CN115260036A - Production process of nitrobenzene - Google Patents
Production process of nitrobenzene Download PDFInfo
- Publication number
- CN115260036A CN115260036A CN202210835448.XA CN202210835448A CN115260036A CN 115260036 A CN115260036 A CN 115260036A CN 202210835448 A CN202210835448 A CN 202210835448A CN 115260036 A CN115260036 A CN 115260036A
- Authority
- CN
- China
- Prior art keywords
- reaction
- production process
- nitrobenzene
- benzene
- nitric acid
- 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.)
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- LQNUZADURLCDLV-UHFFFAOYSA-N nitrobenzene Chemical compound [O-][N+](=O)C1=CC=CC=C1 LQNUZADURLCDLV-UHFFFAOYSA-N 0.000 title claims abstract description 64
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 21
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims abstract description 84
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 51
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 27
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 25
- 238000006243 chemical reaction Methods 0.000 claims description 34
- 238000010791 quenching Methods 0.000 claims description 5
- 230000000171 quenching effect Effects 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 2
- 238000003786 synthesis reaction Methods 0.000 abstract description 2
- 238000006396 nitration reaction Methods 0.000 description 15
- 239000012535 impurity Substances 0.000 description 8
- 239000002253 acid Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 6
- 238000010924 continuous production Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000000802 nitrating effect Effects 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- WDCYWAQPCXBPJA-UHFFFAOYSA-N 1,3-dinitrobenzene Chemical compound [O-][N+](=O)C1=CC=CC([N+]([O-])=O)=C1 WDCYWAQPCXBPJA-UHFFFAOYSA-N 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 238000000622 liquid--liquid extraction Methods 0.000 description 1
- -1 neutralization Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000002699 waste material Substances 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
- C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application provides a production process of nitrobenzene, and relates to the technical field of organic synthesis. The production process adopts the microchannel reactor to replace the traditional kettle type process to prepare nitrobenzene, and adopts the sulfuric acid, the nitric acid and the benzene to continuously flow through the microchannel reactor to produce the nitrobenzene.
Description
Technical Field
The application relates to the technical field of organic synthesis, in particular to a method for producing nitrobenzene by using a microchannel reactor and separating and purifying nitrobenzene by using a liquid-liquid extraction device.
Background
In the production process of nitrobenzene, the temperature control of a nitration reactor is crucial, when the temperature of the reactor is higher, the over-nitration oxidation reaction occurs, the impurity content is increased, and the reaction can be out of control and explode when the impurity content is serious; the nitration reaction is exothermic reaction, the higher the temperature is, the faster the nitration reaction speed is, the more heat is released, the more easily the temperature is out of control to cause explosion. Most of the nitrated substances are inflammable substances, and some substances have toxicity, such as benzene, toluene, absorbent cotton and the like, so that fire disasters are easily caused when the nitrated substances are improperly used or stored. When the temperature is lower, the material is also subjected to nitrification and oxidation, and the impurity content is also increased. In the benzene nitration process production, the involved hazardous substances are more, the hazardous characteristics are complex, the operating temperature requirement is higher, when the temperature control fluctuation is larger, the heat-sensitive materials in the benzene nitration process can be caused to generate exothermic decomposition reaction, and in severe cases, the runaway reaction can be caused, so that the explosion accident can be caused.
At present, the production method of nitrobenzene mainly comprises two methods: direct nitration processes and adiabatic nitration processes.
The direct nitration method is to directly nitrify benzene with mixed acid to produce nitrobenzene. The method has the advantages of mature process technology, easy operation, common equipment materials, normal pressure and low temperature; the main disadvantages are serious corrosion of the equipment and large energy consumption for concentrating and recovering the by-product dilute sulfuric acid. At present, each manufacturer adopts different processes suitable for the condition of the manufacturer according to different technical advantages and energy advantages.
The adiabatic nitration process includes adding excessive benzene and mixture of nitric acid and sulfuric acid into reactor, continuous nitration reaction at 135 deg.c and 0.5MPa pressure, separation of reactant from dilute sulfuric acid, neutralization, water washing and refining of the reaction product to obtain nitrobenzene product. The dilute sulfuric acid is flashed to obtain water under vacuum and then concentrated to 70-75% for recycling. The process has the outstanding advantages that the reaction heat is absorbed by dilute sulphuric acid, a complex cooling system is not required to be arranged in the nitration reactor, and a large amount of energy consumption required by concentration is saved. The process is not widely popularized yet in China, and the main obstacles are strict requirements on equipment materials and high engineering cost. The domestic nitrobenzene production technology mainly comprises a pot-type series continuous production process and a ring-type series continuous production process.
Chinese patent application 200910178747.5 discloses a method for continuously preparing nitrobenzene. The process comprises nitrating benzene in a reaction space with a nitrating acid comprising at least 3.0 wt.% nitric acid and at least 67.0 wt.% sulfuric acid, wherein the reaction is initiated at a temperature above 100.0 ℃ but below 102.0 ℃. In addition, the method requires benzene and nitrating acid to be mutually dispersed for a plurality of times, the temperature set by the method is lower, and benzene and nitrating acid are required to be mutually dispersed for a plurality of times, so that the reaction is not favorably carried out.
