CN118108584A - Continuous production method and continuous production system of parahydroxyben-zaldehyde - Google Patents
Continuous production method and continuous production system of parahydroxyben-zaldehyde Download PDFInfo
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- RGHHSNMVTDWUBI-UHFFFAOYSA-N 4-hydroxybenzaldehyde Chemical compound OC1=CC=C(C=O)C=C1 RGHHSNMVTDWUBI-UHFFFAOYSA-N 0.000 title claims abstract description 156
- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000010924 continuous production Methods 0.000 title claims abstract description 41
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 191
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 150
- IWDCLRJOBJJRNH-UHFFFAOYSA-N p-cresol Chemical compound CC1=CC=C(O)C=C1 IWDCLRJOBJJRNH-UHFFFAOYSA-N 0.000 claims abstract description 147
- 239000000243 solution Substances 0.000 claims abstract description 132
- ZPTVNYMJQHSSEA-UHFFFAOYSA-N 4-nitrotoluene Chemical compound CC1=CC=C([N+]([O-])=O)C=C1 ZPTVNYMJQHSSEA-UHFFFAOYSA-N 0.000 claims abstract description 93
- 239000007864 aqueous solution Substances 0.000 claims abstract description 86
- RZXMPPFPUUCRFN-UHFFFAOYSA-N p-toluidine Chemical compound CC1=CC=C(N)C=C1 RZXMPPFPUUCRFN-UHFFFAOYSA-N 0.000 claims abstract description 79
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 63
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 54
- 239000001301 oxygen Substances 0.000 claims abstract description 54
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 54
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000012954 diazonium Substances 0.000 claims abstract description 50
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims abstract description 50
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 49
- 239000003054 catalyst Substances 0.000 claims abstract description 43
- 239000001257 hydrogen Substances 0.000 claims abstract description 43
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 43
- 230000001546 nitrifying effect Effects 0.000 claims abstract description 42
- 239000003960 organic solvent Substances 0.000 claims abstract description 33
- -1 para-toluidine ammonium salt Chemical class 0.000 claims abstract description 32
- 230000003647 oxidation Effects 0.000 claims abstract description 31
- 150000001989 diazonium salts Chemical class 0.000 claims abstract description 30
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000004202 carbamide Substances 0.000 claims abstract description 28
- 239000012266 salt solution Substances 0.000 claims abstract description 28
- 239000011259 mixed solution Substances 0.000 claims abstract description 25
- 235000010288 sodium nitrite Nutrition 0.000 claims abstract description 25
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 23
- 238000010791 quenching Methods 0.000 claims abstract description 23
- 230000000171 quenching effect Effects 0.000 claims abstract description 23
- 238000006555 catalytic reaction Methods 0.000 claims abstract description 7
- 239000007788 liquid Substances 0.000 claims description 120
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 117
- 238000000926 separation method Methods 0.000 claims description 95
- 238000006243 chemical reaction Methods 0.000 claims description 72
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 64
- 238000005406 washing Methods 0.000 claims description 59
- 239000002994 raw material Substances 0.000 claims description 58
- 238000000746 purification Methods 0.000 claims description 49
- 238000006396 nitration reaction Methods 0.000 claims description 48
- 238000006460 hydrolysis reaction Methods 0.000 claims description 46
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 42
- 239000012074 organic phase Substances 0.000 claims description 39
- AFBPFSWMIHJQDM-UHFFFAOYSA-N N-methyl-N-phenylamine Natural products CNC1=CC=CC=C1 AFBPFSWMIHJQDM-UHFFFAOYSA-N 0.000 claims description 35
- 239000000872 buffer Substances 0.000 claims description 34
- 239000012071 phase Substances 0.000 claims description 34
- 238000007599 discharging Methods 0.000 claims description 32
- 230000007062 hydrolysis Effects 0.000 claims description 32
- 238000003916 acid precipitation Methods 0.000 claims description 26
- 238000003860 storage Methods 0.000 claims description 26
- 230000003197 catalytic effect Effects 0.000 claims description 23
- 238000006193 diazotization reaction Methods 0.000 claims description 23
- 239000000463 material Substances 0.000 claims description 22
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 19
- 239000003513 alkali Substances 0.000 claims description 18
- 238000001914 filtration Methods 0.000 claims description 17
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 claims description 16
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 15
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 claims description 15
- 238000004821 distillation Methods 0.000 claims description 15
- HARAQXUJBZLATE-UHFFFAOYSA-N 1-(diazonioamino)-4-methylbenzene Chemical class N(C1=CC=C(C=C1)C)[N+]#N HARAQXUJBZLATE-UHFFFAOYSA-N 0.000 claims description 14
- 230000035484 reaction time Effects 0.000 claims description 14
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- 239000011552 falling film Substances 0.000 claims description 12
- 230000001105 regulatory effect Effects 0.000 claims description 12
- 239000002904 solvent Substances 0.000 claims description 12
- QZRFIBXIKIRMAR-UHFFFAOYSA-N azane;4-methylaniline Chemical compound N.CC1=CC=C(N)C=C1 QZRFIBXIKIRMAR-UHFFFAOYSA-N 0.000 claims description 11
- FWFGVMYFCODZRD-UHFFFAOYSA-N oxidanium;hydrogen sulfate Chemical compound O.OS(O)(=O)=O FWFGVMYFCODZRD-UHFFFAOYSA-N 0.000 claims description 11
- 229910017052 cobalt Inorganic materials 0.000 claims description 10
- 239000010941 cobalt Substances 0.000 claims description 10
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 10
- 239000007868 Raney catalyst Substances 0.000 claims description 9
- 229910000564 Raney nickel Inorganic materials 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 9
- 229910052723 transition metal Inorganic materials 0.000 claims description 9
- 150000003624 transition metals Chemical group 0.000 claims description 9
- 238000009903 catalytic hydrogenation reaction Methods 0.000 claims description 8
- 239000000413 hydrolysate Substances 0.000 claims description 8
- 229910017604 nitric acid Inorganic materials 0.000 claims description 8
- 239000004317 sodium nitrate Substances 0.000 claims description 8
- 235000010344 sodium nitrate Nutrition 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 7
- 230000000802 nitrating effect Effects 0.000 claims description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 239000007791 liquid phase Substances 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims description 4
- 238000011084 recovery Methods 0.000 claims description 4
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 claims description 3
- JWUJQDFVADABEY-UHFFFAOYSA-N 2-methyltetrahydrofuran Chemical compound CC1CCCO1 JWUJQDFVADABEY-UHFFFAOYSA-N 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- DSVGQVZAZSZEEX-UHFFFAOYSA-N [C].[Pt] Chemical compound [C].[Pt] DSVGQVZAZSZEEX-UHFFFAOYSA-N 0.000 claims description 3
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 3
- 239000002041 carbon nanotube Substances 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- UKVIEHSSVKSQBA-UHFFFAOYSA-N methane;palladium Chemical compound C.[Pd] UKVIEHSSVKSQBA-UHFFFAOYSA-N 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 210000002700 urine Anatomy 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical compound O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 claims description 2
- QTWJRLJHJPIABL-UHFFFAOYSA-N 2-methylphenol;3-methylphenol;4-methylphenol Chemical compound CC1=CC=C(O)C=C1.CC1=CC=CC(O)=C1.CC1=CC=CC=C1O QTWJRLJHJPIABL-UHFFFAOYSA-N 0.000 claims 1
- 229930003836 cresol Natural products 0.000 claims 1
- 150000004992 toluidines Chemical class 0.000 claims 1
- 239000000047 product Substances 0.000 description 24
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 20
- 238000005086 pumping Methods 0.000 description 17
- 230000001276 controlling effect Effects 0.000 description 16
- 238000004519 manufacturing process Methods 0.000 description 15
- 229910000029 sodium carbonate Inorganic materials 0.000 description 10
- VATYWCRQDJIRAI-UHFFFAOYSA-N p-aminobenzaldehyde Chemical compound NC1=CC=C(C=O)C=C1 VATYWCRQDJIRAI-UHFFFAOYSA-N 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 102100028292 Aladin Human genes 0.000 description 6
- 101710065039 Aladin Proteins 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 238000003786 synthesis reaction Methods 0.000 description 6
- PLAZTCDQAHEYBI-UHFFFAOYSA-N 2-nitrotoluene Chemical compound CC1=CC=CC=C1[N+]([O-])=O PLAZTCDQAHEYBI-UHFFFAOYSA-N 0.000 description 5
- QZYHIOPPLUPUJF-UHFFFAOYSA-N 3-nitrotoluene Chemical compound CC1=CC=CC([N+]([O-])=O)=C1 QZYHIOPPLUPUJF-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- 239000013067 intermediate product Substances 0.000 description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 3
- 239000008346 aqueous phase Substances 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- WHRZCXAVMTUTDD-UHFFFAOYSA-N 1h-furo[2,3-d]pyrimidin-2-one Chemical compound N1C(=O)N=C2OC=CC2=C1 WHRZCXAVMTUTDD-UHFFFAOYSA-N 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- 235000006173 Larrea tridentata Nutrition 0.000 description 2
- 244000073231 Larrea tridentata Species 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 229960002126 creosote Drugs 0.000 description 2
- 230000006837 decompression Effects 0.000 description 2
- CBOQJANXLMLOSS-UHFFFAOYSA-N ethyl vanillin Chemical group CCOC1=CC(C=O)=CC=C1O CBOQJANXLMLOSS-UHFFFAOYSA-N 0.000 description 2
- 238000004817 gas chromatography Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- JMMWKPVZQRWMSS-UHFFFAOYSA-N isopropanol acetate Natural products CC(C)OC(C)=O JMMWKPVZQRWMSS-UHFFFAOYSA-N 0.000 description 2
- 229940011051 isopropyl acetate Drugs 0.000 description 2
