

Preferably, in the step 9), the temperature for low-temperature drying is 45-50 ℃.

The application obtains the following beneficial technical effects:

(1) in the synthesis reaction, trichloromethane, dichloromethane or benzene is used as an organic solvent of the 2, 4-dichlorobenzoyl chloride, compared with the prior art that the 2, 4-dichlorobenzoyl chloride is directly dripped into a sodium peroxide solution, the addition of the organic solvent reduces the concentration of the 2, 4-dichlorobenzoyl chloride in the organic solvent, simultaneously, 2, 4-dichlorobenzoyl chloride molecules are wrapped in a hydrophobic organic solvent, in the process of dropwise adding the organic solvent solution of the 2, 4-dichlorobenzoyl chloride, the molecules of the 2, 4-dichlorobenzoyl chloride wrapped by the organic solvent preferentially react with the precipitated sodium peroxide crystals, thereby reducing the contact of the 2, 4-dichlorobenzoyl chloride and water, reducing the hydrolysis of the 2, 4-dichlorobenzoyl chloride and reducing the occurrence of side reactions.

(2) According to the method, trichloromethane, dichloromethane or benzene is used as an organic solvent of 2, 4-dichlorobenzoyl chloride, methanol or acetone is used as a elution agent for elution crystallization, and due to the fact that di (2, 4-dichlorobenzoyl) peroxide has high solubility in trichloromethane, dichloromethane or benzene, the solubility of di (2, 4-dichlorobenzoyl) peroxide in methanol or acetone is low, and the solubility of a byproduct benzoic acid in methanol or acetone is high, the purity of di (2, 4-dichlorobenzoyl) peroxide is improved through the elution crystallization mode, and the purity of the obtained di (2, 4-dichlorobenzoyl) peroxide is more than or equal to 99.70 wt%.

(3) In the application, trichloromethane, dichloromethane or benzene is used as an organic solvent of 2, 4-dichlorobenzoyl chloride, methanol or acetone is used as a solventing-out agent of the solventing-out crystal, and the process of preparing the bis (2, 4-dichlorobenzoyl) peroxide by recrystallization reduces the processes of soaking, alkali washing and water washing in the synthesis process, thereby improving the reaction efficiency, quickening the reaction rate, shortening the reaction time, controlling the whole preparation period of the bis (2, 4-dichlorobenzoyl) peroxide to be about 6-7 h, and ensuring that the reaction is more complete.

(4) According to the method, on the basis of elution crystallization, a low-temperature quenching cooling crystallization mode is matched, so that the particle size of the di (2, 4-dichlorobenzoyl) peroxide is reduced, the low-temperature quenching enables the solubility of a product in a solution to be rapidly reduced and further precipitated, and the low temperature is also beneficial to inhibiting the growth of crystal grains, so that the powdery di (2, 4-dichlorobenzoyl) peroxide is obtained, and the particle size of the obtained di (2, 4-dichlorobenzoyl) peroxide is less than or equal to 100 mu m.

(5) The preparation method provided by the application has the advantages of few side reactions, high and stable product yield of 80.0-90.0%, and easy industrial production.

Drawings

FIG. 1 is a graph showing a distribution of a particle size measurement of high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide prepared in example 1 of the present invention;

FIG. 2 is a graph showing a distribution of a particle size measurement of high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide prepared in example 2 of the present invention;

FIG. 3 is a graph showing a distribution of a particle size measurement of high-purity powdered bis (2, 4-dichlorobenzoyl) peroxide prepared in example 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The application provides a preparation method of high-purity powdery di (2, 4-dichlorobenzoyl) peroxide, which comprises the following steps in sequence:

1) adding a sodium hydroxide solution into a first reaction kettle, and stirring and cooling;

2) under the conditions of cooling and stirring, dropwise adding a hydrogen peroxide solution into the sodium hydroxide solution obtained in the step 1), mixing the sodium hydroxide and the hydrogen peroxide, carrying out a chemical reaction to generate sodium peroxide, and obtaining an intermediate liquid A after the reaction is finished;

3) adding a phase transfer catalyst into the intermediate liquid A prepared in the step 2), and uniformly mixing to obtain an intermediate liquid B;

4) dissolving 2, 4-dichlorobenzoyl chloride in an organic solvent to obtain a mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent;

