CN113233984B - Method for preparing nitrobenzene by recycling nitrified waste acid - Google Patents
Method for preparing nitrobenzene by recycling nitrified waste acid Download PDFInfo
- Publication number
- CN113233984B CN113233984B CN202011206664.5A CN202011206664A CN113233984B CN 113233984 B CN113233984 B CN 113233984B CN 202011206664 A CN202011206664 A CN 202011206664A CN 113233984 B CN113233984 B CN 113233984B
- Authority
- CN
- China
- Prior art keywords
- nitrified
- acid
- recycling
- waste acid
- nitrogen dioxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
- C01B21/38—Nitric acid
- C01B21/40—Preparation by absorption of oxides of nitrogen
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application relates to the technical field of nitrification, and discloses a method for preparing nitrobenzene by recycling nitrified waste acid, which comprises the following steps: 1) Adding waste acid into a reaction kettle, and introducing a nitrogen dioxide-containing gas stream and an oxygen-containing gas stream to obtain nitrified mixed acid; 2) And (3) reacting benzene with the nitrifying mixed acid obtained in the step (1) to obtain a nitrobenzene crude product. The method realizes that the waste acid absorbs the nitrogen oxides to obtain the mixed acid, and is circularly used in the mixed acid nitrification, so that the problems of serious pollution, dangerous treatment process and high cost of the existing mixed acid are solved, and the waste gas containing the nitrogen oxides can be treated simultaneously, thereby reducing the environmental pollution.
Description
Technical Field
The application relates to the technical field of nitrification, in particular to a method for preparing nitrobenzene by recycling nitrified waste acid.
Background
The nitration reaction generally refers to a reaction in which hydrogen atoms in organic compound molecules are directly substituted by nitro groups, and the most common method for producing nitroaromatic compounds at home and abroad at present is a nitro-sulfur mixed acid nitration method. In the 30 s of the 19 th century, students had used the nitration process to nitrate benzene to nitrobenzene. The industrial preparation of nitrobenzene uses benzene and nitric acid as raw materials, sulfuric acid as catalyst, and nitrifies under a certain reaction condition. The nitration reaction of the passivated aromatic ring is relatively difficult, mainly depends on the nitration of the nitro-sulfur mixed acid, and other nitration reagents have difficulty in obtaining better effects.
After the nitration reaction is completed, the organic phase is separated to obtain the nitrationWaste acid. The nitrified waste acid is a potential sulfur resource, and the nitrified waste acid is recycled, so that the nitrified waste acid is a necessary condition for realizing sustainable development. Waste acid is generally concentrated and then recycled in industry, and waste water is generated in the waste acid concentration process and has a certain danger. CN105329864a discloses a method for recycling waste acid solution in nitrobenzene production, firstly adding the waste acid solution into an azeotropic distillation column, separating by azeotropic distillation, wherein the discharged material from the top of the column is nitric acid, the discharged sulfuric acid from the bottom of the column is nitric acid as extractant, adding the nitric acid into an azeotropic extraction distillation column, the discharged material from the bottom of the azeotropic extraction distillation column is sulfuric acid with a content of more than or equal to 95wt%, condensing the mixed steam of nitrobenzene and water obtained from the top of the azeotropic extraction distillation column, adding the condensed mixed steam into a liquid-liquid layering tank, obtaining water from the upper layer of the liquid-liquid layering tank, obtaining nitrobenzene from the lower layer, and recycling. CN104649910A discloses a production method for preparing 2, 5-dichloronitrobenzene by continuous nitration, which realizes recycling and reuse of waste acid in the process, and the nitrified waste acid is added into an organic matter in an acid layer extracted by p-dichlorobenzene, and simultaneously residual HNO in the acid layer is consumed 3 Concentrating the raffinate waste acid, and preparing mixed acid with nitric acid for the next batch of nitrification. The existing waste acid resource utilization method has a complex treatment process.
