Method for treating byproduct hydrogen chloride in acetochlor and butachlor production process

Abstract

The invention relates to a method for treating a byproduct hydrogen chloride in a production process of acetochlor and / or butachlor. The treatment method comprises the step of treating hydrogen chloride by using vaporized methanol. According to the treatment method disclosed by the invention, a byproduct hydrogen chloride gas generated in the process of producing acetochlor and butachlor is solved, a new product chloromethane is also generated, and ammonium chloride which is low in price and relatively strong in corrosivity is replaced. Chloromethane is an important organic compound, and due to special chemical properties and wide application requirements of chloromethane, compared with ammonium chloride, the market demand of chloromethane is larger, and the price of chloromethane is higher. The treatment method disclosed by the invention is high in safety, high in byproduct value, suitable for large-scale industrial production and wide in application prospect.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a method for treating hydrogen chloride which is a byproduct in the production process of acetochlor and butachlor. Background Art

[0002] Hydrogen chloride gas is a colorless, irritating, corrosive and asphyxiating gas. It is an important industrial chemical substance used in the manufacture of dyes, fragrances, medicines, various chlorides and corrosion inhibitors. A large amount of hydrogen chloride gas is produced during the reaction of many pesticides and their intermediates.

[0003] In the process of producing acetochlor and butachlor by the methylene process, there is a condensation reaction (i.e., the reaction between tertiary amine compounds and alcohols) that produces hydrogen chloride gas. In order to deal with the hydrogen chloride in the reaction tail gas, the most common method is to add a tail gas absorption device to dissolve it in water to generate hydrochloric acid. However, this method faces the problem of excess hydrochloric acid that cannot be disposed of, and because hydrochloric acid is highly corrosive, it will lead to problems such as difficulty in on-site equipment maintenance and danger to personnel operation.

[0004] There is also a hydrogen chloride treatment method in the production process of amide crude oil. Ammonia gas reacts with hydrogen chloride to produce by-product ammonium chloride. The resulting ammonium chloride can be sold, but the quality is not high, the price is low, and the processing cost is high. Since ammonium chloride is in powder form and highly corrosive, it may also cause irreversible damage to on-site personnel. It is easy to clog pipes and filters during subsequent processing, which prolongs the operation time of the entire process and wastes manpower and material resources.

[0005] Therefore, there is an urgent need in the art for a safe and efficient method for treating hydrogen chloride, a byproduct generated during the production of acetochlor and butachlor. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In view of the above problems existing in the prior art, the object of the present invention is to provide a safe and efficient method for treating hydrogen chloride produced as a byproduct in the process of acetochlor and butachlor.

[0008] Solutions for solving problems

[0009] The invention provides a method for treating hydrogen chloride which is a byproduct in the production process of acetochlor and / or butachlor. The method comprises: treating the hydrogen chloride by using vaporized methanol.

[0010] Preferably, the processing method comprises the following steps:

[0011] (1) Adding alcohol into a condensation reactor and then adding a tertiary amine compound to carry out a condensation reaction;

[0012] (2) transporting the hydrogen chloride produced by the condensation reaction in step (1) to a synthesis reactor;

[0013] (3) introducing vaporized methanol and a catalyst into the synthesis reactor of step (2) to react and obtain methyl chloride.

[0014] Preferably, the mass ratio of the vaporized methanol to the hydrogen chloride is 2:1 to 1:2.

[0015] Preferably, the mass ratio of the vaporized methanol to the hydrogen chloride is 1:1 to 1:1.5.

[0016] Preferably, the mass ratio of the vaporized methanol to the hydrogen chloride is 1:1.08 to 1:1.1.

[0017] Preferably, the alcohol is ethanol and / or butanol;

[0018] Preferably, the tertiary amine compound is 2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline and / or 2,6-diethyl-N-chloromethyl-α-acetylchloroaniline.

[0019] Preferably, the temperature of the condensation reaction is 30-60°C.

[0020] Preferably, the catalyst in step (3) is an aqueous solution of zinc chloride;

[0021] More preferably, the mass ratio of zinc chloride to water is 3-7:1;

[0022] Further preferably, the mass ratio of zinc chloride to water is 4-5:1.

[0023] Preferably, the reaction temperature in step (3) is 120-180°C;

[0024] More preferably, the reaction temperature in step (3) is 130-160°C.

