Preparation method of 3, 4-dimethyl-2, 6-dinitro-N-(2-amyl) aniline

Abstract

The invention relates to the technical field of aniline substance synthesis, in particular to a preparation method of 3, 4-dimethyl-2, 6-dinitro-N-(2-amyl) aniline, which comprises the following steps: step 1, adding 2-pentanone, alkylol amine and a catalyst into a reaction kettle, fully mixing, introducing hydrogen, controlling the reaction temperature to be 70-90 DEG C and the reaction pressure to be 0.80-2.5 MPa, reacting for 2-4 hours, separating and purifying to obtain 2, 4-dimethyl-2, 6-dinitro-N-(2-amyl) aniline; the 2-aminopentane is obtained; and 2, adding o-xylene and Lewis acid into the batching kettle according to a ratio, uniformly stirring, pumping into the mixing reaction chamber of the microchannel reactor, continuously introducing chlorine into the microchannel reactor, and carrying out a reaction: the preparation method of 3, 4-dimethyl-2, 6-dinitro-N-(2-amyl) aniline provided by the invention is simple, and has the advantages of high yield, high yield and high yield. The preparation raw materials are simple and easy to obtain, few pollutants are generated in the preparation process, the reaction yield is high, the reaction conditions are mild, and the method is suitable for popularization and application.

Description

Technical Field

[0001] The invention relates to the technical field of aniline synthesis, and in particular to a method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline. Background Art

[0002] Pendimethalin is a dinitroaniline herbicide that is mainly absorbed by the germinating weed shoots, binds to the microtubule protein in the plant body, inhibits plant cell mitosis, and thus causes the death of weeds. It is mainly used in a variety of dry fields including cotton, corn, etc. and dry rice seedling fields.

[0003] In the synthesis process of pendimethalin, due to the presence of a small amount of 2-pentanone impurities in the raw materials, 2-pentanone will eventually react with 3,5-dinitro-4-chloro-o-xylene to generate 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline. Studies have found that 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline has certain effects in the fields of pesticides, coatings, plastics, etc. However, there are few reports on the synthesis method of 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline. Therefore, we propose a preparation method of 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline.

[0005] A method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline comprises the following steps:

[0006] Step 1, 2-pentanone, alcohol amine and catalyst are put into a reaction kettle, fully mixed, hydrogen is introduced, the reaction temperature is controlled to be 70-90° C., the reaction pressure is 0.80-2.5 MPa, the reaction is carried out for 2-4 hours, and 2-aminopentane is obtained by separation and purification;

[0007] Step 2, adding o-xylene and Lewis acid into a batching kettle in proportion, stirring evenly, pumping into the mixing reaction chamber of the microchannel reactor, and continuously introducing chlorine into the microchannel reactor to react, the reaction pressure is 0.1-0.3MPa, the reaction temperature is controlled at 40-80°C, after the reaction is completed, removing chlorine and hydrogen chloride to obtain 4-chloro-o-xylene;

[0008] Step 3, adding 4-chloro-o-xylene to a reaction kettle, slowly dropping a mixed solution of sulfuric acid and nitric acid, controlling the reaction temperature at 50-60° C., reacting sufficiently, and separating and purifying to obtain 3,5-dinitro-4-chloro-o-xylene;

[0009] Step 4: Add 2-aminopentane, 3,5-dinitro-4-chloro-o-xylene and a catalyst into a reaction kettle, control the reaction temperature at 30-60° C., and after the reaction is completed, separate and purify to obtain 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline.

[0010] Preferably, in step 1, the alcoholamine is ethanolamine or methanolamine.

[0011] Preferably, in step 1, the catalyst is a Pt / c catalyst, and the specific steps of step 1 are: adding an alcohol amine, 2-pentanone and a catalyst into a reaction kettle, first replacing the atmosphere with nitrogen, and then replacing the atmosphere with hydrogen;

[0012] The molar ratio of 2-pentanone:alkanolamine is 1:1.5-3;

[0013] The mass ratio of 2-pentanone to Pt / c catalyst is 1:0.001-0.1;

[0014] The reaction temperature is controlled at 70-90°C, the reaction pressure is 0.80-2.5MPa, the reaction is carried out for 2-4h, and sampling is performed for analysis. When the conversion rate is qualified, that is, the conversion rate of the alcohol amine is ≥99.0%, the reaction is complete;

[0015] After the reaction is completed, the product is first filtered with a microporous filter, the Pt / c catalyst is recovered, the filtrate is layered, the oil phase is distilled to recover 2-pentanone, and 2-aminopentane is obtained after desolventizing.