Nitrogen oxides are one of harmful substances polluting the atmosphere, bring serious influence to the environment and human health, and can form photochemical smog by acting with hydrocarbon. Xu Shengli et al (coal and chemical industry, 2014,37 (08): 132-134.) studied the absorption of NO by waste acids 2 The gas generates nitroxyl cations and the process of synthesizing nitrobenzene is recycled, but a large amount of tail gas containing NO is formed.
Disclosure of Invention
The invention aims to provide a method for preparing nitrobenzene by recycling nitrified waste acid, which realizes recycling of nitrified waste acid by preparing regenerated mixed acid from nitrified waste acid.
In order to achieve the above purpose, the method for preparing nitrobenzene by recycling nitrified waste acid provided by the invention comprises the following steps:
1) Adding waste acid into a reaction kettle, controlling the pressure of the reaction kettle to be 0.1-1 MPa and the temperature to be-15-25 ℃, introducing a nitrogen dioxide-containing gas stream and an oxygen-containing gas stream, and reacting to obtain nitrified mixed acid;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction to obtain a nitrobenzene crude product.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
The waste acid in the step 1) can be replaced by configured sulfuric acid at the beginning of the reaction.
In some preferred aspects of the invention, the pressure of the reaction vessel is controlled in step 1) to be between about 0.1 and 0.3MPa, between 0.1 and 0.5MPa, between 0.3 and 1MPa or between 0.5 and 1 MPa; in some preferred aspects of the invention, the reactor temperature is controlled between about-15 to-5 ℃, between-15 to 15 ℃, between-15 to 20 ℃, between-5 to 5 ℃, between-5 to 15 ℃, between-5 to 25 ℃, between 5 to 15 ℃, between 5 to 25 ℃, between 10 to 15 ℃, or between 10 to 25 ℃.
Preferably, the nitrogen dioxide is reduced in the nitrogen dioxide-containing gas stream introduced: the molar ratio of the water in the waste acid is 0.75-2.5: 1.
in some preferred aspects of the invention, the nitrogen dioxide is reduced in purity in the introduced nitrogen dioxide-containing gas stream: the molar ratio of the water in the waste acid is about 0.75 to 1:1, 0.75 to 1.5:1, 0.75 to 2:1, 1 to 1.5:1, 1-2: 1, 1 to 2.5:1, 1.5 to 2:1, 1.5 to 2.5:1 or 2 to 2.5:1.
Preferably, the nitrogen dioxide is reduced in the nitrogen dioxide-containing gas stream introduced: the molar ratio of the pure oxygen in the introduced oxygen gas stream is 1.5-4: 1.
in some preferred aspects of the invention, the nitrogen dioxide is reduced in purity in the introduced nitrogen dioxide-containing gas stream: the molar ratio of the pure oxygen in the introduced oxygen gas stream is about 1.5 to 2:1, 1.5 to 3:1, 2-3: 1, 2-4: 1 or 3 to 4:1.
In one embodiment of the present application, the nitrogen dioxide containing gas stream is introduced first, after the pressure in the reactor has stabilized, and then the oxygen containing gas stream is introduced.
In one embodiment of the present application, the oxygen-containing gas stream enters the reaction vessel from the bottom of the reaction vessel.
In the traditional nitration process, the composition of waste acid generated in the benzene series nitration reaction process is about: 65-73 wt% of sulfuric acid, the balance being mainly water, possibly with a small amount of organic phase and nitric acid. The inventor finds that the nitrogen dioxide gas flow and the oxygen gas flow are directly introduced into the waste acid in the research process, and the nitrites prepared by the waste acid are not easy to delaminate after the waste acid is recycled for more than three times, which is probably because a small amount of nitrogen dioxide gas reacts with sulfuric acid to generate nitrosylsulfuric acid, the nitrosylsulfuric acid continuously accumulates after the continuous recycling, and the nitrosylsulfuric acid reacts with organic matters to generate a complex.