- GWYFCOCPABKNJV-UHFFFAOYSA-N isovaleric acid Chemical compound CC(C)CC(O)=O GWYFCOCPABKNJV-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- ZRSNZINYAWTAHE-UHFFFAOYSA-N p-methoxybenzaldehyde Chemical compound COC1=CC=C(C=O)C=C1 ZRSNZINYAWTAHE-UHFFFAOYSA-N 0.000 description 2
- 239000002304 perfume Substances 0.000 description 2
- 239000000575 pesticide Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- HYHCSLBZRBJJCH-UHFFFAOYSA-N sodium polysulfide Chemical compound [Na+].S HYHCSLBZRBJJCH-UHFFFAOYSA-N 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 150000003613 toluenes Chemical class 0.000 description 2
- 238000005160 1H NMR spectroscopy Methods 0.000 description 1
- UPMXNNIRAGDFEH-UHFFFAOYSA-N 3,5-dibromo-4-hydroxybenzonitrile Chemical compound OC1=C(Br)C=C(C#N)C=C1Br UPMXNNIRAGDFEH-UHFFFAOYSA-N 0.000 description 1
- ZXVONLUNISGICL-UHFFFAOYSA-N 4,6-dinitro-o-cresol Chemical group CC1=CC([N+]([O-])=O)=CC([N+]([O-])=O)=C1O ZXVONLUNISGICL-UHFFFAOYSA-N 0.000 description 1
- 239000005489 Bromoxynil Substances 0.000 description 1
- 229930186147 Cephalosporin Natural products 0.000 description 1
- 241000305491 Gastrodia elata Species 0.000 description 1
- FBOZXECLQNJBKD-ZDUSSCGKSA-N L-methotrexate Chemical compound C=1N=C2N=C(N)N=C(N)C2=NC=1CN(C)C1=CC=C(C(=O)N[C@@H](CCC(O)=O)C(O)=O)C=C1 FBOZXECLQNJBKD-ZDUSSCGKSA-N 0.000 description 1
- 241000208422 Rhododendron Species 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- LSQZJLSUYDQPKJ-NJBDSQKTSA-N amoxicillin Chemical compound C1([C@@H](N)C(=O)N[C@H]2[C@H]3SC([C@@H](N3C2=O)C(O)=O)(C)C)=CC=C(O)C=C1 LSQZJLSUYDQPKJ-NJBDSQKTSA-N 0.000 description 1
- 229960003022 amoxicillin Drugs 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- IIBYAHWJQTYFKB-UHFFFAOYSA-N bezafibrate Chemical compound C1=CC(OC(C)(C)C(O)=O)=CC=C1CCNC(=O)C1=CC=C(Cl)C=C1 IIBYAHWJQTYFKB-UHFFFAOYSA-N 0.000 description 1
- 229960000516 bezafibrate Drugs 0.000 description 1
- 229940124587 cephalosporin Drugs 0.000 description 1
- 150000001780 cephalosporins Chemical class 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- MVPPADPHJFYWMZ-IDEBNGHGSA-N chlorobenzene Chemical group Cl[13C]1=[13CH][13CH]=[13CH][13CH]=[13CH]1 MVPPADPHJFYWMZ-IDEBNGHGSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- AQNDDEOPVVGCPG-UHFFFAOYSA-N esmolol Chemical compound COC(=O)CCC1=CC=C(OCC(O)CNC(C)C)C=C1 AQNDDEOPVVGCPG-UHFFFAOYSA-N 0.000 description 1
- 229960003745 esmolol Drugs 0.000 description 1
- 229940073505 ethyl vanillin Drugs 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012527 feed solution Substances 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000003205 fragrance Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000002363 herbicidal effect Effects 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 238000004128 high performance liquid chromatography Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- NRXQIUSYPAHGNM-UHFFFAOYSA-N ioxynil Chemical compound OC1=C(I)C=C(C#N)C=C1I NRXQIUSYPAHGNM-UHFFFAOYSA-N 0.000 description 1
- 229960000485 methotrexate Drugs 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 230000036284 oxygen consumption Effects 0.000 description 1
- LSQZJLSUYDQPKJ-UHFFFAOYSA-N p-Hydroxyampicillin Natural products O=C1N2C(C(O)=O)C(C)(C)SC2C1NC(=O)C(N)C1=CC=C(O)C=C1 LSQZJLSUYDQPKJ-UHFFFAOYSA-N 0.000 description 1
- VWMVAQHMFFZQGD-UHFFFAOYSA-N p-Hydroxybenzyl acetone Natural products CC(=O)CC1=CC=C(O)C=C1 VWMVAQHMFFZQGD-UHFFFAOYSA-N 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- NJGBTKGETPDVIK-UHFFFAOYSA-N raspberry ketone Chemical compound CC(=O)CCC1=CC=C(O)C=C1 NJGBTKGETPDVIK-UHFFFAOYSA-N 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- KCDXJAYRVLXPFO-UHFFFAOYSA-N syringaldehyde Chemical compound COC1=CC(C=O)=CC(OC)=C1O KCDXJAYRVLXPFO-UHFFFAOYSA-N 0.000 description 1
- COBXDAOIDYGHGK-UHFFFAOYSA-N syringaldehyde Natural products COC1=CC=C(C=O)C(OC)=C1O COBXDAOIDYGHGK-UHFFFAOYSA-N 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Abstract
The invention provides a continuous production method and a continuous production system of parahydroxyben-zaldehyde, wherein the method comprises the following steps: toluene and a continuously prepared nitrifying reagent react in a ninth continuous flow reactor, and toluene is nitrified to generate paranitrotoluene; introducing hydrogen into a first continuous flow reactor to carry out hydrogenation reaction on the paranitrotoluene solution to generate paratoluidine; diazotizing sodium nitrite aqueous solution and para-toluidine ammonium salt solution in a third continuous flow reactor to obtain a para-toluidine diazonium salt solution system, quenching the toluidine diazonium salt solution system by using urea aqueous solution in a fourth continuous flow reactor, and carrying out diazonium salt solution Jie Sheng on para-cresol in a mixed solution of second sulfuric acid aqueous solution and an organic solvent in a fifth continuous flow reactor; under the catalysis of an oxidation catalyst, the p-toluol is introduced with oxygen to perform oxidation reaction to generate the p-hydroxybenzaldehyde, so that the problems of low yield and high cost of the p-hydroxybenzaldehyde in the prior art are solved.
Description
Technical Field
The invention relates to the technical field of chemical synthesis, in particular to a continuous production method and a continuous production system of p-hydroxybenzaldehyde.
Background
Para-hydroxybenzaldehyde is an important fine chemical product, and is a key intermediate for many medicines, fragrances and pesticides. The method is used for producing antibacterial synergists TMP (methotrexate), amoxicillin, cephalosporin, artificial gastrodia elata, azalea, bezafibrate and esmolol in the pharmaceutical industry. The method is used for synthesizing perfume such as vanillin, ethyl vanillin, syringaldehyde, anisaldehyde and raspberry ketone in the perfume industry. In the aspect of pesticides, the p-hydroxybenzaldehyde is a precursor of an upstream key raw material (4-hydroxy-3, 5-diiodobenzonitrile) of efficient herbicide dixynil and bromoxynil, and has wider application.
The production of the p-hydroxybenzaldehyde has a plurality of process routes, and the current industrial production mainly comprises raw material routes such as a phenol method, a p-toluol catalytic oxidation method, a p-nitrotoluene method and the like. The process of producing parahydroxybenzaldehyde by using paranitrotoluene method is carried out by three steps of oxidation reduction, diazotization and hydrolysis. The product is extracted, purified and dried to obtain a parahydroxybenzaldehyde product, specifically, in the paranitrotoluene method, paranitrotoluene is reacted with sodium polysulfide to obtain paraaminobenzaldehyde, diazotization is carried out to obtain nitrided paraaminobenzaldehyde, and the diazotized paraaminobenzaldehyde is hydrolyzed to obtain the parahydroxybenzaldehyde. Firstly, raw material sodium polysulfide is prepared by reacting sodium hydroxide with hydrogen sulfide, mixing the obtained sodium sulfide with sodium hydroxide and then mixing with sulfur, H2S gas with peculiar smell used for preparing sulfide is not easy to obtain, is not friendly to environment, and the sulfur content of the prepared sulfide is difficult to control and the process repeatability is poor; secondly, the reaction time is long in the process of preparing the p-aminobenzaldehyde from the p-nitrotoluene by using sulfide, and the process operation is complex and tedious. Therefore, the p-hydroxybenzaldehyde synthesis process with high yield and low cost has important economic value.
Disclosure of Invention
The invention mainly aims to provide a continuous production method and a continuous production system of parahydroxyben-zaldehyde, which are used for solving the problems of low parahydroxyben-zaldehyde yield and high cost in the prior art.
In order to achieve the above object, according to one aspect of the present invention, there is provided a continuous production method of p-hydroxybenzaldehyde comprising the steps of:
step S1, mixing concentrated sulfuric acid and water in a seventh continuous flow reactor to obtain a third sulfuric acid aqueous solution, preparing a nitrifying reagent in an eighth continuous flow reactor by the third sulfuric acid aqueous solution and fuming nitric acid, reacting toluene and the nitrifying reagent in a ninth continuous flow reactor, nitrifying toluene to generate paranitrotoluene, and continuously separating and purifying a system after the nitrifying reaction is completed to obtain the paranitrotoluene;
s2, dissolving paranitrotoluene in an organic solvent to form a paranitrotoluene solution, and introducing hydrogen into the paranitrotoluene solution in a first continuous flow reactor under the catalysis of a hydrogenation catalyst to perform hydrogenation reaction to generate paratoluidine;
S3, dissolving the p-toluidine in a first sulfuric acid aqueous solution in a second continuous flow reactor to obtain a p-toluidine ammonium salt solution, carrying out diazotization reaction on the sodium nitrite aqueous solution and the p-toluidine ammonium salt solution in a third continuous flow reactor to obtain a p-toluidine diazonium salt solution system, carrying out quenching reaction on the toluidine diazonium salt solution system by using a urea aqueous solution in a fourth continuous flow reactor to obtain a diazonium salt quenching system, carrying out diazonium salt Jie Sheng on p-cresol in a mixed solution of the second sulfuric acid aqueous solution and an organic solvent in a fifth continuous flow reactor, and carrying out continuous separation and purification on the system after the diazonium salt hydrolysis reaction is completed to obtain p-toluol;
And S4, dissolving the p-cresol and sodium hydroxide in methanol to form a mixed solution of the p-cresol and the sodium hydroxide, conveying the mixed solution of the p-cresol and the sodium hydroxide to a sixth continuous flow reactor, introducing oxygen to perform oxidation reaction under the catalysis of an oxidation catalyst to generate p-hydroxybenzaldehyde, and continuously separating and purifying the system after the oxidation reaction is completed to obtain the p-hydroxybenzaldehyde.