[0016] Preferably, in step 2, the molar ratio of o-xylene to Lewis acid is: 1:0.2-0.5;

[0017] When injected into the microchannel reactor, the molar ratio of o-xylene to chlorine per unit time is 1:2-3;

[0018] The Lewis acid is one or a mixture of aluminum chloride and ferric chloride.

[0019] In step 3, in the mixed solution of sulfuric acid and nitric acid, the molar ratio of sulfuric acid to nitric acid is 0.5 to 1.5:1;

[0020] The molar ratio of 4-chloro-o-xylene to nitric acid is 1:1.5-2;

[0021] After the reaction is completed, the reactants are separated into layers, and then the oil phase and the water phase are recovered. The oil phase is 3,5-dinitro-4-chloro-o-xylene.

[0022] Preferably, in step 4, the catalyst is one or more of potassium chloride, sodium chloride and calcium chloride;

[0023] The molar ratio of 2-aminopentane to 3,5-dinitro-4-chloro-o-xylene is 1:0.5-0.8;

[0024] The mass ratio of the 2-aminopentane to the catalyst is 1:0.001-0.02.

[0025] Preferably, in step 4, the reaction time is controlled at 2 to 2.5 hours, and after the reaction is completed, the mixture is kept warm and refluxed for 1 to 1.5 hours.

[0026] Preferably, in step 4, after the reaction is completed, 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline is purified by vacuum distillation.

[0027] The beneficial effects of the present invention are as follows: the preparation method of 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline proposed by the present invention is simple in preparation method, the preparation raw materials are simple and easy to obtain, the pollutants generated in the preparation process are few, the reaction yield is high, the reaction conditions are mild, and the preparation method is suitable for popularization and use. DETAILED DESCRIPTION

[0028] The present invention will be further explained below in conjunction with specific embodiments.

[0029] In Example 1, a method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline comprises the following steps:

[0030] Step 1, 2-pentanone, alcohol amine and catalyst are put into a reaction kettle, fully mixed, hydrogen is introduced, the reaction temperature is controlled to 70° C., the reaction pressure is 0.8 MPa, the reaction is carried out for 2 hours, and 2-aminopentane is obtained by separation and purification;

[0031] Step 2, adding o-xylene and Lewis acid into a batching kettle in proportion, stirring evenly, pumping into the mixing reaction chamber of the microchannel reactor, and continuously introducing chlorine into the microchannel reactor to react, the reaction pressure is 0.1 MPa, the reaction temperature is controlled at 40°C, after the reaction is completed, removing chlorine and hydrogen chloride to obtain 4-chloro-o-xylene;

[0032] Step 3, adding 4-chloro-o-xylene into a reaction kettle, slowly adding a mixed solution of sulfuric acid and nitric acid, controlling the reaction temperature at 50° C., reacting sufficiently, and obtaining 3,5-dinitro-4-chloro-o-xylene after separation and purification;

[0033] Step 4: Add 2-aminopentane, 3,5-dinitro-4-chloro-o-xylene and a catalyst into a reaction kettle, and control the reaction temperature at 30° C. After the reaction is completed, separate and purify to obtain 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline.

[0034] In the step 1, the alcoholamine is ethanolamine.

[0035] In the step 1, the catalyst is a Pt / c catalyst, and the specific steps of step 1 are: adding an alcohol amine, 2-pentanone and a catalyst into a reaction kettle, first replacing the gas with nitrogen, and then replacing the gas with hydrogen;

[0036] The molar ratio of 2-pentanone:alkanolamine is 1:1.5;

[0037] The mass ratio of 2-pentanone to Pt / c catalyst is 1:0.001;

[0038] The reaction temperature was controlled to be 70°C, the reaction pressure was 0.80MPa, the reaction was carried out for 2h, and sampling was performed for analysis. When the conversion rate was qualified, that is, the conversion rate of the alcohol amine was ≥99.0%, the reaction was complete.

[0039] After the reaction is completed, the product is first filtered with a microporous filter, the Pt / c catalyst is recovered, the filtrate is layered, the oil phase is distilled to recover 2-pentanone, and 2-aminopentane is obtained after desolventizing.

