CN117843490A - Low-alkali consumption and low-sodium salt residual nitrobenzene washing method - Google Patents
Low-alkali consumption and low-sodium salt residual nitrobenzene washing method Download PDFInfo
- Publication number
- CN117843490A CN117843490A CN202311708864.4A CN202311708864A CN117843490A CN 117843490 A CN117843490 A CN 117843490A CN 202311708864 A CN202311708864 A CN 202311708864A CN 117843490 A CN117843490 A CN 117843490A
- Authority
- CN
- China
- Prior art keywords
- washing
- nitrobenzene
- alkali
- crude nitrobenzene
- alkaline
- 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.)
- Pending
Links
- LQNUZADURLCDLV-UHFFFAOYSA-N nitrobenzene Chemical compound [O-][N+](=O)C1=CC=CC=C1 LQNUZADURLCDLV-UHFFFAOYSA-N 0.000 title claims abstract description 218
- 238000005406 washing Methods 0.000 title claims abstract description 206
- 239000003513 alkali Substances 0.000 title claims abstract description 100
- 238000000034 method Methods 0.000 title claims abstract description 33
- 230000007935 neutral effect Effects 0.000 claims abstract description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 35
- 159000000000 sodium salts Chemical group 0.000 claims abstract description 29
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims abstract description 20
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 18
- UFBJCMHMOXMLKC-UHFFFAOYSA-N 2,4-dinitrophenol Chemical compound OC1=CC=C([N+]([O-])=O)C=C1[N+]([O-])=O UFBJCMHMOXMLKC-UHFFFAOYSA-N 0.000 claims abstract description 9
- BTJIUGUIPKRLHP-UHFFFAOYSA-N 4-nitrophenol Chemical compound OC1=CC=C([N+]([O-])=O)C=C1 BTJIUGUIPKRLHP-UHFFFAOYSA-N 0.000 claims abstract description 9
- OXNIZHLAWKMVMX-UHFFFAOYSA-N picric acid Chemical compound OC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O OXNIZHLAWKMVMX-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229950002929 trinitrophenol Drugs 0.000 claims abstract description 8
- 239000002351 wastewater Substances 0.000 claims abstract description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Inorganic materials [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 56
- 239000007788 liquid Substances 0.000 claims description 31
- 230000002378 acidificating effect Effects 0.000 claims description 21
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 18
- IQUPABOKLQSFBK-UHFFFAOYSA-N 2-nitrophenol Chemical compound OC1=CC=CC=C1[N+]([O-])=O IQUPABOKLQSFBK-UHFFFAOYSA-N 0.000 claims description 11
- 238000006396 nitration reaction Methods 0.000 claims description 4
- 238000004064 recycling Methods 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 4
- 239000003054 catalyst Substances 0.000 claims description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 2
- 230000003068 static effect Effects 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims 2
- 238000006243 chemical reaction Methods 0.000 abstract description 4
- 150000003839 salts Chemical class 0.000 abstract description 3
- 239000002699 waste material Substances 0.000 abstract description 3
- 239000012535 impurity Substances 0.000 abstract description 2
- 230000003472 neutralizing effect Effects 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 10
- 239000012071 phase Substances 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- 235000013824 polyphenols Nutrition 0.000 description 7
- 239000002253 acid Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000012670 alkaline solution Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 150000008442 polyphenolic compounds Chemical class 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- MHKBMNACOMRIAW-UHFFFAOYSA-N 2,3-dinitrophenol Chemical compound OC1=CC=CC([N+]([O-])=O)=C1[N+]([O-])=O MHKBMNACOMRIAW-UHFFFAOYSA-N 0.000 description 2
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 239000003518 caustics Substances 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 150000002989 phenols Chemical class 0.000 description 2
- AXKBOWBNOCUNJL-UHFFFAOYSA-M sodium;2-nitrophenolate Chemical compound [Na+].[O-]C1=CC=CC=C1[N+]([O-])=O AXKBOWBNOCUNJL-UHFFFAOYSA-M 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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
- C07C201/16—Separation; Purification; Stabilisation; Use of additives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a nitrobenzene washing method with low alkali consumption and low sodium salt residue, which comprises the following steps: the method comprises the steps of two-stage alkaline washing, wherein the first stage alkaline washing is used for neutralizing residual sulfuric acid, trinitrophenol and most dinitrophenol, the second stage alkaline washing is used for removing residual dinitrophenol and mononitrophenol through reaction, and finally, the residual salt content is removed through neutral water washing, so that a refined nitrobenzene product is obtained. According to the method, the alkali liquor addition amount is accurately controlled through sectional alkali washing, so that alkali liquor waste is avoided, alkali consumption is reduced by 50% compared with the traditional washing process, and the sodium salt residue in refined nitrobenzene is reduced to below 2ppm. The method can reduce the alkali consumption of the system without increasing the wastewater amount, simultaneously reduce the residual quantity of sodium salt in the refined nitrobenzene and ensure that phenolic impurities in the nitrobenzene are removed to below 2ppm.
