CN111825554A - Resource recovery method of pendimethalin high-boiling point residual liquid - Google Patents

Resource recovery method of pendimethalin high-boiling point residual liquid Download PDF

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CN111825554A
CN111825554A CN202010823630.4A CN202010823630A CN111825554A CN 111825554 A CN111825554 A CN 111825554A CN 202010823630 A CN202010823630 A CN 202010823630A CN 111825554 A CN111825554 A CN 111825554A
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pendimethalin
solution
residual liquid
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point residual
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CN111825554B (en
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张超智
郑猛
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Nanjing University of Information Science and Technology
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Nanjing University of Information Science and Technology
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
    • C07C209/42—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitrogen-to-nitrogen bonds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
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    • C07C17/00—Preparation of halogenated hydrocarbons
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/82—Purification; Separation; Stabilisation; Use of additives
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
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Abstract

The invention provides a method for recycling pendimethalin high-boiling point residual liquid, which can recycle pendimethalin after treating the residual liquid and comprises the following steps: high-boiling-point residual liquid of pendimethalin, urea, white carbon black and a solvent are mixed according to a mass ratio of 1: 0.3-0.8: 0-3: putting the mixture into a container in a ratio of 0.9-1.3 for mixing; and adding an acid solution into the container, wherein the mass ratio of the high-boiling point residual liquid of the pendimethalin to the acid solution is 1: 0.6 to 1; stirring at 45-55 deg.C for 12-18 hr, cooling to room temperature to crystallize and separate out product, filtering to obtain pendimethalin solid, vacuum drying, distilling the filtrate and recovering solvent.

Description

Resource recovery method of pendimethalin high-boiling point residual liquid
The technical field is as follows:
the invention belongs to the field of waste liquid and residual liquid recycling, and particularly relates to a method for recycling high-boiling-point residual liquid of pendimethalin. The pyrolysis temperature of the industrial pendimethalin production process is about 180 ℃, a large amount of residual liquid is generated after pyrolysis distillation and mainly generated by two processes of nitration and refining, the residual liquid is called high boiling point residual liquid, and the high boiling point residual liquid mainly contains nitric acid, pendimethalin and nitrosopendimethalin.
Background art:
pendimethalin (pendimethalin), the chemical name of which is N- (3-pentyl) -3, 4-dimethyl-2, 6-dinitroaniline, is a dinitroaniline herbicide and is a selective preemergence herbicide developed and popularized by American Cyanamid Company; has good effect on most annual gramineous weeds and certain broad-leaved weeds. The herbicide has good effect, low toxicity and good safety, is widely popularized and applied, is a selective herbicide with the largest dosage in the world at present, and has large internal and external demands and wide market.
At present, 3, 4-dimethyl nitrobenzene is used as a raw material in the production process of pendimethalin, and the product pendimethalin is obtained by hydrogenation, alkylation with 3-pentone, hydrogenation, nitration, purification and refining (US 4136117). The reaction route of the process is shown in figure 1, the process route has short steps, less construction investment, higher process yield, cheap and easily obtained raw materials and low production cost, and is not only generally adopted abroad, but also a general method for producing pendimethalin at home. During the nitration, nitrosamine (N-nitrosopendimethalin) by-products are produced, up to 20% of the product. The N-nitroso-pendimethalin byproduct not only has high toxicity and mutation induction, but also has low nitration efficiency due to large amount, seriously influences the production cost and must be reduced and degraded. Therefore, the process adds a purification and refining step. Although the purification adopts two methods of acidolysis and thermal cracking, a large amount of high-boiling-point residual liquid is generated in the purification process. Therefore, during the nitrification and the purification, a large amount of raffinate is produced, and the raffinate has a large acidity, is difficult to volatilize and degrade, and has a large content of organic contaminants. The prior method for treating the residual liquid is mainly incineration, but the treatment of the method can generate black carbon pollution and reduce the production efficiency. Therefore, a method for recycling the residual liquid is urgently needed.
The invention content is as follows:
in view of the above technical problems, the present invention provides a method for recycling pendimethalin from high boiling point raffinate, which can recycle pendimethalin after treatment of the raffinate.
