A clean production method for preparing trichloroacetyl chloride from acetyl chloride

Abstract

The invention discloses a clean production method for preparing trichloroacetyl chloride from acetyl chloride, comprising the following steps: activating activated carbon, placing it in a first mixed solution consisting of a 1-sulfonic acid butyl-3-methylimidazole inner salt solution and a phosphotungstic acid solution, and calcining to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst; then mixing acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst, and reacting to obtain trichloroacetyl chloride. The present invention uses acetyl chloride as a raw material, realizes the recycling of acetyl chloride, and uses imidazole-modified phosphotungstic acid / activated carbon catalyst to enhance the selectivity of continuous chlorination reaction, thereby improving the purity and yield of trichloroacetyl chloride.

Description

Technical Field

[0001] The invention relates to the technical field of synthesizing trichloroacetyl chloride, and in particular to a clean production method for preparing trichloroacetyl chloride from acetyl chloride. Background Art

[0002] Trichloroacetyl chloride, with the chemical formula C2Cl4O, is an important intermediate for the synthesis of chlorpyrifos, methyl chlorpyrifos and herbicides. Chlorpyrifos and other pesticides can control more than 100 kinds of pests and can be used in agriculture, animal husbandry and the prevention of sanitary pests. Methyl chlorpyrifos is a low-toxic pesticide that can be used to control pests in stored grains and sanitary pests. The use of trichloroacetyl chloride to synthesize chlorpyrifos has a wide range of raw materials, low prices, and simple operation equipment. Therefore, the industrial production of the intermediate trichloroacetyl chloride is of great significance to the growth of crops.

[0003] At present, the synthesis methods of trichloroacetyl chloride mainly include: (1) industrially using trichloroacetic acid and thionyl chloride to react with each other in the presence of a catalyst for preparation, but HCl and SO2 gases are generated in the process. In order to prevent environmental pollution, they need to be absorbed by water and alkali solution respectively, and HCl and SO2 will take out a part of the thionyl chloride catalyst, thereby causing catalyst loss; (2) in order to reduce environmental pollution, trichloroacetyl chloride is synthesized by direct oxidation of tetrachloroethylene with O2 under ultraviolet catalysis; (3) nitric acid or hydrogen peroxide is used as an oxidant to oxidize trichloroacetaldehyde to trichloroacetic acid. Phosphorus trichloride is then added to obtain trichloroacetyl chloride. Although this method does not require a catalyst or special equipment, the generation of NO2 during the reaction will cause environmental pollution; (4) Dichloroacetyl chloride is used as a raw material to synthesize trichloroacetyl chloride under the action of chlorine and an organic base. This method has high raw material prices and is not suitable for industrial production; (5) Carbon tetrachloride and carbon dioxide are used as raw materials to synthesize trichloroacetyl chloride at 120°C and 10MPa with AlCl3, FeCl3 and CuCl as catalysts. This method has high reaction conditions and is difficult to use for industrial production; (6) The phosgene method is used for synthesis, which has high raw material costs and is not suitable for industrial production.

[0004] The document "Synthesis of Trichloroacetyl Chloride by Acetyl Chloride Gas Solid Phase Catalytic Chlorination" (Huang Junqi, Wang Liangjie, Luo Hean, Journal of Natural Science of Xiangtan University, 2006.28 (4): 61-64) discloses the use of acetyl chloride and chlorine as raw materials, and the use of gas-solid phase catalytic chlorination method to prepare trichloroacetyl chloride, the purity of which can reach 99.7%, but the reaction process is continuous chlorination, and the product includes some intermediate products such as chloroacetyl chloride and dichloroacetyl chloride in addition to the target product of trichloroacetyl chloride, so the yield of trichloroacetyl chloride prepared by the method is not high. At the same time, acetyl chloride is a by-product of industrial production, volatile, and has a strong pungent odor. If it is directly discharged without treatment, it will cause environmental pollution and waste of raw materials.

