阅读说明：本技术 一种二甲戊灵工艺中37%的硝酸的处理方法 (Treatment method of 37% nitric acid in pendimethalin process ) 是由 季品俊 王晓军 姚林希 荀卫利 于 2021-10-15 设计创作，主要内容包括：本发明提供了一种二甲戊灵工艺中37％的硝酸的处理方法,属于化学废料无害化处理和资源化利用技术领域,包括以下步骤：将N-(3-戊基)-3,4-二甲基苯胺经溶剂溶解,得到的溶液与37％废硝酸混合、热反应,静置分层后收集有机相,有机相与硝酸溶液混合后进行硝化反应,得到二甲戊灵。采用本发明的方法不仅实现了利用37％废硝酸制备二甲戊灵,还能够使得37％废硝酸循环利用。(The invention provides a method for treating 37% nitric acid in pendimethalin process, belonging to the technical field of harmless treatment and resource utilization of chemical wastes, comprising the following steps: dissolving N- (3-amyl) -3, 4-dimethylaniline by a solvent, mixing the obtained solution with 37 percent waste nitric acid, carrying out thermal reaction, standing for layering, collecting an organic phase, mixing the organic phase with the nitric acid solution, and carrying out nitration reaction to obtain the pendimethalin. The method not only realizes the preparation of pendimethalin by using 37% of waste nitric acid, but also can recycle the 37% of waste nitric acid.)

1. A treatment method of 37% nitric acid in pendimethalin process is characterized by comprising the following steps:

1) dissolving N- (3-amyl) -3, 4-dimethylaniline by a solvent to obtain a solution;

2) mixing the solution obtained in the step 1) with 37% waste nitric acid, carrying out thermal reaction, standing for layering, and collecting an organic phase;

3) mixing the organic phase obtained in the step 2) with a nitric acid solution, and then carrying out nitration reaction to obtain pendimethalin.

2. The method according to claim 1, wherein the mass ratio of the N- (3-pentyl) -3, 4-dimethylaniline in the step 1) to the solvent is 1: 2-3.

3. The method of claim 1 or 2, wherein the solvent comprises one or more of 1, 2-dichloropropane, dichloroethane, 1, 3-dichloropropane, toluene and cyclohexane.

4. The method according to claim 1, wherein the mass ratio of the 37% waste nitric acid in the step 2) to the solvent in the step 1) is 45-60: 100.

5. The method according to claim 1, wherein the temperature of the thermal reaction in the step 2) is 50-60 ℃, and the time of the thermal reaction is 0.5-1 h.

6. The method according to claim 1, wherein the mass ratio of the nitric acid solution in the step 3) to the solvent in the step 1) is 48-53: 100, and the volume percentage of the nitric acid solution is 70%.

7. The method according to claim 1, wherein the temperature of the nitration reaction in the step 3) is 50-60 ℃, and the time of the nitration reaction is 40 min.

8. The method as claimed in claim 1, wherein pendimethalin and a waste nitric acid solution are obtained after the nitration reaction in the step 3), and 37% of waste nitric acid is obtained after the waste nitric acid solution is treated.

9. The method of claim 8, wherein the processing comprises: extracting the waste nitric acid by halogenated hydrocarbon, and distilling the obtained organic phase to obtain 37% waste nitric acid.

10. The method of claim 8, wherein the processing comprises: and reacting the waste nitric acid solution for 6 hours under the pressure of 2MPa and at the temperature of 130 ℃ to obtain 37 percent waste nitric acid.

Technical Field

The invention belongs to the technical field of harmless treatment and resource utilization of chemical wastes, and particularly relates to a treatment method of 37% nitric acid in a pendimethalin process.

Background

Along with the improvement of national economy, environmental protection, energy conservation and emission reduction become one of the problems to be solved in the chemical industry, and along with the increasing of productivity, the cost of nitric acid wastewater treatment is also getting higher and higher, so that the development of a waste nitric acid recovery technology is more and more important.

The 37 percent waste nitric acid contains mononitrate, is unstable and is easy to accumulate heat and store. The prior art treats 37 percent of waste nitric acid, and the nitrified waste acid is directly treated by an environmental protection center, so that the energy conservation and emission reduction can not be achieved, and the environmental protection pressure and the cost of wastewater treatment are increased.

Disclosure of Invention

In view of the above, the invention aims to provide a treatment method of 37% nitric acid in a pendimethalin process, and by adopting the method, the pendimethalin can be prepared by recycling 37% waste nitric acid, energy can be saved, emission can be reduced, and environmental protection pressure and wastewater treatment cost can be reduced.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention provides a method for treating 37% nitric acid in pendimethalin process, which comprises the following steps:

1) dissolving N- (3-amyl) -3, 4-dimethylaniline by a solvent to obtain a solution;

2) mixing the solution obtained in the step 1) with 37% waste nitric acid, carrying out thermal reaction, standing for layering, and collecting an organic phase;

3) mixing the organic phase obtained in the step 2) with a nitric acid solution, and then carrying out nitration reaction to obtain pendimethalin.

