CN113354541A - Method for cleanly producing 2, 4-dinitro benzene chloride - Google Patents
Method for cleanly producing 2, 4-dinitro benzene chloride Download PDFInfo
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- CN113354541A CN113354541A CN202110620699.1A CN202110620699A CN113354541A CN 113354541 A CN113354541 A CN 113354541A CN 202110620699 A CN202110620699 A CN 202110620699A CN 113354541 A CN113354541 A CN 113354541A
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- dinitrochlorobenzene
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- benzene chloride
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
- C07C201/06—Preparation of nitro compounds
- C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
- C07C201/06—Preparation of nitro compounds
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Abstract
The invention provides a method for cleanly producing 2, 4-dinitrochlorobenzene, which comprises the steps of taking 99 mass percent of o-nitrochlorobenzene as a raw material, taking a mixed acid solution prepared from 98 mass percent of sulfuric acid and nitric acid as a nitrating agent, carrying out continuous nitration reaction in a tubular reactor, pumping the nitrated mixed solution into a heat preservation kettle, preserving heat for 2 hours, pumping the nitrated mixed solution into a liquid separation kettle, separating an upper-layer oil phase, namely the mixed solution of 2, 4-dinitrochlorobenzene and 2, 6-dinitrochlorobenzene, and a lower-layer water phase, namely a waste acid solution; adding fuming sulfuric acid into the separated waste acid solution to ensure that the water content in the waste acid solution is below 2 percent; the separated mixed solution of the 2, 4-dinitro benzene chloride and the 2, 6-dinitro benzene chloride is neutralized, washed and crystallized to obtain the main product 2, 4-dinitro benzene chloride and the byproduct 2, 6-dinitro benzene chloride.
Description
Technical Field
The invention belongs to the technical field of chemical production, and particularly relates to a method for cleanly producing 2, 4-dinitrochlorobenzene.
Background
2, 4-dinitro benzene chloride is an important fine chemical intermediate, and is widely applied to the fields of medicines, pesticides, fuels, explosives, chemical additives and the like, the production process of 2, 4-dinitro benzene chloride is more, and the preparation method is different according to different raw materials, and according to the second edition, the upper volume, the 2 nd edition in 1998, 5 months, and page 840, two common preparation processes mentioned in the second edition, the 2 nd edition, and the 840 of Chinese chemical products are all provided with mixed acid formed by mixing concentrated sulfuric acid and concentrated nitric acid, but serious harm and burden are caused to the environment and enterprises along with the generation of waste acid in the industrial production along with the reaction.
Disclosure of Invention
The invention aims to provide a method for cleanly producing 2, 4-dinitro chlorobenzene by adopting a continuous production process, reducing the cost, reducing the waste acid discharge and lightening the environmental burden by mechanically using the prepared waste acid.
In order to solve the technical problems, the invention adopts the technical scheme that: a method for cleanly producing 2, 4-dinitro benzene chloride comprises the following steps:
the method comprises the following steps: nitration reaction: taking 99% o-nitrochlorobenzene in mass fraction as a raw material, taking a mixed acid solution prepared from 98% sulfuric acid and nitric acid in mass fraction as a nitrating agent, and carrying out continuous nitration reaction in a tubular reactor at a reaction temperature of 65-70 ℃ to obtain a nitrated mixed solution;
step two: and (3) heat preservation: pumping the nitrified mixed solution in the step one into a heat preservation kettle, and preserving heat for 2 hours;
step three: liquid separation: pumping the nitrified mixed solution subjected to heat preservation in the step two into a liquid separation kettle, separating out an upper oil phase, namely a mixed solution of 2, 4-dinitrochlorobenzene and 2, 6-dinitrochlorobenzene, and a lower water phase, namely a waste acid solution;
step four: and (3) dehydrating: adding oleum into the waste acid solution separated in the third step to ensure that the water content in the waste acid solution is below 2 percent;
step five: mechanically using waste acid: adding a mixed acid solution prepared from sulfuric acid and nitric acid with the mass fraction of 98% into the waste acid solution treated in the fourth step, and allowing the mixed acid solution and o-nitrochlorobenzene with the mass fraction of 99% to enter a next circulation nitration reaction;
step six: the product is as follows: and (3) neutralizing, washing and crystallizing the mixed solution of the 2, 4-dinitro benzene chloride and the 2, 6-dinitro benzene chloride separated in the third step to obtain a main product 2, 4-dinitro benzene chloride and a byproduct 2, 6-dinitro benzene chloride.