The specific technical scheme of the invention is as follows:
the invention provides a method for recycling high-boiling point residual liquid of pendimethalin, which comprises the following steps:
high-boiling-point residual liquid of pendimethalin, urea, white carbon black and a solvent are mixed according to a mass ratio of 1: 0.3-0.8: 0-3: putting the mixture into a container in a ratio of 0.9-1.3 for mixing; and adding an acid solution into the container, wherein the mass ratio of the high-boiling point residual liquid of the pendimethalin to the acid solution is 1: 0.6 to 1; at 45-55oStirring for 12-18 hours at the temperature of C, cooling to room temperature to separate out the product crystal, filtering to obtain pendimethalin solid, drying in vacuum, distilling the filtrate, and recovering the solvent.
Further, the solvent is one or more than two mixed solvents of dichloromethane, 1, 2-dichloromethane, chloroform, methanol, ethanol, triethylamine, diethylamine, ethylenediamine, acetone, isopropanol or n-butanol;
further, the acid solution is one or a mixture of more than two of sulfuric acid, phosphoric acid or hydrochloric acid;
further, the mass concentration of the sulfuric acid is 25-90%;
further, the mass concentration of the phosphoric acid is 25-80%;
further, the mass concentration of the hydrochloric acid is 5-30%;
further, the mass ratio of the high-boiling-point residual liquid of pendimethalin to urea, white carbon black and isopropanol is 1: 0.5: 2.5: 1;
further, the acid solution is a sulfuric acid solution with the mass concentration of 50%, and the mass ratio of the high-boiling-point residual liquid of the pendimethalin to the acid solution is 1: 0.8;
further, the reaction temperature was 48 deg.CoC; the reaction time is 16 h;
further, after recovering the solvent, sodium bicarbonate was added to the remaining acidic solution to neutralize it until the solution became neutral, and then it was discharged.
The principle of the invention is as follows:
under the acidic condition, the invention takes urea as a reducing agent, and the urea reacts with nitroso-pendimethalin under the heating reflux state to obtain pendimethalin product, without adding other components and introducing organic impurities, and the used reagents are nontoxic and harmless. The whole reaction can convert the nitroso-pendimethalin into pendimethalin products, thereby improving the production efficiency; and the solvent recovered by distillation can be repeatedly used in the reaction process, so that the recycling of the solvent is realized. The white carbon black is porous material, and its composition can be SiO2·nH2O represents, wherein nH2O exists in the form of surface hydroxyl group and can be combined with nitroso to facilitate the reduction of nitroso pendimethalin. As can be seen from the reaction equation of fig. 2, no other contaminants are generated during the process.
Compared with the prior art, the invention has the following advantages:
1. the invention recycles the poisonous and harmful residual liquid without economic value to obtain the pendimethalin product, realizes the recycling of the residual liquid, has obvious economic benefit, and achieves the purposes of reducing the production cost and improving the ecological environment.
2. In the method, under an acidic condition (wherein a sulfuric acid solution with the mass concentration of 50% is the best, an acidic environment is provided, and the reduction of nitroso is facilitated), in a solvent with a low boiling point, urea can reduce nitroso-pendimethalin at a lower temperature, and white carbon black shows that the white carbon black contains hydroxyl, can fix nitroso and is beneficial to the reduction of the urea. The method reduces the pollution of residual liquid to the environment and improves the production benefit. In the whole process, the reaction operation is simple, the condition is mild, the safety is high, the requirement on equipment is low, the large-scale production is easy, and the solvent recovered by distillation can be repeatedly used in the reaction process, so that the recycling of the solvent is realized.
3. The invention relates to a method for preparing pendimethalin, which comprises the following steps of mixing high-boiling-point residual liquid of pendimethalin, urea, white carbon black, a solvent and an acid solution according to a mass ratio of 1: 0.3-0.8: 0-3: 0.9-1.3: 0.6-1, carrying out reaction; and in the range of 45-55oAnd stirring and reacting for 12-18 hours at the temperature of C. By comparison of examples, the mass ratio of the high-boiling-point residual liquid of pendimethalin to urea, white carbon black, isopropanol and acidic solution is as follows: 1: 0.5: 2.5: 1:0.8, the acid solution is a 50% sulfuric acid solution in 48oWhen C is reacted for 16 hours, the reaction effect is best, the recovery rate is 34%, the obtained pendimethalin infrared spectrogram is good, and the peak of nitroso is small, which indicates that the nitroso is basically reduced; and an N-H stretching vibration peak appears, which indicates that the nitroso-pendimethalin is converted into pendimethalin.
