CN111825554B - Method for recycling pendimethalin high-boiling-point residual liquid - Google Patents

Method for recycling pendimethalin high-boiling-point residual liquid Download PDF

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CN111825554B
CN111825554B CN202010823630.4A CN202010823630A CN111825554B CN 111825554 B CN111825554 B CN 111825554B CN 202010823630 A CN202010823630 A CN 202010823630A CN 111825554 B CN111825554 B CN 111825554B
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pendimethalin
solution
raffinate
high boiling
solvent
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CN111825554A (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
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/38—Separation; Purification; Stabilisation; Use of additives
    • 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
    • C07C209/86—Separation
    • 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
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/78—Separation; Purification; Stabilisation; Use of additives

Abstract

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

Description

Method for recycling pendimethalin high-boiling-point residual liquid
Technical field:
the invention belongs to the field of recycling of waste liquid and residual liquid, and particularly relates to a recycling method of 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 is mainly generated by two procedures of nitration and refining, and the residual liquid is called high-boiling-point raffinate which mainly contains nitric acid, pendimethalin and nitropendimethalin.
The background technology is as follows:
pendimethalin (pendimethalin), the chemical name of which is N- (3-amyl) -3, 4-dimethyl-2, 6-dinitroaniline, is a dinitroaniline herbicide, and is a selective pre-emergent herbicide developed and popularized by Americun Cyanamid Company (American cyanamide company); has good effect on most annual grassy weeds and certain broadleaf weeds. The herbicide has good effect, low toxicity and good safety, thus being widely popularized and applied, and becoming the selective herbicide with the largest dosage in the world at present, and having large internal and external demands and wide market.
The current production process of pendimethalin uses 3, 4-dimethylnitrobenzene as raw material, and the product pendimethalin (US 4136117) is obtained through hydrogenation, alkylation with 3-pentanone, hydrogenation, nitration and purification. The reaction route of the process is shown in figure 1, the process route has short steps, less construction investment, higher process yield, low-cost and easily-obtained raw materials and low production cost, and is not only widely used abroad, but also a common method for producing pendimethalin in China. During the nitration process, nitrosamine (N-nitrosopendimethalin) byproducts are produced, up to 20% of the product. N-nitrosopendimethalin by-product has high toxicity, mutation, and high amount of N-nitrosopendimethalin by-product, so that the nitration efficiency is reduced, the production cost is seriously influenced, and the N-nitrosopendimethalin must be reduced and degraded. Therefore, this process increases the purification and refining steps. Although both acidolysis and thermal cracking are used for purification, a large amount of high boiling raffinate is produced during purification. Therefore, during the nitration and refining process, a large amount of residual liquid is produced, and the residual liquid has high acidity, is difficult to volatilize and degrade, and has a high organic pollutant content. The current treatment method of residual liquid is mainly incineration, but the treatment method can produce black carbon pollution and reduce the production efficiency. Thus, there is an urgent need for a method for recycling the raffinate.
The invention comprises the following steps:
aiming at the technical problems, the invention provides a method for recycling the high-boiling-point raffinate of pendimethalin, and the method can recycle pendimethalin after the raffinate is treated.
The specific technical scheme of the invention is as follows:
the invention provides a method for recycling pendimethalin high-boiling-point residual liquid, which comprises the following steps:
the method comprises the steps of mixing high-boiling-point raffinate of pendimethalin, urea, white carbon black and a solvent according to a mass ratio of 1:0.3 to 0.8: 0-3: mixing in a container according to the proportion of 0.9-1.3; adding an acidic solution into the container, wherein the mass ratio of the high boiling point raffinate of pendimethalin to the acidic solution is 1: 0.6-1; at 45-55 o Stirring at C for 12-18 hr, cooling to room temperature, crystallizing and separating out the product, filtering to obtain pendimethalin solid, vacuum drying, distilling the filtrate, and recovering solvent.
Further, the solvent is selected from 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 acidic solution is selected from one or 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 raffinate of pendimethalin to urea, white carbon black and isopropanol is 1:0.5:2.5:1, a step of;
further, the acidic solution is sulfuric acid solution with the mass concentration of 50%, and the mass ratio of the high boiling point raffinate of pendimethalin to the acidic solution is 1:0.8;
further, the reaction temperature was 48 o C, performing operation; the reaction time was 16 h;
further, after recovering the solvent, sodium bicarbonate was added to the remaining acidic solution for neutralization until the solution was neutral, which was then discharged.
The principle of the invention is as follows:
under the acidic condition, urea is used as a reducing agent, and the urea and the nitropendimethalin react under the heating reflux state to obtain the pendimethalin product, other components are not added, organic impurities are not introduced, and the used reagents are nontoxic and harmless. The whole reaction can convert nitropendimethalin into pendimethalin products, so that the production efficiency is improved; and the recovered solvent can be distilled and reused in the reaction process, so that the solvent can be recycled. White carbon black is a porous material having a composition of SiO 2 ·nH 2 O represents, where nH 2 O exists in the form of surface hydroxyl, can be combined with nitroso, and is favorable for reducing nitrosopendimethalin. 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 obtains the pendimethalin product by recycling the toxic and harmful residual liquid without economic value, 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. The method of the invention is that under the acid condition (wherein the sulfuric acid solution with the mass concentration of 50% is best, the acid environment is provided, the reduction of nitroso is facilitated), the urea can reduce the nitropendimethalin in a low boiling point solvent at a lower temperature, and the white carbon black shows that the white carbon black contains hydroxyl, can fix the 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 equipment requirement is low, the large-scale production is easy, the solvent recovered by distillation can be reused in the reaction process, and the recycling of the solvent is realized.
