CN116891416A - Preparation method of 3, 5-diaminobenzoic acid - Google Patents
Preparation method of 3, 5-diaminobenzoic acid Download PDFInfo
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- CN116891416A CN116891416A CN202310714122.6A CN202310714122A CN116891416A CN 116891416 A CN116891416 A CN 116891416A CN 202310714122 A CN202310714122 A CN 202310714122A CN 116891416 A CN116891416 A CN 116891416A
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- UENRXLSRMCSUSN-UHFFFAOYSA-N 3,5-diaminobenzoic acid Chemical compound NC1=CC(N)=CC(C(O)=O)=C1 UENRXLSRMCSUSN-UHFFFAOYSA-N 0.000 title claims abstract description 47
- 238000002360 preparation method Methods 0.000 title claims abstract description 35
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 99
- 238000006243 chemical reaction Methods 0.000 claims abstract description 92
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 72
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims abstract description 68
- 238000006722 reduction reaction Methods 0.000 claims abstract description 62
- 238000006396 nitration reaction Methods 0.000 claims abstract description 57
- 239000002253 acid Substances 0.000 claims abstract description 48
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 47
- VYWYYJYRVSBHJQ-UHFFFAOYSA-N 3,5-dinitrobenzoic acid Chemical compound OC(=O)C1=CC([N+]([O-])=O)=CC([N+]([O-])=O)=C1 VYWYYJYRVSBHJQ-UHFFFAOYSA-N 0.000 claims abstract description 45
- 239000003054 catalyst Substances 0.000 claims abstract description 44
- 238000000034 method Methods 0.000 claims abstract description 42
- 239000002699 waste material Substances 0.000 claims abstract description 42
- 239000005711 Benzoic acid Substances 0.000 claims abstract description 34
- 235000010233 benzoic acid Nutrition 0.000 claims abstract description 34
- UKVIEHSSVKSQBA-UHFFFAOYSA-N methane;palladium Chemical compound C.[Pd] UKVIEHSSVKSQBA-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000013067 intermediate product Substances 0.000 claims abstract description 24
- 238000000605 extraction Methods 0.000 claims abstract description 23
- 239000000047 product Substances 0.000 claims abstract description 23
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 claims abstract description 18
- 239000000706 filtrate Substances 0.000 claims abstract description 13
- KNKRKFALVUDBJE-UHFFFAOYSA-N 1,2-dichloropropane Chemical compound CC(Cl)CCl KNKRKFALVUDBJE-UHFFFAOYSA-N 0.000 claims abstract description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 39
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 claims description 31
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 26
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 20
- 238000010009 beating Methods 0.000 claims description 19
- 230000035484 reaction time Effects 0.000 claims description 19
- 238000001914 filtration Methods 0.000 claims description 17
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 16
- 239000012043 crude product Substances 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 13
- 238000002156 mixing Methods 0.000 claims description 12
- QIJIUJYANDSEKG-UHFFFAOYSA-N 2,4,4-trimethylpentan-2-amine Chemical compound CC(C)(C)CC(C)(C)N QIJIUJYANDSEKG-UHFFFAOYSA-N 0.000 claims description 10
- 230000001546 nitrifying effect Effects 0.000 claims description 10
- 229910052763 palladium Inorganic materials 0.000 claims description 10
- 230000001105 regulatory effect Effects 0.000 claims description 10
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical group [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 9
- 238000001179 sorption measurement Methods 0.000 claims description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 8
- 229910052739 hydrogen Inorganic materials 0.000 claims description 8
- 239000001257 hydrogen Substances 0.000 claims description 8
- 238000005086 pumping Methods 0.000 claims description 8
- 238000011049 filling Methods 0.000 claims description 7
- 239000003638 chemical reducing agent Substances 0.000 claims description 3
- LZZYPRNAOMGNLH-UHFFFAOYSA-M Cetrimonium bromide Chemical compound [Br-].CCCCCCCCCCCCCCCC[N+](C)(C)C LZZYPRNAOMGNLH-UHFFFAOYSA-M 0.000 claims description 2
- XKBGEWXEAPTVCK-UHFFFAOYSA-M methyltrioctylammonium chloride Chemical compound [Cl-].CCCCCCCC[N+](C)(CCCCCCCC)CCCCCCCC XKBGEWXEAPTVCK-UHFFFAOYSA-M 0.000 claims description 2
- 235000019333 sodium laurylsulphate Nutrition 0.000 claims 2
- HFQQZARZPUDIFP-UHFFFAOYSA-M sodium;2-dodecylbenzenesulfonate Chemical compound [Na+].CCCCCCCCCCCCC1=CC=CC=C1S([O-])(=O)=O HFQQZARZPUDIFP-UHFFFAOYSA-M 0.000 claims 1
- 239000002994 raw material Substances 0.000 abstract description 9
- 239000006227 byproduct Substances 0.000 abstract description 5
- 238000005984 hydrogenation reaction Methods 0.000 abstract description 5
- 238000009903 catalytic hydrogenation reaction Methods 0.000 abstract description 4
- 239000007795 chemical reaction product Substances 0.000 abstract description 4
- 238000004064 recycling Methods 0.000 abstract description 4
- 238000010521 absorption reaction Methods 0.000 abstract description 3
- GAHCNYHAKKGGHF-UHFFFAOYSA-N 5,5-dimethylhexan-1-amine Chemical compound CC(C)(C)CCCCN GAHCNYHAKKGGHF-UHFFFAOYSA-N 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 78
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 239000013589 supplement Substances 0.000 description 6
- 239000002351 wastewater Substances 0.000 description 6
- 238000010812 external standard method Methods 0.000 description 5
- 238000004128 high performance liquid chromatography Methods 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 229920001721 polyimide Polymers 0.000 description 4
- NWZSZGALRFJKBT-KNIFDHDWSA-N (2s)-2,6-diaminohexanoic acid;(2s)-2-hydroxybutanedioic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O.NCCCC[C@H](N)C(O)=O NWZSZGALRFJKBT-KNIFDHDWSA-N 0.000 description 3