In step S1, separating liquid, alkali washing and rectifying the system after the nitration reaction is finished to obtain paranitrotoluene.
Preferably, in step S1, the system after the nitration reaction is separated, the organic phase after the separation is washed with alkali, the organic phase after the alkali washing is washed with water, and the organic phase after the water washing is rectified to obtain paranitrotoluene.
More preferably, in step S1, the separated organic phase is washed with an aqueous sodium carbonate solution, and then washed with water to a pH of 6.8 to 7.2.
Still more preferably, in step S1, the mass fraction of sodium carbonate in the sodium carbonate aqueous solution is 20 to 30%.
Preferably, in step S2, the system after the hydrogenation reaction is completed is subjected to hydrogen removal and concentration to remove the solvent, thereby obtaining the p-toluidine.
More preferably, in step S2, the organic solvent is selected from one or more of methanol, ethanol, ethyl acetate, isopropyl acetate.
More preferably, in step S2, the concentration of paranitrotoluene in the paranitrotoluene solution is 0.01-1 g/mL.
Preferably, in step S3, the system after the hydrolysis reaction is completed is subjected to liquid separation, alkali washing and distillation to obtain p-toluene.
More preferably, in step S3, the system after the completion of the hydrolysis reaction is subjected to liquid separation, the organic phase after the liquid separation is subjected to alkali washing, the solvent is distilled off under reduced pressure after the alkali washing, and then p-cresol is obtained by distillation under reduced pressure.
Still more preferably, in step S3, the separated organic phase is washed with an aqueous sodium carbonate solution or an aqueous sodium bicarbonate solution to a pH of 6.8 to 7.2.
Preferably, in step S4, the system after the oxidation reaction is subjected to acid precipitation, filtration and drying to obtain parahydroxyben-zaldehyde.
More preferably, in step S4, the system after the completion of the oxidation reaction is placed in an aqueous hydrochloric acid solution with a mass fraction of 20% -40% for precipitation.
Further, in step S2, the hydrogenation catalyst is selected from one or more of palladium carbon, platinum carbon, raney nickel, and supported nickel-based catalyst.
Preferably, in the step S2, the molar ratio of hydrogen to paranitrotoluene is 4 to 10:1, more preferably (4 to 5): 1.
Preferably, in step S2, the reaction temperature of the hydrogenation reaction is 50 to 90 ℃, preferably 50 to 70 ℃.
Preferably, in step S2, the reaction pressure of the hydrogenation reaction is 0.1 to 1MPa, more preferably 0.1 to 0.5MPa.
Further, in step S3, the temperature of the diazotization reaction is 0 to 20 ℃, more preferably 10 to 20 ℃.
Preferably, in step S3, the diazotization reaction time is 6 to 30min, more preferably 6 to 10min.
Preferably, in step S3, the quenching reaction temperature is 0 to 20 ℃, more preferably 10 to 20 ℃.
Preferably, in step S3, the quenching reaction time is 6 to 60min, more preferably 6 to 10min.
Preferably, in step S3, the reaction temperature of the diazonium salt hydrolysis reaction is 50 to 100 ℃, more preferably 70 to 90 ℃, still more preferably 80 to 90 ℃.
Preferably, in the step S3, the diazonium salt hydrolysis reaction time is 7-30 min, more preferably 10-20 min.
Preferably, in the step S3, the mass fraction of the sulfuric acid in the first sulfuric acid aqueous solution is 20-30%.
Preferably, in the step S3, the mass fraction of the para-tolueneammonium salt in the para-tolueneammonium salt solution is 20-30%.
Preferably, in the step S3, the mass fraction of the sodium nitrite in the sodium nitrite aqueous solution is 20-30%.
Preferably, in the step S3, the mass fraction of urine in the urea aqueous solution is 3-8%.
Preferably, in the step S3, the mass fraction of the sulfuric acid in the second sulfuric acid aqueous solution is 20-30%.
Preferably, in step S3, the organic solvent is selected from one or more of chlorobenzene, 2-methyltetrahydrofuran, toluene, 1,4 dioxane, more preferably from chlorobenzene.
Preferably, in step S3, the mass ratio of the para-tolueneammonium salt in the para-tolueneammonium salt solution, the sodium nitrite in the sodium nitrite aqueous solution, and the urea in the urea aqueous solution is 1: (0.2 to 0.8): (0.01 to 0.1).
Further, in step S4, the oxidation catalyst is a transition metal supported catalyst;
Preferably, in the transition metal supported catalyst, the carrier is selected from one of activated carbon, silica and carbon nanotubes, and the transition metal is selected from at least one of cobalt and copper.
Preferably, in step S4, the molar ratio of oxygen to p-cresol is (5-15): 1, more preferably (7 to 10): 1.
Preferably, in step S4, the mass ratio of p-cresol to sodium hydroxide is 1: (0.9 to 1.1).
Preferably, in the step S4, the concentration of the p-cresol in the mixed solution of the p-cresol and the sodium hydroxide is 0.08-0.2 g/ml.
Preferably, in step S4, the concentration of sodium hydroxide in the mixed solution of p-cresol and sodium hydroxide is 0.08-0.2 g/ml, more preferably 0.12-0.16 g/ml.
Preferably, in step S4, the temperature of the oxidation reaction is 60 to 90 ℃, more preferably 80 to 90 ℃.
Preferably, in step S4, the pressure of the oxidation reaction is 0.1 to 0.6MPa, more preferably 0.1 to 0.4MPa.
In step S1, the mass fraction of sulfuric acid in the third sulfuric acid aqueous solution is 60-80%.
Preferably, in the step S1, the molar ratio of nitric acid to toluene is 1 to 1.5:1, feeding a nitrifying reagent and toluene into a ninth continuous flow reactor, more preferably, according to the molar ratio of nitric acid to toluene of 1.22-1.3: 1.
Preferably, in step S1, the molar ratio of sulfuric acid to toluene is 3-5: 1, feeding a nitrifying reagent and toluene into a ninth continuous flow reactor.
Preferably, in step S1, the reaction temperature of the nitration reaction is 55 to 70 ℃, more preferably 60 to 70 ℃.
Preferably, in step S1, the reaction time of the nitration reaction is 10 to 90min, more preferably 12 to 30min.
According to another aspect of the present invention, there is also provided a continuous production system employed in the continuous production method as above, comprising: the device comprises a nitration reaction unit, a first continuous separation and purification unit, a catalytic hydrogenation reaction unit, a second continuous separation and purification unit, a diazotization and hydrolysis unit, a third continuous separation and purification unit, a catalytic oxidation unit and a fourth continuous separation and purification unit;
The nitration reaction unit includes:
a seventh continuous flow reactor, which is provided with a concentrated sulfuric acid feeding pipe, a water inlet pipe and a third sulfuric acid aqueous solution discharging hole;
the eighth continuous flow reactor is provided with a third sulfuric acid water solution feeding pipe, a fuming nitric acid feeding pipe and a nitrifying reagent discharging hole, and the third sulfuric acid water solution feeding pipe is connected with the third sulfuric acid water solution discharging hole;
A ninth continuous flow reactor, wherein the ninth continuous flow reactor is provided with a nitrifying agent feeding pipe, a toluene feeding pipe and a system discharge port after the nitrifying reaction is finished, and the nitrifying agent feeding pipe is connected with the nitrifying agent discharge port; the system discharge port after the nitration reaction is finished is connected with the feed inlet of the first continuous separation and purification unit;
the catalytic hydrogenation reaction unit comprises:
the first charging tank is used for preparing the paranitrotoluene solution, and a charging port of the first charging tank is connected with a paranitrotoluene discharging port of the first continuous separation and purification unit;
The first continuous flow reactor is provided with a hydrogen feeding pipe, a paranitrotoluene solution feeding pipe and a discharge hole of a hydrogenation reaction system, and is connected with a hydrogen cylinder through the hydrogen feeding pipe; the first continuous flow reactor is connected with a discharge hole of the first charging bucket through a paranitrotoluene solution feeding pipe; the discharge port of the system after hydrogenation reaction is connected with the feed port of the second continuous separation and purification unit;
the diazotisation and hydrolysis unit comprises:
the second continuous flow reactor is provided with a first sulfuric acid water solution feeding pipe, a p-toluidine feeding pipe and a p-toluidine ammonium salt solution discharging port, and the p-toluidine feeding pipe is connected with the discharging port of the second continuous separation and purification unit;
The third continuous flow reactor is provided with a sodium nitrite water solution feeding pipe, a para-toluidine ammonium salt solution feeding pipe and a para-toluidine diazonium salt solution discharging hole, and the para-toluidine ammonium salt solution feeding pipe is connected with the para-toluidine ammonium salt solution discharging hole;
The fourth continuous flow reactor is provided with a urea water solution feeding pipe, a para-toluidine diazonium salt solution feeding pipe and a diazonium salt quenching system discharge port, and the para-toluidine diazonium salt solution feeding pipe is connected with the toluidine diazonium salt solution discharge port;
The fifth continuous flow reactor is provided with a diazonium salt quenching system feeding pipe, a second sulfuric acid water solution feeding pipe, an organic solvent feeding pipe and a hydrolysate discharging port, and the p-toluidine diazonium salt solution feeding pipe is connected with the diazonium salt quenching system discharging port; the hydrolysate discharge port is connected with the feed port of the third continuous separation and purification unit;
The catalytic oxidation unit includes:
the second charging bucket is used for preparing the mixed solution of the p-cresol and the sodium hydroxide, and a discharge hole of the mixed solution of the p-cresol and the sodium hydroxide is arranged on the second charging bucket;
The sixth continuous flow reactor is provided with an oxygen conveying pipeline, a p-cresol conveying pipeline and a system discharge port after the oxidation reaction is finished, and is connected with an oxygen bottle through the oxygen conveying pipeline; the sixth continuous flow reactor is connected with a discharge port of the mixed solution of the creosote and the sodium hydroxide through a p-cresol conveying pipeline; and a system discharge port after the oxidation reaction is finished is connected with a feed inlet of a fourth continuous separation and purification unit.