Thus, in a preferred embodiment of the present application, the preparation process is divided into at least two stages, said step 1) being carried out as follows: adding waste acid into a reaction kettle, introducing a nitrogen dioxide-containing gas stream and an oxygen-containing gas stream, dividing the reaction into two stages, controlling the pressure of the reaction kettle to be 0.1-0.3 MPa, controlling the temperature to be 10-25 ℃ in the first stage, and introducing at least 7% of the total amount of nitrogen dioxide required by the reaction; then, at the pressure of 0.3-1 MPa and the temperature of-15-10 ℃, introducing an oxygen-containing gas stream and the rest nitrogen dioxide-containing gas stream until the pressure is stable, and stopping the reaction to obtain the nitrified mixed acid.
Preferably, the first stage reaction time is from 5 to 10 minutes.
Preferably, the nitrogen dioxide required by the reaction is introduced into the first stage in an amount of 7-30%.
In some preferred aspects of the invention, the first stage is fed with between about 7% and 15%, between 7% and 25%, between 15% and 30% or between 25% and 30% of the total amount of nitrogen dioxide required for the reaction.
In the first stage reaction, mainly water and NO occur by control of the reaction conditions 2 The reaction between the gases produces nitric acid, which reduces the concentration of sulfuric acid in the aqueous phase, and thus in the subsequent stepDuring the reaction, even if a large amount of NO is introduced 2 Gas, the formation of nitrosylsulfuric acid is also substantially prevented.
Preferably, the gas exhausted from the reaction kettle is recycled.
It will be appreciated by those skilled in the art that the spent acid may be spent acid obtained after nitration, or may be replaced with sulfuric acid solution obtained by commercially available dilute sulfuric acid or commercially available concentrated sulfuric acid in combination with water.
The mass concentration of sulfuric acid in the waste acid is about 60% -78%; preferably, the mass concentration of sulfuric acid in the waste acid is 65% -75%.
The nitrogen dioxide containing gas stream may be nitrogen dioxide gas or an exhaust gas of nitrogen oxide containing gas generated during the nitric acid generation process.
Preferably, the nitrogen dioxide containing gas stream is pure nitrogen dioxide gas.
Particularly preferably, the nitrogen dioxide-containing gas stream is a mixed gas of nitrogen dioxide gas and nitric oxide gas. The ratio of the nitrogen dioxide gas to the nitrogen monoxide gas is not particularly limited, and the preferred volume ratio of the nitrogen monoxide gas to the nitrogen dioxide gas is 0.5 to 3:10.
The oxygen-containing gas stream may be, for example, oxygen or air.
Preferably, in the step 2), the temperature of the reactor is controlled to be 60-75 ℃, and the materials are discharged after staying in the reactor for 25 minutes to 1 hour.
Compared with the prior art, the method for preparing nitrobenzene by recycling the nitrified waste acid realizes that the waste acid absorbs nitrogen oxides to obtain mixed acid, is circularly used in the nitrifying of mixed acid, solves the problems of serious pollution, dangerous treatment process and high cost of the existing waste acid, and can simultaneously treat waste gas containing nitrogen oxides to reduce environmental pollution.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
Example 1
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 60% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 20L of nitrogen dioxide gas and 12L of oxygen are introduced at the temperature of 5-6 ℃, the kettle pressure is 0.6Mpa, the reaction is stopped until the pressure is stable for about 30min, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 75 ℃, and discharging after the materials stay in the reactor for 1 hour to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 2
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 65% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 22L of nitrogen dioxide gas and 10L of oxygen are introduced into the kettle at the temperature of-4 to-5 ℃ by using a low-temperature constant-temperature tank, the kettle pressure is 0.2Mpa, the reaction is stopped until the pressure is stable for about 40min, and the residual gas is discharged and introduced into another pressure reaction kettle to obtain nitrified mixed acid;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 70 ℃, and discharging after the materials stay in the reactor for 45 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 3
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the sulfuric acid mass concentration of 70% is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 25L of nitrogen dioxide gas and 13L of oxygen are introduced at the temperature of 5-6 ℃, the kettle pressure is 0.6Mpa, the reaction is stopped until the pressure is stable for about 30min, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to 65 ℃, and discharging after the materials stay in the reactor for 25 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 4