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine monohydrate Substances O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- AFPHTEQTJZKQAQ-UHFFFAOYSA-N 3-nitrobenzoic acid Chemical compound OC(=O)C1=CC=CC([N+]([O-])=O)=C1 AFPHTEQTJZKQAQ-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 125000006575 electron-withdrawing group Chemical group 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 230000000802 nitrating effect Effects 0.000 description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 208000024172 Cardiovascular disease Diseases 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- YVPYQUNUQOZFHG-UHFFFAOYSA-N amidotrizoic acid Chemical compound CC(=O)NC1=C(I)C(NC(C)=O)=C(I)C(C(O)=O)=C1I YVPYQUNUQOZFHG-UHFFFAOYSA-N 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 208000026106 cerebrovascular disease Diseases 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 239000002872 contrast media Substances 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 229960005223 diatrizoic acid Drugs 0.000 description 1
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000002526 effect on cardiovascular system Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007336 electrophilic substitution reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012450 pharmaceutical intermediate Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- FDDDEECHVMSUSB-UHFFFAOYSA-N sulfanilamide Chemical compound NC1=CC=C(S(N)(=O)=O)C=C1 FDDDEECHVMSUSB-UHFFFAOYSA-N 0.000 description 1
- 229940124530 sulfonamide Drugs 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 208000014001 urinary system disease Diseases 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/04—Formation of amino groups in compounds containing carboxyl groups
-
- 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
- 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
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/38—Separation; Purification; Stabilisation; Use of additives
- C07C227/40—Separation; Purification
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a preparation method of 3, 5-diaminobenzoic acid, which takes benzoic acid and waste acid as reaction raw materials, screens out specific nitration catalyst and reduction catalyst, firstly carries out nitration reaction to obtain intermediate product 3, 5-dinitrobenzoic acid, and then carries out hydrogenation reduction reaction to obtain 3, 5-diaminobenzoic acid. In the nitration reaction process, the production of byproducts can be reduced, the yield of the products is improved, the obtained reaction liquid is filtered, and the filtrate is subjected to absorption extraction and concentration of dichloropropane and tertiary octylamine and can be used as a reaction raw material for recycling, so that the consumption of sulfuric acid and nitric acid can be reduced, the production cost is reduced, and the environment is protected. In the hydrogenation reaction process, the intermediate product 3, 5-dinitrobenzoic acid is subjected to catalytic hydrogenation reaction in a fixed bed reactor filled with a palladium-carbon catalyst, so that the consumption of the catalyst is reduced, the product yield is improved, the operation process of separating the catalyst of the reaction product is not needed, and the production efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of chemical intermediate preparation, and particularly relates to a preparation method of 3, 5-diaminobenzoic acid.
Background
The 3, 5-diaminobenzoic acid is an important monomer of a novel material polyimide film, and the polyimide film is a high Wen Xinxing-resistant polymer material with excellent comprehensive performance, is widely applied to the fields of high-temperature-resistant coatings, electromagnetic wires, semiconductor protective layers, flexible printed circuit boards, solar components and the like, and the tough and transparent polyimide film synthesized by taking the 3, 5-diaminobenzoic acid as a monomer can effectively improve the difficult problem of high-strength firm adhesion between the film and other materials while keeping the excellent performance of the original polyimide.
In addition, 3, 5-diaminobenzoic acid is also an important dye and pharmaceutical intermediate. In the medical field, 3, 5-diaminobenzoic acid is mainly used for synthesizing contrast agents for diagnosis of cardiovascular and cerebrovascular diseases and urinary system diseases, for example, diatrizoic acid; can also synthesize the sulfanilamide medicines with wide antibacterial spectrum, low cost and high efficiency.
At present, two main routes exist for the synthesis of 3, 5-diaminobenzoic acid: (1) Directly reducing 3, 5-dinitrobenzoic acid to obtain 3, 5-diaminobenzoic acid; (2) The intermediate product 3, 5-dinitrobenzoic acid is prepared by adopting benzoic acid to perform nitration reaction, and then 3, 5-diaminobenzoic acid is obtained by reduction.
The synthesis method of the 3, 5-dinitrobenzoic acid mainly comprises two steps: (1) Adopting concentrated nitric acid as a nitrating agent and sulfuric acid as a solvent, and directly nitrifying benzoic acid to generate 3, 5-dinitrobenzoic acid; (2) M-nitrobenzoic acid is used as a raw material, concentrated nitric acid is used as a nitrating agent, and 3, 5-dinitrobenzoic acid is generated through one-step nitration. The two methods adopt intermittent kettle type reaction, which has the problems of long reaction time, easy accumulation of materials, difficult control of process parameters, large liquid holdup of the reaction kettle and the like, and the 3, 5-dinitrobenzoic acid synthesized by the nitration of benzoic acid is a strong exothermic reaction, the reaction heat is about 278.96kJ/mol, the reaction temperature is not easy to control, and the phenomenon of 'flying temperature' is easy to generate. The temperature is an important factor influencing the quality and safety of the nitration reaction, so that a process with stable and rapid heat transfer effect is required to meet the requirement of mass production.