Further, the first continuous separation and purification unit includes: the second liquid separating device, the second alkali washing device, the water washing device and the second rectifying device; the feeding pipe of the second liquid separation device is connected with the system discharge port after the nitration reaction is finished, the organic phase outlet of the second liquid separation device is connected with the feeding pipe of the second alkaline washing device, and the feeding pipe of the water washing device is connected with the organic phase discharge port of the second alkaline washing device; the feeding pipe of the second rectifying device is connected with the organic phase discharge port of the water washing device, and the p-nitrotoluene discharge port of the second rectifying device is connected with the feeding port of the first charging bucket.
Preferably, the second continuous separation and purification unit comprises: the device comprises a first gas-liquid separation tank, a first receiving tank, a third buffer tank, a falling film evaporator, a second receiving tank, a condenser, a light phase tank, a second liquid delivery pump, a heavy phase tank and a first buffer tank for containing p-toluidine, wherein a gas-liquid feeding pipe of the first gas-liquid separation tank is connected with a discharge port of a hydrogenation reaction system, a back pressure valve is arranged on the gas-liquid feeding pipe of the first gas-liquid separation tank, and a discharge port of the first gas-liquid separation tank is connected with a feeding pipe of the first receiving tank; the material inlet of the third buffer tank is connected with the material outlet of the first receiving tank through a third liquid delivery pump; the material inlet of the falling film evaporator is connected with the material outlet of the third buffer tank, and the material outlet of the falling film evaporator is connected with the material inlet of the second receiving tank; the gas phase outlet of the second receiving tank is connected with a condenser, the discharge port of the condenser is connected with a light phase tank, and the outlet of the light phase tank is connected with a solvent recovery device; the liquid phase outlet of the second receiving tank is connected with the feed inlet of the heavy phase tank through a second liquid delivery pump; the discharge port of the heavy phase tank is connected with the feeding pipe of the first buffer tank; and a discharge hole of the first buffer tank is connected with a p-toluidine feeding pipe.
Preferably, the third continuous separation and purification unit comprises: the organic phase outlet of the first liquid separating device is connected with the feeding pipe of the first alkaline washing device; the discharge port of the first alkaline washing device is connected with the feed pipe of the first distillation device; the outlet of the p-toluidine fraction of the first distillation device is connected with a second buffer tank for containing p-cresol.
Preferably, the fourth continuous separation and purification unit comprises: the device comprises a second gas-liquid separation tank, a third receiving tank, an acid precipitation device and a filtering device, wherein a gas-liquid feeding pipe of the second gas-liquid separation tank is connected with a discharge port of the oxidized system, and a liquid phase outlet of the second gas-liquid separation tank is connected with a feed port of the third receiving tank; a gas outlet of the second gas-liquid separation tank is provided with a second back pressure valve; the material inlet pipe of the acid precipitation device is connected with the material outlet of the third receiving tank, and the material outlet of the acid precipitation device is connected with the material inlet of the filtering device; the feeding pipe of the acid precipitation device is provided with a first liquid delivery pump and a fifth mass flow controller, and the acid liquid inlet of the acid precipitation device is connected with the acid liquid storage device.
Further, the first continuous flow reactor is one of a fixed bed reactor and a continuous kettle reactor.
Preferably, the second continuous flow reactor is one of a microchannel reactor and a tubular reactor.
Preferably, the third continuous flow reactor is one of a microchannel reactor and a tubular reactor.
Preferably, the fourth continuous flow reactor is one of a microchannel reactor and a tubular reactor.
Preferably, the fifth continuous flow reactor is one of a microchannel reactor, a tubular reactor, a cylindrical stirred reactor, and a continuous tank reactor.
Preferably, the sixth continuous flow reactor is one of a fixed bed reactor and a continuous tank reactor.
Preferably, the seventh continuous flow reactor, the eighth continuous flow reactor and the ninth continuous flow reactor are each independently selected from one of a microchannel reactor and a tubular reactor.
Further, a nitrifying material preheater is arranged on the toluene feeding pipe and the nitrifying agent feeding pipe.
Preferably, the hydrogen feeding pipe is sequentially provided with a regulating valve, a hydrogen buffer tank, a first mass flow controller and a hydrogen preheater, wherein the regulating valve is close to the hydrogen cylinder, and the hydrogen preheater is close to the first continuous flow reactor.
Preferably, a fourth liquid delivery pump, a third mass flow controller and a raw material preheater are sequentially arranged on the paranitrotoluene solution feeding pipe, the fourth liquid delivery pump is arranged close to the first charging bucket, and the raw material preheater is arranged close to the first continuous flow reactor.
Preferably, the oxygen transmission pipeline is sequentially provided with a second mass flow controller and an oxygen buffer tank, wherein the second mass flow controller is arranged close to the oxygen bottle, and the oxygen buffer tank is arranged close to the sixth continuous flow reactor.
Preferably, a fifth liquid delivery pump and a fourth mass flow controller are sequentially arranged on the p-cresol delivery pipeline, the fifth liquid delivery pump is arranged close to the second charging bucket, and the fourth mass flow controller is arranged close to the sixth continuous flow reactor.
Preferably, the diazotisation and hydrolysis unit further comprises: the device comprises a sodium nitrate aqueous solution tank, a urea solution tank and an organic solvent tank, wherein the sodium nitrate aqueous solution tank is connected with a sodium nitrate aqueous solution feeding pipe, the urea aqueous solution tank is connected with a urea aqueous solution feeding pipe, and the organic solvent tank is connected with an organic solvent feeding pipe.
Preferably, the diazotisation and hydrolysis unit further comprises: the device comprises a third water storage tank, a first concentrated sulfuric acid tank and a tenth continuous flow reactor, wherein a concentrated sulfuric acid inlet of the tenth continuous flow reactor is connected with the first concentrated sulfuric acid tank, a water inlet pipe of the tenth continuous flow reactor is connected with the third water storage tank, and a discharge hole of the tenth continuous flow reactor is connected with a first sulfuric acid aqueous solution feeding pipe.
Preferably, the diazotisation and hydrolysis unit further comprises: the device comprises a fourth water storage tank, a third concentrated sulfuric acid tank and an eleventh continuous flow reactor, wherein a concentrated sulfuric acid inlet of the eleventh continuous flow reactor is connected with the third concentrated sulfuric acid tank, a water body inlet of the eleventh continuous flow reactor is connected with the fourth water storage tank, and a discharge port of the eleventh continuous flow reactor is connected with a second sulfuric acid aqueous solution feeding pipe.
By adopting the technical scheme of the invention, toluene is used as a starting material to prepare paranitrotoluene, the toluene is nitrified by a nitrifying reagent to prepare paranitrotoluene, the paranitrotoluene is catalyzed and hydrogenated by a hydrogenation catalyst to generate paratoluidine, the paratoluidine is diazotized to generate paratoluidine diazonium salt, the paratoluidine diazonium salt water Jie Sheng is catalyzed and oxidized to generate parahydroxybenzaldehyde, the parahydroxybenzaldehyde with high yield is obtained, and raw materials (such as hydrogen, oxygen, toluene and the like) used in the synthesis process have low price and are easy to obtain; in addition, the method takes the toluene nitration product paranitrotoluene as an intermediate product for further synthesis, so that the paranitrotoluene has a new utilization path, and the product value of the paranitrotoluene is increased; in addition, the intermediate p-nitrotoluene is used as a raw material to prepare p-toluidine and p-toluidine diazonium salt successively, and then the p-toluidine diazonium salt is hydrolyzed to generate p-cresol, so that the hydrolysis efficiency is high and the time cost is reduced compared with the p-amino formaldehyde diazonium salt hydrolysis route in the p-nitrotoluene method in the prior art; the invention can realize continuous production of nitration reaction, hydrogenation reaction, diazotization reaction, oxidation reaction and other reactions, and compared with the traditional kettle type production, the invention solves the problem of extremely high safety risk in the reaction process, ensures that the production process is safer and more stable, and simultaneously greatly improves the production efficiency, thereby having remarkable safety and economic value. By adopting the method, toluene is taken as a raw material, and the p-hydroxybenzaldehyde with high yield is obtained through nitration reaction, hydrogenation reaction, diazotization reaction and oxidation reaction, and the continuous production can be realized, so that the production efficiency is high, and the method is safe and economical.
By adopting the method, toluene is taken as a raw material, and the p-hydroxybenzaldehyde with high yield is obtained through nitration reaction, hydrogenation reaction, diazotization reaction and oxidation reaction, and the continuous production can be realized, so that the production efficiency is high, and the method is safe and economical.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 is a schematic diagram showing the structures of a nitration reaction unit and a first continuous separation and purification unit in a continuous production system of parahydroxyben-zaldehyde according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing the structures of a catalytic hydrogenation reaction unit and a second continuous separation and purification unit in a continuous production system of parahydroxyben-zaldehyde according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing the structures of a diazotizing and hydrolyzing unit and a third continuous separation and purification unit in a continuous production system of parahydroxyben-zaldehyde according to an embodiment of the present invention;
Fig. 4 is a schematic diagram showing the structures of a catalytic oxidation unit and a fourth continuous separation and purification unit in a continuous production system of parahydroxyben-zaldehyde according to an embodiment of the present invention;
FIG. 5 is a 1H NMR chart of p-hydroxybenzaldehyde as the reaction product in example 1 according to the invention;
FIG. 6 is a liquid chromatogram of the feed solution prior to catalytic oxidation in example 22;
FIG. 7 is a liquid chromatogram of the effluent after completion of catalytic oxidation in example 22;
FIG. 8 is a liquid chromatogram of the p-hydroxybenzaldehyde product obtained in example 22.