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the sulfuric acid mass concentration of 75% is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 38L of nitrogen dioxide gas and 10L of oxygen are introduced at room temperature, the kettle pressure is 0.9Mpa, the reaction is stopped until the pressure is stable for about 30min, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 60 ℃, and discharging after the materials stay in the reactor for 30 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 5
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 65% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 22L of nitrogen dioxide gas and 48L of air are introduced into the kettle at the temperature of-4 to-5 ℃ by using a low-temperature constant-temperature tank, the kettle pressure is 0.2Mpa, the reaction is stopped until the pressure is stable for about 40min, and the residual gas is discharged and introduced into another pressure reaction kettle to obtain nitrified mixed acid;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 70 ℃, and discharging after the materials stay in the reactor for 45 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 6
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the sulfuric acid mass concentration of 70% is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 25L of nitrogen dioxide gas is introduced at the temperature of 5-6 ℃, after the pressure of the kettle is stabilized, 13L of oxygen is introduced from an inlet at the upper part of the reaction kettle until the pressure is stabilized for about 30min, the reaction is stopped, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to 65 ℃, and discharging after the materials stay in the reactor for 25 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 7
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 70% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 25L of nitrogen dioxide gas is introduced at the temperature of 5-6 ℃, after the pressure of the kettle is stabilized, 13L of oxygen is introduced from the bottom of the reaction kettle, the reaction is stopped after the pressure is stabilized for about 30min, and the residual gas is discharged and introduced into another pressure reaction kettle, so that the nitrified mixed acid is obtained. Oxygen is introduced from the bottom, so that the oxidation effect of the nitric oxide as a reaction intermediate can be improved;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to 65 ℃, and discharging after the materials stay in the reactor for 25 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 8
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 65% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, a nitrogen dioxide gas stream and an oxygen gas stream are introduced, the reaction is divided into two stages, the pressure of the reaction kettle is controlled to be 0.2MPa, the temperature is 10 ℃, and 4.05L of nitrogen dioxide gas is introduced for the reaction in the first stage; after 5-10 minutes, the pressure of the reaction kettle is raised to 0.3MPa, 18L of nitrogen dioxide gas and 10L of oxygen gas are introduced at the temperature of-4-5 ℃, after the pressure is stabilized for 10 minutes, the reaction is stopped, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 70 ℃, and discharging after the materials stay in the reactor for 45 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 9
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the sulfuric acid mass concentration of 70% is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, a nitrogen dioxide gas stream and an oxygen gas stream are introduced, the reaction is divided into two stages, the pressure of the reaction kettle is controlled to be 0.1MPa, the temperature is 15 ℃, and 6.75L of nitrogen dioxide gas is introduced; after 5-10 minutes, the pressure of the reaction kettle is raised to 0.6MPa, 18.3L of nitrogen dioxide gas and 13L of oxygen gas are introduced at the temperature of 5-6 ℃, after the pressure is stabilized for 20 minutes, the reaction is stopped, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to 65 ℃, and discharging after the materials stay in the reactor for 25 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 10
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the sulfuric acid mass concentration of 75% is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, a nitrogen dioxide gas stream and an oxygen gas stream are introduced, the reaction is divided into two stages, the pressure of the reaction kettle is controlled to be 0.3MPa in the first stage, and 9.5L of nitrogen dioxide gas is introduced at room temperature; after 5-10 minutes, the pressure of the reaction kettle is raised to 0.9MPa, the temperature is 10 ℃, 28.5L of nitrogen dioxide gas and 10L of oxygen gas are introduced, after the pressure is stabilized for 30 minutes, the reaction is stopped, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 60 ℃, and discharging after the materials stay in the reactor for 30 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 11