The nitric acid can generate ionization to generate H under the catalysis of sulfuric acid 2 NO 3 + When the mixed solution of benzoic acid, nitric acid and sulfuric acid is undergone the process of primary nitration reaction, the electrophilic substitution reaction can be implemented on ortho-position, meta-position and para-position of benzene ring, but the carboxyl group belongs to meta-position positioning group, and has no C + Resonance type connected to strong electron withdrawing group, so that the primary nitration product is mainly m-nitrobenzoic acid; the reaction proceeds rapidly at room temperature, but after introduction of a nitro group, due to NO 2 + The electron withdrawing group can further reduce the electron cloud density on the benzene ring, greatly reduce the dinitration speed and require more intensified reaction conditions, and the specific synthetic route is shown as follows.
Aiming at the problems, chinese patent CN 111253261A discloses a preparation method of 3, 5-dinitrobenzoic acid, which comprises the following steps: 1) Dissolving benzoic acid in concentrated sulfuric acid to obtain a benzoic acid solution; adding fuming sulfuric acid into fuming nitric acid to obtain a mixed acid solution; 2) Mixing a benzoic acid solution and a mixed acid solution to obtain a reaction raw material liquid, and reacting the reaction raw material liquid in a microchannel reactor to obtain the 3, 5-dinitrobenzoic acid. In the reaction process, a mixed acid solution of fuming sulfuric acid and fuming nitric acid is used as a nitrifying reagent of benzoic acid, the yield is about 60%, the problem of low yield exists, and meanwhile, more waste acid can be generated in the reaction process, so that the cost is saved and the environment is protected. In addition, because the micro-channel reactor has small channel size, usually between a few micrometers and hundreds of micrometers, the reactants are slightly sticky or the particles are large to cause channel blockage, which has a certain influence on the safe use and cleaning of the micro-reactor.
There are three main methods for the reduction of 3, 5-dinitrobenzoic acid: including iron powder reduction, hydrazine hydrate reduction and hydrogenation reduction. The reduction method of iron powder is the earliest method, has low cost and mature technology, but can produce a large amount of waste liquid and waste solid, and especially the produced iron mud can cause serious environmental pollution. The hydrazine hydrate reduction method avoids the generation of pollutant iron mud, but the reduction reaction needs high-concentration hydrazine hydrate, and has great potential safety hazards in the storage, transportation and use processes, and meanwhile, the byproducts are more and the product color is poor. At present, although a catalytic hydrogenation reduction method is adopted in the reduction reaction of 3, 5-diaminobenzoic acid, kettle type intermittent reaction is adopted in the reaction process, and although the yield is higher, the stirring abrasion of a catalyst inevitably exists in the kettle type intermittent reaction, and a new catalyst needs to be supplemented in the catalyst recycling process, so that the catalyst cost is increased, meanwhile, the quality of an intermittent reaction product is unstable, the production efficiency is low, and the synthetic route is as follows:
disclosure of Invention
The invention aims to provide a preparation method of 3, 5-diaminobenzoic acid based on the prior art, which takes benzoic acid and waste acid as reaction raw materials, fuming sulfuric acid and fuming nitric acid as nitrifying agents, screens out specific nitrifying catalysts and reducing catalysts, carries out nitrifying reaction through a dynamic circulation microchannel reactor and a tubular reactor to obtain an intermediate product 3, 5-dinitrobenzoic acid, and carries out hydrogenation reduction reaction in a fixed bed reactor to obtain the 3, 5-diaminobenzoic acid.
In the nitration reaction process, for example, sodium dodecyl sulfate is used as a nitration catalyst, so that the production of byproducts can be reduced, the yield of products is improved, the obtained nitration reaction liquid is filtered, and filtrate can be used as nitration reaction raw materials for recycling after being subjected to absorption, extraction and concentration of dichloropropane and tert-octylamine, so that the consumption of sulfuric acid and nitric acid can be reduced, the production cost is reduced, the environment is protected, the resources are comprehensively utilized, the clean production is realized, the safety and the economy are realized, and the method is suitable for continuous and industrial production.
In the hydrogenation reaction process, palladium-carbon is used as a reduction catalyst, and the intermediate product 3, 5-dinitrobenzoic acid is subjected to catalytic hydrogenation reaction in a fixed bed reactor filled with the palladium-carbon catalyst, so that the consumption of the palladium-carbon catalyst is reduced, the product yield and the product quality are improved, the operation process of separating the reaction product catalyst is not needed, and the production efficiency is improved.
The technical scheme of the invention is as follows:
a preparation method of 3, 5-diaminobenzoic acid, which comprises the following steps:
(1) Uniformly mixing benzoic acid and waste acid to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is not less than 96wt percent, and the concentration of nitric acid is not less than 96wt percent;
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid, and adding a nitrification catalyst to obtain a component 2 solution;
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the reaction temperature is 75-85 ℃, the reaction pressure is 0.4-0.6 MPa, and the reaction time is 30-60 min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction at the reaction temperature of 80-90 ℃ and the reaction pressure of 0.4-0.6 MPa for 10-30 min to obtain an intermediate product of 3, 5-dinitrobenzoic acid;
(4) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 10-30% in the beating process, and then adding 20-40% sodium hydroxide solution to adjust the pH value to 7-8, thus obtaining a component 3 solution;
(5) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, the reaction temperature is 80-90 ℃, the reaction pressure is 0.8-1.2 MPa, and the reaction time is 60-120 min; after the reduction reaction is finished, the pH of the obtained reduction reaction solution is regulated to 4-6 by 25-35% hydrochloric acid, and the 3, 5-diaminobenzoic acid product is obtained by filtering and drying.
For the purposes of the present invention, in step (1), the molar ratio of benzoic acid to sulfuric acid and nitric acid in the spent acid is 1:2 to 3:1 to 1.5, and may be, but is not limited to, 1:2:1, 1:2.5:1.2, or 1:3:1.5.