Further, the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1: 0.9-1.6: 0.98-1.3.
Further, the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1:1.4: 1.15.
Further, the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1:1.4: 1.1.
Further, the temperature of the second step is between 70 and 120 ℃.
Further, the temperature in the second step is between 90 and 95 ℃.
Further, the temperature of the liquid separation in the third step is between 55 and 65 ℃.
Further, the oleum in step four is 50% by mass.
Compared with the prior art, the invention has the advantages and beneficial effects that:
the tubular reactor is used for continuous nitration reaction, so that the production cost is effectively reduced, the waste acid is reused, 41 percent of the total amount of the waste acid generated by the reaction can be reused, the nitration reaction effect is not influenced by the waste acid reusing frequency, the cost for treating the waste acid is saved, the waste acid discharge is reduced, and the ecological environment is protected.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a process flow diagram of a clean production process for 2, 4-dinitrochlorobenzene according to the invention.
Detailed Description
In order that the above objects, features and advantages of the present invention may be more clearly understood, a more particular description of the invention will be rendered by reference to fig. 1, which is illustrated in the appended drawings. It should be noted that the technical solutions and features in the technical solutions of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific techniques disclosed below.
The technical solutions of the present invention will be described below with reference to specific embodiments, and the described embodiments are only a part of embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person skilled in the art on the basis of the present invention shall fall within the scope of protection of the present invention without making any creative effort.
A method for cleanly producing 2, 4-dinitro benzene chloride comprises the following steps:
the method comprises the following steps: nitration reaction: taking 99% o-nitrochlorobenzene by mass as a raw material, taking a mixed acid solution prepared from 98% sulfuric acid and nitric acid by mass as a nitrating agent, and carrying out continuous nitration reaction in a tubular reactor at a reaction temperature of 65-70 ℃ to obtain a nitrated mixed solution, wherein the reaction residence time in the tubular reactor is 10-30 minutes, so that the reaction is more complete;
step two: and (3) heat preservation: pumping the nitrified mixed solution in the step one into a heat preservation kettle, and preserving heat for 2 hours;
step three: liquid separation: pumping the nitrified mixed solution subjected to heat preservation in the step two into a liquid separation kettle, separating an upper oil phase, namely a mixed solution of 2, 4-dinitrochlorobenzene and 2, 6-dinitrochlorobenzene, and a lower water phase, namely a waste acid solution, wherein the liquid separation temperature is between 55 ℃ and 65 ℃, and the liquid separation effect is better;
step four: and (3) dehydrating: adding fuming sulfuric acid into the waste acid solution separated in the third step to ensure that the moisture content in the waste acid solution is below 2%, wherein the waste acid is used indiscriminately under the condition without influencing the product quality, and the fuming sulfuric acid is fuming sulfuric acid with the mass fraction of 50%;
step five: mechanically using waste acid: adding sulfuric acid with the mass fraction of 98% and nitric acid into the waste acid solution treated in the fourth step to prepare mixed acid solution, allowing the mixed acid solution and o-nitrochlorobenzene with the mass fraction of 99% to enter a next circulation nitration reaction, adding nitric acid to provide a raw material for the reaction, and adding sulfuric acid to ensure the acidity for initiating nitration and ensure that the total amount of the waste acid and the sulfuric acid after adding sulfuric acid is consistent with the total amount of the sulfuric acid in the initial reaction;
step six: the product is as follows: and (3) neutralizing, washing and crystallizing the mixed solution of the 2, 4-dinitro benzene chloride and the 2, 6-dinitro benzene chloride separated in the third step to obtain a main product 2, 4-dinitro benzene chloride and a byproduct 2, 6-dinitro benzene chloride.
Further, the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1: 0.9-1.6: 0.98-1.3.