Description
Technical Field
The invention relates to a nitrobenzene washing method, in particular to a crude nitrobenzene washing method with low alkali consumption and low sodium salt residual quantity.
Background
Nitrobenzene is one of the important organic chemical raw materials. The production process produces nitrophenol explosive substances, and the nitrophenol substances can be removed by alkali elution. However, about 1% of water can be dissolved in nitrobenzene, so that residual part of sodium nitrophenolate and sodium sulfate are difficult to completely remove in the nitrobenzene after alkali washing, if heating equipment is involved in the downstream use process, salts are separated out on the surface of the heating equipment, so that the heating equipment is blocked, and even the existence of sodium nitrophenolate causes safety risks.
Chinese patent CN113248385a provides a method for reducing the alkali consumption by adding a first water wash before alkali wash to reduce the acid content in nitrobenzene before alkali wash, thereby realizing the salt content in nitrobenzene after alkali wash.
Chinese patent CN106278902B is added with primary water washing, and alkali washing liquid is circulated to increase alkali washing effect and reduce sodium salt content in nitrobenzene to 5-8ppm.
Both methods require adding a water washing unit, so that the amount of wastewater is increased in the process of reducing the alkali consumption and the residual amount of sodium salt, and the wastewater treatment cost is increased.
In addition, in the traditional primary alkaline washing process, in order to ensure the phenol removal efficiency, excessive alkaline solution is often required to be added, and huge waste of alkaline solution exists. Meanwhile, the concentration of alkali liquor in the washing liquid is high, and residual sodium salt in the nitrobenzene after washing is still higher, so that the residual sodium salt cannot be further reduced.
Therefore, there is still a need to develop a new crude nitrobenzene washing process that reduces the alkali consumption and eventually produces nitrobenzene products with low sodium salt content.
Disclosure of Invention
The inventors have found that phenols in nitrobenzene are classified into mononitrophenol, dinitrophenol and trinitrophenol, wherein the dinitrophenol and trinitrophenol react with a base preferentially over mononitrophenol due to the greater number of phenolic hydroxyl groups than mononitrophenol. In an environment rich in dinitrophenoxide and trinitrophenoxide, the remaining phenolic hydroxyl groups in dinitrophenoxide and trinitrophenoxide still compete with mononitrophenol for reaction with the base. Thus, the primary alkaline washing process consumes a large amount of alkali to ensure the removal rate of the monophenol.
Based on the above findings, the inventors developed a two-stage alkaline washing process: the primary alkaline wash aims at removing acid components, dinitrophenol and trinitrophenol. The method for controlling pH is used for precisely controlling the addition amount of alkali, reducing the reaction of alkali and second/third phenolic hydroxyl groups in polyphenol and the residual amount of alkali in washing liquid while realizing the purpose of removing polyphenol, and simultaneously reducing the residual amount of polyphenol in nitrobenzene after primary alkali washing so as to reduce the alkali excess rate required by removing secondary alkali washing monophenol and comprehensively realize the reduction of alkali consumption and sodium salt residual amount, thereby completing the invention.
The invention aims to provide a crude nitrobenzene washing method with low alkali consumption and low sodium salt residual quantity, which can reduce the alkali consumption and finally prepare nitrobenzene products with sodium salt mass concentration lower than 2ppm under the condition of not increasing the wastewater quantity.