For the purposes of the present invention, in step (2), the molar ratio of benzoic acid to sulfuric acid in oleum is 1:2 to 3, and may be, but is not limited to, 1:2, 1:2.5 or 1:3.
In step (2), the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 2-3:1-1.5, and can be but is not limited to 2:1, 2.5:1.2 or 3:1.5.
In the step (2), the concentration of sulfuric acid in fuming sulfuric acid is 95-98 wt%.
In the step (2), the concentration of the nitric acid in fuming nitric acid is 90-98 wt%.
In step (2), the nitration catalyst is sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, cetyltrimethylammonium bromide or methyltrioctylammonium chloride, preferably sodium dodecyl sulfate.
In a preferred embodiment, in step (2), the mass ratio of nitration catalyst to benzoic acid is from 0.0001 to 0.01:1, preferably 0.001:1.
In a preferred scheme, in the step (3), the reaction temperature is 80 ℃ and the reaction pressure is 0.5MPa during the primary nitration reaction; the reaction time was 40min.
In a preferred scheme, in the step (3), the reaction temperature is 85 ℃ and the reaction pressure is 0.5MPa during the secondary nitration reaction; the reaction time was 20min.
In the present invention, in the step (3), the flow rate of the component 1 solution is 2.00 to 3.00L/min, preferably 2.50L/min; the flow rate of the component 2 solution is 1.50-2.50L/min, preferably 2.00L/min.
In the invention, in the step (3), after the secondary nitration reaction is finished, the obtained reaction liquid is cooled and filtered to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid.
In a preferred scheme, in the step (3), after the secondary reaction is finished, the obtained nitration reaction liquid is cooled and filtered, dichloropropane and tert-octylamine are added into the obtained filtrate after filtration for adsorption extraction, and the separated liquid is concentrated to the concentration of sulfuric acid of not less than 96wt% and is reused in the step (1) to prepare the component 1 solution.
In the present invention, the dynamic loop microchannel reactor has a tube structure for dynamic mixing, rapid heat transfer, and back mixing prevention.
In step (4), the 3, 5-dinitrobenzoic acid content during beating is 10-30%, which may be, but is not limited to, 10%, 15%, 20%, 25% or 30%, and in a preferred embodiment, the 3, 5-dinitrobenzoic acid content during beating is 20%.
In the step (4), after pulping, adding 20-40% sodium hydroxide solution to adjust the pH value to 7-8; preferably, a further 30% sodium hydroxide solution is added to adjust the pH to 7-8, e.g. to adjust the pH to 7, 7.5 or 8; more preferably, a further 30% sodium hydroxide solution is added to adjust the pH to 7.5.
For the present invention, in step (5), the column tube of the fixed bed reactor is filled with palladium carbon as a reduction catalyst, and the content of palladium is 0.5 to 2%, which may be, but is not limited to, 0.5%, 1%, 1.5% or 2%; preferably, when palladium carbon is used as a reducing agent catalyst, the content of palladium is 0.5-2%; more preferably, palladium carbon is used as the reducing agent catalyst, and the palladium content is 1%.
In a preferred embodiment, when palladium carbon is filled in the tube array as the reduction catalyst, the filling height of the palladium carbon is 80 to 90%, preferably 85% of the length of the tube array.
In a preferred embodiment, in step (5), the reaction temperature is 85 ℃ during the reduction reaction; the reaction pressure is 1.0MPa; the reaction time was 90min.
In the step (5), the pH of the obtained reduction reaction solution is regulated to 4-6 by 25-35% hydrochloric acid; preferably, the resulting reduction reaction solution is adjusted to a pH of 4-6 with 30% hydrochloric acid, for example, to a pH of 4, 5 or 6; more preferably, the resulting reduction reaction solution is adjusted to pH 5 with 30% hydrochloric acid.
By adopting the technical scheme of the invention, the advantages are as follows:
(1) According to the preparation method of the 3, 5-diaminobenzoic acid, in the nitration reaction process, the dynamic circulation microchannel reactor and the tubular reactor are adopted for two-step nitration reaction, so that the mass transfer performance and the heat transfer performance are improved, the reaction temperature is stably controlled, the temperature runaway phenomenon is avoided, the generation of byproducts is reduced, the problem that the dynamic circulation microchannel reactor is easy to block is solved, and the safety of the reaction process is improved.
(2) According to the preparation method of the 3, 5-diaminobenzoic acid, the benzoic acid and the waste acid are used as reaction raw materials, fuming sulfuric acid and fuming nitric acid are used as nitrifying agents, and specific nitrifying catalysts such as sodium dodecyl sulfate are screened out, so that the production of byproducts can be reduced, the yield of an intermediate product 3, 5-dinitrobenzoic acid is improved, the obtained nitrifying reaction liquid is filtered, and filtrate is subjected to absorption extraction and concentration by dichloropropane and tert-octylamine and can be used as the nitrifying reaction raw materials for recycling, so that the consumption of sulfuric acid and nitric acid can be reduced, the production cost is reduced, the environment is protected, the comprehensive utilization of resources is realized, and the method is clean in production, safe and economical, and suitable for continuous and industrial production.
(3) According to the preparation method of the 3, 5-diaminobenzoic acid, after the nitration reaction is finished, the obtained nitration reaction liquid is cooled and filtered, and dichloropropane and tert-octylamine are added into the obtained filtrate after filtration for adsorption extraction, so that the extraction speed and the concentration safety can be improved.