[0025] The present invention also provides a device for treating hydrogen chloride produced as a byproduct in the production process of acetochlor and / or butachlor, the device comprising:

[0026] A condensation kettle (3) is used for condensing an alcohol with a tertiary amine compound to prepare acetochlor or butachlor, and the condensation kettle (3) is provided with a gas outlet for discharging a by-product, hydrogen chloride;

[0027] A synthesis reactor (4), the synthesis reactor (4) is connected to the gas outlet of the condensation reactor (3), and is used to react the hydrogen chloride with the vaporized methanol to treat the hydrogen chloride.

[0028] Effects of the Invention

[0029] The treatment method of the present invention not only solves the byproduct hydrogen chloride gas generated in the process of producing acetochlor and butachlor, but also generates a new product methyl chloride, which replaces the low-priced and highly corrosive ammonium chloride. Methyl chloride is an important organic compound. Due to its special chemical properties and wide application requirements, the market demand is larger than that of ammonium chloride and the price is higher. The treatment method of the present invention has high safety and high byproduct value, is suitable for large-scale industrial production, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of hydrogen chloride treatment in this application.

[0031] Figure 2 The following is the detection result of methyl chloride obtained in Example 1.

[0032] Figure 3 The following is the test result of ammonium chloride prepared in Comparative Example 1.

[0033] Description of reference numerals:

[0034] 1-reaction kettle, 2-alcohol tank, 3-condensation kettle, 4-synthesis kettle, 5-dealcoholization kettle. DETAILED DESCRIPTION

[0035] In order to make the technical solutions and beneficial effects of the present invention more clearly understandable, the following is a detailed description by listing specific embodiments. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0036] The invention provides a method for treating hydrogen chloride which is a byproduct in the production process of acetochlor and / or butachlor. The method comprises: treating the hydrogen chloride by using vaporized methanol.

[0037] In some embodiments, the treatment method comprises the following steps:

[0038] (1) Adding alcohol into a condensation reactor and then adding a tertiary amine compound to carry out a condensation reaction;

[0039] (2) transporting the hydrogen chloride produced by the condensation reaction in step (1) to a synthesis reactor;

[0040] (3) introducing vaporized methanol and a catalyst into the synthesis reactor of step (2) to react and obtain methyl chloride.

[0041] In certain embodiments, the mass ratio of the vaporized methanol to the hydrogen chloride is 2:1 to 1:2.

[0042] In certain embodiments, the mass ratio of the vaporized methanol to the hydrogen chloride is 2:1, or 1.9:1, or 1.8:1, or 1.7:1, or 1.6:1, or 1.5:1, or 1.4:1, or 1.3:1, or 1.2:1, or 1.1:1, or 1:1, or 1:1.01, or 1:1.02, or 1:1.03, or 1:1.04, or 1:1.05, or 1:1.06, or 1:1.07, or 1:1.08, or 1:1.09, or 1:1.1, or 1:1.2, or 1:1.3, or 1:1.4, or 1:1.5, or 1:1.6, or 1:1.7, or 1:1.8, or 1:1.9, or 1:2.

[0043] In certain embodiments, the mass ratio of the vaporized methanol to the hydrogen chloride is 1:1 to 1:1.5.

[0044] In some embodiments, the mass ratio of the vaporized methanol to the hydrogen chloride is 1:1.08 to 1:1.1. In some embodiments, the molar ratio of the alcohol to the tertiary amine compound is 2:1 to 1:5.

[0045] In certain embodiments, the molar ratio of the alcohol to the tertiary amine compound is 2:1, or 1.5:1, or 1:1, or 1:1.1, or 1:1.2, or 1:1.3, or 1:1.4, or 1:1.5, or 1:1.6, or 1:1.7, or 1:1.8, or 1:1.9, or 1:2, or 1:2.5, or 1:3, or 1:3.5, or 1:4, or 1:4.5, or 1:5.

[0046] In certain embodiments, the molar ratio of the alcohol to the tertiary amine compound is 1:1 to 1:2.

[0047] In certain embodiments, the alcohol is ethanol and / or butanol.

[0048] In certain embodiments, the alcohol is ethanol.

[0049] In certain embodiments, the alcohol is butanol.

[0050] In certain embodiments, the tertiary amine compound is 2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline and / or 2,6-diethyl-N-chloromethyl-α-acetylchloroaniline.