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) Preparing 50g of sulfuric acid with the mass concentration of 60%, adding the sulfuric acid into a high-pressure reaction kettle with a polytetrafluoroethylene lining, introducing a nitrogen dioxide gas stream and an oxygen gas stream, and performing reaction in two stages, wherein the pressure of the reaction kettle is controlled to be 0.3MPa, the temperature is 10 ℃, and 1.35L of nitrogen dioxide gas is introduced in the first stage; after 5-10 minutes, the pressure of the reaction kettle is raised to 1MPa, 17.65L of nitrogen dioxide gas and 13L of oxygen gas are introduced at the temperature of minus 12 ℃, after the pressure is stabilized for 20 minutes, the reaction is stopped, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 70 ℃, and discharging after the materials stay in the reactor for 40 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Example 12
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the sulfuric acid mass concentration of 75% is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, a nitrogen dioxide gas stream and an oxygen gas stream are introduced, the reaction is divided into two stages, the pressure of the reaction kettle is controlled to be 0.3MPa in the first stage, and 9.5L of mixed gas of nitrogen dioxide gas and 0.95L of nitric oxide gas is introduced at room temperature; after 5-10 minutes, the pressure of the reaction kettle is raised to 0.9MPa, the temperature is 10 ℃, 28.5L of mixed gas of nitrogen dioxide gas and 2.85L of nitric oxide gas and 10L of oxygen gas are introduced, after the pressure is stabilized for 30 minutes, the reaction is stopped, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 60 ℃, and discharging after the materials stay in the reactor for 30 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Comparative example 1
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 55% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 25L of nitrogen dioxide gas and 13L of oxygen are introduced at the temperature of 5-6 ℃, the kettle pressure is 0.6Mpa, the reaction is stopped until the pressure is stable for about 30min, and the residual gas is discharged and introduced into another pressure reaction kettle, so that nitrified mixed acid is obtained;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to 65 ℃, and discharging after the materials stay in the reactor for 25 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Comparative example 2
The method for preparing nitrobenzene by recycling nitrified waste acid comprises the following steps:
1) 50g of waste acid with the mass concentration of 80% of sulfuric acid is added into a high-pressure reaction kettle with a polytetrafluoroethylene lining, 22L of nitrogen dioxide gas and 10L of oxygen are introduced into the kettle at the temperature of-4 to-5 ℃ by using a low-temperature constant-temperature tank, the kettle pressure is 0.2Mpa, the reaction is stopped until the pressure is stable for about 40min, and the residual gas is discharged and introduced into another pressure reaction kettle to obtain nitrified mixed acid;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction, controlling the temperature of the reactor to be 70 ℃, and discharging after the materials stay in the reactor for 45 minutes to obtain a nitrobenzene crude product. In the operation process, the molar ratio of benzene to nitric acid is controlled to be 1:1.02-1.05.
And 2) separating the phase of the nitrobenzene crude product obtained in the step 2) to obtain an acid phase and an organic phase respectively, wherein the acid phase can be sent to the step 1) for recycling.
Calculating the yield of the nitrobenzene crude product based on benzene, and recycling the waste acid obtained after oil-water phase separation by adopting the method of each example, for example, the nitrified waste acid obtained in example 1, continuously preparing nitrified mixed acid according to the method of example 1, and repeatedly recycling, wherein the specific results are shown in the following table 1:
table 1 results of recycle of nitrated Mixed acids prepared in examples 1 to 12
During the experimental process, it is observed that the nitrified mixed acid obtained in examples 1-5 and comparative example 2 has the condition that the oil-water phase of the nitrified product is difficult to separate after passing through the tertiary circulation jacket; the nitrified mixed acid obtained in the examples 6 and 7 has the condition that the nitrified product is slightly difficult to separate from oil-water phase after passing through a tertiary circulation sleeve; the nitrated mixed acid obtained in examples 8-12 and comparative example 11 did not show the problem of difficult separation of the oil and water phases after repeated recycling.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the claims without affecting the spirit of the invention.