[0040] In the step 2, the molar ratio of o-xylene to Lewis acid is 1:0.2;

[0041] When injected into the microchannel reactor, the molar ratio of o-xylene to chlorine per unit time is 1:2;

[0042] The Lewis acid is one or a mixture of aluminum chloride and ferric chloride.

[0043] In step 3, in the mixed solution of sulfuric acid and nitric acid, the molar ratio of sulfuric acid to nitric acid is 0.5:1;

[0044] The molar ratio of 4-chloro-o-xylene to nitric acid is 1:1.5;

[0045] After the reaction is completed, the reactants are separated into layers, and then the oil phase and the water phase are recovered. The oil phase is 3,5-dinitro-4-chloro-o-xylene.

[0046] In step 4, the catalyst is one or more of potassium chloride, sodium chloride, and calcium chloride;

[0047] The molar ratio of 2-aminopentane and 3,5-dinitro-4-chloro-o-xylene is 1:0.5;

[0048] The mass ratio of the 2-aminopentane to the catalyst is 1:0.001.

[0049] In step 4, the reaction time is controlled at 2 h, and after the reaction is completed, the mixture is kept at reflux for 1 h.

[0050] In the step 4, after the reaction is completed, 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline is purified by vacuum distillation.

[0051] In Example 2, a method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline comprises the following steps:

[0052] Step 1, 2-pentanone, alcohol amine and catalyst are put into a reaction kettle, fully mixed, hydrogen is introduced, the reaction temperature is controlled to 90° C., the reaction pressure is 2.5 MPa, the reaction is carried out for 4 hours, and 2-aminopentane is obtained by separation and purification;

[0053] Step 2, adding o-xylene and Lewis acid into a batching kettle in proportion, stirring evenly, pumping into the mixing reaction chamber of the microchannel reactor, and continuously introducing chlorine into the microchannel reactor to react, the reaction pressure is 0.3MPa, the reaction temperature is controlled at 80°C, after the reaction is completed, removing chlorine and hydrogen chloride to obtain 4-chloro-o-xylene;

[0054] Step 3, adding 4-chloro-o-xylene into a reaction kettle, slowly adding a mixed solution of sulfuric acid and nitric acid, controlling the reaction temperature at 60° C., reacting sufficiently, and obtaining 3,5-dinitro-4-chloro-o-xylene after separation and purification;

[0055] Step 4: Add 2-aminopentane, 3,5-dinitro-4-chloro-o-xylene and a catalyst into a reaction kettle, and control the reaction temperature at 60° C. After the reaction is completed, separate and purify to obtain 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline.

[0056] In the step 1, the alcoholamine is ethanolamine or methanolamine.

[0057] In the step 1, the catalyst is a Pt / c catalyst, and the specific steps of step 1 are: adding an alcohol amine, 2-pentanone and a catalyst into a reaction kettle, first replacing the gas with nitrogen, and then replacing the gas with hydrogen;

[0058] The molar ratio of 2-pentanone:alkanolamine is 1:3;

[0059] The mass ratio of 2-pentanone to Pt / c catalyst is 1:0.1;

[0060] The reaction temperature is controlled at 70-90°C, the reaction pressure is 2.5MPa, the reaction is carried out for 4 hours, and sampling is performed for analysis. When the conversion rate is qualified, that is, the conversion rate of the alcohol amine is ≥99.0%, the reaction is complete;

[0061] After the reaction is completed, the product is first filtered with a microporous filter, the Pt / c catalyst is recovered, the filtrate is layered, the oil phase is distilled to recover 2-pentanone, and 2-aminopentane is obtained after desolventizing.

[0062] In the step 2, the molar ratio of o-xylene to Lewis acid is 1:0.5;

[0063] When injected into the microchannel reactor, the molar ratio of o-xylene to chlorine per unit time is 1:3;

[0064] The Lewis acid is one or a mixture of aluminum chloride and ferric chloride.

[0065] In step 3, in the mixed solution of sulfuric acid and nitric acid, the molar ratio of sulfuric acid to nitric acid is 1.5:1;

[0066] The molar ratio of 4-chloro-o-xylene to nitric acid is 1:2;

[0067] After the reaction is completed, the reactants are separated into layers, and then the oil phase and the water phase are recovered. The oil phase is 3,5-dinitro-4-chloro-o-xylene.