[0051] In certain embodiments, the tertiary amine compound is 2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline.

[0052] In certain embodiments, the tertiary amine compound is 2,6-diethyl-N-chloromethyl-α-acetylchloroaniline.

[0053] In certain embodiments, the condensation reaction temperature is 30-60°C.

[0054] In certain embodiments, the temperature of the condensation reaction is 30°C, or 31°C, or 32°C, or 33°C, or 34°C, or 35°C, or 36°C, or 37°C, or 38°C, or 39°C, or 40°C, or 41°C, or 42°C, or 43°C, or 44°C, or 45°C, or 46°C, or 47°C, or 48°C, or 49°C, or 50°C, or 51°C, or 52°C, or 53°C, or 54°C, or 55°C, or 56°C, or 57°C, or 58°C, or 59°C, or 60°C.

[0055] In certain embodiments, the catalyst in step (3) is an aqueous solution of zinc chloride.

[0056] In certain embodiments, the mass ratio of zinc chloride to water is 3-7:1.

[0057] In certain embodiments, the mass ratio of zinc chloride to water is 3:1, or 3.1:1, or 3.2:1, or 3.3:1, or 3.4:1, or 3.5:1, or 3.6:1, or 3.7:1, or 3.8:1, or 3.9:1, or 4:1, or 4.1:1, or 4.2:1, or 4.3:1, or 4.4:1, or 4.5:1, or 4.6:1, or 4.7:1, or 4.8:1 , or 4.9:1, or 5:1, or 5.1:1, or 5.2:1, or 5.3:1, or 5.4:1, or 5.5:1, or 5.6:1, or 5.7:1, or 5.8:1, or 5.9:1, or 6:1, or 6.1:1, or 6.2:1, or 6.3:1, or 6.4:1, or 6.5:1, or 6.6:1, or 6.7:1, or 6.8:1, or 6.9:1, or 7:1.

[0058] In certain embodiments, the mass ratio of zinc chloride to water is 4-5:1.

[0059] In certain embodiments, the reaction temperature in step (3) is 120-180°C.

[0060] In certain embodiments, the reaction temperature in step (3) is 120°C, or 121°C, or 122°C, or 123°C, or 124°C, or 125°C, or 126°C, or 127°C, or 128°C, or 129°C, or 130°C, or 131°C, or 132°C, or 133°C, or 134°C, or 135°C, or 136°C, or 137°C, or 138°C, or 139°C, or 140°C, or 141°C, or 142°C, or 143°C, or 144°C, or 145°C, or 146°C, or 147°C, or 148°C. ℃, or 149℃, or 150℃, or 151℃, or 152℃, or 153℃, or 154℃, or 155℃, or 156℃, or 157℃, or 158℃, or 159℃, or 160℃, or 161℃, or 162℃, or 163℃, or 164℃, or 165℃, or 166℃, or 167℃, or 168℃, or 169℃, or 170℃, or 171℃, or 172℃, or 173℃, or 174℃, or 175℃, or 176℃, or 177℃, or 178℃, or 179℃, or 180℃.

[0061] In certain embodiments, the reaction temperature in step (3) is 130-160°C.

[0062] The present invention also provides a device for treating hydrogen chloride produced as a byproduct in the production process of acetochlor and / or butachlor, the device comprising:

[0063] A condensation kettle (3) is used for condensing an alcohol with a tertiary amine compound to prepare acetochlor or butachlor, and the condensation kettle (3) is provided with a gas outlet for discharging a by-product, hydrogen chloride;

[0064] A synthesis reactor (4), the synthesis reactor (4) is connected to the gas outlet of the condensation reactor (3), and is used to react the hydrogen chloride with the vaporized methanol to treat the hydrogen chloride.

[0065] In certain embodiments, the device further comprises: a reaction kettle (1), wherein the reaction kettle (1) is connected to the condensation kettle (3) and is used for preparing the tertiary amine compound.

[0066] In certain embodiments, the device further comprises: an alcohol tank (2), wherein the alcohol tank (2) is connected to the condensation reactor (3) and is used to store the alcohol.

[0067] In certain embodiments, the device further comprises: a dealcoholization kettle (5), wherein the dealcoholization kettle (5) is connected to the liquid outlet of the condensation kettle (3) to carry out dealcoholization treatment on the prepared acetochlor or butachlor.