[0005] Therefore, it is a current research hotspot to prepare high-yield and high-purity trichloroacetyl chloride using acetyl chloride as raw material and to achieve clean production of trichloroacetyl chloride to solve the increasingly serious chemical pollution problem. Summary of the invention

[0006] In view of the above prior art, the purpose of the present invention is to provide a clean production method for preparing trichloroacetyl chloride from acetyl chloride. Acetyl chloride is used as a reaction raw material to solve the pollution caused by the direct discharge of acetyl chloride without treatment in the prior art, and dichlorohydantoin and imidazole are used to modify the phosphotungstic acid / activated carbon catalyst to improve the selectivity of acetyl chloride for continuous chlorination reaction, reduce the generation of chloroacetyl chloride and dichloroacetyl chloride, and improve the purity and yield of trichloroacetyl chloride.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a clean production method for preparing trichloroacetyl chloride from acetyl chloride, comprising the following steps:

[0009] (1) dropping a 1-sulfonic acid butyl-3-methylimidazolium inner salt solution into a phosphotungstic acid solution, mixing well, obtaining a first mixed solution, immersing the activated carbon after activation treatment in the first mixed solution, drying, and then calcining to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst;

[0010] (2) Acetyl chloride, dichlorohydantoin and the imidazole-modified phosphotungstic acid / activated carbon catalyst prepared in step (1) are mixed and reacted to obtain trichloroacetyl chloride.

[0011] Preferably, in step (1), the activated carbon is activated by crushing the activated carbon, and then activating the crushed activated carbon with nitric acid at 83-87° C. for 1.8-2.2 h. After the activation is completed, the activated carbon is washed with distilled water until it is neutral and dried.

[0012] More preferably, the particle size of the activated carbon after crushing is 30-50 mesh.

[0013] Further preferably, the mass fraction of the nitric acid is 43-46%.

[0014] Further preferably, the solid-liquid ratio of activated carbon to nitric acid is 1 g: (80-90) mL.

[0015] More preferably, the drying temperature is 60-80° C. and the drying time is 5-6 h.

[0016] Preferably, in step (1), the mass ratio of the phosphotungstic acid solution to the 1-sulfonic acid butyl-3-methylimidazole inner salt solution is (275-280):1.

[0017] Preferably, in step (1), the mass ratio of the activated carbon to the first mixed liquid is 10:(0.2-0.6).

[0018] Preferably, in step (1), the immersion time is 24 hours.

[0019] Preferably, in step (1), the drying temperature is 120-140° C. and the drying time is 10-12 h.

[0020] Preferably, in step (1), the calcination temperature is 320-360° C., the calcination time is 1.5-2 h, and the calcination environment is a nitrogen atmosphere.

[0021] Preferably, in step (2), the mass ratio of acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst is 1:(6-8):(0.03-0.06).

[0022] Preferably, in step (2), the reaction temperature is 80-90°C.

[0023] Beneficial effects of the present invention:

[0024] The invention adopts acetyl chloride as a raw material for preparing trichloroacetyl chloride, solves the technical problem in the prior art that acetyl chloride needs to be treated and then discharged, and realizes the recycling of acetyl chloride. At the same time, the phosphotungstic acid-activated carbon catalyst modified with 1-sulfonic acid butyl-3-methylimidazole inner salt is adopted to enhance the selectivity of continuous chlorination reaction, reduce the content of chloroacetyl chloride and dichloroacetyl chloride in the product, and increase the purity and yield of trichloroacetyl chloride. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : The infrared spectrum of trichloroacetyl chloride obtained in Example 1;

[0026] Figure 2 : Infrared spectrogram of trichloroacetyl chloride obtained in Example 2;

[0027] Figure 3 : Example 3 obtained the infrared spectrogram of trichloroacetyl chloride. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0029] As described in the background technology, in the prior art, trichloroacetic acid, tetrachloroethylene, etc. are mostly used as raw materials, and thionyl chloride, phosphorus trichloride, organic bases, AlCl3, FeCl3 and Lewis acids such as CuCl are used as catalysts. Most of these reactions have high raw material prices, produce polluting gases, etc., and are not suitable for large-scale industrial production.