(4) The intermediate product 3, 5-dinitrobenzoic acid is subjected to catalytic hydrogenation reaction in a fixed bed reactor, so that the consumption of palladium and carbon of a catalyst is reduced, the product yield and the product quality are improved, the operation process of separating the reaction product catalyst is not needed, and the production efficiency is improved.
(5) In the whole preparation method, the nitration reaction and the reduction reaction are suitable for continuous and industrialized production.
Drawings
FIG. 1 is a flow chart of the preparation of 3, 5-diaminobenzoic acid in the present invention;
wherein 1 is a component 1 formulation tank; 2 is a component 2 formulation tank; 3 is a dynamic loop microchannel reactor; 4 is a component 1 metering pump; the method comprises the steps of 5, a component 2 metering pump, 6, a centrifuge, 7, a waste acid concentration tower, 8, a condenser, 9, an acid pump, 10, a tubular reactor, 11, an extraction kettle, 12, a component 3 preparation tank, 13, a component 3 circulating pump and 14, wherein the fixed bed reactor.
Detailed Description
The following examples are provided for a better understanding of the present invention and are not limited to the preferred embodiments described herein, but are intended to limit the scope of the invention, any and all products which are the same or similar to the present invention, in light of the present teaching or by combining the present invention with other prior art features, are within the scope of the present invention.
FIG. 1 is a flow chart of the preparation of 3, 5-dinitrobenzoic acid according to the present invention. As shown in FIG. 1, the reaction device adopted by the invention comprises a component 1 preparation tank 1, a component 2 preparation tank 2, a dynamic circulation micro-channel reactor 3, a centrifuge 6, a waste acid concentration tower 7, a concentration tower top condenser 8, a tubular reactor 10, an extraction kettle 11, a component 3 preparation tank 12 and a fixed bed reactor 14.
Wherein, the component 1 preparation tank 1 and the component 2 preparation tank 2 are respectively connected with the feed inlet of the dynamic circulation microchannel reactor 3 through pipelines, the discharge outlet of the dynamic circulation microchannel reactor 3 is connected with the liquid inlet of the tubular reactor 10 through pipelines, the liquid outlet of the tubular reactor 10 is connected with the inlet of the centrifugal machine 6 through pipelines, the outlet of the centrifugal machine 6 is connected with the inlet of the extraction kettle 11 through pipelines, the outlet of the extraction kettle 11 is connected with the inlet of the waste acid concentration tower 7 through pipelines, the outlet of the waste acid concentration tower 7 is connected with the inlet of the acid pump 9 through pipelines, and the outlet of the acid pump 9 is connected with the component 1 preparation tank 1 through pipelines. A condenser 8 is arranged at the top of the waste acid concentration tower 7.
The discharge port of the component 3 preparation tank 12 is connected with the lower port of the fixed bed reactor 14 through a pipeline, and the upper port of the fixed bed reactor 14 is connected with the feed port of the preparation tank 12.
A component 1 metering pump is arranged on a pipeline between the component 1 preparation tank 1 and the dynamic circulation microchannel reactor 3, and a component 2 metering pump is arranged on a pipeline between the component 2 preparation tank 2 and the dynamic circulation microchannel reactor 3. A circulation pump 13 is provided between the component 3 compounding tank 12 and the fixed bed reactor 14.
The application process of the invention is as follows:
(1) Preparing a component 1 solution in a component 1 preparing tank 1, and preparing a component 2 solution in a component 2 preparing tank 2;
(2) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor 3 through a component 1 metering pump and a component 2 metering pump respectively in sequence for primary nitration reaction, wherein the reaction temperature is 75-85 ℃, the reaction pressure is 0.4-0.6 MPa, and the reaction time is 40-60 min; transferring the obtained reaction liquid into a tubular reactor 10 for secondary nitration reaction, wherein the reaction temperature is 80-90 ℃, the reaction pressure is 0.4-0.6 MPa, and the reaction time is 10-20 min; after the secondary nitration reaction is finished, the obtained nitration reaction liquid is cooled and is transferred to a centrifugal machine 6 for filtering and separating to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid.
(3) Transferring the filtrate obtained after separation by a centrifuge 6 into an extraction kettle 11, adding dichloropropane and tertiary octylamine for adsorption extraction, transferring the separated filtrate into a waste acid concentration tower 7 for concentration until the concentration of sulfuric acid is not less than 96wt%, and selecting whether to supplement nitric acid according to the concentration of nitric acid or not as waste acid to be recycled in the step (1) for preparing a component 1 solution. And the superfluous waste water in the concentration process is discharged from the condenser 8 arranged at the top of the concentration tower.
(4) The component 3 solution is prepared in a component 3 preparation tank 12, and the specific preparation process is as follows: adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 10-30% in the beating process, and then adding 20-40% sodium hydroxide solution to adjust the pH value to 7-8, thus obtaining a component 3 solution; (5) Transferring the component 3 solution and hydrogen into a fixed bed reactor 14 for reduction reaction, wherein the bed layer of the fixed bed reactor 14 is filled with 0.5-2% palladium carbon as a reduction catalyst, the reaction temperature is 80-90 ℃, the reaction pressure is 0.8-1.2 MPa, and the reaction time is 60-120 min; after the reduction reaction is finished, the pH of the obtained reduction reaction solution is regulated to 4-6 by 25-35% hydrochloric acid, and the 3, 5-diaminobenzoic acid product is obtained by filtering and drying.
Example 1
A preparation method of 3, 5-diaminobenzoic acid comprises the following steps:
(1) 122Kg of benzoic acid is added into waste acid and mixed uniformly to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is 96wt%, and the concentration of nitric acid is 96wt%; the molar ratio of benzoic acid to sulfuric acid and nitric acid in the waste acid is 1:2:1.