In order to achieve the above object, the present invention has the following technical scheme:
a low-alkali consumption and low-sodium salt residual crude nitrobenzene washing method comprises the following steps:
(1) Mixing acidic crude nitrobenzene with alkali liquor from secondary alkali washing and part of fresh alkali liquor for primary alkali washing, standing and separating to obtain a lower-layer oil phase which is the crude nitrobenzene after primary alkali washing, and an upper-layer water phase which is alkali washing wastewater;
(2) Mixing the crude nitrobenzene after primary alkali washing with washing liquid from neutral water washing and part of fresh alkali liquid for secondary alkali washing, standing and separating to obtain a lower-layer oil phase which is the crude nitrobenzene after secondary alkali washing, and recycling the alkali liquid of the upper-layer water phase which is the secondary alkali washing to the primary alkali washing in the step (1);
(3) And (3) mixing the crude nitrobenzene after the secondary alkaline washing with fresh desalted water for neutral water washing, standing and separating to obtain refined nitrobenzene, and recycling the washing liquid of the neutral water washing to the secondary alkaline washing in the step (2).
In some specific embodiments, the acidic crude nitrobenzene in step (1) is an oil phase of benzene nitration product after standing and layering with catalyst sulfuric acid;
preferably, the acidic crude nitrobenzene comprises 93wt% nitrobenzene, 6.5wt% benzene, 0.3wt% sulfuric acid, and 0.2wt% total nitrophenol, wherein the total nitrophenol comprises 150ppm mononitrophenol, and the balance of dinitrophenol and trinitrophenol.
In some specific embodiments, the primary alkaline wash, secondary alkaline wash, or neutral water wash is performed in a mixing scrubber, preferably using a tank mixer or a tubular static mixer; preferably, countercurrent washing is employed.
In some specific embodiments, the stationary separation is performed in a demixing device, preferably a tank demixing device.
In some specific embodiments, the fresh lye is a 5% -32% strength by mass lye, for example a 5%, 8%, 10%, 12%, 15%, 17%, 20%, 25%, 27%, 29%, 30%, 32% strength by mass lye, preferably an aqueous sodium hydroxide solution or an aqueous sodium carbonate solution, preferably an aqueous 25% -32% sodium hydroxide solution. The influence of different concentrations and alkali liquor types on the washing effect is mainly that the eluting efficiency of phenol is different, the alkali liquor amount required by alkali weak alkali liquor is increased, and the eluting efficiency of sodium can be improved but the waste water amount is increased.
In some specific embodiments, the volume flow ratio of the alkaline liquor of the secondary caustic wash to the acidic nitrobenzene in step (1) is controlled to be in the range of 1:3 to 3:1, for example 1: 3. 1: 2. 1:1. 1.5: 1. 2: 1. 2.5: 1. 3:1, etc.;
preferably, the pH of the mixed lye of the primary alkaline wash is controlled between 7 and 9, preferably 7 to 8, by adding fresh lye.
In some specific embodiments, the volume flow ratio of neutral wash liquor to crude nitrobenzene after primary caustic wash in step (2) is controlled from 1:3 to 3:1, for example 1: 3. 1: 2. 1:1. 1.5: 1. 2: 1. 2.5: 1. 3:1, etc.;
preferably, the pH of the mixed lye of the secondary alkaline wash is controlled to be between 10 and 11, preferably between 10 and 10.5, by adding part of the fresh lye.
In some specific embodiments, the volume flow ratio of fresh desalted water to crude nitrobenzene after secondary alkaline washing in step (3) is controlled from 1:3 to 3:1, for example 1: 3. 1: 2. 1:1. 1.5: 1. 2: 1. 2.5: 1. 3:1, etc.
In some specific embodiments, the primary alkaline wash has a wash temperature of 60 ℃ to 70 ℃, e.g., 65 ℃, and a wash time of 3 to 10 minutes, e.g., 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.; generally, the washing time exceeds 3 minutes to meet the washing requirement, and further the washing time is prolonged without obvious influence on the washing effect.
The washing temperature of the secondary alkaline washing is 60-70 ℃, such as 65 ℃, and the washing time is 3-10min, such as 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min and the like;
the washing temperature of the neutral water washing is 60-70 ℃, such as 65 ℃, and the washing time is 3-10min, such as 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min and the like.
In some embodiments, the sodium salt content of the washed refined nitrobenzene is not more than 2ppm and the total phenol content is not more than 2ppm.
Compared with the prior art, the invention has the following positive effects:
the invention provides a method for reducing the consumption of crude nitrobenzene washing alkali and simultaneously reducing the residual quantity of sodium salt in refined nitrobenzene.
The washing method can reduce the alkali consumption by more than 50 percent, the residual sodium salt content in the nitrobenzene is lower than 2ppm, and the total phenol content is not more than 2ppm.