Chinese patent application 201110037401.0 discloses a method for continuously preparing nitrobenzene, wherein nitrobenzene is continuously produced by nitration reaction of benzene and mixed acid under adiabatic conditions. In this process, the pressure upstream of the nitration reactor is 14 to 40 bar higher than the pressure of the gas phase in the phase separation apparatus used for separating crude nitrobenzene and waste acid, the process has to be carried out under adiabatic conditions and the requirements of the plant conditions are high.
Therefore, there is a need to provide a process for the continuous production of nitrobenzene at higher temperatures.
Disclosure of Invention
Based on the defects in the prior art, the application provides a continuous nitrobenzene preparation process, a microchannel reactor is adopted to replace a reaction kettle for continuous production, the reaction time is shortened, the product yield and the product quality are improved, and the intrinsic safety is realized.
The production process of nitrobenzene comprises the following steps: adding sulfuric acid, nitric acid and benzene into the microchannel reactor, mixing, reacting in a reaction module, separating in a reaction separator after the reaction is finished, and washing to obtain nitrobenzene.
The purity of the benzene is more than or equal to 99wt%; the flow rate of the benzene is 5-20kg/min, preferably 5kg/min.
The purity of the nitric acid is 58-98wt%;
the purity of the sulfuric acid is more than or equal to 95wt%;
the mass ratio (dry basis) of the total mass of the sulfuric acid and the nitric acid to the benzene is 2; the mass ratio (dry basis) of the sulfuric acid to the nitric acid is 1;
preferably, the mass ratio of the total mass of the sulfuric acid and the nitric acid to the benzene (dry basis) is 3.5: 1-9.5; the mass ratio (dry basis) of the sulfuric acid to the nitric acid is 1;
the reaction temperature is 50-170 ℃;
preferably, the reaction temperature is 100-140 ℃;
the microchannel reactor is made of glass or/and silicon carbide; the microchannel reactor adopts a modular reactor or/and a tubular reactor; the microchannel reactor can be subjected to temperature control through a heat exchanger, and each temperature zone in the microchannel reactor comprises 1-10 reaction modules; the last 1-5 reaction modules of the microchannel reactor are low-temperature quenching modules, and the quenching temperature is-10-15 ℃;
preferably, each temperature zone in the microchannel reactor comprises 5 or 10 reaction modules.
Has the advantages that:
according to the continuous nitrobenzene production process disclosed by the application, a microchannel reactor is selected to replace the traditional kettle type process to prepare nitrobenzene in the preparation process, and sulfuric acid, nitric acid and benzene are adopted to pass through the continuous flow of the microchannel reactor to produce nitrobenzene.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
For a better understanding of the present invention, the present invention is further described in conjunction with the following specific examples, wherein the terminology used in the examples is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Basic embodiment example:
in a microchannel reactor, sulfuric acid, nitric acid and benzene are metered by a pump and then enter a reaction module to be mixed for reaction at a certain reaction temperature, quenching reaction is carried out at 0 ℃ after the reaction is finished, and the nitrobenzene is obtained by separation and washing by a separator.
The contents of nitrobenzene and impurities (dinitrobenzene, etc.) were checked by gas chromatography, and the reaction conditions and results are shown in table 1 below.
TABLE 1
From the data in table 1 above, it can be seen that:
the application examples 1-2,3-4 differ in that the reaction temperatures are different, 100 ℃ and 140 ℃ respectively, and the other conditions are the same, which shows that under the condition of the feed ratio, the temperature is increased, the yield of the nitrobenzene obtained and the content of impurity substances are increased, the nitrobenzene with higher yield can be obtained, and the impurities are removed by rectification within the range.
Comparative examples 1-2, the reaction was carried out at 40 ℃ and 200 ℃ respectively, the other conditions were the same as in application example 1, the reaction rate was slow at low temperature, the yield was low, and the pseudo-activity was low; high temperature, high reaction rate, more side reactions, more product decomposition and low yield.
Comparing application examples 1 and 3, application examples 2 and 4, and application examples 8 and 9, the difference is that the nitric acid concentration is different, and the nitric acid content is 68% or 95%, respectively, and it can be seen that the higher the nitric acid concentration is, the higher the nitrobenzene content is, and the more impurities are. Meanwhile, higher yield can be achieved at lower nitric acid content.
The difference of application examples 5-6 lies in that the mass of the sulfuric acid is different and is respectively 33.33kg and 66.67kg, namely the mixture ratio of the raw materials is different, the obtained nitrobenzene content is respectively 99.31 percent and 99.59 percent, and the impurity content is respectively 0.28 percent and 0.31 percent; the mass ratio of the total weight of the nitric acid and the sulfuric acid to the benzene is improved, which is beneficial to improving the yield; compared with the comparative example 4, the mass ratio of the total weight of the nitric acid and the sulfuric acid to the benzene is too high, the micro-channel is not uniformly mixed, the phenomenon that the benzene and other substances are uniformly mixed is easy to occur, and the yield is reduced to some extent.