3. The invention uses pendimethalin high boiling point residual liquid, urea, white carbon black, solvent and acid solution according to the mass ratio of 1:0.3 to 0.8: 0-3: 0.9 to 1.3: 0.6-1, and reacting; and at 45-55 o And C, stirring and reacting for 12-18 hours at the temperature. By comparison of examples, the mass ratio of the high boiling point raffinate of pendimethalin to urea, white carbon black, isopropanol and acid solution is as follows: 1:0.5:2.5:1:0.8, the acid solution is sulfuric acid solution with the mass concentration of 50 percent, 48 o C, in the reaction of 16 h, the reaction effect is best, the recovery rate is 34 percent, the obtained pendimethalin infrared spectrogram is relatively good, and the peak of nitroso is relatively small, which indicates that the pendimethalin is basically reduced; and a stretching vibration peak of N-H appears, which indicates that the nitropendimethalin is converted into pendimethalin.
Description of the drawings:
FIG. 1 is a chemical formula (abstract drawing) of synthesizing pendimethalin from 3, 4-dimethylnitrobenzene;
FIG. 2 is an equation for the reaction of nitropendimethalin with urea;
FIG. 3 is an infrared spectrum of the product obtained in example 1; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 4 is an infrared spectrum of the product obtained in example 2; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 5 is an infrared spectrum of the product obtained in example 3; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 6 is an infrared spectrum of the product obtained in example 5; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 7 is an infrared spectrum of the product obtained in example 34; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 8 is an infrared spectrum of the product obtained in example 55; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 9 is an infrared spectrum of the product obtained in example 62; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
FIG. 10 is an infrared spectrum of the product obtained in example 64; wherein (A) is pendimethalin pure form, and (B) is the obtained product;
note that: other examples the FT-IR patterns of the resulting products are similar thereto and are not listed here.
The specific embodiment is as follows:
the invention provides a method for recycling pendimethalin high-boiling residual liquid, which is further described by the following examples:
example 1:
a method for recycling high boiling point raffinate of pendimethalin, wherein the chemical equation of synthesizing pendimethalin by 3, 4-dimethyl nitrobenzene is shown in figure 1; the equation for the reaction of nitropendimethalin with urea is shown in FIG. 2 (the reaction in other examples is the same), and the specific steps are as follows:
The high boiling raffinate of pendimethalin (10 g), urea (3 g) and methylene chloride (9 g) were put into a vessel, and sulfuric acid solution (6 g) with a mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested and the infrared spectrum was as shown in FIG. 3, at 3439 cm -1 Is the-OH stretching vibration peak of water; 3328 cm -1 The N-H telescopic vibration peak shows that nitroso in nitropendimethalin is reduced, the water peak in a pure sample is larger, and the peak of secondary amine is covered; 2967 2929, 2875 cm -1 Is the telescopic vibration peak of alkane (C-H), 1624, 1576 and 1490, 1490 cm -1 Is the telescopic vibration peak of benzene ring, 1533 and 1533 cm -1 Is aromatic NO 2 Is an antisymmetric telescopic vibration peak of 1329 cm -1 Is aromatic NO 2 Is symmetrical with respect to the stretching vibration peak 1249 and 1249 cm -1 Is C-N telescopic vibration peak 926 cm -1 Is the bending vibration peak of C-H, 760 and 760 cm -1 Is the outward extending vibration peak of C-H surface on benzene ring. Stretching vibration of aromatic nitroso group (-N=O) is 1425 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced.
Example 2:
the high boiling raffinate of pendimethalin (10 g), urea (8 g) and methylene chloride (9 g) were put into a vessel, and sulfuric acid solution (6 g) with a mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was shown in FIG. 4, in which the stretching vibration of aromatic nitroso (-N=O) was 1424 and 1424 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced.
Example 3:
the high boiling raffinate of pendimethalin (10 g), urea (5 g) and methylene chloride (9 g) were placed in a vessel, and 25% sulfuric acid solution (6 g) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was shown in FIG. 5, in which the stretching vibration of aromatic nitroso (-N=O) was 1426 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced.
Conclusion one in the examples, the mass ratio of pendimethalin high boiling raffinate to urea was 1: at 0.5, the reaction was best (example 3) (the recovery of pendimethalin was relatively high, the infrared spectrum of the pendimethalin product was also relatively good, the peak of nitroso was relatively small, indicating that it was reduced), so urea continued to react at 5 g in the examples.
Example 4:
the high boiling residue of pendimethalin (10, g), urea (5, g), white carbon black (30, g) and methylene chloride (9, g) are put into a container, and a 25% sulfuric acid solution (6, g) is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 5:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and methylene chloride (9 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was as shown in FIG. 6, in which the stretching vibration of aromatic nitroso (-N=O) was 1420 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced. And at 3324 cm -1 There is a stretching vibration peak of a bit N-H.
Conclusion two in the examples, under the condition of the other conditions, when the mass of the high boiling point raffinate of pendimethalin and the white carbon black is 1:2.5 In this case, the effect of the reaction was best (example 5) (the recovery rate of pendimethalin was relatively high, the infrared spectrum of pendimethalin product was also relatively good, the peak of nitroso group was small, indicating that it was reduced), and the example with white carbon black was better than the example without adding white carbon black, so white carbon black was favorable for recycling the residual liquid, and the reaction of white carbon black was continued at 25 g in the example.