Drawings
FIG. 1 is a schematic flow chart of the production method for preparing aniline by liquid-phase hydrogenation of nitrobenzene with low phenol yield.
FIG. 2 is a schematic flow chart of a conventional primary alkaline washing method for crude nitrobenzene washing.
In the figure, 101 is a primary alkaline washing unit; 102 is a secondary alkaline washing unit; 103 is a neutral washing unit; 104 is acidic crude nitrobenzene; 105 is crude nitrobenzene after primary alkali washing; 106 is coarse nitrobenzene after secondary alkali washing; 107 is nitrobenzene; 108 is fresh lye A;109 is fresh lye B;110 is desalted water; 111 is neutral washing liquid; 112 is a secondary alkaline cleaning solution; 113 is a primary alkaline wash.
Detailed Description
Specific embodiments of the present process are further described below in conjunction with the examples. The invention is not limited to the embodiments listed but includes any other known modification within the scope of the claims that follow.
In the conventional nitrobenzene washing method, as shown in fig. 2, the oil phase acidic crude nitrobenzene 104 layered by the nitration reaction product enters a primary alkaline washing unit 101, is mixed with neutral washing liquid 111 from a neutral washing unit 103 and fresh alkali liquid A108 to be washed to remove sulfuric acid and nitrophenol, and then enters the neutral washing unit 103. The sodium salt and the excessive sodium hydroxide carried in the nitrobenzene after primary alkali washing are mixed and eluted with desalted water 110 in a neutral washing unit 103, and the nitrobenzene 107 is obtained.
However, in the traditional primary alkaline washing process, 20% -25% of the added alkali liquor is used for neutralizing the acid component in the acidic nitrobenzene, 8% -10% of the added alkali liquor is used for reacting with the nitrophenol, 65% -72% of the added alkali liquor is remained in alkaline washing wastewater in a sodium hydroxide form, huge waste of the alkali liquor exists, and the residual sodium salt in the nitrobenzene after washing is still higher and cannot be further reduced.
In the invention, a two-stage alkaline washing process is designed, as shown in figure 1, oil phase acidic crude nitrobenzene 104 layered by nitration reaction products enters a first-stage alkaline washing unit 101, is mixed with a second-stage alkaline washing liquid 112 from the second-stage alkaline washing unit 102 and fresh alkali liquor A108 to be subjected to first-stage alkaline washing, sulfuric acid, dinitrophenol and trinitrophenol are removed by washing, and then the mixture is subjected to standing separation to obtain a first-stage alkaline washing liquid 113 and crude nitrobenzene 105 after first-stage alkaline washing; the primary alkali washed crude nitrobenzene 105 enters a secondary alkali washing unit 102, is mixed with neutral washing liquid 111 from a neutral washing unit 103 and fresh alkali liquid B109 to be washed to remove mononitrophenol, and then is subjected to standing separation to obtain secondary alkali washed crude nitrobenzene 106, and the secondary alkali washed crude nitrobenzene enters the neutral washing unit 103. The sodium salt and the excessive sodium hydroxide carried in the crude nitrobenzene after the secondary alkaline washing are mixed and eluted with desalted water 110 in a neutral washing unit 103, thus obtaining the nitrobenzene 107. The method reduces the alkali consumption of the system without increasing the wastewater amount, reduces the residual quantity of sodium salt in the refined nitrobenzene and ensures the removal efficiency of phenolic impurities in the nitrobenzene.
The invention is further illustrated, but not limited, by the following more specific examples.
The sources of acidic crude nitrobenzene are as follows: the mixed acid from benzene, nitric acid and sulfuric acid reacts to produce nitrobenzene and by-product nitrophenol, etc., and after the reaction solution is stood for layering, the oil phase is acidic crude nitrobenzene, and the main components of the acidic crude nitrobenzene are 93% nitrobenzene, 6.5% benzene, 0.3% sulfuric acid and 0.2% total nitrophenol. Wherein the total nitrophenol comprises 150ppm of mononitrophenol and the balance of dinitrophenol and trinitrophenol.
The alkaline solution used in the examples is a 32% aqueous sodium hydroxide solution, the washing temperatures are 65℃and the volume ratio of the washing solution to nitrobenzene is 1:1, the washing time is 5min.
The method for detecting the total phenol content and the sodium salt content in nitrobenzene used in the example is as follows:
the method for detecting the total phenols comprises the following steps: using an instrument model Agilent 1260 inch II, the column was Inertsil ODS-SP (150 mm. Times.4.6 mm), and gradient elution was performed with 0.1% phosphoric acid solution and 99.9% reagent methanol.