[0068] Example 1: Treatment of Hydrogen Chloride in the Acetochlor Production Process Using Vaporized Methanol

[0069] When producing acetochlor, ethanol is first placed in a condensation reactor, and then a tertiary amine compound (2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline) is added. The ethanol and the tertiary amine compound are condensed at a molar ratio of 1:(1-2) at 30-60°C.

[0070] While the reaction is in progress, negative pressure (-5 to -15 KPa) is applied to transport the generated hydrogen chloride gas (360 kg) to the synthesis reactor through a pipeline, vaporized methanol (327 kg) is introduced into the synthesis reactor, and then an aqueous solution of zinc chloride (the mass ratio of zinc chloride to water is 4-5:1) is added as a catalyst to react at a reaction temperature of 130-160°C.

[0071] The acetochlor after the condensation reaction is completed enters the dealcoholization kettle and is distilled at normal pressure. The terminal temperature of the dealcoholization kettle is 90-100° C., and the content of the final acetochlor is above 94%.

[0072] Example 2: Treatment of Hydrogen Chloride in the Acetochlor Production Process Using Vaporized Methanol

[0073] When producing acetochlor, ethanol is first placed in a condensation reactor, and then a tertiary amine compound (2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline) is added. The ethanol and the tertiary amine compound are condensed at a molar ratio of 1:(1-2) at 30-60°C.

[0074] While the reaction is in progress, negative pressure (-5 to -15 KPa) is applied to transport the generated hydrogen chloride gas (365 kg) to the synthesis reactor through a pipeline, vaporized methanol (332 kg) is introduced into the synthesis reactor, and then an aqueous solution of zinc chloride (the mass ratio of zinc chloride to water is 4-5:1) is added as a catalyst to react at a reaction temperature of 130-160°C.

[0075] The acetochlor after the condensation reaction is completed enters the dealcoholization kettle and is distilled at normal pressure. The terminal temperature of the dealcoholization kettle is 90-100° C., and the content of the final acetochlor is above 94%.

[0076] Example 3: Using vaporized methanol to treat hydrogen chloride in the butachlor production process

[0077] When producing butachlor, butanol is first placed in a condensation reactor, and then a tertiary amine compound (2,6-diethyl-N-chloromethyl-α-acetylchloroaniline) is added. The butanol and the tertiary amine compound are condensed at a molar ratio of 1:(1-2) at 30-60°C.

[0078] While the reaction is in progress, negative pressure (-5 to -15 KPa) is applied to transport the generated hydrogen chloride gas (280 kg) to the synthesis reactor through a pipeline, vaporized methanol (260 kg) is introduced into the synthesis reactor, and then an aqueous solution of zinc chloride (the mass ratio of zinc chloride to water is 4-5:1) is added as a catalyst to react at a reaction temperature of 130-160°C.

[0079] The butachlor after the condensation reaction is completed enters the dealcoholization kettle and is distilled at normal pressure. The terminal temperature of the dealcoholization kettle is 130-140° C., and the content of butachlor finally obtained is above 94%.

[0080] Example 4: Treatment of Hydrogen Chloride in Butachlor Production Using Vaporized Methanol

[0081] When producing butachlor, butanol is first placed in a condensation reactor, and then a tertiary amine compound (2,6-diethyl-N-chloromethyl-α-acetylchloroaniline) is added. The butanol and the tertiary amine compound are condensed at a molar ratio of 1:(1-2) at 30-60°C.

[0082] While the reaction is in progress, negative pressure (-5 to -15 KPa) is applied to transport the generated hydrogen chloride gas (285 kg) to the synthesis reactor through a pipeline, vaporized methanol (259 kg) is introduced into the synthesis reactor, and then an aqueous solution of zinc chloride (the mass ratio of zinc chloride to water is 4-5:1) is added as a catalyst to react at a reaction temperature of 130-160°C.

[0083] The butachlor after the condensation reaction is completed enters the dealcoholization kettle and is distilled at normal pressure. The terminal temperature of the dealcoholization kettle is 130-140° C., and the content of butachlor finally obtained is above 94%.