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid, and adding 0.122Kg of sodium dodecyl sulfate to obtain a component 2 solution; wherein, the molar ratio of benzoic acid to sulfuric acid in fuming sulfuric acid is 1:2; the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 2:1; the concentration of sulfuric acid in fuming sulfuric acid is 98wt%; the concentration of nitric acid in fuming nitric acid is 98wt%.
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the flow rate of the component 1 is 2.50L/min, and the flow rate of the component 2 is 2.00L/min; the reaction temperature is 80 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 40min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction, wherein the reaction temperature is 85 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 20min. After the secondary nitration reaction is finished, the obtained nitration reaction liquid is cooled and is transferred to a centrifugal machine for filtering and separating to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid, wherein the yield is 85.8 percent and the purity is 98.5 percent.
(4) Transferring the filtrate obtained after separation by a centrifuge to an extraction kettle, adding dichloropropane and tert-octylamine for adsorption extraction, transferring the separated liquid to a waste acid concentration tower for concentration until the concentration of sulfuric acid is not less than 96wt%, and selecting whether to supplement nitric acid according to the concentration of nitric acid as waste acid to be recycled to the step (1) for preparing the component 1 solution. And the superfluous waste water in the concentration process is discharged from a condenser arranged at the top of the concentration tower.
(5) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 15% in the beating process, and then adding 20% sodium hydroxide solution to adjust the pH value to 7 to obtain a component 3 solution;
(6) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, and the content of palladium is 1%; when the palladium carbon is filled in the tube array as a reduction catalyst, the filling height of the palladium carbon is 85% of the length of the tube array; the reaction temperature is 80 ℃, the reaction pressure is 0.8MPa, and the reaction time is 70min; after the reduction reaction is finished, the pH value of the obtained reduction reaction solution is regulated to 4 by 30% hydrochloric acid, the product 3, 5-diaminobenzoic acid is obtained by filtering and drying, and the purity is measured by an HPLC external standard method, and the product yield is 98.4% and the purity is more than 99.2%.
Example 2
A preparation method of 3, 5-diaminobenzoic acid comprises the following steps:
(1) 122Kg of benzoic acid is added into waste acid and mixed uniformly to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is 96wt%, and the concentration of nitric acid is 96wt%; the molar ratio of benzoic acid to sulfuric acid and nitric acid in the waste acid is 1:2.5:1.2.
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid, and adding 0.122Kg of sodium dodecyl sulfate to obtain a component 2 solution; wherein, the molar ratio of the benzoic acid to the sulfuric acid in the fuming sulfuric acid is 1:2.5; the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 2.5:1.2; the concentration of sulfuric acid in fuming sulfuric acid is 98wt%; the concentration of nitric acid in fuming nitric acid is 98wt%.
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the flow rate of the component 1 is 2.50L/min, and the flow rate of the component 2 is 2.00L/min; the reaction temperature is 80 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 40min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction, wherein the reaction temperature is 85 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 20min. After the secondary nitration reaction is finished, the obtained nitration reaction liquid is cooled and is transferred to a centrifugal machine for filtering and separating to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid, wherein the yield is 85.9%, and the purity is 98.7%.
(4) Transferring the filtrate obtained after separation by a centrifuge to an extraction kettle, adding dichloropropane and tert-octylamine for adsorption extraction, transferring the separated liquid to a waste acid concentration tower for concentration until the concentration of sulfuric acid is not less than 96wt%, and selecting whether to supplement nitric acid according to the concentration of nitric acid as waste acid to be recycled to the step (1) for preparing the component 1 solution. And the superfluous waste water in the concentration process is discharged from a condenser arranged at the top of the concentration tower.
(5) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 20% in the beating process, and then adding 30% sodium hydroxide solution to adjust the pH value to 7.5, so as to obtain a component 3 solution;
(6) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, and the content of palladium is 1%; when the palladium carbon is filled in the tube array as a reduction catalyst, the filling height of the palladium carbon is 85% of the length of the tube array; the reaction temperature is 85 ℃, the reaction pressure is 1.0MPa, and the reaction time is 90min; after the reduction reaction is finished, the pH value of the obtained reduction reaction solution is regulated to 5 by 30% hydrochloric acid, the product 3, 5-diaminobenzoic acid is obtained by filtering and drying, and the purity is measured by an HPLC external standard method, and the product yield is 98.8% and the purity is more than 99.6%.
Example 3
A preparation method of 3, 5-diaminobenzoic acid comprises the following steps:
(1) 122Kg of benzoic acid is added into waste acid and mixed uniformly to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is 96wt%, and the concentration of nitric acid is 96wt%; the molar ratio of benzoic acid to sulfuric acid and nitric acid in the waste acid is 1:3:1.5.
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid, and adding 0.122Kg of sodium dodecyl sulfate to obtain a component 2 solution; wherein, the molar ratio of benzoic acid to sulfuric acid in fuming sulfuric acid is 1:3; the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 3:1.5; the concentration of sulfuric acid in fuming sulfuric acid is 98wt%; the concentration of nitric acid in fuming nitric acid is 98wt%.
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the flow rate of the component 1 is 2.50L/min, and the flow rate of the component 2 is 2.00L/min; the reaction temperature is 80 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 40min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction, wherein the reaction temperature is 85 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 20min. After the secondary nitration reaction is finished, the obtained nitration reaction liquid is cooled and is transferred to a centrifugal machine for filtering and separating to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid, wherein the yield is 85.6%, and the purity is 98.4%.