[0030] Based on this, the present invention provides a clean production method for preparing trichloroacetyl chloride from acetyl chloride. Acetyl chloride is used as a raw material to realize the recycling of acetyl chloride, thereby reducing the environmental pollution caused by the emission of acetyl chloride into the air. A heteropolyacid-activated carbon catalyst is used to enhance the selectivity of the continuous chlorination reaction, reduce the contents of chloroacetyl chloride and dichloroacetyl chloride in the product, and increase the purity and yield of trichloroacetyl chloride.

[0031] The clean production method for preparing trichloroacetyl chloride from acetyl chloride comprises the following steps:

[0032] (1) crushing the activated carbon into 30-50 mesh, and activating the crushed activated carbon with 43-46% nitric acid at 83-87°C for 1.8-2.2h. After the activation is completed, washing with distilled water until neutral, and drying at 60-80°C for 5-6h;

[0033] The 1-sulfonic acid butyl-3-methylimidazole inner salt solution and the phosphotungstic acid solution are mixed at a mass ratio of (275-280):1 to obtain a first mixed solution, and the activated carbon after activation is placed in the first mixed solution, and the mass ratio of the activated activated carbon to the first mixed solution is 10:(0.2-0.6), immersed for 24 hours, dried at 120-140°C for 10-12 hours, and then calcined at 320-360°C under a nitrogen atmosphere for 1.5-2 hours to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst;

[0034] (2) Acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst are mixed in a mass ratio of 1:(6-8):(0.03-0.06), and reacted at 80-90° C. to obtain trichloroacetyl chloride.

[0035] The preparation method of the 1-sulfonic acid butyl-3-methylimidazolium salt solution is as follows: 0.0015 mol of 1-sulfonic acid butyl-3-methylimidazolium salt is weighed and dissolved in 5 mL of deionized water, and stirred to mix.

[0036] The preparation method of phosphotungstic acid solution is as follows: weigh 0.0005 mol of tungsten phosphate and dissolve it in 30 mL of deionized water, and stir it to make it completely dissolved.

[0037] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0038] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0039] Example 1

[0040] (1) The activated carbon was crushed into 40 meshes, and the crushed activated carbon was activated with 45% nitric acid at 85°C for 2 hours. After the activation was completed, it was washed with distilled water until neutral, and dried at 70°C for 5.5 hours;

[0041] The 1-sulfonic acid butyl-3-methylimidazole inner salt solution and the phosphotungstic acid solution were mixed at a mass ratio of 278:1 to obtain a first mixed solution, and the activated carbon after activation was placed in the first mixed solution, the mass ratio of the activated activated carbon to the first mixed solution was 10:0.4, immersed for 24 hours, dried at 130°C for 11 hours, and then calcined at 340°C under a nitrogen atmosphere for 1.8 hours to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst;

[0042] (2) Acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst are mixed in a mass ratio of 1:7:0.05 and reacted at 85° C. to obtain trichloroacetyl chloride.

[0043] The yield of the obtained trichloroacetyl chloride was 99.7% and the purity was 99.8%.

[0044] Example 2

[0045] (1) The activated carbon was crushed into 30 meshes, and the crushed activated carbon was activated with 43% nitric acid at 83°C for 1.8 hours. After the activation was completed, it was washed with distilled water until neutral, and dried at 60°C for 5 hours;

[0046] The 1-sulfonic acid butyl-3-methylimidazole inner salt solution and the phosphotungstic acid solution were mixed at a mass ratio of 275:1 to obtain a first mixed solution, and the activated carbon after activation was placed in the first mixed solution, and the mass ratio of the activated activated carbon to the first mixed solution was 10:0.2, and was immersed for 24 hours, dried at 120°C for 10 hours, and then calcined at 320°C for 1.5 hours under a nitrogen atmosphere to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst;

[0047] (2) Acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst are mixed in a mass ratio of 1:6:0.03 and reacted at 80° C. to obtain trichloroacetyl chloride.