5) under the conditions of cooling and increasing the stirring speed, dropwise adding the uniformly mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent prepared in the step 4) into the intermediate liquid B prepared in the step 3), and carrying out a chemical reaction on sodium peroxide and the 2, 4-dichlorobenzoyl chloride in the presence of a phase transfer catalyst to generate bis (2, 4-dichlorobenzoyl) peroxide to obtain an intermediate liquid C;

6) adding water into the intermediate liquid C prepared in the step 5), then sequentially stirring and separating by using a separating funnel, wherein the upper layer is an aqueous solution (inorganic salt aqueous solution) and the lower layer is an organic liquid after the separation is finished;

7) adding the organic liquid obtained in the step 6) into an inert solvent in a second reaction kettle, using the inert solvent as a dissolving-out agent to perform dissolving-out crystallization, using an ice maker to perform quenching operation on the liquid in the second reaction kettle, and continuously stirring at a low temperature to perform cooling crystallization to obtain an intermediate liquid D;

8) filtering the intermediate liquid D prepared in the step 7), and obtaining filter residue and filtrate after filtering;

9) drying the filter residue obtained in the step 8) at a low temperature to obtain powdery di (2, 4-dichlorobenzoyl) peroxide after drying.

In one embodiment of the present application, in step 1), the sodium hydroxide solution is a 32% mass fraction sodium hydroxide aqueous solution.

In one embodiment of the application, in the step 2), the amount of the hydrogen peroxide is 1 (2-2.5);

and (3) dropwise adding a hydrogen peroxide solution when the temperature of the sodium hydroxide solution in the first reaction kettle is controlled to be 5-10 ℃.

In one embodiment of the present application, in step 3), the phase transfer catalyst is sodium dodecyl sulfate, or sodium dodecyl benzene sulfonate;

the mass of the phase transfer catalyst is that the mass of 2, 4-dichlorobenzoyl chloride (0.2-0.5%) is 1.

In one embodiment of the present application, in step 4), the organic solvent is chloroform, dichloromethane or benzene; the amount of 2, 4-dichlorobenzoyl chloride (2-2.3) of hydrogen peroxide is 1; the mass of the organic solvent is (3-6) and the mass of the 2, 4-dichlorobenzoyl chloride is 1.

In one embodiment of the present application, in the step 5), a mixed solution of 2, 4-dichlorobenzoyl chloride and an organic solvent is added dropwise while controlling the temperature of the intermediate liquid B in the first reaction tank to be 5 to 10 ℃.

In one embodiment of the present application, in the step 6), the mass of water, i.e., the mass of the aqueous solution of sodium hydroxide with a mass fraction of 32% (0.5 to 2), is 1, and the stirring time is 5 to 15 min.

In one embodiment of the application, in the step 7), the liquid in the second reaction kettle is subjected to a quenching operation until the temperature of the liquid in the second reaction kettle is reduced to-15 ℃ to-5 ℃;

the inert solvent is methanol or acetone;

continuously stirring for 20min to 30min at the temperature of between 15 ℃ below zero and 5 ℃ below zero.

In one embodiment of the present application, in step 9), the temperature of the low-temperature drying is 45 ℃ to 50 ℃.

In the application, the organic liquid obtained in the step 6) is added into an inert solvent in a second reaction kettle, and the inert solvent is used as a elution agent to perform elution crystallization; carrying out rapid cooling operation on the liquid in the second reaction kettle by using an ice maker and continuously stirring at a low temperature, namely cooling crystallization; the elution crystallization and the cooling crystallization are carried out simultaneously.

In this application, in step 6), water is added to the intermediate liquid C prepared in step 5), and in this case, the water is added in order to completely dissolve the sodium chloride solid generated by the reaction, and since the solubility of the sodium chloride solid in water at 10 ℃ is 35.8g/100g, the amount of sodium chloride generated by the reaction cannot be completely dissolved in the upper aqueous solution, and the amount of sodium chloride is large but the amount of water is small, it is necessary to add water so that the sodium chloride is completely dissolved in water, and to remove the sodium chloride in the upper aqueous solution by liquid separation.

Methods and devices not described in detail in the present invention are all the prior art and are not described in detail.

For further understanding of the present invention, the following examples are provided to illustrate the preparation of high purity powdered bis (2, 4-dichlorobenzoyl) peroxide according to the present invention, and the scope of the present invention is not limited by the following examples.