Wherein the above figures include the following reference numerals:
1. A first continuous flow reactor; 11. a hydrogen feeding pipe; 111. a regulating valve; 112. a first mass flow controller; 113. a hydrogen buffer tank; 114. a hydrogen preheater; 12. paranitrotoluene solution feeding pipe; 121. a fourth liquid transfer pump; 122. a third mass flow controller; 123. a raw material preheater; 13. a discharge port of the system after hydrogenation reaction; 14. a first bucket; 15. a hydrogen gas cylinder;
2. A second continuous flow reactor; 21. a first sulfuric acid aqueous solution feeding pipe; 22. para-toluidine feeding pipe; 23. sodium nitrite solution tank; 24. a urea aqueous solution tank; 25. an organic solvent tank; 26. a third water storage tank; 261. a first concentrated sulfuric acid tank; 262. a tenth continuous flow reactor; 27. a fourth water storage tank; 271. a third concentrated sulfuric acid tank; 272. an eleventh continuous flow reactor; 3. a third continuous flow reactor; 31. sodium nitrate water solution feeding pipe; 32. para-toluene ammonium salt solution feeding pipe; 33. a fourth continuous flow reactor; 34. urea aqueous solution feeding pipe; 35. feeding pipe for diazonium salt solution of p-toluidine;
36. A fifth continuous flow reactor; 37. a diazonium salt quenching system feeding pipe; 38. a second sulfuric acid aqueous solution feeding pipe; 39. an organic solvent feeding pipe;
5. a sixth continuous flow reactor; 53. an oxygen cylinder; 54. a p-toluene phenol transfer line; 541. a fifth liquid transfer pump; 542. a fourth mass flow controller; 55. a second charging bucket; 56. an oxygen delivery conduit; 561. a second mass flow controller; 562. an oxygen buffer tank;
6. A first gas-liquid separation tank; 61. a first back pressure valve; 62. a third liquid transfer pump; 63. a first receiving tank; 64. a third buffer tank; 651. a falling film evaporator; 652. a second receiving tank; 653. a condenser; 654. a second liquid transfer pump; 655. a heavy phase tank; 656. a light phase tank; 66. a solvent recovery device; 67. a first buffer tank; 68. a first liquid separating device; 681. a first alkaline washing device; 682. a first distillation device; 69. a second gas-liquid separation tank; 691. a third receiving tank; 692. an acid precipitation device; 693. a filtering device; 694. an acid liquid storage device; 695. a second back pressure valve; 696. a first liquid transfer pump; 697. a fifth mass flow controller;
7. A seventh continuous flow reactor; 71. an eighth continuous flow reactor; 711. a third sulfuric acid aqueous solution feeding pipe; 712. fuming nitric acid feeding pipe; 72. a ninth continuous flow reactor; 721. a nitrifying agent feeding pipe; 722. toluene feeding pipe; 73. a second liquid separation device; 74. a second alkaline washing device; 75. a water washing device; 76. a second rectifying device; 771. a first water storage tank; 772. a second concentrated sulfuric acid tank; 773. a fuming nitric acid tank; 774. a toluene tank; 775. a nitrating material preheater; 776. a waste liquid storage device; 777. a second water storage tank; 778. an alkali liquor storage tank.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
As described in the background art, there is a problem in the prior art that the yield of parahydroxyben-zaldehyde is low and the cost is high, and in order to solve the above problem, according to an aspect of the present invention, there is provided a continuous production method of parahydroxyben-zaldehyde, comprising the steps of: step S1, mixing concentrated sulfuric acid and water in a seventh continuous flow reactor to obtain a third sulfuric acid aqueous solution, preparing a nitrifying reagent in an eighth continuous flow reactor by the third sulfuric acid aqueous solution and fuming nitric acid, reacting toluene and the nitrifying reagent in a ninth continuous flow reactor, nitrifying toluene to generate paranitrotoluene, and continuously separating and purifying a system after the nitrifying reaction is completed to obtain the paranitrotoluene; s2, dissolving paranitrotoluene in an organic solvent to form a paranitrotoluene solution, and introducing hydrogen into the paranitrotoluene solution in a first continuous flow reactor under the catalysis of a hydrogenation catalyst to perform hydrogenation reaction to generate paratoluidine; s3, dissolving the p-toluidine in a first sulfuric acid aqueous solution in a second continuous flow reactor to obtain a p-toluidine ammonium salt solution, carrying out diazotization reaction on the sodium nitrite aqueous solution and the p-toluidine ammonium salt solution in a third continuous flow reactor to obtain a p-toluidine diazonium salt solution system, carrying out quenching reaction on the toluidine diazonium salt solution system by using a urea aqueous solution in a fourth continuous flow reactor to obtain a diazonium salt quenching system, carrying out diazonium salt Jie Sheng on p-cresol in a mixed solution of the second sulfuric acid aqueous solution and an organic solvent in a fifth continuous flow reactor, and carrying out continuous separation and purification on the system after the diazonium salt hydrolysis reaction is completed to obtain p-toluol; and S4, dissolving the p-cresol and sodium hydroxide in methanol to form a mixed solution of the p-cresol and the sodium hydroxide, conveying the mixed solution of the p-cresol and the sodium hydroxide to a sixth continuous flow reactor, introducing oxygen to perform oxidation reaction under the catalysis of an oxidation catalyst to generate p-hydroxybenzaldehyde, and continuously separating and purifying the system after the oxidation reaction is completed to obtain the p-hydroxybenzaldehyde.
The invention takes toluene as the initial raw material for preparation, the toluene is nitrified by nitrifying agent to obtain paranitrotoluene, the paranitrotoluene is catalyzed and hydrogenated by hydrogenation catalyst to generate paratoluidine, the paratoluidine is diazotized to generate paratoluidine diazonium salt, the paratoluidine diazonium salt water Jie Sheng is catalyzed and oxidized to generate parahydroxybenzaldehyde, the parahydroxybenzaldehyde with high yield is obtained, and the raw materials (such as hydrogen, oxygen, toluene, etc.) used in the synthesis process are low in price and easy to obtain; in addition, the method takes the toluene nitration product paranitrotoluene as an intermediate product for further synthesis, so that the paranitrotoluene has a new utilization path, and the product value of the paranitrotoluene is increased; in addition, the intermediate p-nitrotoluene is used as a raw material to prepare p-toluidine and p-toluidine diazonium salt successively, and then the p-toluidine diazonium salt is hydrolyzed to generate p-cresol, so that the hydrolysis efficiency is high and the time cost is reduced compared with the p-amino formaldehyde diazonium salt hydrolysis route in the p-nitrotoluene method in the prior art; the invention can realize continuous production of nitration reaction, hydrogenation reaction, diazotization reaction, oxidation reaction and other reactions, and compared with the traditional kettle type production, the invention solves the problem of extremely high safety risk in the reaction process, ensures that the production process is safer and more stable, and simultaneously greatly improves the production efficiency, thereby having remarkable safety and economic value. By adopting the method, toluene is taken as a raw material, and the p-hydroxybenzaldehyde with high yield is obtained through nitration reaction, hydrogenation reaction, diazotization reaction and oxidation reaction, and the continuous production can be realized, so that the production efficiency is high, and the method is safe and economical.
In a preferred embodiment, in order to obtain higher yields and purities of intermediate products and target products, in step S1, the system after the completion of the nitration reaction is subjected to liquid separation, alkaline washing and rectification to obtain paranitrotoluene; in the preferred step S1, separating the system after the nitration reaction is finished, washing an organic phase after the separation by alkali, washing the organic phase after the alkali washing by water, and rectifying the organic phase after the water washing to obtain paranitrotoluene; more preferably, in the step S1, the separated organic phase is washed by sodium carbonate aqueous solution, and then the pH value of the organic phase is washed by water to 6.8-7.2; in the step S1, the mass fraction of sodium carbonate in the sodium carbonate aqueous solution is 20-30%; in the preferred step S2, removing hydrogen and concentrating the system after the hydrogenation reaction is completed to remove the solvent, thereby obtaining the p-toluidine; more preferably, in step S2, the organic solvent is selected from one or more of methanol, ethanol, ethyl acetate, isopropyl acetate; more preferably, in the step S2, the concentration of the paranitrotoluene in the paranitrotoluene solution is 0.01-1 g/mL; in the preferred step S3, the system after the hydrolysis reaction is subjected to liquid separation, alkali washing and distillation to obtain p-toluene; more preferably, in the step S3, the system after the hydrolysis reaction is separated, the organic phase after the separation is subjected to alkali washing, the solvent is removed by reduced pressure distillation after the alkali washing, and then the p-toluene is obtained by reduced pressure distillation; in a further preferred step S3, the separated organic phase is washed with an aqueous sodium carbonate solution or an aqueous sodium bicarbonate solution to a pH of 6.8-7.2; in the preferred step S4, the system after the oxidation reaction is subjected to acid precipitation, filtration and drying to obtain the parahydroxyben-zaldehyde; more preferably, in the step S4, the system after the oxidation reaction is placed in an aqueous hydrochloric acid solution with the mass fraction of 20% -40% for precipitation.
The hydrogenation catalyst is used for catalyzing the reduction of nitro groups on paranitrotoluene into amine groups, and in a preferred embodiment, the hydrogenation catalyst is selected from one or more of palladium carbon, platinum carbon, raney nickel and supported nickel-based catalysts, and the catalysts are commonly used hydrogenation catalysts and are commercially available; in the preferred step S2, the molar ratio of hydrogen to paranitrotoluene is 4 to 10:1, more preferably (4 to 5): 1, on the basis of ensuring normal mass transfer and full reaction of raw materials, the consumption of hydrogen is small, and the waste of hydrogen is avoided; in the preferred step S2, the reaction temperature of the hydrogenation reaction is 50-90 ℃, preferably 50-70 ℃; in the preferred step S2, the reaction pressure of the hydrogenation reaction is 0.1-1 MPa, more preferably 0.1-0.5 MPa, and the hydrogenation reaction is performed under a lower pressure system, so that the service life of the catalyst is prolonged, and the cost is saved.