(4) Transferring the filtrate obtained after separation by a centrifuge to an extraction kettle, adding dichloropropane and tert-octylamine for adsorption extraction, transferring the separated liquid to a waste acid concentration tower for concentration until the concentration of sulfuric acid is not less than 96wt%, and selecting whether to supplement nitric acid according to the concentration of nitric acid as waste acid to be recycled to the step (1) for preparing the component 1 solution. And the superfluous waste water in the concentration process is discharged from a condenser arranged at the top of the concentration tower.
(5) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 30% in the beating process, and then adding 30% sodium hydroxide solution to adjust the pH value to 8, so as to obtain a component 3 solution;
(6) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, and the content of palladium is 1%; when the palladium carbon is filled in the tube array as a reduction catalyst, the filling height of the palladium carbon is 85% of the length of the tube array; the reaction temperature is 90 ℃, the reaction pressure is 1.2MPa, and the reaction time is 120min; after the reduction reaction is finished, the pH of the obtained reduction reaction solution is regulated to 6 by 30% hydrochloric acid, the product 3, 5-diaminobenzoic acid is obtained by filtering and drying, and the purity is measured by an HPLC external standard method, and the product yield is 98.5% and the purity is more than 99.4%.
Comparative example 1
A preparation method of 3, 5-diaminobenzoic acid comprises the following steps:
(1) 122Kg of benzoic acid is added into waste acid and mixed uniformly to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is 96wt%, and the concentration of nitric acid is 96wt%; the molar ratio of benzoic acid to sulfuric acid and nitric acid in the waste acid is 1:1.8:0.9.
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid to obtain a component 2 solution; wherein, the molar ratio of the benzoic acid to the sulfuric acid in the fuming sulfuric acid is 1:1.8; the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 1.8:0.9; the concentration of sulfuric acid in fuming sulfuric acid is 98wt%; the concentration of nitric acid in fuming nitric acid is 98wt%.
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the flow rate of the component 1 is 2.50L/min, and the flow rate of the component 2 is 2.00L/min; the reaction temperature is 70 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 65min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction, wherein the reaction temperature is 85 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 20min. After the secondary nitration reaction is finished, the obtained nitration reaction liquid is cooled and is transferred to a centrifugal machine for filtering and separating to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid, wherein the yield is 70.6 percent and the purity is 96.2 percent.
(4) Transferring the filtrate obtained after separation by a centrifuge to an extraction kettle, adding dichloropropane and tert-octylamine for adsorption extraction, transferring the separated liquid to a waste acid concentration tower for concentration until the concentration of sulfuric acid is not less than 96wt%, and selecting whether to supplement nitric acid according to the concentration of nitric acid as waste acid to be recycled to the step (1) for preparing the component 1 solution. And the superfluous waste water in the concentration process is discharged from a condenser arranged at the top of the concentration tower.
(5) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 10% in the beating process, and then adding 15% sodium hydroxide solution to adjust the pH value to 6 to obtain a component 3 solution;
(6) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, and the content of palladium is 1%; when the palladium carbon is filled in the tube array as a reduction catalyst, the filling height of the palladium carbon is 85% of the length of the tube array; the reaction temperature is 75 ℃, the reaction pressure is 0.75MPa, and the reaction time is 55min; after the reduction reaction is finished, the pH value of the obtained reduction reaction solution is regulated to 4 by 30% hydrochloric acid, the product 3, 5-diaminobenzoic acid is obtained by filtering and drying, and the purity is measured by an HPLC external standard method, and the product yield is 96.2% and the purity is more than 97.6%.
Comparative example 2
A preparation method of 3, 5-diaminobenzoic acid comprises the following steps:
(1) 122Kg of benzoic acid is added into waste acid and mixed uniformly to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is 96wt%, and the concentration of nitric acid is 96wt%; the molar ratio of benzoic acid to sulfuric acid and nitric acid in the waste acid is 1:3.2:1.7.
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid to obtain a component 2 solution; wherein, the molar ratio of the benzoic acid to the sulfuric acid in the fuming sulfuric acid is 1:3.2; the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 3.2:1.7; the concentration of sulfuric acid in fuming sulfuric acid is 98wt%; the concentration of nitric acid in fuming nitric acid is 98wt%.
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the flow rate of the component 1 is 2.50L/min, and the flow rate of the component 2 is 2.00L/min; the reaction temperature is 70 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 65min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction, wherein the reaction temperature is 75 ℃, the reaction pressure is 0.5MPa, and the reaction residence time is 20min. After the secondary nitration reaction is finished, the obtained nitration reaction liquid is cooled and transferred to a centrifugal machine 6 for filtering and separating to obtain a crude product, and the obtained crude product is washed by water and ethanol to obtain an intermediate product 3, 5-dinitrobenzoic acid, wherein the yield is 72.8% and the purity is 96.4%.
(4) Transferring the filtrate obtained after separation by a centrifuge to an extraction kettle, adding dichloropropane and tert-octylamine for adsorption extraction, transferring the separated liquid to a waste acid concentration tower for concentration until the concentration of sulfuric acid is not less than 96wt%, and selecting whether to supplement nitric acid according to the concentration of nitric acid as waste acid to be recycled to the step (1) for preparing the component 1 solution. And the superfluous waste water in the concentration process is discharged from a condenser arranged at the top of the concentration tower.