Example 6:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and methylene chloride (13 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 7:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and methylene chloride (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.3 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 8:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and chloroform (9 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 9:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and chloroform (13 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 10:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and chloroform (10 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 11:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and 1, 2-dichloroethane (9 g) are put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 12:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and 1, 2-dichloroethane (13 g) were put into a vessel, and a 25% sulfuric acid solution (6 g) was added to the vessel. Stirring at 45deg.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 to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 13:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and 1, 2-dichloroethane (10 g) were put into a vessel, and a 25% sulfuric acid solution (6 g) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 14:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and methanol (9 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 15:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and methanol (13 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 16:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and methanol (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 17:
the high boiling residue of pendimethalin (10, g), urea (5, g), white carbon black (25, g) and ethanol (9, g) are put into a container, and sulfuric acid solution (6, g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 18:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and ethanol (13 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 19:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and ethanol (10 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.0 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 20:
the high boiling residue of pendimethalin (10, g), urea (5, g), white carbon black (25, g) and triethylamine (9, g) are put into a container, and sulfuric acid solution (6, g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 21:
the high boiling residue of pendimethalin (10, g), urea (5, g), white carbon black (25, g) and triethylamine (13, g) were put into a vessel, and a 25% sulfuric acid solution (6, g) was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 22:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and triethylamine (10 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 23:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and diethylamine (9 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 24:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and diethylamine (13 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 25:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and diethylamine (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 26:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and ethylenediamine (9 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 27:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and ethylenediamine (13 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 28:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and ethylenediamine (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.0 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 29:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and acetone (9 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 30:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and acetone (13 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.4, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 31:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and acetone (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 32:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (9 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 33:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (13 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 34:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.6 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was shown in FIG. 7, in which the stretching vibration of aromatic nitroso (-N=O) was 1424 and 1424 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced. And at 3321 cm -1 There is a stretching vibration peak of a bit N-H.
Example 35:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and n-butanol (9 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.7, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 36:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and n-butanol (13 g) are put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 37:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and n-butanol (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 38:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and mixed solvent (isopropanol (4 g) and n-butanol (5 g)) were put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.0 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 39:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and mixed solvent (isopropanol (6 g) and n-butanol (7 g)) were put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 40:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and mixed solvent (isopropanol (5 g) and n-butanol (5 g)) were put into a container, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.0 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Conclusion III in the examples, the mass of the high boiling raffinate with pendimethalin was 1 when isopropanol was used as solvent under otherwise unchanged conditions: 1. in this case, the reaction was carried out in the best mode (example 34) (the recovery rate of pendimethalin was relatively high, the infrared spectrum of pendimethalin product was also relatively good, the peak of nitroso group was small, which means that it was reduced, and the stretching vibration peak of N-H occurred), so that in the example, the solvent was isopropyl alcohol, and the mass was 10 g.
Example 41:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (6 g) with mass concentration of 25% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.0 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 42:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (6 g) with a mass concentration of 90% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 43:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (6 g) with a mass concentration of 50% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 44:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (10 g) with a mass concentration of 50% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 45:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (8 g) with a mass concentration of 50% was added into the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.3 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 46:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a 5% hydrochloric acid solution (6 g) is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 47:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a hydrochloric acid solution (6 g) with the mass concentration of 30% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 48:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and 25% hydrochloric acid solution (6 g) is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.0 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 49:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and 25% hydrochloric acid solution (10 g) is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.1 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 50:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and 25% hydrochloric acid solution (8 g) is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 51:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a phosphoric acid solution (6 g) with mass concentration of 25% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 52:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a phosphoric acid solution (6 g) with mass concentration of 80% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (1.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 53:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a phosphoric acid solution (6 g) with the mass concentration of 50% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 54:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a phosphoric acid solution (10 g) with the mass concentration of 50% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.3 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 55:
the high boiling residue of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) are put into a container, and a phosphoric acid solution (8 g) with the mass concentration of 50% is added into the container. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was shown in FIG. 8, in which the stretching vibration of aromatic nitroso (-N=O) was 1426 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced. And at 3332 cm -1 A stretching vibration peak of N-H appears, which indicates that nitroso in nitropendimethalin is reduced.
Example 56:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropyl alcohol (10 g) were placed in a vessel and a mixed acidic solution (25% phosphoric acid solution (3 g) and 25% sulfuric acid solution (3 g)) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.2 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 57:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropyl alcohol (10 g) were placed in a vessel, and a mixed acidic solution (80% phosphoric acid solution (3 g) and 90% sulfuric acid solution (3 g)) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.4, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 58:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropyl alcohol (10 g) were placed in a vessel, and a mixed acidic solution (50% phosphoric acid solution (3 g) and 50% sulfuric acid solution (3 g)) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.5 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 59:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropyl alcohol (10 g) were placed in a vessel and a mixed acidic solution (50% phosphoric acid solution (5 g) and 50% sulfuric acid solution (5 g)) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.3 g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 60:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropyl alcohol (10 g) were placed in a vessel and a mixed acidic solution (50% phosphoric acid solution (4 g) and 50% sulfuric acid solution (4 g)) was added to the vessel. Stirred at 45 ℃ for 12 hours, filtered to obtain pendimethalin (2.4, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Conclusion IV: in the examples, the best effect of the reaction was obtained when the acidic solution was 50% sulfuric acid solution by mass and the mass ratio to the high boiling raffinate of pendimethalin was 1:0.8 under the other conditions (examples55 (pendimethalin recovery is relatively high, and the peak of nitroso is relatively small from the infrared spectrum of pendimethalin, indicating that it is reduced. And at 3332 cm -1 The stretching vibration peak of N-H appears, indicating that nitroso in nitropendimethalin is reduced), so in the example the acidic solution is a sulfuric acid solution with a mass concentration of 50% and a mass of 8 g.
Example 61:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (8 g) with a mass concentration of 50% was added into the vessel. Stirred at 55 ℃ for 12 hours, filtered to obtain pendimethalin (2.8, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 62:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (8 g) with a mass concentration of 50% was added into the vessel. Stirred at 48 ℃ for 12 hours, filtered to obtain pendimethalin (2.9, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was shown in FIG. 9, in which the stretching vibration of aromatic nitroso (-N=O) was 1425 and 1425 cm -1 From the infrared spectrum, the peak of nitroso is smaller, indicating that it is reduced. And at 3322 cm -1 A stretching vibration peak of N-H appears, which indicates that nitroso in nitropendimethalin is reduced.
Conclusion five: in the examples, the reaction temperature was 48 under the other conditions o The best reaction effect at C (example 62) (higher recovery of pendimethalin and also better IR spectrum of pendimethalin product, smaller peak of nitroso, indicating that it is reduced, and in 3322 cm) -1 Appearance ofThe stretching vibration peak of N-H indicates that nitroso in nitropendimethalin is reduced), so the reaction temperature is 48 in the examples o C。
Example 63:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (8 g) with a mass concentration of 50% was added into the vessel. Stirred at 48 ℃ for 18 hours, filtered to give pendimethalin (2.7, g), and the filtrate was distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
Example 64:
the high boiling raffinate of pendimethalin (10 g), urea (5 g), white carbon black (25 g) and isopropanol (10 g) were put into a vessel, and sulfuric acid solution (8 g) with a mass concentration of 50% was added into the vessel. Stirred at 48 ℃ for 16 hours, filtered to obtain pendimethalin (3.4, g), and the filtrate is distilled to recover the solvent. And adding sodium bicarbonate to the final remaining acidic solution for neutralization until the solution is neutral, and discharging the solution.
The pendimethalin obtained in this example was tested, and the infrared spectrum was shown in FIG. 10, in which the stretching vibration of aromatic nitroso (-N=O) was 1427 and 1427 cm -1 From the infrared spectrum, the peak of nitroso is small, indicating that it is reduced. And at 3345 cm -1 A stretching vibration peak of N-H appears, which indicates that nitroso in nitropendimethalin is reduced.
Conclusion six: in the examples, the reaction time was best (example 64) at 16 h (the recovery of pendimethalin was high, up to 34%, and the infrared spectrum of pendimethalin product was also good, the peak of nitroso was small, indicating that it was reduced, and at 3345 cm -1 The stretching vibration peak of N-H appears, indicating that nitroso in nitropendimethalin is reduced), so the reaction time is 16H in the example.
Conclusion by the above embodiments, it is possibleThe reducer is selected from urea 5 g, white carbon black 25 g and isopropanol (10 g), and the mass ratio of the high boiling point raffinate of pendimethalin to the urea, the white carbon black and the isopropanol is: 1:0.5:2.5:1 is the most preferred; the acid solution is sulfuric acid solution (8 g) with the mass concentration of 50%, and the mass ratio of the high boiling point raffinate of pendimethalin to the acid solution is 1:0.8 is optimal, at 48 o In the case of reaction 16 h, the reaction effect was the best (example 64, recovery 34%).