[0068] In step 4, the catalyst is one or more of potassium chloride, sodium chloride, and calcium chloride;

[0069] The molar ratio of 2-aminopentane and 3,5-dinitro-4-chloro-o-xylene is 1:0.8;

[0070] The mass ratio of the 2-aminopentane to the catalyst is 1:0.02.

[0071] In step 4, the reaction time is controlled at 2.5 h. After the reaction is completed, the mixture is kept at reflux for 1.5 h.

[0072] In the step 4, after the reaction is completed, 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline is purified by vacuum distillation.

[0073] In Example 3, a method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline comprises the following steps:

[0074] Step 1, 2-pentanone, alcohol amine and catalyst are put into a reaction kettle, fully mixed, hydrogen is introduced, the reaction temperature is controlled to 80° C., the reaction pressure is 0.9 MPa, the reaction is carried out for 3 hours, and 2-aminopentane is obtained by separation and purification;

[0075] Step 2, adding o-xylene and Lewis acid into a batching kettle in proportion, stirring evenly, pumping into the mixing reaction chamber of the microchannel reactor, and continuously introducing chlorine into the microchannel reactor to react, the reaction pressure is 0.2MPa, the reaction temperature is controlled at 60°C, after the reaction is completed, removing chlorine and hydrogen chloride to obtain 4-chloro-o-xylene;

[0076] Step 3, adding 4-chloro-o-xylene into a reaction kettle, slowly dropping a mixed solution of sulfuric acid and nitric acid, controlling the reaction temperature at 55° C., reacting sufficiently, and obtaining 3,5-dinitro-4-chloro-o-xylene after separation and purification;

[0077] Step 4: Add 2-aminopentane, 3,5-dinitro-4-chloro-o-xylene and a catalyst into a reaction kettle, and control the reaction temperature at 45° C. After the reaction is completed, separate and purify to obtain 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline.

[0078] In the step 1, the alcoholamine is ethanolamine or methanolamine.

[0079] In the step 1, the catalyst is a Pt / c catalyst, and the specific steps of step 1 are: adding an alcohol amine, 2-pentanone and a catalyst into a reaction kettle, first replacing the gas with nitrogen, and then replacing the gas with hydrogen;

[0080] The molar ratio of 2-pentanone:alkanolamine is 1:2;

[0081] The mass ratio of 2-pentanone to Pt / c catalyst is 1:0.02;

[0082] The reaction temperature was controlled to be 80°C, the reaction pressure was 0.9MPa, the reaction was carried out for 3h, and sampling was performed for analysis. When the conversion rate was qualified, i.e., the conversion rate of the alcohol amine was ≥99.0%, the reaction was complete.

[0083] After the reaction is completed, the product is first filtered with a microporous filter, the Pt / c catalyst is recovered, the filtrate is layered, the oil phase is distilled to recover 2-pentanone, and 2-aminopentane is obtained after desolventizing.

[0084] In the step 2, the molar ratio of o-xylene to Lewis acid is 1:0.3;

[0085] When injected into the microchannel reactor, the molar ratio of o-xylene to chlorine per unit time is 1:2.5;

[0086] The Lewis acid is one or a mixture of aluminum chloride and ferric chloride.

[0087] In step 3, in the mixed solution of sulfuric acid and nitric acid, the molar ratio of sulfuric acid to nitric acid is 1:1;

[0088] The molar ratio of 4-chloro-o-xylene to nitric acid is 1:1.8;

[0089] After the reaction is completed, the reactants are separated into layers, and then the oil phase and the water phase are recovered. The oil phase is 3,5-dinitro-4-chloro-o-xylene.

[0090] In step 4, the catalyst is one or more of potassium chloride, sodium chloride, and calcium chloride;

[0091] The molar ratio of 2-aminopentane and 3,5-dinitro-4-chloro-o-xylene is 1:0.6;

[0092] The mass ratio of the 2-aminopentane to the catalyst is 1:0.01.

[0093] In step 4, the reaction time is controlled at 2.2 h. After the reaction is completed, the mixture is kept at reflux for 1.2 h.

[0094] In the step 4, after the reaction is completed, 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline is purified by vacuum distillation.