Description of the drawings:
FIG. 1 is the chemical equation for synthesizing pendimethalin from 3, 4-dimethylnitrobenzene (also shown as the abstract figure);
FIG. 2 is an equation for the reaction of nitrosopendimethalin with urea;
FIG. 3 is an IR spectrum of the product obtained in example 1; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 4 is an IR spectrum of the product obtained in example 2; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 5 is an IR spectrum of the product obtained in example 3; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 6 is an IR spectrum of the product obtained in example 5; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 7 is an IR spectrum of the product obtained in example 34; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 8 is an IR spectrum of the product of example 55; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 9 is an IR spectrum of the product of example 62; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
FIG. 10 is an IR spectrum of the product of example 64; wherein (A) is pendimethalin pure sample, and (B) is the obtained product;
note: the FT-IR plots of the products obtained in the other examples are similar to the FT-IR plots and are not listed here.
The specific implementation mode is as follows:
the invention provides a method for recycling high-boiling point residual liquid of pendimethalin, which is further illustrated by the following embodiments:
example 1:
a method for recycling high-boiling point residual liquid of pendimethalin, wherein a chemical equation for synthesizing pendimethalin by 3, 4-dimethylnitrobenzene is shown in figure 1; the equation for the reaction of nitrosopendimethalin with urea is shown in FIG. 2 (the reaction in other examples is the same), and the specific steps are as follows:
high-boiling point raffinate (10 g) of pendimethalin, urea (3 g) and dichloromethane (9 g) were put into a container, and a sulfuric acid solution (6 g) having a mass concentration of 25% was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and the infrared spectrum was measured as shown in FIG. 3 at 3439 cm-1Is the-OH stretching vibration peak of water; 3328 cm-1Is the stretching vibration peak of N-H, which indicates nitrosationThe nitroso in pendimethalin is reduced, the water peak in the pure sample is large, and the peak of secondary amine is covered; 2967, 2929, 2875 cm-1Are the stretching vibration peaks of alkane (C-H), 1624, 1576 and 1490 cm-1Is the stretching vibration peak of benzene ring, 1533 cm-1Is aromatic NO 21329 cm-1Is aromatic NO2Symmetric telescopic vibration peak of 1249 cm-1Is the C-N stretching vibration peak, 926 cm-1Is the peak of flexural vibration of C-H, 760 cm-1Is the out-of-plane stretching vibration peak of C-H on the benzene ring. Stretching vibration of aromatic nitroso (-N = O) is 1425 cm-1The peak of nitroso is small as seen in the infrared spectrum, indicating that it is reduced.
Example 2:
high-boiling point raffinate (10 g) of pendimethalin, urea (8 g) and dichloromethane (9 g) were put into a container, and a sulfuric acid solution (6 g) having a mass concentration of 25% was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and showed an infrared spectrum as shown in FIG. 4, in which the stretching vibration of aromatic nitroso group (-N = O) was 1424 cm-1The peak of nitroso is small as seen in the infrared spectrum, indicating that it is reduced.
Example 3:
high-boiling point raffinate (10 g) of pendimethalin, urea (5 g) and dichloromethane (9 g) were put into a container, and a sulfuric acid solution (6 g) having a mass concentration of 25% was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and the IR spectrum is shown in FIG. 5, where the stretching vibration of aromatic nitroso group (-N = O) is 1426cm-1The smaller peak of the nitroso group in the IR spectrum indicates that it is reduced.
Conclusion-in the examples, under otherwise unchanged conditions, when the mass ratio of the pendimethalin high-boiling raffinate to urea is 1: at 0.5, the reaction was most effective (example 3) (the recovery of pendimethalin was relatively high, the IR spectrum of pendimethalin product was also relatively good, the peak of nitroso group was relatively small, indicating that it was reduced), so the reaction continued at 5 g urea in the example.