Further, the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1:1.4: 1.15.
Further, the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1:1.4: 1.1.
Further, the temperature of the second step is between 70 and 120 ℃.
Further, the temperature in the second step is between 90 and 95 ℃.
Specifically, firstly, carrying out experimental analysis on the influence of the material ratio of o-nitrochlorobenzene, sulfuric acid and nitric acid on the reaction effect, carrying out an experiment for producing 2, 4-dinitrochlorobenzene by utilizing a tubular reactor to continuously nitrify the o-nitrochlorobenzene (50mol), taking 7.88kg of o-nitrochlorobenzene, heating to 55 ℃, melting the o-nitrochlorobenzene into oil, slowly adding mixed acid consisting of 8kg (1.6eq), 7.5kg (1.5eq), 7.06kg (1.4eq), 6kg (1.2eq), 5kg (1.0eq) and 4.5kg (0.9eq) of 98% sulfuric acid and 3.53kg (1.15eq) of 98% nitric acid, respectively, carrying out reaction for 23 minutes, controlling the reaction temperature to be between 65 and 70 ℃, heating to 95 ℃ after the reaction temperature does not rise, carrying out heat preservation for 2 hours, cooling to about 60 ℃, layering, and inspecting the influence of different 98% sulfuric acid dosage on the reaction effect, wherein eq represents the equivalent symbol.
The experimental results are shown in table 1 at different dosages of 98% sulfuric acid, and the optimal charge ratio of 98% sulfuric acid to 98% nitric acid in the continuous nitration reaction is 1.4 eq: 1.15eq, and in the continuous production process, if the raw material remains too much, the reaction effect can be adjusted by adjusting the feeding amounts of 98% sulfuric acid and 98% nitric acid, and if more impurities are present, the reaction effect can be adjusted by reducing the feeding amount of 98% sulfuric acid.
TABLE 1 Effect of different amounts of 98% sulfuric acid on the reaction
| Sulfuric acid dosage/eq | Content of product/%) | Content of by-products/%) | Percentage of impurities/%) | Residual proportion of raw material/%) |
| 1.6 | 88.3 | 10.54 | 0.4 | 0.06 |
| 1.5 | 88.5 | 11.8 | 1.3 | 0.24 |
| 1.4 | 91.1 | 7.8 | 0.67 | 0.01 |
| 1.2 | 86.3 | 11.3 | 0.5 | 1.78 |
| 1.0 | 81.2 | 10.6 | 0.21 | 7.8 |
| 0.9 | 80.5 | 10.3 | 0.5 | 8.34 |
In an experiment for producing 2, 4-dinitrochlorobenzene by continuous nitration through a tubular reactor, 7.88kg of o-nitrochlorobenzene (50mol) is taken and heated to 55 ℃ to be melted into oil, 3.99kg (1.3eq), 3.68kg (1.2eq), 3.38kg (1.1eq), 3.22kg (1.05eq) and 3.07kg (1.0eq) of mixed acid consisting of 98% nitric acid and 7.06kg (1.4eq) of 98% sulfuric acid are slowly added, the reaction residence time is 23 minutes, the reaction temperature is controlled between 65 ℃ and 70 ℃, after the reaction temperature does not rise, the reaction temperature is heated to 95 ℃, kept for 2 hours, cooled to about 60 ℃ and layered, and the influence of different 98% nitric acid dosage on the reaction effect is examined, wherein eq is a symbol representing equivalent.
Under different dosage of the 98 percent nitric acid, the experimental results are shown in Table 2, the dosage of the 98 percent nitric acid directly influences the content of the product, when the dosage of the 98 percent nitric acid is too small, the raw material reaction is not complete, and when the dosage of the 98 percent nitric acid is too large, the content of the by-product 2, 6-dinitrochlorobenzene is increased, so the optimal dosage of the nitric acid in the reaction is 1.1 eq.