Sodium salt detection method: desalted water was used to 1: mixing the sample nitrobenzene with the volume ratio of 1 for 10min in a vibrating way, standing for layering, and analyzing the water phase. The instrument used was Varian 715; the flow rate of the plasma gas is 15.0L/min; the auxiliary air flow is 1.50L/min; the observation height was 10mm.
Example 1
As shown in FIG. 1, the volume flow rate was 60m 3 Delivering the acidic nitrobenzene per hour into an alkaline washing unit, and enabling the volume flow to be 60m 3 Delivering desalted water per hour into a neutral washing unit for countercurrent washing, wherein the volume ratio of primary and secondary alkaline washing water to nitrobenzene is 1:1. wherein 200kg/h of alkali liquor with the mass concentration of 32% is added into the primary alkali washing unit, the pH value is controlled to be 8.8, the washing temperature is controlled to be 65 ℃, and the washing is carried outThe interval is 5min; 560kg/h of alkali liquor with the mass concentration of 32% is added into the secondary alkali washing liquid, the pH value is controlled to be 10.8, the washing temperature is controlled to be 65 ℃, and the washing time is 5min; the neutral washing temperature is controlled to 65 ℃, and the washing time is 5min. The total consumption of alkali liquor is 760kg/h, the total phenol content in the nitrobenzene product is 0.1ppm, and the sodium salt content is 2ppm.
Example two
As shown in FIG. 1, the volume flow rate was 60m 3 Delivering the acidic nitrobenzene per hour into an alkaline washing unit, and enabling the volume flow to be 60m 3 Delivering desalted water per hour into a neutral washing unit for countercurrent washing, wherein the volume ratio of primary and secondary alkaline washing liquid to nitrobenzene is 1:1. wherein 180kg/h of alkali liquor with the mass concentration of 32% is added into the primary alkali washing unit, the pH value is controlled to be 8.1, the washing temperature is controlled to be 65 ℃, and the washing time is 5min; adding 450kg/h of alkali liquor with the mass concentration of 32% into the secondary alkali washing liquid, controlling the pH value to be 10.5, controlling the washing temperature to be 65 ℃ and the washing time to be 5min; the neutral washing temperature is controlled to 65 ℃, and the washing time is 5min. The total consumption of alkali liquor is 630kg/h, the total phenol content in the nitrobenzene product is 0.5ppm, and the sodium salt content is 1.5ppm.
Example III
As shown in FIG. 1, the volume flow rate was 60m 3 Delivering the acidic nitrobenzene per hour into an alkaline washing unit, and enabling the volume flow to be 60m 3 Delivering desalted water per hour into a neutral washing unit for countercurrent washing, wherein the volume ratio of primary and secondary alkaline washing liquid to nitrobenzene is 1:1. wherein 120kg/h of alkali liquor with the mass concentration of 32% is added into the primary alkali washing unit, the pH value is controlled to 7.2, the washing temperature is controlled to 65 ℃, and the washing time is 5min; adding 300kg/h of alkali liquor with the mass concentration of 32% into the secondary alkali washing liquid, controlling the pH value to be 10.1, controlling the washing temperature to be 65 ℃ and the washing time to be 5min; the neutral washing temperature is controlled to 65 ℃, and the washing time is 5min. The total consumption of the alkali liquor is 420kg/h, the total phenol content in the nitrobenzene product is 2ppm, and the sodium salt content is 0.2ppm.
Example IV
As shown in FIG. 1, the volume flow rate was 60m 3 Delivering the acidic nitrobenzene per hour into an alkaline washing unit, and enabling the volume flow to be 60m 3 The desalted water of/h is sent to a neutral washing unit,countercurrent washing is carried out, and the volume ratio of the primary and secondary alkaline washing liquid to the neutral washing liquid to the nitrobenzene is 1:1. wherein 200kg/h of alkali liquor with the mass concentration of 32% is added into the primary alkali washing unit, the pH value is controlled to be 8.8, the washing temperature is controlled to be 65 ℃, and the washing time is 5min; 280kg/h of alkali liquor with the mass concentration of 32% is added into the secondary alkali washing liquid, the pH value is controlled to be 10, the washing temperature is controlled to be 65 ℃, and the washing time is 5min; the neutral washing temperature is controlled to 65 ℃, and the washing time is 5min. The total consumption of alkali liquor is 480kg/h, the total phenol content in the nitrobenzene product is 1.2ppm, and the sodium salt content is 0.6ppm.