Claims (12)
1. The method for preparing nitrobenzene by recycling nitrified waste acid is characterized by comprising the following steps:
1) Adding waste acid into a reaction kettle, controlling the pressure of the reaction kettle to be 0.1-1 MPa and the temperature to be-15-25 ℃, introducing a nitrogen dioxide-containing gas stream and an oxygen-containing gas stream, and reacting to obtain nitrified mixed acid;
2) Continuously feeding benzene and the nitrified mixed acid obtained in the step 1) into a reactor for reaction to obtain a nitrobenzene crude product;
the mass concentration of sulfuric acid in the waste acid is 60% -78%.
2. The method for preparing nitrobenzene by recycling nitrified waste acid according to claim 1, wherein nitrogen dioxide is purified by folding in the introduced nitrogen dioxide-containing gas stream: the molar ratio of the water in the waste acid is 0.75-2.5: 1.
3. the method for preparing nitrobenzene by recycling nitrified waste acid according to claim 1, wherein nitrogen dioxide is purified by folding in the introduced nitrogen dioxide-containing gas stream: the molar ratio of the pure oxygen in the introduced oxygen gas stream is 1.5-4: 1.
4. the method for preparing nitrobenzene by recycling nitrified waste acid according to claim 1, wherein the nitrogen dioxide-containing gas stream is introduced first until the pressure of the reaction kettle is stabilized, and then the oxygen-containing gas stream is introduced.
5. The method for preparing nitrobenzene by recycling nitrified waste acid according to claim 1, wherein the oxygen-containing gas stream enters the reaction kettle from the bottom of the reaction kettle.
6. The method for preparing nitrobenzene by recycling nitrified waste acid according to claim 1, wherein the specific operation process of the step 1) is as follows: adding waste acid into a reaction kettle, introducing a nitrogen dioxide-containing gas stream and an oxygen-containing gas stream, dividing the reaction into two stages, controlling the pressure of the reaction kettle to be 0.1-0.3 MPa, controlling the temperature to be 10-25 ℃ in the first stage, and introducing at least 7% of the total amount of nitrogen dioxide required by the reaction; then, at the pressure of 0.3-1 MPa and the temperature of-15-10 ℃, introducing an oxygen-containing gas stream and the rest nitrogen dioxide-containing gas stream until the pressure is stable, and stopping the reaction to obtain the nitrified mixed acid.
7. The method for preparing nitrobenzene by recycling nitrified waste acid according to claim 6, wherein the nitrogen dioxide required by the reaction is introduced into the first stage in an amount of 7% -30%.
8. The method for preparing nitrobenzene by recycling nitrified waste acid according to any one of claims 1 to 7, characterized in that said waste acid can be replaced by sulfuric acid solution obtained by preparing commercial dilute sulfuric acid or commercial concentrated sulfuric acid with water.
9. The method for preparing nitrobenzene by recycling nitrified waste acid according to any one of claims 1 to 7, characterized in that the mass concentration of sulfuric acid in the waste acid is 65% to 75%.
10. The method for preparing nitrobenzene by recycling nitrified waste acid according to any one of claims 1 to 7, characterized in that the nitrogen dioxide-containing gas stream is pure nitrogen dioxide gas or a mixed gas of nitrogen dioxide gas and nitric oxide gas.
11. The method for preparing nitrobenzene by recycling nitrified waste acid according to claim 10, characterized in that the volume ratio of nitric oxide gas to nitrogen dioxide is 0.5-3:10.