In application example 7, the mass ratio of the total mass of nitric acid + sulfuric acid (dry basis) to benzene is 9.468: the mass ratio of nitric acid to nitric acid is 1; it shows that higher yield can be achieved by the microchannel reactor in a wider range of feed ratio.
Comparative examples 3-4, which illustrate the presence of benzene: in the range of mixed acid of sulfuric acid and nitric acid, the feed ratio is too low or too high, so that the reaction is incomplete and the yield is reduced.
The difference between the application examples 3 and 8, and between the application examples 4 and 9 is that the number of reaction modules is different, and the results show that the increase of the number of the modules is beneficial to the implementation of the nitration reaction, the improvement of the yield of the nitrobenzene and the increase of the side reaction.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof.
The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (10)
1. A production process of nitrobenzene is characterized in that: the method comprises the following steps: adding sulfuric acid, nitric acid and benzene into a microchannel reactor, mixing, reacting in a reaction module, separating in a reaction separator after the reaction is finished, and washing to obtain nitrobenzene; the flow rate of the benzene is 5-20kg/min.
2. The production process according to claim 1, characterized in that: the purity of the benzene is more than or equal to 99wt%; the flow rate of the benzene is 5kg/min.
3. The production process according to claim 1, characterized in that: the purity of the nitric acid is 58-98wt%.
4. The production process according to claim 1, characterized in that: the purity of the sulfuric acid is more than or equal to 95wt%.
5. The production process according to claim 1, characterized in that: the mass ratio of the total mass of the sulfuric acid and the nitric acid to the benzene (dry basis) is (2).
6. The production process according to claim 5, characterized in that: the mass ratio of the total mass of the sulfuric acid and the nitric acid to the benzene (dry basis) is 3.5.
7. The production process according to claim 1, characterized in that: the mass (dry basis) ratio of the sulfuric acid to the nitric acid is 1.
8. The production process according to claim 7, characterized in that: the mass (dry basis) ratio of the sulfuric acid to the nitric acid is 1.
9. The production process according to claim 1, characterized in that: the reaction temperature is 50-170 ℃.
10. The production process according to claim 1, characterized in that: each temperature zone in the microchannel reactor comprises 1-10 reaction modules; the last 1-5 reaction modules of the microchannel reactor are low-temperature quenching modules, and the quenching temperature is-10-15 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210835448.XA CN115260036A (en) | 2022-07-15 | 2022-07-15 | Production process of nitrobenzene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210835448.XA CN115260036A (en) | 2022-07-15 | 2022-07-15 | Production process of nitrobenzene |
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| Publication Number | Publication Date |
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| CN115260036A true CN115260036A (en) | 2022-11-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210835448.XA Pending CN115260036A (en) | 2022-07-15 | 2022-07-15 | Production process of nitrobenzene |
Country Status (1)
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6515189B1 (en) * | 1997-11-05 | 2003-02-04 | British Nuclear Fuels Plc | Reactions of aromatic compounds |
| CN1406151A (en) * | 2000-03-02 | 2003-03-26 | 陶氏环球技术公司 | Tubular reactor, method for carrying out a liquid/liquid multiphase reaction in a tubular reactor, and a method for ring-nitrating aromatic compounds in a tubular reactor |
| CN101613285A (en) * | 2008-06-25 | 2009-12-30 | 中国科学院大连化学物理研究所 | A kind of oil of mirbane synthetic method and equipment special |
| CN111018715A (en) * | 2019-12-14 | 2020-04-17 | 中国科学院大连化学物理研究所 | Microchannel synthesis method of dinitrobenzene |
| CN111393299A (en) * | 2020-05-06 | 2020-07-10 | 沈阳感光化工研究院有限公司 | Method for nitrifying nitrobenzene by using micro-channel continuous flow reactor |
-
2022
- 2022-07-15 CN CN202210835448.XA patent/CN115260036A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6515189B1 (en) * | 1997-11-05 | 2003-02-04 | British Nuclear Fuels Plc | Reactions of aromatic compounds |
| CN1406151A (en) * | 2000-03-02 | 2003-03-26 | 陶氏环球技术公司 | Tubular reactor, method for carrying out a liquid/liquid multiphase reaction in a tubular reactor, and a method for ring-nitrating aromatic compounds in a tubular reactor |
| CN101613285A (en) * | 2008-06-25 | 2009-12-30 | 中国科学院大连化学物理研究所 | A kind of oil of mirbane synthetic method and equipment special |
| CN111018715A (en) * | 2019-12-14 | 2020-04-17 | 中国科学院大连化学物理研究所 | Microchannel synthesis method of dinitrobenzene |
| CN111393299A (en) * | 2020-05-06 | 2020-07-10 | 沈阳感光化工研究院有限公司 | Method for nitrifying nitrobenzene by using micro-channel continuous flow reactor |
Non-Patent Citations (1)
| Title |
|---|
| 魏微，等: "微反应器中的苯硝化反应" * |
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