[0048] The yield of the obtained trichloroacetyl chloride was 98.8% and the purity was 98.5%.

[0049] Example 3

[0050] (1) The activated carbon was crushed into 50 meshes, and the crushed activated carbon was activated with 46% nitric acid at 87°C for 2.2 hours. After the activation was completed, it was washed with distilled water until neutral, and dried at 80°C for 6 hours;

[0051] The 1-sulfonic acid butyl-3-methylimidazole inner salt solution and the phosphotungstic acid solution were mixed at a mass ratio of 280:1 to obtain a first mixed solution, and the activated carbon after activation was placed in the first mixed solution, the mass ratio of the activated activated carbon to the first mixed solution was 10:0.6, immersed for 24 hours, dried at 140°C for 12 hours, and then calcined at 360°C under a nitrogen atmosphere for 2 hours to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst;

[0052] (2) Acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst are mixed in a mass ratio of 1:8:0.06 and reacted at 90° C. to obtain trichloroacetyl chloride.

[0053] The yield of the obtained trichloroacetyl chloride was 99.2% and the purity was 99.1%.

[0054] Comparative Example 1

[0055] (1) pulverizing activated carbon into 40 meshes, activating the pulverized activated carbon with 45% by mass nitric acid at 85° C. for 2 h, washing with distilled water until neutral, and drying at 70° C. for 5.5 h to obtain an activated carbon catalyst;

[0056] (2) Acetyl chloride, dichlorohydantoin and activated carbon catalyst are mixed in a mass ratio of 1:7:0.05 and reacted at 85°C to obtain trichloroacetyl chloride.

[0057] The yield of the obtained trichloroacetyl chloride was 87.7% and the purity was 88.0%.

[0058] Comparative Example 2

[0059] (1) mixing a 1-sulfonic acid butyl-3-methylimidazole inner salt solution and a phosphotungstic acid solution at a mass ratio of 278:1 to obtain a first mixed solution, drying the first mixed solution to obtain an imidazole-modified phosphotungstic acid catalyst;

[0060] (2) Acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid catalyst are mixed in a mass ratio of 1:7:0.05 and reacted at 85° C. to obtain trichloroacetyl chloride.

[0061] The yield of the obtained trichloroacetyl chloride was 89.1% and the purity was 92.8%.

[0062] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A clean production method for preparing trichloroacetyl chloride from acetyl chloride, characterized in that: The following steps are involved: (1) mixing a 1-sulfonic acid butyl-3-methylimidazole inner salt solution and a phosphotungstic acid solution at a mass ratio of (275-280):1 to obtain a first mixed solution, immersing the activated carbon after activation treatment in the first mixed solution for 24 hours, drying, and then calcining at 320-360° C. for 1.5-2 hours to obtain an imidazole-modified phosphotungstic acid / activated carbon catalyst; Wherein, the mass ratio of the activated carbon to the first mixed liquid is 10:(0.2-0.6); (2) Acetyl chloride, dichlorohydantoin and imidazole-modified phosphotungstic acid / activated carbon catalyst are mixed in a mass ratio of 1:(6-8):(0.03-0.06), and reacted at 80-90° C. to obtain trichloroacetyl chloride.

2. The clean production method for preparing trichloroacetyl chloride from acetyl chloride according to claim 1, characterized in that: The activated carbon activation treatment operation is as follows: the activated carbon is crushed into 30-50 meshes, and the crushed activated carbon is activated with nitric acid having a mass fraction of 43-46% at 83-87° C. for 1.8-2.2 hours, wherein the solid-liquid ratio of the activated carbon to the nitric acid is 1 g: (80-90) mL. After the activation is completed, the activated carbon is washed with distilled water until it is neutral, and dried at 60-80° C. for 5-6 hours.

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