12. The method for preparing nitrobenzene by recycling nitrified waste acid according to claim 1, wherein the temperature of the reactor in the step 2) is controlled to be 60-75 ℃, and materials are discharged after staying in the reactor for 25 minutes to 1 hour.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011206664.5A CN113233984B (en) | 2020-11-03 | 2020-11-03 | Method for preparing nitrobenzene by recycling nitrified waste acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011206664.5A CN113233984B (en) | 2020-11-03 | 2020-11-03 | Method for preparing nitrobenzene by recycling nitrified waste acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113233984A CN113233984A (en) | 2021-08-10 |
| CN113233984B true CN113233984B (en) | 2023-04-21 |
Family
ID=77130000
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011206664.5A Active CN113233984B (en) | 2020-11-03 | 2020-11-03 | Method for preparing nitrobenzene by recycling nitrified waste acid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113233984B (en) |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3799993A (en) * | 1972-08-25 | 1974-03-26 | Us Army | Process for the manufacture of trinitrotoluene |
| US4123466A (en) * | 1977-12-12 | 1978-10-31 | The Upjohn Company | Process for nitrating aromatic hydrocarbons |
| JPH06179639A (en) * | 1992-12-15 | 1994-06-28 | Nissan Chem Ind Ltd | Production of 1-nitroanthraquinone |
| JPH06293709A (en) * | 1993-04-09 | 1994-10-21 | Nissan Chem Ind Ltd | Production of aromatic nitro compound |
| KR19990070265A (en) * | 1998-02-18 | 1999-09-15 | 이본수 | Process for nitration of aromatic compounds using a non-acid type nitration process |
| DE102005050106A1 (en) * | 2005-10-18 | 2007-04-19 | Josef Meissner Gmbh & Co. Kg | Recovery of nitrating acid mixtures from nitrite processes |
| CN103755572A (en) * | 2014-01-07 | 2014-04-30 | 江苏丰山集团有限公司 | Trifluralin nitration section waste acid recycling technology |
| CN104649910A (en) * | 2013-11-25 | 2015-05-27 | 江苏扬农化工集团有限公司 | Method capable of recycling acids for preparing 2,5-dichloronitrobenzene (DCNB) through continuous nitration |
| CN105329864A (en) * | 2015-12-01 | 2016-02-17 | 南京师范大学 | Resourceful treatment method of waste acid solution in nitrobenzene production process |
| CN106431930A (en) * | 2015-08-05 | 2017-02-22 | 湘潭大学 | Method for preparing nitrobenzene from benzene |
| CN106744746A (en) * | 2017-02-17 | 2017-05-31 | 交城县金兰化工有限公司 | A kind of nitric acid preparation method of environment-friendly high-efficiency |
| CN109320423A (en) * | 2018-11-22 | 2019-02-12 | 四川金象赛瑞化工股份有限公司 | A kind of method of micro passage reaction synthesizing nitryl compound |
| CN109467508A (en) * | 2018-11-22 | 2019-03-15 | 四川金象赛瑞化工股份有限公司 | A kind of method of micro passage reaction synthesizing dinitrotoluene |
-
2020
- 2020-11-03 CN CN202011206664.5A patent/CN113233984B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3799993A (en) * | 1972-08-25 | 1974-03-26 | Us Army | Process for the manufacture of trinitrotoluene |
| US4123466A (en) * | 1977-12-12 | 1978-10-31 | The Upjohn Company | Process for nitrating aromatic hydrocarbons |
| JPH06179639A (en) * | 1992-12-15 | 1994-06-28 | Nissan Chem Ind Ltd | Production of 1-nitroanthraquinone |
| JPH06293709A (en) * | 1993-04-09 | 1994-10-21 | Nissan Chem Ind Ltd | Production of aromatic nitro compound |
| KR19990070265A (en) * | 1998-02-18 | 1999-09-15 | 이본수 | Process for nitration of aromatic compounds using a non-acid type nitration process |
| DE102005050106A1 (en) * | 2005-10-18 | 2007-04-19 | Josef Meissner Gmbh & Co. Kg | Recovery of nitrating acid mixtures from nitrite processes |
| CN104649910A (en) * | 2013-11-25 | 2015-05-27 | 江苏扬农化工集团有限公司 | Method capable of recycling acids for preparing 2,5-dichloronitrobenzene (DCNB) through continuous nitration |