Example 4:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (30 g) and dichloromethane (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 5:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and dichloromethane (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum thereof was as shown in FIG. 6, wherein the stretching vibration of the aromatic nitroso group (-N = O) was 1420 cm-1The smaller peak of the nitroso group in the IR spectrum indicates that it is reduced. And is at 3324cm-1There is a slight stretching vibration peak of N-H.
In the embodiment, under the condition of keeping other conditions unchanged, when the mass of the high-boiling-point residual liquid of pendimethalin and the white carbon black is 1: at 2.5, the reaction effect is best (example 5) (the recovery rate of pendimethalin is higher, the infrared spectrum of pendimethalin product is better, the peak of nitroso is smaller, which indicates that it is reduced), and the reaction of the example with white carbon black is better compared with the example without white carbon black, so that the white carbon black is beneficial to the recycling of residual liquid, and the white carbon black in the example continuously reacts at 25 g.
Example 6:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and dichloromethane (13 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 7:
putting pendimethalin high-boiling-point residual liquid (10 g), urea (5 g), white carbon black (25 g) and dichloromethane (10 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.3 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 8:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and trichloromethane (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 9:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and trichloromethane (13 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 10:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and trichloromethane (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 11:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and 1, 2-dichloroethane (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 12:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and 1, 2-dichloroethane (13 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring at 45 deg.C for 12 hr, and filtering; pendimethalin (2.1 g) was obtained, and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 13:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and 1, 2-dichloroethane (10 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 14:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and methanol (9 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 15:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and methanol (13 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 16:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and methanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 17:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and ethanol (9 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 18:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and ethanol (13 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 19:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and ethanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.0 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 20:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and triethylamine (9 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 21:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and triethylamine (13 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 22:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and triethylamine (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 23:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and diethylamine (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 24:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and diethylamine (13 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 25:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and diethylamine (10 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring at 45 deg.C for 12 hr, filtering to obtain pendimethalin (1.9 g), distilling the filtrate, and recovering solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 26:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and ethylenediamine (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 27:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and ethylenediamine (13 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 28:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and ethylenediamine (10 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.0 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 29:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and acetone (9 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 30:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and acetone (13 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.4 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 31:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and acetone (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 32:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (9 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 33:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (13 g) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 34:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.6 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and showed an infrared spectrum of FIG. 7, in which the stretching vibration of aromatic nitroso group (-N = O) was 1424 cm-1The smaller peak of the nitroso group in the IR spectrum indicates that it is reduced. And is at 3321cm-1There is a slight stretching vibration peak of N-H.
Example 35:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and n-butanol (9 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.7 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 36:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and n-butanol (13 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 37:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and n-butanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 38:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and a mixed solvent (isopropanol (4 g) and n-butanol (5 g)) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.0 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 39:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and a mixed solvent (isopropanol (6 g) and n-butanol (7 g)) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 40:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and a mixed solvent (isopropanol (5 g) and n-butanol (5 g)) into a container, and adding a sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.0 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Conclusion III in the examples, the solvent is isopropanol, and the quality of the high boiling point raffinate with pendimethalin is 1: the best reaction results were obtained at 1 (example 34) (higher recovery of pendimethalin and better IR spectrum of pendimethalin product, smaller peak of nitroso indicating that it was reduced and a peak of N-H stretching vibration occurred), so in the example the solvent was isopropanol and the mass was 10 g.
Example 41:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.0 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 42:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 90% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 43:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding sulfuric acid solution (6 g) with the mass concentration of 50% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 44:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a sulfuric acid solution (10 g) with the mass concentration of 50% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 45:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a sulfuric acid solution (8 g) with the mass concentration of 50% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.3 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 46:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a hydrochloric acid solution (6 g) with the mass concentration of 5% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 47:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding hydrochloric acid solution (6 g) with the mass concentration of 30% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 48:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding hydrochloric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.0 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 49:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding hydrochloric acid solution (10 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.1 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 50:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding hydrochloric acid solution (8 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 51:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding phosphoric acid solution (6 g) with the mass concentration of 25% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 52:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding phosphoric acid solution (6 g) with the mass concentration of 80% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (1.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 53:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding phosphoric acid solution (6 g) with the mass concentration of 50% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 54:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding phosphoric acid solution (10 g) with the mass concentration of 50% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.3 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 55:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding phosphoric acid solution (8 g) with the mass concentration of 50% into the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and the IR spectrum is shown in FIG. 8, in which the stretching vibration of aromatic nitroso group (-N = O) is 1426 cm-1The peak of nitroso is small as seen in the infrared spectrum, indicating that it is reduced. And is at 3332cm-1A stretching vibration peak of N-H appears, which indicates that nitroso in the nitroso-pendimethalin is reduced.