In a preferred embodiment, in step S3, the temperature of the diazotisation reaction is 0 to 20 ℃, more preferably 10 to 20 ℃; in the preferred step S3, the diazotization reaction time is 6 to 30min, more preferably 6 to 10min; in the preferred step S3, the quenching reaction temperature is 0-20 ℃, more preferably 10-20 ℃; in the preferred step S3, the quenching reaction time is 6-60 min, more preferably 6-10 min; in the preferred step S3, the reaction temperature of the diazonium salt hydrolysis reaction is 50-100 ℃, more preferably 70-90 ℃, still more preferably 80-90 ℃; in the preferred step S3, the diazonium salt hydrolysis reaction time is 7-30 min, more preferably 10-20 min; in the preferred step S3, the mass fraction of sulfuric acid in the first sulfuric acid aqueous solution is 20-30%; in the preferred step S3, the mass fraction of the para-tolueneammonium salt in the para-tolueneammonium salt solution is 20-30%; in the preferred step S3, the mass fraction of sodium nitrite in the sodium nitrite aqueous solution is 20-30%; in the preferred step S3, the mass fraction of urine in the urea aqueous solution is 3-8%; in the preferred step S3, the mass fraction of sulfuric acid in the second sulfuric acid aqueous solution is 20-30%; preferably in step S3, the organic solvent is selected from one or more of chlorobenzene, 2-methyltetrahydrofuran, toluene, 1,4 dioxane, more preferably from chlorobenzene; in the preferred step S3, the mass ratio of the para-tolueneammonium salt in the para-tolueneammonium salt solution to the sodium nitrite in the sodium nitrite aqueous solution to the urea in the urea aqueous solution is 1: (0.2 to 0.8): (0.01 to 0.1).
In a preferred embodiment, in step S4, the oxidation catalyst is a transition metal supported catalyst; preferably, in the transition metal supported catalyst, the carrier is selected from one of active carbon, silicon dioxide and carbon nano tubes, and the transition metal is selected from at least one of cobalt and copper; in the preferred step S4, the molar ratio of oxygen to p-cresol is (5 to 15): 1, more preferably (7 to 10): 1, on the basis of ensuring normal mass transfer and full reaction of raw materials, the oxygen consumption is less, and the cost is lower; preferably, in the step S4, the mass ratio of the p-cresol to the sodium hydroxide is 1: (0.9 to 1.1); in the preferred step S4, the concentration of the p-cresol in the mixed solution of the p-cresol and the sodium hydroxide is 0.08-0.2 g/ml; in the preferred step S4, the concentration of sodium hydroxide in the mixed solution of p-cresol and sodium hydroxide is 0.08-0.2 g/ml, more preferably 0.12-0.16 g/ml; in the preferred step S4, the temperature of the oxidation reaction is 60-90 ℃, more preferably 80-90 ℃; in the step S4, the pressure of the oxidation reaction is preferably 0.1 to 0.6MPa, more preferably 0.1 to 0.4MPa.
In a preferred embodiment, in step S1, the mass fraction of sulfuric acid in the third sulfuric acid aqueous solution is 60-80%; in the preferred step S1, the molar ratio of nitric acid to toluene is 1-1.5: 1, a nitrifying reagent and toluene are supplied to a ninth continuous flow reactor, more preferably, the molar ratio of nitric acid to toluene is 1.22-1.3: 1, feeding; in the preferred step S1, the molar ratio of sulfuric acid to toluene is 3-5: 1, feeding a nitrifying reagent and toluene into a ninth continuous flow reactor; in the preferred step S1, the reaction temperature of the nitration reaction is 55-70 ℃, more preferably 60-70 ℃; in the step S1, the reaction time of the nitration reaction is preferably 10 to 90 minutes, more preferably 12 to 30 minutes.
As shown in fig. 1 to 4, according to another aspect of the present invention, there is provided a continuous production system employed in the above-described continuous production method of p-hydroxybenzaldehyde, comprising: the device comprises a nitration reaction unit, a first continuous separation and purification unit, a catalytic hydrogenation reaction unit, a second continuous separation and purification unit, a diazotization and hydrolysis unit, a third continuous separation and purification unit, a catalytic oxidation unit and a fourth continuous separation and purification unit; the nitration reaction unit includes: the seventh continuous flow reactor 7, the seventh continuous flow reactor 7 is provided with a concentrated sulfuric acid feeding pipe, a water inlet pipe and a third sulfuric acid aqueous solution discharging hole; the eighth continuous flow reactor 71, the eighth continuous flow reactor 71 is provided with a third sulfuric acid water solution feeding pipe 711, a fuming nitric acid feeding pipe 712 and a nitrifying agent discharging hole, and the third sulfuric acid water solution feeding pipe 711 is connected with the third sulfuric acid water solution discharging hole; a ninth continuous flow reactor 72, wherein the ninth continuous flow reactor 72 is provided with a nitrifying agent feeding pipe 721, a toluene feeding pipe 722 and a system discharging port after the nitrifying reaction is completed, and the nitrifying agent feeding pipe 721 is connected with the nitrifying agent discharging port; the system discharge port after the nitration reaction is finished is connected with the feed inlet of the first continuous separation and purification unit; specifically, as shown in fig. 1, the water in the first water storage tank 771 and the concentrated sulfuric acid in the second concentrated sulfuric acid tank 772 can be pumped into the seventh continuous flow reactor 7 respectively for mixing by a liquid conveying pump, the fuming nitric acid in the fuming nitric acid tank 773 is pumped into the eighth continuous flow reactor 71 by the liquid conveying pump for mixing with the sulfuric acid aqueous solution to prepare a nitrifying reagent, and the toluene in the toluene tank 774 is pumped into the ninth continuous flow reactor 72 by the liquid conveying pump for nitrifying reaction; the catalytic hydrogenation reaction unit comprises: a first charging tank 14 for preparing the paranitrotoluene solution, wherein an inlet of the first charging tank 14 is connected with a paranitrotoluene discharge port of the first continuous separation and purification unit; the first continuous flow reactor 1 is provided with a hydrogen feeding pipe 11, a paranitrotoluene solution feeding pipe 12 and a discharge hole 13 of a hydrogenation reaction system, and the first continuous flow reactor 1 is connected with a hydrogen cylinder 15 through the hydrogen feeding pipe 11; the first continuous flow reactor 1 is connected with a discharge port of a first charging tank 14 through a paranitrotoluene solution feeding pipe 12; the diazotisation and hydrolysis unit comprises: the second continuous flow reactor 2 is provided with a first sulfuric acid water solution feeding pipe 21, a p-toluidine feeding pipe 22 and a p-toluidine ammonium salt solution discharging hole, and the p-toluidine feeding pipe 22 is connected with the discharging hole of the second continuous separation and purification unit; the third continuous flow reactor 3, the third continuous flow reactor 3 is provided with a sodium nitrite water solution feeding pipe 31, a para-toluidine ammonium salt solution feeding pipe 32 and a para-toluidine diazonium salt solution discharging port, and the para-toluidine ammonium salt solution feeding pipe 32 is connected with the para-toluidine ammonium salt solution discharging port; the fourth continuous flow reactor 33, the fourth continuous flow reactor 33 is provided with a urea aqueous solution feeding pipe 34, a para-toluidine diazonium salt solution feeding pipe 35 and a diazonium salt quenching system discharge port, and the para-toluidine diazonium salt solution feeding pipe 35 is connected with the toluidine diazonium salt solution discharge port; the fifth continuous flow reactor 36, the fifth continuous flow reactor 36 is provided with a diazonium salt quenching system feeding pipe 37, a second sulfuric acid aqueous solution feeding pipe 38, an organic solvent feeding pipe 39 and a hydrolysate discharging port, and the p-toluidine diazonium salt solution feeding pipe 35 is connected with the diazonium salt quenching system discharging port; the hydrolysate discharge port is connected with the feed port of the third continuous separation and purification unit; the catalytic oxidation unit includes: a second material tank 55 for preparing mixed solution of p-cresol and sodium hydroxide, wherein a discharge port of the mixed solution of p-cresol and sodium hydroxide is arranged on the second material tank 55; the sixth continuous flow reactor 5, the sixth continuous flow reactor 5 is provided with an oxygen conveying pipeline 56, a p-cresol conveying pipeline 54 and a system discharge port after the oxidation reaction is finished, and the sixth continuous flow reactor is connected with an oxygen bottle 53 through the oxygen conveying pipeline 56; the sixth continuous flow reactor 5 is connected with a discharge port of the mixed solution of the creosote and the sodium hydroxide through a p-cresol conveying pipeline 54; and a system discharge port after the oxidation reaction is finished is connected with a feed inlet of a fourth continuous separation and purification unit. In the synthetic route based on the p-hydroxybenzaldehyde, a plurality of reaction processes of nitration, hydrogenation, diazotization and oxidation are involved, and the reaction heat (such as timely removal of the nitration and hydrogenation reaction heat) can be timely removed by adopting a continuous production system (a continuous flow reactor and a corresponding continuous separation and purification unit), so that impurities in the reaction can be effectively controlled and reduced; in addition, by adopting the continuous production system, the gas-liquid mass transfer effect in the hydrogenation reaction and the oxidation reaction and the utilization rate of the catalyst in the hydrogenation reaction and the oxidation reaction can be improved; furthermore, by adopting the continuous production system, diazotization products can be hydrolyzed in time, the generation efficiency and the hydrolysis efficiency of unstable diazotization products are improved, the yield and the reaction efficiency are improved, and the problem of high temporary risk of a diazotization system is avoided. The continuous production system can effectively solve the problems of low yield and high impurity content caused by unstable intermediate products in the intermittent reaction device, reduces risks in the operation process, has short production period, small occupied area of the device, small production energy consumption and low cost, and remarkably improves the yield, the production efficiency and the safety.