| CN103755572A (en) * | 2014-01-07 | 2014-04-30 | 江苏丰山集团有限公司 | Trifluralin nitration section waste acid recycling technology |
| CN106431930A (en) * | 2015-08-05 | 2017-02-22 | 湘潭大学 | Method for preparing nitrobenzene from benzene |
| CN105329864A (en) * | 2015-12-01 | 2016-02-17 | 南京师范大学 | Resourceful treatment method of waste acid solution in nitrobenzene production process |
| CN106744746A (en) * | 2017-02-17 | 2017-05-31 | 交城县金兰化工有限公司 | A kind of nitric acid preparation method of environment-friendly high-efficiency |
| CN109320423A (en) * | 2018-11-22 | 2019-02-12 | 四川金象赛瑞化工股份有限公司 | A kind of method of micro passage reaction synthesizing nitryl compound |
| CN109467508A (en) * | 2018-11-22 | 2019-03-15 | 四川金象赛瑞化工股份有限公司 | A kind of method of micro passage reaction synthesizing dinitrotoluene |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113233984A (en) | 2021-08-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2404917C2 (en) | Method and installation for concentrating spent sulphuric acid from nitration processes | |
| KR890003673B1 (en) | High pressure process for sulfur recovery from hydrogen sulfide containing gas stream | |
| JP4554622B2 (en) | Method for producing dinitrotoluene | |
| CN105348145B (en) | The method of ammonia type flue gas desulfurizing by-product cyclohexanone oxime | |
| JP2017531641A (en) | Exhaust gas cleaning in continuous production process of dinitrotoluene | |
| FI67833C (en) | FOERFARANDE FOER FRAMSTAELLNING AV SVAVELSYRA | |
| US5196591A (en) | Process for the production of polynuclear aromatic polyamines | |
| CN110803999A (en) | Production process and equipment system for improving quality and yield of cyclohexanone-oxime | |
| US4257986A (en) | Process for refining aqueous acid mixtures utilized in nitration of aromatics | |
| JP4901883B2 (en) | Method of distillatively removing dinitrotoluene in process wastewater from the process of producing dinitrotoluene by nitrating toluene with nitration acid | |
| US3204000A (en) | Manufacture of nitrotoluenes | |
| CN113233984B (en) | Method for preparing nitrobenzene by recycling nitrified waste acid | |
| US3152870A (en) | Process for manufacturing chlorine by oxidation of hydrochloric acid | |
| CN113244759B (en) | Method for preparing regenerated mixed acid from nitrified waste acid | |
| CN112194299A (en) | Resource treatment method of waste liquid | |
| US9771291B2 (en) | Process for working up waste water from nitrobenzene preparation | |
| CN113184815B (en) | Method for preparing nitrified mixed acid by using nitrogen oxides | |
| CN113248386A (en) | Method for preparing dinitrobenzene by recycling nitration waste acid | |
| CN109456197B (en) | Method for recycling low-concentration nitric acid solution in process of preparing ethylene glycol from calcium carbide furnace tail gas | |
| KR101070006B1 (en) | Method for producing aromatic amines which reduces amount of waste water and is cost-efficient | |
| US6191325B1 (en) | Recovering/recycling nitric acid from dinitration process streams comprising HNO3/dinitro compounds | |
| US4018872A (en) | Process for the production of concentrated nitric acid | |
| JPS59186975A (en) | Method for separating trioxane | |
| CN112047824B (en) | Method for producing o/p-chlorobenzaldehyde by low-temperature catalytic oxidation | |
| US6355223B1 (en) | Closed loop process for producing chlorine from hydrogen chloride |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230619 Address after: 223100 west of Taibo Avenue and south of Guoqiao Road, salt chemical industry zone, Hongze County, Huai'an City, Jiangsu Province Patentee after: Fangyuan New Material Technology Co.,Ltd. Address before: 223100 west side of Taibo Avenue and south side of Guoqiao Road, Huai'an salt chemical new material industrial park, Huai'an City, Jiangsu Province Patentee before: Jiangsu Fangyuan aramid Research Institute Co.,Ltd. |
|
| TR01 | Transfer of patent right |