Example 56:
high boiling point residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a container, and a mixed acidic solution (25% phosphoric acid solution (3 g) and 25% sulfuric acid solution (3 g)) was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.2 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 57:
high boiling point raffinate (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a container, and a mixed acidic solution (80% phosphoric acid solution (3 g) and 90% sulfuric acid solution (3 g)) was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.4 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 58:
high boiling point raffinate (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a container, and a mixed acidic solution (50% phosphoric acid solution (3 g) and 50% sulfuric acid solution (3 g)) was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.5 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 59:
high boiling point raffinate (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a container, and a mixed acidic solution (50% phosphoric acid solution (5 g) and 50% sulfuric acid solution (5 g)) was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.3 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 60:
high boiling point raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a container, and a mixed acidic solution (50% phosphoric acid solution (4 g) and 50% sulfuric acid solution (4 g)) was added to the container. Stirring was carried out at 45 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.4 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
And conclusion four: in the examples, when the acid solution was a 50% strength by mass sulfuric acid solution and the ratio of the acid solution to pendimethalin high boiling residue was 1:0.8, the reaction was most effective (example 55) (pendimethalin has a high recovery ratio and nitroso group has a small peak in the infrared spectrum indicating that it was reduced, 3332cm, and the reaction time was constant at all times)-1A stretching vibration peak of N — H appears indicating that the nitroso group in the nitrosopendimethalin is reduced), so the acid solution in the example is a sulfuric acid solution with a mass concentration of 50% and the mass is 8 g.
Example 61:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a sulfuric acid solution (8 g) with the mass concentration of 50% into the container. Stirring was carried out at 55 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.8 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 62:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a sulfuric acid solution (8 g) with the mass concentration of 50% into the container. Stirring was carried out at 48 ℃ for 12 hours, and filtration was carried out to give pendimethalin (2.9 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and showed an infrared spectrum of 1425 cm in stretching vibration of aromatic nitroso group (-N = O) as shown in FIG. 9-1The peak of nitroso is small as seen in the infrared spectrum, indicating that it is reduced. And is at 3322cm-1A stretching vibration peak of N-H appears, which indicates that nitroso in the nitroso-pendimethalin is reduced.
And a fifth conclusion: in the examples, the reaction temperature was 48 ℃ under otherwise unchanged conditionsoC, the reaction was best (example 62) (higher recovery of pendimethalin and better IR spectrum of pendimethalin product, smaller peak of nitroso indicating reduction and 3322cm-1A stretching vibration peak of N-H appears, indicating that the nitroso group in the nitrosopendimethalin is reduced), so the reaction temperature is 48 ℃ in the exampleoC。
Example 63:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a sulfuric acid solution (8 g) with the mass concentration of 50% into the container. Stirring was carried out at 48 ℃ for 18 hours, and filtration was carried out to give pendimethalin (2.7 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
Example 64:
putting high-boiling-point residual liquid (10 g) of pendimethalin, urea (5 g), white carbon black (25 g) and isopropanol (10 g) into a container, and adding a sulfuric acid solution (8 g) with the mass concentration of 50% into the container. Stirring was carried out at 48 ℃ for 16 hours, and filtration was carried out to give pendimethalin (3.4 g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate into the last remaining acidic solution for neutralization until the solution is neutral, and then discharging the solution.