TABLE 2 Effect of different amounts of 98% nitric acid on the reaction
| Dosage of nitric acid per eq | Content of product/%) | Content of by-products/%) | Percentage of impurities/%) | Residual proportion of raw material/%) |
| 1.3 | 81.04 | 10.1 | 0.99 | 7.58 |
| 1.2 | 85.5 | 11.04 | 2.5 | 0.82 |
| 1.1 | 91.1 | 8.0 | 0.65 | 0.01 |
| 1.05 | 84.1 | 10.03 | 0.94 | 4.84 |
| 1.0 | 77.3 | 9.75 | -- | 9.49 |
In the experiment of producing 2, 4-dinitrochlorobenzene by continuous nitration of a tubular reactor, 7.88kg of o-nitrochlorobenzene (50mol) is taken and heated to 55 ℃ to be melted into oil, 7.06kg (1.4eq) of 98 percent sulfuric acid and 3.38kg (1.1eq) of 98 percent nitric acid are slowly added, the reaction residence time is 23 minutes, the reaction temperature is controlled between 65 ℃ and 70 ℃, the product quality of heat preservation for 2 hours at different heat preservation temperatures is inspected, wherein eq is a symbol representing equivalent.
At different heat preservation temperatures, the experimental results are shown in table 3, the higher the heat preservation temperature is, the more the byproduct content is, and the optimal heat preservation temperature for the reaction is between 90 ℃ and 95 ℃.
TABLE 3 influence of incubation temperature on reaction Effect
| Temperature/. degree.C | Content of product/%) | Content of by-products/%) | Percentage of impurities/%) | Residual proportion of raw material/%) |
| 70-75 | 88.3 | 10.7 | 0.02 | 0.86 |
| 80-85 | 89.0 | 10.81 | 0.03 | 0.44 |
| 90-95 | 89.9 | 9.5 | 0.1 | 0.13 |
| 100-105 | 88.9 | 11.0 | -- | -- |
| 115-120 | 74.6 | 23.7 | 0.41 | 1.1 |
As shown in Table 1, Table 2 and Table 3, the optimum reaction conditions for the continuous nitration reaction using the tubular reactor are that the molar ratio of the ortho-nitrochlorobenzene to the sulfuric acid to the nitric acid is 1:1.4:1.1, and the reaction effect is best when the temperature is maintained between 90 ℃ and 95 ℃ for 2 hours.
The waste acid is diluted by water generated in the reaction process, so the waste acid is required to be applied to the nitration reaction after being prepared with 50% fuming sulfuric acid, the table 4 shows that the influence of the water content in the prepared waste acid on the reaction effect is detected after the waste acid is prepared with 50% fuming sulfuric acid, and the table 4 shows that the more the water content in the waste acid is, the more the water content is, the adverse effect is on the forward direction of the reaction, so the 50% fuming sulfuric acid is required to be added to concentrate or absorb the generated water, and the water content in the waste acid is enabled to be below 2%.
TABLE 4 influence of the Water content of the spent acid on the reaction effectiveness
| Water content/%) | Product/%) | By-product/%) | Residual of raw material/%) | |
| Original process | 2.0 | 88.19 | 11.57 | 0.07 |
| Waste acid configuration 1 | 7.0 | 73.0 | 9.8 | 16.8 |
| Waste acid preparation 2 | 15.0 | 59.8 | 8.31 | 31.75 |
Studying the influence of the waste acid application frequency on the product quality, in an experiment for producing 2, 4-dinitrochlorobenzene by using a tubular reactor through continuous nitration, taking 7.88kg of o-nitrochlorobenzene (50mol), heating to 55 ℃ to melt into oil, slowly adding 7.06kg (1.4eq) of 98% sulfuric acid and 3.38kg (1.1eq) of 98% nitric acid, keeping the reaction time for 23 minutes, controlling the reaction temperature between 65 ℃ and 70 ℃, pumping the reaction liquid into a heat preservation kettle to preserve heat at 95 ℃ for 2 hours after the reaction is completed, pumping the heat preserved reaction liquid into a liquid separation kettle to carry out layering, wherein an oil phase is the product, a water phase is the waste acid, the water content of the waste acid after preparation is below 2%, and the waste acid is continuously applied for 5 times, and eq is a sign of equivalent weight.