Comparative example one
As shown in FIG. 2, the volume flow rate was 60m 3 Delivering the acidic nitrobenzene per hour into an alkaline washing unit, and enabling the volume flow to be 60m 3 Delivering desalted water per hour into a neutral washing unit for countercurrent washing, wherein the volume ratio of primary alkaline washing liquid to neutral washing liquid to nitrobenzene is 1:1. wherein 1520kg/h of 32% sodium hydroxide solution is added into the alkaline washing unit, the pH is controlled to be 11.8, the washing temperature is controlled to be 65 ℃, and the washing time is 5min; the neutral washing temperature is controlled to 65 ℃, and the washing time is 5min. The total phenol content in the nitrobenzene product is 2ppm and the sodium salt content is 8ppm.
Comparative example two
As shown in FIG. 2, the volume flow rate was 60m 3 Delivering the acidic nitrobenzene per hour into an alkaline washing unit, and enabling the volume flow to be 60m 3 Delivering desalted water per hour into a neutral washing unit for countercurrent washing, wherein the volume ratio of primary alkaline washing liquid to neutral washing liquid to nitrobenzene is 1:1. wherein 760kg/h of 32% sodium hydroxide solution is added into an alkaline washing unit, the pH is controlled to be 11, the washing temperature is controlled to be 65 ℃, and the washing time is 5min; the neutral washing temperature is controlled to 65 ℃, and the washing time is 5min. The total phenol content in the nitrobenzene product is 9ppm and the sodium salt content is 2.8ppm.
Claims (10)
1. The method for washing the crude nitrobenzene with low alkali consumption and low sodium salt residue is characterized by comprising the following steps of:
(1) Mixing acidic crude nitrobenzene with alkali liquor from secondary alkali washing and part of fresh alkali liquor for primary alkali washing, standing and separating to obtain a lower-layer oil phase which is the crude nitrobenzene after primary alkali washing, and an upper-layer water phase which is alkali washing wastewater;
(2) Mixing the crude nitrobenzene after primary alkali washing with washing liquid from neutral water washing and part of fresh alkali liquid for secondary alkali washing, standing and separating to obtain a lower-layer oil phase which is the crude nitrobenzene after secondary alkali washing, and recycling the alkali liquid of the upper-layer water phase which is the secondary alkali washing to the primary alkali washing in the step (1);
(3) And (3) mixing the crude nitrobenzene after the secondary alkaline washing with fresh desalted water for neutral water washing, standing and separating to obtain refined nitrobenzene, and recycling the washing liquid of the neutral water washing to the secondary alkaline washing in the step (2).
2. The method for washing crude nitrobenzene according to claim 1, characterized in that the acidic crude nitrobenzene in step (1) is an oil phase obtained by standing and layering benzene nitration product and catalyst sulfuric acid;
preferably, the acidic crude nitrobenzene comprises 93wt% nitrobenzene, 6.5wt% benzene, 0.3wt% sulfuric acid, and 0.2wt% total nitrophenol, wherein the total nitrophenol comprises 150ppm mononitrophenol, and the balance of dinitrophenol and trinitrophenol.
3. The method for washing crude nitrobenzene according to claim 1 or 2, characterized in that the primary alkaline washing, secondary alkaline washing or neutral water washing is carried out in a mixing washer, preferably a tank mixer or a tubular static mixer; preferably, countercurrent washing is employed.
4. A crude nitrobenzene washing method according to any one of claims 1-3, characterized in that the stationary separation is carried out in a demixing device, preferably a tank demixing device.
5. The method for washing crude nitrobenzene according to any one of claims 1 to 4, characterized in that the fresh lye is 5% to 32% by mass sodium hydroxide or sodium carbonate aqueous solution, preferably 25% to 32% sodium hydroxide aqueous solution.
6. The method for washing crude nitrobenzene according to any one of claims 1 to 5, characterized in that the volume flow ratio of alkaline liquor of the secondary alkaline washing to acidic nitrobenzene in the step (1) is controlled to be 1:3 to 3:1;
preferably, the pH of the mixed lye of the primary alkaline wash is controlled between 7 and 9, preferably 7 to 8, by adding fresh lye.