The pendimethalin obtained in this example was tested and the IR spectrum is shown in FIG. 10The stretching vibration of aromatic nitroso (-N = O) in (1) is 1427 cm-1The peak of nitroso is small as seen in the IR spectrum, indicating that it is reduced. And is at 3345cm-1A stretching vibration peak of N-H appears, which indicates that nitroso in the nitroso-pendimethalin is reduced.
And conclusion six: in the examples, the best reaction results were obtained at 16 h reaction time (example 64) with otherwise unchanged conditions (high pendimethalin recovery, up to 34% and good pendimethalin product ir spectrum, small peak of nitroso indicating reduction and 3345cm-1A stretching vibration peak of N — H appeared indicating that the nitroso group in the nitrosopendimethalin was reduced), so the reaction time was 16H in the example.
In summary, according to the above embodiment, 5 g of urea, 25 g of white carbon black, 10 g of isopropanol as a solvent, and the mass ratio of the high-boiling-point residual liquid of pendimethalin to urea, white carbon black and isopropanol are as follows: 1: 0.5: 2.5: 1 is the best; the acid solution is a sulfuric acid solution (8 g) with the mass concentration of 50%, and the mass ratio of the high-boiling-point residual liquid of pendimethalin to the acid solution is selected from 1:0.8 is most preferred, at 48oThe reaction effect was best when C was reacted for 16 h (example 64, recovery rate 34%).

Claims (10)

1. The method for recycling pendimethalin high-boiling point residual liquid comprises the following steps:
high-boiling-point residual liquid of pendimethalin, urea, white carbon black and a solvent are mixed according to a mass ratio of 1: 0.3-0.8: 0-3: putting the mixture into a container in a ratio of 0.9-1.3 for mixing; and adding an acid solution into the container, wherein the mass ratio of the high-boiling point residual liquid of the pendimethalin to the acid solution is 1: 0.6 to 1; stirring at 45-55 deg.C for 12-18 hr, cooling to room temperature to crystallize and separate out product, filtering to obtain pendimethalin solid, vacuum drying, distilling the filtrate and recovering solvent.
2. The method for recycling pendimethalin high-boiling point residual liquid as claimed in claim 1, wherein the solvent is one or more of dichloromethane, 1, 2-dichloromethane, chloroform, methanol, ethanol, triethylamine, diethylamine, ethylenediamine, acetone, isopropanol or n-butanol.
3. The method for recycling pendimethalin high-boiling point residual liquid as claimed in claim 1, wherein the acidic solution is one or more of sulfuric acid, phosphoric acid and hydrochloric acid.
4. The process of recovering resource from high boiling point residual liquid of pendimethalin as claimed in claim 3, wherein the mass concentration of sulfuric acid is 25-90%.
5. The process of recovering resource from high-boiling point residual liquid of pendimethalin as claimed in claim 3, wherein the phosphoric acid has a mass concentration of 25-80%.
6. The method for recycling pendimethalin high-boiling point residual liquid as claimed in claim 3, wherein the mass concentration of the hydrochloric acid is 5-30%.
7. The method for recycling pendimethalin high-boiling point residual liquid according to any one of claims 1 to 6, wherein the mass ratio of the pendimethalin high-boiling point residual liquid to the urea, the white carbon black and the isopropanol is 1: 0.5: 2.5: 1.
8. the method for recycling pendimethalin high-boiling point residual liquid as claimed in claim 7, wherein the acid solution is a 50% sulfuric acid solution, and the mass ratio of pendimethalin high-boiling point residual liquid to the acid solution is 1: 0.8.
9. the process of recovering resource from high boiling point residual liquid of pendimethalin as claimed in claim 8, wherein the reaction temperature is 48%oC; the reaction time was 16 h.
10. The process of recovering resource from high boiling point residual liquid of pendimethalin as claimed in claim 1, wherein after recovering the solvent, sodium bicarbonate is added to the remaining acidic solution to neutralize the solution until it becomes neutral, and then the solution is discharged.
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Publication number Priority date Publication date Assignee Title
CN116621707A (en) * 2023-04-20 2023-08-22 江苏永安化工有限公司 Method for converting N-NO pendimethalin into pendimethalin

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CN116621707B (en) * 2023-04-20 2023-11-03 江苏永安化工有限公司 Method for converting N-NO pendimethalin into pendimethalin

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