Preferably, the mass ratio of the N- (3-pentyl) -3, 4-dimethylaniline in the step 1) to the solvent is 1: 2-3.

Preferably, the solvent comprises one or more of 1, 2-dichloropropane, dichloroethane, 1, 3-dichloropropane, toluene and cyclohexane.

Preferably, the mass ratio of the 37% waste nitric acid in the step 2) to the solvent in the step 1) is 45-60: 100.

Preferably, the temperature of the thermal reaction in the step 2) is 50-60 ℃, and the time of the thermal reaction is 0.5-1.

Preferably, the mass ratio of the nitric acid solution in the step 3) to the solvent in the step 1) is 48-53: 100, and the volume percentage content of the nitric acid solution is 70%.

Preferably, the temperature of the nitration reaction in the step 3) is 50-60 ℃, and the time of the nitration reaction is 40 min.

Preferably, pendimethalin and a waste nitric acid solution are obtained after the nitration reaction in the step 3), and the waste nitric acid solution is treated to obtain 37% waste nitric acid.

Preferably, the processing comprises: extracting the waste nitric acid by halogenated hydrocarbon, and distilling the obtained organic phase to obtain 37% waste nitric acid.

Preferably, the processing comprises: and reacting the waste nitric acid solution for 6 hours under the pressure of 2MPa and at the temperature of 130 ℃ to obtain 37 percent waste nitric acid.

The invention provides a method for treating 37% nitric acid in pendimethalin process, which comprises the following steps: 1) dissolving N- (3-amyl) -3, 4-dimethylaniline by a solvent to obtain a solution; 2) mixing the solution obtained in the step 1) with 37% waste nitric acid, carrying out thermal reaction, standing for layering, and collecting an organic phase; 3) mixing the organic phase obtained in the step 2) with a nitric acid solution, and then carrying out nitration reaction to obtain pendimethalin. In the invention, the N- (3-amyl) -3, 4-dimethylaniline reacts with nitric acid in 37% waste nitric acid to generate N- (3-amyl) -3, 4-dimethylaniline nitrate, the generated nitrate reacts with a nitric acid solution to generate nitration reaction to obtain pendimethalin, and the waste nitric acid solution obtained by the nitration reaction is treated to obtain 37% waste nitric acid, so that the recycling of the 37% waste nitric acid is realized.

Drawings

FIG. 1 is a chemical formula of a thermal reaction;

FIG. 2 is a chemical formula of a nitration reaction;

fig. 3 is a flow diagram of the preparation of pendimethalin using 37% waste nitric acid.

Detailed Description

The invention provides a method for treating 37% nitric acid in pendimethalin process, which comprises the following steps:

1) dissolving N- (3-amyl) -3, 4-dimethylaniline by a solvent to obtain a solution;

2) mixing the solution obtained in the step 1) with 37% waste nitric acid, carrying out thermal reaction, standing for layering, and collecting an organic phase;

3) mixing the organic phase obtained in the step 2) with a nitric acid solution, and then carrying out nitration reaction to obtain pendimethalin.

The invention dissolves N- (3-amyl) -3, 4-dimethylaniline by a solvent to obtain a solution.

In the invention, the mass ratio of the N- (3-pentyl) -3, 4-dimethylaniline to the solvent is preferably 1: 2-3. In the present invention, the solvent preferably includes one or more of 1, 2-dichloropropane, dichloroethane, 1, 3-dichloropropane, toluene and cyclohexane. In the present invention, when the solvent includes two or more kinds, the mass ratio of the solvent is not particularly limited, and any mass ratio may be used.

The obtained solution is mixed with 37 percent of waste nitric acid, thermally reacted, kept stand for layering and then an organic phase is collected. In the present invention, the mechanism of the thermal reaction is shown in FIG. 1.

The source of the 37% waste nitric acid is not particularly limited in the present invention. In the invention, the mass ratio of the 37% waste nitric acid to the solvent is preferably 45-60: 100. In the invention, the mass percentage of the nitric acid in the 37% waste nitric acid is 37%. In the invention, the temperature of the thermal reaction is preferably 50-60 ℃, and the time of the thermal reaction is preferably 0.5-1 h. In the present invention, the standing layering is until the reactants do not change in layering any more. The method for collecting the organic phase in the present invention is not particularly limited, and those skilled in the art may adopt a conventional method for collecting an organic phase.

The obtained organic phase is mixed with nitric acid solution and then is subjected to nitration reaction to obtain pendimethalin. In the present invention, the mechanism of the nitration reaction is shown in FIG. 2.