In a preferred embodiment, the first continuous separation and purification unit comprises: a second liquid separation device 73, a second alkali washing device 74, a water washing device 75 and a second rectification device 76; the feeding pipe of the second liquid separation device 73 is connected with the system discharge port after the nitration reaction is finished, the organic phase outlet of the second liquid separation device 73 is connected with the feeding pipe of the second alkaline washing device 74, and the feeding pipe of the water washing device 75 is connected with the organic phase discharge port of the second alkaline washing device 74; the feeding pipe of the second rectifying device 76 is connected with the organic phase discharge port of the water washing device 75, and the p-nitrotoluene discharge port of the second rectifying device 76 is connected with the feeding port of the first charging tank 14; specifically, the system after the nitration reaction is divided into two layers of an organic phase and an aqueous phase in a second liquid separation device 73, the aqueous phase is pumped to a waste liquid storage device 776 by a liquid conveying pump, the organic phase is pumped to a second alkaline washing device 74 by a liquid conveying pump, alkaline liquid in an alkaline liquid storage tank 778 is pumped to the second alkaline washing device 74 to wash the organic phase, the alkaline washed organic phase enters a water washing device 75, the water in the second water storage tank 777 is pumped to the water washing device 75 to wash the organic phase, and the water washed organic phase is rectified by a second rectifying device 76 to obtain o-nitrotoluene, m-nitrotoluene and target product p-nitrotoluene respectively; the system after the hydrogenation reaction is concentrated to remove the solvent and then the subsequent reaction is carried out, so that higher yield can be obtained, and the solvent can be recovered, preferably, the second continuous separation and purification unit comprises: the first gas-liquid separation tank 6, the first receiving tank 63, the third buffer tank 64, the falling film evaporator 651, the second receiving tank 652, the condenser 653, the light phase tank 656, the second liquid delivery pump 654, the heavy phase tank 655 and the first buffer tank 67 for containing p-toluidine, the gas-liquid feeding pipe of the first gas-liquid separation tank 6 is connected with the discharge port 13 of the hydrogenation reaction system, the gas-liquid feeding pipe of the first gas-liquid separation tank 6 is provided with a first back pressure valve 61, the discharge port of the first gas-liquid separation tank 6 is connected with the feed pipe of the first receiving tank 63, and the separated tail gas can be sent to a tail gas treatment device for treatment so as to ensure safety; the feeding port of the third buffer tank 64 is connected with the discharging port 63 of the first receiving tank through a third liquid conveying pump 62; the feed inlet of the falling film evaporator 651 is connected with the discharge outlet of the third buffer tank 64, and the discharge outlet of the falling film evaporator 651 is connected with the feed inlet of the second receiving tank 652; the gas phase outlet of the second receiving tank 652 is connected with a condenser 653, the discharge hole of the condenser is connected with a light phase tank 656, and the outlet of the light phase tank is connected with a solvent recovery device 66; the liquid phase outlet of the second receiving tank 652 is connected to the feed inlet of the heavy phase tank 655 through a second liquid transfer pump 654; the discharge port of the heavy phase tank 655 is connected with the feeding pipe of the first buffer tank 67; the discharge port of the first buffer tank 67 is connected with the p-toluidine feeding pipe 22; preferably, the third continuous separation and purification unit comprises: the organic phase outlet of the first liquid separating device 68 is connected with the feeding pipe of the first alkaline washing device 681; the discharge port of the first alkaline washing device 681 is connected with the feed pipe of the first distillation device 682; the p-toluidine fraction outlet of the first distillation device 682 is connected to a second buffer tank (not depicted) for holding p-cresol, for supplying p-toluol to the second tank; preferably, the fourth continuous separation and purification unit comprises: at least one second gas-liquid separation tank 69, a third receiving tank 691, an acid precipitation device 692 and a filtering device 693, wherein a gas-liquid feeding pipe of each second gas-liquid separation tank 69 is connected with a discharge hole of the oxidized system, and a liquid phase outlet of the second gas-liquid separation tank 69 is connected with a feed hole of the third receiving tank 691; a second back pressure valve 695 is provided at the gas outlet of the second gas-liquid separation tank 69; the feeding pipe of the acid precipitation device 692 is connected with the discharge port of the third receiving tank 691, and the discharge port of the acid precipitation device 692 is connected with the feeding port of the filtering device 693; a first liquid delivery pump 696 and a fifth mass flow controller 697 are arranged on a feeding pipe of the acid precipitation device 692, and an acid liquid inlet of the acid precipitation device is connected with an acid liquid storage device 694.
In a preferred embodiment, the first continuous flow reactor 1 is one of a fixed bed reactor, a continuous tank reactor; preferably, the second continuous flow reactor 2 is one of a microchannel reactor and a tubular reactor; preferably, the third continuous flow reactor 3 is one of a micro-channel reactor and a tubular reactor; preferably, the fourth continuous flow reactor 33 is one of a microchannel reactor and a tubular reactor; preferably, fifth continuous flow reactor 36 is one of a microchannel reactor, a tubular reactor, a cylindrical stirred reactor, and a continuous tank reactor; preferably, the sixth continuous flow reactor 5 is one of a fixed bed reactor and a continuous kettle reactor; preferably, the seventh continuous flow reactor 7, the eighth continuous flow reactor 71 and the ninth continuous flow reactor 72 are each independently selected from one of a microchannel reactor and a tubular reactor.
In a preferred embodiment, as shown in FIG. 1, a nitrating material preheater 775 is provided on the toluene feed line 722 and the nitrating agent feed line 721 for pre-heating toluene and nitrating agent for the nitration reaction; preferably, as shown in fig. 2, a regulating valve 111, a hydrogen buffer tank 113, a first mass flow controller 112 and a hydrogen preheater 114 are sequentially arranged on the hydrogen feeding pipe 11, the regulating valve 111 is arranged close to the hydrogen cylinder 15, and the hydrogen preheater 114 is arranged close to the first continuous flow reactor 1; preferably, a fourth liquid delivery pump 121, a third mass flow controller 122 and a raw material preheater 123 are sequentially arranged on the paranitrotoluene solution feeding pipe 12, the fourth liquid delivery pump 121 is arranged close to the first charging tank 14, and the raw material preheater 123 is arranged close to the first continuous flow reactor 1; preferably, a second mass flow controller 561 and an oxygen buffer tank 562 are sequentially arranged on the oxygen conveying pipeline 56, the second mass flow controller 561 is arranged close to the oxygen bottle 53, and the oxygen buffer tank 562 is arranged close to the sixth continuous flow reactor; preferably, a fifth liquid delivery pump 541 and a fourth mass flow controller 542 are sequentially disposed on the p-cresol delivery conduit 54, the fifth liquid delivery pump 541 is disposed adjacent to the second feed tank 55, and the fourth mass flow controller 542 is disposed adjacent to the sixth continuous flow reactor 5; preferably, the diazotisation and hydrolysis unit further comprises: the sodium nitrite solution tank 23, the urea aqueous solution tank 24 and the organic solvent tank 25, wherein the sodium nitrite solution tank 23 is connected with a sodium nitrate aqueous solution feeding pipe 31, the urea aqueous solution tank 24 is connected with a fourth continuous flow reactor 33, and the organic solvent tank is connected with an organic solvent feeding pipe 39; preferably, the diazotisation and hydrolysis unit further comprises: the third water storage tank 26, the first concentrated sulfuric acid tank 261 and the tenth continuous flow reactor 262, wherein a concentrated sulfuric acid inlet of the tenth continuous flow reactor 262 is connected with the first concentrated sulfuric acid tank 261, a water inlet pipe of the tenth continuous flow reactor 262 is connected with the third water storage tank 26, and a discharge port of the tenth continuous flow reactor 262 is connected with the first sulfuric acid aqueous solution feeding pipe 21; preferably, the diazotisation and hydrolysis unit further comprises: the fourth water storage tank 27, the third concentrated sulfuric acid tank 271 and the eleventh continuous flow reactor 272, wherein a concentrated sulfuric acid inlet of the eleventh continuous flow reactor 272 is connected with the third concentrated sulfuric acid tank 271, a water body inlet of the eleventh continuous flow reactor 272 is connected with the fourth water storage tank 27, and a discharge port of the eleventh continuous flow reactor 272 is connected with the second sulfuric acid aqueous solution feeding pipe 38.
The application is described in further detail below in connection with specific examples which are not to be construed as limiting the scope of the application as claimed.
Example 1:
The continuous production system of parahydroxyben-zaldehyde shown in fig. 1-4 is used for producing parahydroxyben-zaldehyde, comprising the following steps:
(1) Toluene nitration to produce para-nitrotoluene:
Pumping 98% by mass of concentrated sulfuric acid (with the flow rate of 22.01 g/min) and water (with the flow rate of 7.34 g/min) into a seventh continuous flow reactor quantitatively to prepare 75% by mass of dilute sulfuric acid aqueous solution, controlling the temperature to 40 ℃ and the residence time to 15min, continuously pumping 98% by mass of fuming nitric acid quantitatively (with the flow rate of 4.02 g/min) into an eighth continuous flow reactor to prepare a nitrifying reagent after the preparation is completed, controlling the temperature to 40 ℃ and the residence time to 15min, continuously pumping toluene with the flow rate of 4.7g/min (namely, the mole ratio of nitric acid to toluene in the nitrifying reagent input into the ninth continuous flow reactor to carry out nitration reaction after the preheating to 40 ℃, controlling the temperature to 65 ℃ and the residence time to 30min, obtaining a nitrifying reaction system, continuously separating liquid, pumping an organic phase 25% sodium carbonate aqueous solution after the liquid separation into an alkaline washing device at 6.99g/min and 5.64g/min respectively, continuously washing the organic phase after the alkaline washing phase into a rectifying device at 6.99g/min and 2.35g/min respectively, and continuously pumping the organic phase into a rectifying device at the alkaline washing device at the temperature of 36.05% by water to obtain the continuous phase purity after the continuous phase washing device at the time of 48% by the rectification, and the continuous phase washing device at the time of 48 g/min;
Wherein the seventh continuous flow reactor, the eighth continuous flow reactor and the ninth continuous flow reactor are respectively plate reactors.
(2) Catalytic hydrogenation to p-toluidine:
2.1, dissolving the prepared paranitrotoluene with methanol in a batching kettle to form paranitrotoluene solution with the concentration of 0.1g/mL, pumping the paranitrotoluene solution into a fixed bed reactor, and carrying out hydrogenation reaction under the following conditions: the flow rate of the paranitrotoluene solution was controlled to 5g/min, raney nickel (Aladin, R111435) 45g, the temperature was 70 ℃, the pressure in the fixed bed reactor was 0.1MPa, and the hydrogen inlet was adjusted so that the molar ratio of hydrogen to paranitrotoluene was 4:1. the purity of p-toluidine was monitored by HPLC, and when 0.1% of the raw material remained, the yield of p-toluidine was 95%, the purity was 98.0% or more, and the residence time was 9min.