Claims (8)

1. A method for recycling a high boiling residue of pendimethalin, the method comprising the steps of:
the method comprises the steps of mixing high-boiling-point raffinate of pendimethalin, urea, white carbon black and isopropanol according to a mass ratio of 1:0.5:2.5:1, mixing in a container; adding an acidic solution into the container, wherein the mass ratio of the high boiling point raffinate of pendimethalin to the acidic solution is 1: 0.6-1; stirring at 45-55deg.C for 12-18 hr, cooling to room temperature, crystallizing and separating out the product, filtering to obtain pendimethalin solid, vacuum drying, distilling the filtrate, and recovering solvent.
2. The method for recycling the high boiling point raffinate of pendimethalin according to claim 1, wherein the acidic solution is selected from one or more than two of sulfuric acid, phosphoric acid or hydrochloric acid.
3. The method for recycling high boiling raffinate of pendimethalin according to claim 2, wherein the mass concentration of the sulfuric acid is 25-90%.
4. The method for recycling high boiling raffinate of pendimethalin according to claim 2, wherein the mass concentration of phosphoric acid is 25-80%.
5. The method for recycling the high boiling point raffinate of pendimethalin according to claim 2, wherein the mass concentration of the hydrochloric acid is 5-30%.
6. The method for recycling the high-boiling raffinate of pendimethalin according to any one of claims 1 to 5, wherein the acidic solution is sulfuric acid solution with the mass concentration of 50%, and the mass ratio of the high-boiling raffinate of pendimethalin to the acidic solution is 1:0.8.
7. the method for recycling high boiling raffinate of pendimethalin as claimed in claim 6, wherein the reaction temperature is 48 o C, performing operation; the reaction time was 16 h.
8. The method for recycling high boiling raffinate of pendimethalin as claimed in claim 1, wherein after recovering the solvent, sodium bicarbonate is added into the remaining acidic solution for neutralization until the solution is neutral, and then discharged.
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CN109867607A (en) * 2019-03-21 2019-06-11 江苏永安化工有限公司 The method of product is continuously recycled from pendimethalin residue
CN109970573A (en) * 2019-05-17 2019-07-05 江苏永安化工有限公司 The method of N- nitroso compound is sloughed from pendimethalin

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GB1586003A (en) * 1977-04-25 1981-03-11 American Cyanamid Co Denitrosation of organic nitrosamines
US4621157A (en) * 1984-05-07 1986-11-04 Jerome A. Gross Nitration processes
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