Example 1

A method for preparing high purity powdered bis (2, 4-dichlorobenzoyl) peroxide comprising the following sequential steps:

1) adding 150g of sodium hydroxide solution into a first reaction kettle, and stirring and cooling;

in the step 1), the sodium hydroxide solution is 32% sodium hydroxide aqueous solution in mass fraction;

2) under the conditions of cooling and stirring, 74.18g of aqueous solution of 27.5 percent hydrogen peroxide is dropwise added into the sodium hydroxide solution in the step 1), the sodium hydroxide and the hydrogen peroxide are mixed and then undergo a chemical reaction to generate sodium peroxide, and an intermediate liquid A is obtained after the reaction is finished;

when the temperature of the sodium hydroxide solution in the first reaction kettle is controlled to be 5 ℃, dropwise adding a hydrogen peroxide solution;

the dropwise adding is completed within 1h, the reaction temperature is 5-10 ℃, and the reaction time is 0.5 h;

3) adding 0.85g of sodium dodecyl sulfate into the intermediate liquid A prepared in the step 2), and uniformly mixing to obtain an intermediate liquid B;

4) 211.58g of 99 mass percent 2, 4-dichlorobenzoyl chloride is fully dissolved into 846.30g of trichloromethane, and the mixture is uniformly mixed to obtain a uniform and stable trichloromethane solution of 20 mass percent 2, 4-dichlorobenzoyl chloride;

5) under the conditions of cooling and increasing the stirring speed, dropwise adding the uniformly mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent prepared in the step 4) into the intermediate liquid B prepared in the step 3), and obtaining an intermediate liquid C after completion;

the dropwise adding is completed within 2 hours, the reaction temperature is 5-10 ℃, and the reaction time is 2 hours;

6) adding 150g of water into the intermediate liquid C prepared in the step 5), then sequentially stirring for 10min, and separating by using a separating funnel to obtain an upper layer which is an aqueous solution and a lower layer which is an organic liquid after the separation is finished;

7) adding the organic liquid obtained in the step 6) into a second reaction kettle which is low in temperature and contains 500g of methanol, carrying out quenching operation on the liquid in the second reaction kettle by using an ice maker, and continuously stirring at low temperature to obtain an intermediate liquid D;

in the step 7), carrying out quenching operation on the liquid in the second reaction kettle until the temperature of the liquid in the second reaction kettle is reduced to-15 ℃;

continuously stirring at-15 deg.C for 25 min;

8) filtering the intermediate liquid D prepared in the step 7), and obtaining filter residue and filtrate after filtering;

9) drying the filter residue obtained in the step 8) at a low temperature to obtain powdery di (2, 4-dichlorobenzoyl) peroxide after drying;

in the step 9), the temperature for low-temperature drying is 50 ℃.

By detection and measurement, the bis (2, 4-dichlorobenzoyl) peroxide prepared in example 1 was 163.08g, the yield was 85.83%, the product was white powder in appearance, the purity was 99.78 wt%, and the particle size was not more than 100 μm.

Example 2

A method for preparing high purity powdered bis (2, 4-dichlorobenzoyl) peroxide comprising the following sequential steps:

1) adding 150g of sodium hydroxide solution into a first reaction kettle, and stirring and cooling;

in the step 1), the sodium hydroxide solution is 32% sodium hydroxide aqueous solution in mass fraction;

2) under the conditions of cooling and stirring, 74.18g of aqueous solution of 27.5 percent hydrogen peroxide is dropwise added into the sodium hydroxide solution in the step 1), the sodium hydroxide and the hydrogen peroxide are mixed and then undergo a chemical reaction to generate sodium peroxide, and an intermediate liquid A is obtained after the reaction is finished;

when the temperature of the sodium hydroxide solution in the first reaction kettle is controlled to be 5 ℃, dropwise adding a hydrogen peroxide solution;

the dropwise adding is completed within 1h, the reaction temperature is 5-10 ℃, and the reaction time is 0.5 h;

3) adding 0.85g of sodium dodecyl sulfate into the intermediate liquid A prepared in the step 2), and uniformly mixing to obtain an intermediate liquid B;

4) 211.58g of 99 mass percent 2, 4-dichlorobenzoyl chloride is fully dissolved into 846.30g of trichloromethane, and the mixture is uniformly mixed to obtain a uniform and stable trichloromethane solution of 20 mass percent 2, 4-dichlorobenzoyl chloride;

5) under the conditions of cooling and increasing the stirring speed, dropwise adding the uniformly mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent prepared in the step 4) into the intermediate liquid B prepared in the step 3), and obtaining an intermediate liquid C after completion;

the dropwise adding is completed within 2 hours, the reaction temperature is 5-10 ℃, and the reaction time is 2 hours;