7. The method for washing crude nitrobenzene according to any one of claims 1 to 6, characterized in that the volume flow ratio of the neutral washing liquid to the crude nitrobenzene after primary alkali washing in the step (2) is controlled to be 1:3 to 3:1;
preferably, the pH of the mixed lye of the secondary alkaline wash is controlled to be between 10 and 11, preferably between 10 and 10.5, by adding part of the fresh lye.
8. The method for washing crude nitrobenzene according to any one of claims 1 to 7, characterized in that the volume flow ratio of fresh desalted water to crude nitrobenzene after secondary alkaline washing in step (3) is controlled to be 1:3 to 3:1.
9. The method for washing crude nitrobenzene according to any one of claims 1 to 8, characterized in that the washing temperature of the primary alkaline washing is 60 ℃ to 70 ℃ and the washing time is 3 to 10min; and/or
The washing temperature of the secondary alkaline washing is 60-70 ℃ and the washing time is 3-10min; and/or
The washing temperature of the neutral water washing is 60-70 ℃ and the washing time is 3-10min.
10. The method for washing crude nitrobenzene according to any one of claims 1 to 9, characterized in that the sodium salt content of the refined nitrobenzene obtained from the washing is not more than 2ppm and the total phenol content is not more than 2ppm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311708864.4A CN117843490A (en) | 2023-12-12 | 2023-12-12 | Low-alkali consumption and low-sodium salt residual nitrobenzene washing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311708864.4A CN117843490A (en) | 2023-12-12 | 2023-12-12 | Low-alkali consumption and low-sodium salt residual nitrobenzene washing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117843490A true CN117843490A (en) | 2024-04-09 |
Family
ID=90541040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311708864.4A Pending CN117843490A (en) | 2023-12-12 | 2023-12-12 | Low-alkali consumption and low-sodium salt residual nitrobenzene washing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117843490A (en) |
-
2023
- 2023-12-12 CN CN202311708864.4A patent/CN117843490A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1593654B1 (en) | Process for treating waste waters containing aromatic nitro compounds | |
| US20120241374A1 (en) | Method of treating waste water produced during preparing nitro compound | |
| EP1493730B1 (en) | Process for working up side products of the dinitrotoluene production | |
| KR20120102120A (en) | Acidic toluene extraction of dnt wastewaters | |
| EP2288591B1 (en) | Method for producing diphenylmethane diamine | |
| JP6193358B2 (en) | How to wash dinitrotoluene | |
| US9771291B2 (en) | Process for working up waste water from nitrobenzene preparation | |
| CN117843490A (en) | Low-alkali consumption and low-sodium salt residual nitrobenzene washing method | |
| CN112939781B (en) | Adiabatic process for continuous operation for the preparation of nitrobenzene by nitration of benzene | |
| CN112094194A (en) | Method for controlling TOC in waste brine in DAM production process | |
| EP2986563B1 (en) | Method for the treatment of wastewater from the production of nitrobenzene | |
| KR102282234B1 (en) | Process for the acid scrub of dinitrotoluene in the presence of hydrocyanic acid | |
| CN104030927A (en) | Method for preparing 1-nitroanthraquinone by using metal-modified molecular sieve as catalyst | |
| CN105367471B (en) | A kind of method for adding stabilizer and suppressing N methyl pyrrolidones/chloroform separation process chloroform acidifying | |
| CN110256302B (en) | Method for producing H acid by complex extraction | |
| CN110526325B (en) | Diisopropyl ether-based high-concentration phenol-containing wastewater extracting agent and extracting method | |
| DE102018217955B4 (en) | Process for working up mixed acid and waste water from the nitration of aromatics and device for carrying out the process | |
| CN117923705A (en) | Method for reducing TOC content in salt-containing organic wastewater generated in DAM preparation process | |
| CN115724722A (en) | Method for reducing content of neutral oil in crude phenol | |
| CN116813481A (en) | Recovery treatment method of 2, 5-diaminotoluene sulfate production wastewater | |
| CN116239179A (en) | Extractant for extracting nitro-T acid from H acid denitration liquid | |
| CN115676952A (en) | Method for extracting and dephenolizing phenolic wastewater | |
| CN117229118A (en) | Method for separating cyclohexanone and cyclohexanol in cyclohexane | |
| DD146751A3 (en) | PROCESS FOR PROCESSING PROCESS WASTE OF UREA MANUFACTURE | |
| KR20050025358A (en) | Method for recovery of phenol from aqueous streams |
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 |