As shown in Table 5, after the waste acid is continuously used for 5 times, the purity, the reaction degree and the impurity ratio of the product are not affected, so that the reaction effect is not affected by the use times of the waste acid, the cost for treating the waste acid is saved, the waste water discharge is reduced, and the ecological environment is protected.
TABLE 5 influence of the number of times of applying waste acid to the reaction
While one embodiment of the present invention has been described in detail, the description is only a preferred embodiment of the present invention and should not be taken as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (8)
1. A method for cleanly producing 2, 4-dinitro benzene chloride is characterized by comprising the following steps: the method comprises the following steps:
the method comprises the following steps: nitration reaction: taking 99% o-nitrochlorobenzene in mass fraction as a raw material, taking a mixed acid solution prepared from 98% sulfuric acid and nitric acid in mass fraction as a nitrating agent, and carrying out continuous nitration reaction in a tubular reactor at a reaction temperature of 65-70 ℃ to obtain a nitrated mixed solution;
step two: and (3) heat preservation: pumping the nitrified mixed solution in the step one into a heat preservation kettle, and preserving heat for 2 hours;
step three: liquid separation: pumping the nitrified mixed solution subjected to heat preservation in the step two into a liquid separation kettle, separating out an upper oil phase, namely a mixed solution of 2, 4-dinitrochlorobenzene and 2, 6-dinitrochlorobenzene, and a lower water phase, namely a waste acid solution;
step four: and (3) dehydrating: adding oleum into the waste acid solution separated in the third step to ensure that the water content in the waste acid solution is below 2 percent;
step five: mechanically using waste acid: adding a mixed acid solution prepared from sulfuric acid and nitric acid with the mass fraction of 98% into the waste acid solution treated in the fourth step, and allowing the mixed acid solution and o-nitrochlorobenzene with the mass fraction of 99% to enter a next circulation nitration reaction;
step six: the product is as follows: and (3) neutralizing, washing and crystallizing the mixed solution of the 2, 4-dinitro benzene chloride and the 2, 6-dinitro benzene chloride separated in the third step to obtain a main product 2, 4-dinitro benzene chloride and a byproduct 2, 6-dinitro benzene chloride.
2. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 1, characterized in that: the mol ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the first step is 1: 0.9-1.6: 0.98-1.3.
3. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 2, characterized in that: the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1:1.4: 1.15.
4. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 2, characterized in that: the molar ratio of the o-nitrochlorobenzene, the sulfuric acid and the nitric acid added in the step one is 1:1.4: 1.1.
5. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 1, characterized in that: and in the second step, the heat preservation temperature is between 70 and 120 ℃.
6. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 5, characterized in that: and in the second step, the heat preservation temperature is between 90 and 95 ℃.
7. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 1, characterized in that: and the temperature of the liquid separation in the third step is between 55 and 65 ℃.
8. A process for the clean production of 2, 4-dinitrochlorobenzene according to claim 1, characterized in that: the oleum in step four is 50% by mass.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114349678A (en) * | 2021-11-24 | 2022-04-15 | 珠海派锐尔新材料有限公司 | Continuous industrial production method of N-alkyl-nitrophthalimide |
Citations (2)
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|---|---|---|---|---|
| GB439055A (en) * | 1933-05-26 | 1935-11-28 | Du Pont | Improvements in or relating to the manufacture of amines |
| CN1513830A (en) * | 2003-07-29 | 2004-07-21 | 徐德军 | Preparation method of 2,4-dinitochloro benzene |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB439055A (en) * | 1933-05-26 | 1935-11-28 | Du Pont | Improvements in or relating to the manufacture of amines |
| CN1513830A (en) * | 2003-07-29 | 2004-07-21 | 徐德军 | Preparation method of 2,4-dinitochloro benzene |
Non-Patent Citations (1)
| Title |
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| 史英杰: "关于二硝基氯苯的工艺", 《染料工业》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114349678A (en) * | 2021-11-24 | 2022-04-15 | 珠海派锐尔新材料有限公司 | Continuous industrial production method of N-alkyl-nitrophthalimide |
| CN114349678B (en) * | 2021-11-24 | 2024-04-26 | 珠海派锐尔新材料有限公司 | Continuous industrial production method of N-alkyl-nitrophthalimide |
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