6) adding 150g of water into the intermediate liquid C prepared in the step 5), then sequentially stirring for 10min, and separating by using a separating funnel to obtain an upper layer which is an aqueous solution and a lower layer which is an organic liquid after the separation is finished;

7) adding the organic liquid obtained in the step 6) into a second reaction kettle which is low in temperature and contains 500g of methanol, carrying out quenching operation on the liquid in the second reaction kettle by using an ice maker, and continuously stirring at low temperature to obtain an intermediate liquid D;

in the step 7), carrying out quenching operation on the liquid in the second reaction kettle until the temperature of the liquid in the second reaction kettle is reduced to-10 ℃;

continuously stirring at-10 deg.C for 25 min;

8) filtering the intermediate liquid D prepared in the step 7), and obtaining filter residue and filtrate after filtering;

9) drying the filter residue obtained in the step 8) at a low temperature to obtain powdery di (2, 4-dichlorobenzoyl) peroxide after drying;

in the step 9), the temperature for low-temperature drying is 50 ℃.

By detection and measurement, the bis (2, 4-dichlorobenzoyl) peroxide prepared in example 2 was 161.69g, the yield was 85.10%, the product was white powder in appearance, the purity was 99.81 wt%, and the particle size was not more than 100 μm.

Example 3

A method for preparing high purity powdered bis (2, 4-dichlorobenzoyl) peroxide comprising the following sequential steps:

1) adding 150g of sodium hydroxide solution into a first reaction kettle, and stirring and cooling;

in the step 1), the sodium hydroxide solution is 32% sodium hydroxide aqueous solution in mass fraction;

2) under the conditions of cooling and stirring, 74.18g of aqueous solution of 27.5 percent hydrogen peroxide is dropwise added into the sodium hydroxide solution in the step 1), the sodium hydroxide and the hydrogen peroxide are mixed and then undergo a chemical reaction to generate sodium peroxide, and an intermediate liquid A is obtained after the reaction is finished;

when the temperature of the sodium hydroxide solution in the first reaction kettle is controlled to be 5 ℃, dropwise adding a hydrogen peroxide solution;

the dropwise adding is completed within 1h, the reaction temperature is 5-10 ℃, and the reaction time is 0.5 h;

3) adding 0.85g of sodium dodecyl sulfate into the intermediate liquid A prepared in the step 2), and uniformly mixing to obtain an intermediate liquid B;

4) 211.58g of 99 mass percent 2, 4-dichlorobenzoyl chloride is fully dissolved into 846.30g of trichloromethane, and the mixture is uniformly mixed to obtain a uniform and stable trichloromethane solution of 20 mass percent 2, 4-dichlorobenzoyl chloride;

5) under the conditions of cooling and increasing the stirring speed, dropwise adding the uniformly mixed solution of the 2, 4-dichlorobenzoyl chloride and the organic solvent prepared in the step 4) into the intermediate liquid B prepared in the step 3), and obtaining an intermediate liquid C after completion;

the dropwise adding is completed within 2 hours, the reaction temperature is 5-10 ℃, and the reaction time is 2 hours;

6) adding 150g of water into the intermediate liquid C prepared in the step 5), then sequentially stirring for 10min, and separating by using a separating funnel to obtain an upper layer which is an aqueous solution and a lower layer which is an organic liquid after the separation is finished;

7) adding the organic liquid obtained in the step 6) into a second reaction kettle which is low in temperature and contains 500g of methanol, carrying out quenching operation on the liquid in the second reaction kettle by using an ice maker, and continuously stirring at low temperature to obtain an intermediate liquid D;

in the step 7), carrying out quenching operation on the liquid in the second reaction kettle until the temperature of the liquid in the second reaction kettle is reduced to-5 ℃;

continuously stirring at-5 deg.C for 25 min;

8) filtering the intermediate liquid D prepared in the step 7), and obtaining filter residue and filtrate after filtering;

9) drying the filter residue obtained in the step 8) at a low temperature to obtain powdery di (2, 4-dichlorobenzoyl) peroxide after drying;

in the step 9), the temperature for low-temperature drying is 50 ℃.

By detection and measurement, the bis (2, 4-dichlorobenzoyl) peroxide prepared in example 3 was 160.10g, the yield was 84.26%, the product was white powder in appearance, the purity was 99.75 wt%, and the particle size was not more than 100 μm.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.