[0084] Comparative Example 1: Using ammonia to treat hydrogen chloride in the production process of acetochlor

[0085] When producing acetochlor, ethanol is first placed in a condensation reactor, and then a tertiary amine compound (2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline) is added. The ethanol and the tertiary amine compound are condensed at a molar ratio of 1:(1-2) at 30-60°C for 1 hour, and then ammonia gas (the amount of ethanol added is about 13.5 times the amount of ammonia added) is introduced to neutralize the hydrogen chloride gas to produce ammonium chloride.

[0086] During the subsequent processing of ammonium chloride, the filter will be clogged and need to be cleaned frequently. In addition, there is a lot of ammonium chloride dust on site, which is very harmful to the human body.

[0087] Comparative Example 2: Using ammonia to treat hydrogen chloride in the production process of butachlor

[0088] When producing butachlor, butanol is first placed in a condensation reactor, and then a tertiary amine compound (2,6-diethyl-N-chloromethyl-α-acetylchloroaniline) is added. The butanol and the tertiary amine compound are condensed at a molar ratio of 1:(1-2) at 30-60°C for 1 hour, and then ammonia (the amount of butanol added is about 13.5 times the amount of ammonia added) is introduced to neutralize the hydrogen chloride gas to produce ammonium chloride.

[0089] During the subsequent processing of ammonium chloride, the filter will be clogged and need to be cleaned frequently. In addition, there is a lot of ammonium chloride dust on site, which is very harmful to the human body.

[0090] Example 5: Quality testing of by-products

[0091] The methyl chloride prepared in Example 1 was tested according to HG / T 3674-2018, and the results were as follows: Figure 2 As shown, the quality of methyl chloride is qualified, and the content is 99.9%.

[0092] The ammonium chloride prepared in Comparative Example 1 was tested according to GB / T 2946-2018, and the results were as follows: Figure 3 As shown, the quality of ammonium chloride is qualified.

[0093] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes may be made on the basis of the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present invention and do not limit the scope of protection of the patent of the present invention.

Claims

1. A method for treating hydrogen chloride as a byproduct in the production process of acetochlor and / or butachlor, characterized in that: The treatment method comprises: treating hydrogen chloride with vaporized methanol.

2. The processing method according to claim 1, characterized in that: The processing method comprises the following steps: (1) Adding alcohol into a condensation reactor and then adding a tertiary amine compound to carry out a condensation reaction; (2) transporting the hydrogen chloride produced by the condensation reaction in step (1) to a synthesis reactor; (3) introducing vaporized methanol and a catalyst into the synthesis reactor of step (2) to react and obtain methyl chloride.

3. The processing method according to claim 2, characterized in that: The mass ratio of the vaporized methanol to the hydrogen chloride is 2:1 to 1:

2.

4. The processing method according to claim 3, characterized in that: The mass ratio of the vaporized methanol to the hydrogen chloride is 1:1 to 1:1.

5.

5. The processing method according to claim 4, characterized in that: The mass ratio of the vaporized methanol to the hydrogen chloride is 1:1.08 to 1:1.

1.

6. The processing method according to claim 2, characterized in that: The alcohol is ethanol and / or butanol; Preferably, the tertiary amine compound is 2-methyl-6-ethyl-N-chloromethyl-α-acetylchloroaniline and / or 2,6-diethyl-N-chloromethyl-α-acetylchloroaniline.

7. The processing method according to claim 2, characterized in that: The temperature of the condensation reaction is 30-60°C.

8. The processing method according to claim 2, characterized in that: The catalyst in step (3) is an aqueous solution of zinc chloride; Preferably, the mass ratio of zinc chloride to water is 3-7:1; More preferably, the mass ratio of zinc chloride to water is 4-5:

1.

9. The processing method according to claim 2, characterized in that: The reaction temperature in step (3) is 120-180°C; Preferably, the reaction temperature in step (3) is 130-160°C.

10. A device for treating hydrogen chloride produced as a byproduct in the production process of acetochlor and / or butachlor, characterized in that: The device comprises: A condensation kettle (3) is used for condensing an alcohol with a tertiary amine compound to prepare acetochlor or butachlor, and the condensation kettle (3) is provided with a gas outlet for discharging a by-product, hydrogen chloride; A synthesis reactor (4), the synthesis reactor (4) is connected to the gas outlet of the condensation reactor (3), and is used to react the hydrogen chloride with the vaporized methanol to treat the hydrogen chloride.

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