In the invention, the mass ratio of the nitric acid solution to the solvent is preferably 48-53: 100, and the volume percentage content of the nitric acid solution is preferably 70%. In the invention, the temperature of the nitration reaction is preferably 50-60 ℃, and the time of the nitration reaction is preferably 40 min. In the present invention, when the temperature of the nitration reaction is 40 ℃, the reaction of the raw materials is incomplete, and when it is 65 ℃ or more, phenol, chloride, aldehyde and tar are generated.

In the invention, pendimethalin and waste nitric acid solution are obtained after the nitration reaction, and 37% waste nitric acid is obtained after the waste nitric acid solution is treated.

In the present invention, the treatment preferably includes: extracting the waste nitric acid by halogenated hydrocarbon, and distilling the obtained organic phase to obtain 37% waste nitric acid. In the present invention, the kind of the halogenated hydrocarbon preferably includes 1, 2-dichloropropane, dichloroethane or 1, 3-dichloropropane. In the present invention, the number of times of the extraction is preferably 3 times. In the present invention, the distillation preferably includes atmospheric distillation followed by vacuum distillation to obtain 37% waste nitric acid, and the obtained 37% waste nitric acid does not contain phenols, chlorides, aldehydes and tar. In the invention, the atmospheric distillation temperature is 80-90 ℃, when liquid is not discharged, the reduced pressure distillation temperature is 60-70 ℃, and the distillation is stopped when the liquid in the distillation flask turns black.

In the present invention, the treatment preferably includes: and (3) reacting the waste nitric acid solution for 6 hours at the pressure of 2MPa and the temperature of 130 ℃ to obtain 37% waste nitric acid. In the invention, the COD removal rate of the waste nitric acid solution is 70%, and the obtained 37% waste nitric acid can be recycled.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

And (3) a source of 37% waste nitric acid, wherein the 37% waste nitric acid contains 37% nitric acid by mass percentage.

50g of N- (3-amyl) -3, 4-dimethylaniline is added into 100g of 1, 2-dichloropropane to be dissolved, the mixture is heated to 54 ℃, 50g of 37 percent waste nitric acid is dripped, the temperature is kept to be 55 ℃, an organic phase obtained by layering is dripped into 50g of nitric acid solution with the mass percentage content of 70 percent, the dripping temperature is controlled to be 55 ℃, the heat preservation reaction is carried out for 40min after the dripping is finished, 67.4g of pendimethalin is obtained, and the waste nitric acid solution (38g) is separated out by standing. The pendimethalin is obtained by conventional denitritification, water washing, acid washing, alkali washing and desolventizing, and is determined to be pendimethalin by comparing with a standard product, the content is 96 percent, and the yield is 88 percent.

Example 2

38g of the waste nitric acid solution separated in the example 1 is retained for 20min at 160 ℃ by a microchannel reactor, the COD removal rate reaches 82 percent, and 37 percent of waste nitric acid is obtained and can be recycled.

Example 3

38g of the waste nitric acid solution separated in the example 1 is absorbed by macroporous resin, a peristaltic pump is adopted, the waste water is absorbed into the resin at the flow rate of 20ml/min for absorption, the COD removal rate reaches 74%, 37% of waste nitric acid is obtained, and the waste nitric acid can be recycled.

Comparative example 1

50g of N- (3-pentyl) -3, 4-dimethylaniline is added into 100g of 1, 2-dichloropropane to be dissolved, the mixture is heated to 40 ℃, 50g of 37% waste nitric acid is dripped, the temperature is kept at 40 ℃, an organic phase obtained by layering (15% of raw materials are not reacted by sampling analysis) is dripped with 50g of 70% nitric acid, the dripping temperature is controlled to be 65 ℃, the mixture is kept for reaction for 40min after the dripping is finished, 56g of pendimethalin is obtained, the yield of the pendimethalin is 73.7%, the purity of the pendimethalin is 90%, the content of a byproduct nitrous acid in the product is 43%, tar is contained in a reaction bottle, and 38g of waste nitric acid solution is separated.

Example 5

38g of the waste nitric acid solution separated in example 1 was extracted 3 times with 30g of 1, 2-dichloropropane, and the obtained organic phase (solvent) was distilled under atmospheric pressure and then under reduced pressure to obtain 96g of 1, 2-dichloropropane and 30g of 37% waste nitric acid, which were used in the preparation of pendimethalin in example 1. The distillation temperature under normal pressure is 85 ℃, when the liquid is not discharged, the distillation temperature under reduced pressure is 65 ℃, and the distillation is stopped when the liquid in the distillation flask turns black.

Example 6

38g of the waste nitric acid solution separated in the example 1 is reacted for 6 hours at 130 ℃ by using an autoclave, the COD removal rate reaches 70%, and 37% of waste nitric acid is obtained and can be recycled.

According to the embodiment, the pendimethalin is prepared by fully utilizing 37% of waste nitric acid, and the pendimethalin can be prepared by repeatedly utilizing 37% of waste nitric acid.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.