(5) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 35% in the beating process, and then adding 45% sodium hydroxide solution to adjust the pH value to 8.5, so as to obtain a component 3 solution;
(6) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, and the content of palladium is 1%; when the palladium carbon is filled in the tube array as a reduction catalyst, the filling height of the palladium carbon is 85% of the length of the tube array; the reaction pressure is 1.25MPa, and the reaction time is 125min; after the reduction reaction is finished, the pH of the obtained reduction reaction solution is regulated to 6.5 by 30% hydrochloric acid, the product 3, 5-diaminobenzoic acid is obtained by filtering and drying, and the purity is measured by an HPLC external standard method, and the product yield is 97.4% and the purity is more than 98.1%.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments may be modified or some technical features may be replaced equivalently; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. The preparation method of the 3, 5-diaminobenzoic acid is characterized by comprising the following steps:
(1) Uniformly mixing benzoic acid and waste acid to obtain a component 1 solution; wherein the concentration of sulfuric acid in the waste acid is not less than 96wt percent, and the concentration of nitric acid is not less than 96wt percent;
(2) Uniformly mixing fuming sulfuric acid and fuming nitric acid, and adding a nitrification catalyst to obtain a component 2 solution;
(3) Pumping the component 1 solution and the component 2 solution into a dynamic circulation microchannel reactor respectively for one-time nitration reaction, wherein the reaction temperature is 75-85 ℃, the reaction pressure is 0.4-0.6 MPa, and the reaction time is 30-60 min; transferring the obtained reaction liquid into a tubular reactor for secondary nitration reaction at the reaction temperature of 80-90 ℃ and the reaction pressure of 0.4-0.6 MPa for 10-30 min to obtain an intermediate product of 3, 5-dinitrobenzoic acid;
(4) Adding the obtained intermediate product 3, 5-dinitrobenzoic acid into water to carry out beating at 20-30 ℃, wherein the content of the 3, 5-dinitrobenzoic acid is 10-30% in the beating process, and then adding 20-40% sodium hydroxide solution to adjust the pH value to 7-8, thus obtaining a component 3 solution;
(5) Transferring the component 3 solution and hydrogen into a fixed bed reactor respectively for reduction reaction, wherein palladium carbon is filled in a tube array of the fixed bed reactor as a reduction catalyst, the reaction temperature is 80-90 ℃, the reaction pressure is 0.8-1.2 MPa, and the reaction time is 60-120 min; after the reduction reaction is finished, the pH of the obtained reduction reaction solution is regulated to 4-6 by 25-35% hydrochloric acid, and the 3, 5-diaminobenzoic acid product is obtained by filtering and drying.
2. The process for producing 3, 5-diaminobenzoic acid according to claim 1 wherein in step (1), the molar ratio of benzoic acid to sulfuric acid and nitric acid in the spent acid is 1:2 to 3:1 to 1.5.
3. The method for producing 3, 5-diaminobenzoic acid according to claim 1 wherein in step (2), the molar ratio of benzoic acid to sulfuric acid in fuming sulfuric acid is 1:2 to 3; the molar ratio of sulfuric acid in fuming sulfuric acid to nitric acid in fuming nitric acid is 2-3:1-1.5; the concentration of sulfuric acid in fuming sulfuric acid is 95-98 wt%; the concentration of the nitric acid in fuming nitric acid is 90-98 wt%.
4. A process for the preparation of 3, 5-diaminobenzoic acid according to claim 3 wherein in step (2) the nitration catalyst is sodium dodecyl sulphate, sodium dodecyl benzene sulphonate, cetyltrimethylammonium bromide or methyltrioctylammonium chloride; preferably sodium lauryl sulfate; the mass ratio of the nitrifying catalyst to the benzoic acid is 0.0001-0.01:1; preferably 0.001:1.
5. The process for producing 3, 5-diaminobenzoic acid according to claim 1 wherein in step (3), the reaction pressure is 0.5MPa at the time of the primary nitration reaction; the reaction temperature is 80 ℃ and the reaction time is 40min; in the secondary nitration reaction, the reaction pressure is 0.5MPa; the reaction temperature was 85℃and the reaction time was 20min.
6. The process for the preparation of 3, 5-diaminobenzoic acid according to claim 1 wherein in step (3) the flow of the component 1 solution is 2.00 to 3.00L/min, preferably 2.50L/min; the flow rate of the component 2 solution is 1.50-2.50L/min, preferably 2.00L/min.
7. The process for producing 3, 5-diaminobenzoic acid according to claim 1 wherein in step (3), after the completion of the secondary nitration reaction, the obtained nitration reaction liquid is cooled and filtered to obtain a crude product, and the obtained crude product is washed with water and ethanol to obtain an intermediate 3, 5-dinitrobenzoic acid.
8. The method for producing 3, 5-diaminobenzoic acid according to claim 7 wherein dichloropropane and t-octylamine are added to the obtained filtrate after filtration for adsorption extraction, and the separated liquid is concentrated to a sulfuric acid concentration of not less than 96wt% and reused in step (1) for preparing a component 1 solution.
9. The method for producing 3, 5-diaminobenzoic acid according to claim 1 wherein in step (4), the content of 3, 5-dinitrobenzoic acid during beating is 20%; adding 30% sodium hydroxide solution to adjust the pH to 7-8; preferably, a further 30% sodium hydroxide solution is added to adjust the pH to 7.5.
10. The method for producing 3, 5-diaminobenzoic acid according to claim 1 wherein in step (5), palladium content is 0.5 to 2%, preferably 1 to 1.5%, more preferably 1% when palladium-carbon is used as a reducing agent catalyst; when the palladium carbon is filled in the tube array as a reduction catalyst, the filling height of the palladium carbon is 80-90 percent, preferably 85 percent, of the length of the tube array; in the reduction reaction, the reaction temperature is 85 ℃; the reaction pressure is 1.0MPa; the reaction time is 90min; the pH of the obtained reduction reaction solution is regulated to 4-6 by 30% hydrochloric acid; preferably, the resulting reduction reaction solution is adjusted to pH 5 with 30% hydrochloric acid.
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