[0095] The yield of Example 1 is 96.3%, the yield of Example 2 is 97.1%, and the yield of Example 3 is 96.8%, all of which are greater than 95%.

[0096] Main reaction formula:

[0097]

[0098] Wherein, in reaction formula (1), R represents a C1-C2 alkane, reaction formula (1) is the main reaction process of step 1; reaction formula (2) is the main reaction process of step 2; reaction formula (3) is the main reaction process of step 3; reaction formula (4) is the main reaction process of step 4.

[0099] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline, characterized in that: The following steps are involved: Step 1, 2-pentanone, alcohol amine and catalyst are put into a reaction kettle, fully mixed, hydrogen is introduced, the reaction temperature is controlled to be 70-90° C., the reaction pressure is 0.80-2.5 MPa, the reaction is carried out for 2-4 hours, and 2-aminopentane is obtained by separation and purification; Step 2, adding o-xylene and Lewis acid into a batching kettle in proportion, stirring evenly, pumping into the mixing reaction chamber of the microchannel reactor, and continuously introducing chlorine into the microchannel reactor to react, the reaction pressure is 0.1-0.3MPa, the reaction temperature is controlled at 40-80°C, after the reaction is completed, removing chlorine and hydrogen chloride to obtain 4-chloro-o-xylene; Step 3, adding 4-chloro-o-xylene to a reaction kettle, slowly dropping a mixed solution of sulfuric acid and nitric acid, controlling the reaction temperature at 50-60° C., reacting sufficiently, and separating and purifying to obtain 3,5-dinitro-4-chloro-o-xylene; Step 4: Add 2-aminopentane, 3,5-dinitro-4-chloro-o-xylene and a catalyst into a reaction kettle, and control the reaction temperature at 30 to 60° C. After the reaction is completed, separate and purify to obtain 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline.

2. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 1, characterized in that: In the step 1, the alcoholamine is ethanolamine or methanolamine.

3. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 2, characterized in that: In the step 1, the catalyst is a Pt / c catalyst, and the specific steps of step 1 are: adding an alcohol amine, 2-pentanone and a catalyst into a reaction kettle, first replacing the gas with nitrogen, and then replacing the gas with hydrogen; The molar ratio of 2-pentanone:alkanolamine is 1:1.5-3; The mass ratio of 2-pentanone to Pt / c catalyst is 1:0.001-0.1; The reaction temperature is controlled at 70-90°C, the reaction pressure is 0.80-2.5MPa, the reaction is carried out for 2-4h, and sampling is performed for analysis. When the conversion rate is qualified, that is, the conversion rate of the alcohol amine is ≥99.0%, the reaction is complete; After the reaction is completed, the product is first filtered with a microporous filter, the Pt / c catalyst is recovered, the filtrate is layered, the oil phase is distilled to recover 2-pentanone, and 2-aminopentane is obtained after desolventizing.

4. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 1, characterized in that: In the step 2, the molar ratio of o-xylene to Lewis acid is 1:0.2-0.5; When injected into the microchannel reactor, the molar ratio of o-xylene to chlorine per unit time is 1:2-3; The Lewis acid is one or a mixture of aluminum chloride and ferric chloride.

5. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 1, characterized in that: In step 3, in the mixed solution of sulfuric acid and nitric acid, the molar ratio of sulfuric acid to nitric acid is 0.5 to 1.5:1; The molar ratio of 4-chloro-o-xylene to nitric acid is 1:1.5-2; After the reaction is completed, the reactants are separated into layers, and then the oil phase and the water phase are recovered. The oil phase is 3,5-dinitro-4-chloro-o-xylene.

6. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 1, characterized in that: In step 4, the catalyst is one or more of potassium chloride, sodium chloride, and calcium chloride; The molar ratio of 2-aminopentane to 3,5-dinitro-4-chloro-o-xylene is 1:0.5-0.8; The mass ratio of the 2-aminopentane to the catalyst is 1:0.001-0.

02.

7. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 6, characterized in that: In step 4, the reaction time is controlled at 2 to 2.5 hours. After the reaction is completed, the mixture is kept warm and refluxed for 1 to 1.5 hours.

8. The method for preparing 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline according to claim 6, characterized in that: In the step 4, after the reaction is completed, 3,4-dimethyl-2,6-dinitro-N-(2-pentyl)aniline is purified by vacuum distillation.

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