2.2, Pumping the hydrogenated system into a falling film evaporation device for treatment, controlling the concentration temperature of the falling film evaporator to be 55 ℃, adjusting the internal vacuum degree, pumping the hydrogenated system into the evaporator at a flow rate of 5g/min, recovering the light phase solvent methanol, wherein the heavy phase compound is p-toluidine, and the purity of the p-toluidine is 98 percent, and the yield is 95 percent.
(3) Diazotizing and hydrolyzing to prepare p-toluene phenol:
3.1, adding p-toluidine into a dilute sulfuric acid solution prepared from concentrated sulfuric acid, wherein the mass fraction of the dilute sulfuric acid solution is 24%, and stirring until the dilute sulfuric acid solution is clear to prepare a p-toluidine ammonium salt solution with the mass fraction of the p-toluidine ammonium salt being 25%; sodium nitrite is dissolved in water to prepare sodium nitrite aqueous solution with the mass fraction of 20 percent; dissolving urea in water to prepare urea aqueous solution with the mass fraction of urea of 5%; diluting concentrated sulfuric acid with water to prepare dilute sulfuric acid hydrolysate with the mass fraction of sulfuric acid of 20%.
3.2, Quantitatively pumping para-tolueneammonium salt solution into a third continuous flow reactor through a metering pump at a flow rate of 23.96g/min and a sodium nitrite aqueous solution through a metering pump at a flow rate of 6.9g/min, carrying out diazotization reaction at 20 ℃, after a residence time of 6min, mixing with a urea aqueous solution at a flow rate of 1.68g/min at 20 ℃, then mixing with a dilute sulfuric acid hydrolysate at a flow rate of 9.15g/min and an organic solvent at a flow rate of 6.65g/min through a fourth continuous flow reactor after a residence time of 6min, mixing with a fifth continuous flow reactor, wherein the organic solvent is chlorobenzene, a hydrolysis temperature of 90 ℃ and a hydrolysis residence time of 15min, separating aqueous phase dilute sulfuric acid, collecting an organic phase, pumping the separated organic phase and 25% sodium carbonate aqueous solution into an alkaline washing device at a mass fraction of 8.5g/min respectively, carrying out continuous alkaline washing to neutrality, recovering the organic solvent chlorobenzene at a decompression distillation at 70 ℃, continuously collecting fraction at a decompression distillation at 130 ℃, obtaining a colorless liquid with a yield of 5326% of p-toluenephenol;
Wherein the third continuous flow reactor and the fourth continuous flow reactor are plate reactors, and the fifth continuous flow reactor is a columnar stirring reactor.
(4) Catalytic oxidation to p-hydroxybenzaldehyde:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, and p-cresol (10 g) and sodium hydroxide (10 g) prepared were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, controlling the reaction temperature at 83 ℃, controlling the reaction pressure at 0.4MPa, stopping the raw material solution for 3.3 hours through a fixed bed reactor, flowing out, detecting the reaction solution by a liquid chromatograph, controlling the conversion rate of the raw material to 99.5%, controlling the yield of the parahydroxyben-zaldehyde in the reaction solution to 92.2%, placing the reaction solution into a hydrochloric acid aqueous solution with the mass fraction of 36.5% for acid precipitation, filtering and drying to obtain the parahydroxyben-zaldehyde with the purity of 99.5% and the yield of 84.9%. Characterization of the product Structure, which The diagram is shown in fig. 5, and specific nuclear magnetic data: /(I)：/>，，/>，/>。
Examples 2 to 4
It differs from example 1 only in the residence time in the nitration reaction carried out in the ninth continuous flow reactor.
The contents of the components in the system after the nitration reaction of examples 1 to 4 were analyzed by gas chromatography, and the residual amounts of toluene (the mass of unreacted toluene in the system after the nitration reaction was a percentage of the initial mass of toluene) were shown in Table 1, respectively, along with the mass fractions of ortho-, meta-, and para-nitrotoluene in the system after the nitration reaction (i.e., the mass fraction of ortho-, meta-, and para-nitrotoluene).
TABLE 1
As can be seen from Table 1, the yield of paranitrotoluene of 33% or more can be obtained in 12 minutes of residence time of the nitration reaction, the reaction time is short, the production efficiency is high, the paranitrotoluene can be rapidly and timely separated out through the continuous flow reactor, and the production of byproducts (dinitrosubstituted toluene and other polynitrosubstituted toluene) is reduced.
Example 5
It differs from example 1 only in that the flow rate of toluene is 4.89 g/min (i.e., the molar ratio of nitric acid to toluene in the nitrating reagent fed to the ninth continuous flow reactor is 1.3:1).
The contents of the components in the system after the nitration reaction of example 1 and example 5 were analyzed by gas chromatography, and the residual amount of toluene (the mass of unreacted toluene in the system after the nitration reaction is a percentage of the initial mass of toluene) and the mass fractions of ortho-, meta-, and para-nitrotoluene (i.e., the mass fraction of ortho-, meta-, and para-nitrotoluene) and the mass fraction of dinitro (i.e., the mass fraction of dinitro-substituted toluene) in the system after the nitration reaction are shown in Table 2, respectively.
TABLE 2
As can be seen from Table 2, the molar ratio of nitric acid to toluene is 1.22 to 1.3, the conversion of toluene feedstock is substantially complete and the content of dinitrosubstituted toluene and other polynitrosubstituted toluene by-products is low.
Example 6
It differs from example 1 only in that the hydrogenation reaction conditions are: the feeding flow rate of the paranitrotoluene solution is controlled to be 5g/min, the temperature of Raney nickel (Aladin, R111435) is 45g, the temperature is 70 ℃, the pressure in a fixed bed reactor is 1MPa, and the hydrogen gas inlet flow rate is regulated to ensure that the molar ratio of the hydrogen gas phase to the paranitrotoluene is 4:1.
When the raw material is left at 0.1%, the yield of the obtained p-toluidine is 95%, and the purity is more than 98%.
Example 7
It differs from example 1 only in that the hydrogenation reaction conditions are: the feeding flow rate of the paranitrotoluene solution is controlled to be 0.5g/min, the temperature of Raney nickel (Aladin, R111435) is 45g, the temperature is 70 ℃, the pressure in a fixed bed reactor is 1MPa, and the hydrogen gas inlet flow rate is regulated so that the molar ratio of a hydrogen gas phase to the paranitrotoluene is 4:1.
When the raw material is left at 0.1%, the yield of the obtained p-toluidine is 95%, and the purity is more than 98%.
Example 8
It differs from example 1 only in that the hydrogenation reaction conditions are: the feeding flow rate of the paranitrotoluene solution is controlled to be 5g/min, raney nickel (Aladin, R111435) is controlled to be 45g, the temperature is 70 ℃, the pressure in a fixed bed reactor is 1MPa, and the hydrogen gas inlet flow rate is regulated to ensure that the molar ratio of a hydrogen gas phase to the paranitrotoluene is 10:1.
When the raw material is left at 0.1%, the yield of the obtained p-toluidine is 95%, and the purity is more than 98%.
Example 9
It differs from example 1 only in that the hydrogenation reaction conditions are: the feeding flow rate of the paranitrotoluene solution is controlled to be 5g/min, the temperature of Raney nickel (Aladin, R111435) is 45g, the temperature is 50 ℃, the pressure in a fixed bed reactor is 1MPa, and the hydrogen gas inlet flow rate is regulated so that the molar ratio of a hydrogen gas phase to the paranitrotoluene is 4:1.
When the raw material is left at 0.1%, the yield of the obtained p-toluidine is 95%, and the purity is more than 98%.
Example 10
It differs from example 1 only in that the hydrogenation reaction conditions are: the feeding flow rate of the paranitrotoluene solution is controlled to be 5g/min, the temperature of Raney nickel (Aladin, R111435) is 45g, the temperature is 90 ℃, the pressure in a fixed bed reactor is 1MPa, and the hydrogen gas inlet flow rate is regulated to ensure that the molar ratio of the hydrogen gas phase to the paranitrotoluene is 4:1.
When the raw material is left at 0.1%, the yield of the obtained p-toluidine is 92%, and the purity is more than 95%.
Examples 11 to 13
This differs from example 1 in that the organic solvent used in step (3) is different from the organic solvent used, and the yield of p-cresol and the purity of p-cresol are shown in Table 3, respectively.
TABLE 3 Table 3
As is clear from Table 3, the above-mentioned organic solvent was added to the diazonium salt hydrolysis system of p-toluidine to obtain a high yield and purity of p-toluol, and the yield of p-toluol was remarkably improved particularly when the organic solvent was chlorobenzene.
Examples 14 to 15
This differs from example 1 in that the hydrolysis residence time in step (3) is different, and the residence time, the yield of p-cresol, and the purity of p-cresol are shown in Table 4, respectively.
TABLE 4 Table 4
As can be seen from Table 4, the hydrolysis reaction of p-toluidine diazonium salt is fast, the hydrolysis time is short, most of the raw materials are already hydrolyzed after the hydrolysis residence time is 7 minutes, and the hydrolysis yield and the product purity of the raw materials are highest when the residence time is 15 minutes.
Examples 16 to 17
This differs from example 1 in that the hydrolysis temperature in step (3) is different, and the hydrolysis temperature, the yield of p-cresol as a product, and the purity of p-cresol are shown in Table 5.
TABLE 5
As can be seen from Table 5, the diazonium salt has higher hydrolysis yield at 70-90 ℃ and the highest hydrolysis yield at 90 ℃.
Example 18
Which is different from example 1 in the step of preparing p-hydroxybenzaldehyde by catalytic oxidation. Specifically, the steps for preparing parahydroxyben-zaldehyde by catalytic oxidation are as follows:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, p-cresol (10 g) and sodium hydroxide (9 g) were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, controlling the temperature of a bed layer at 65 ℃, controlling the pressure of the bed layer at normal pressure, stopping the raw material solution for 3.3 hours through a fixed bed reactor, then flowing out, detecting the reaction solution by a liquid chromatograph, wherein the conversion rate of the raw material is 96.5%, the yield of the reaction solution to the hydroxybenzaldehyde is 89.8%, and obtaining the hydroxybenzaldehyde product by continuous acid precipitation, filtration and drying of the reaction solution, the purity is 98.4%, and the yield is 79.8%.
Example 19
Which is different from example 1 in the step of preparing p-hydroxybenzaldehyde by catalytic oxidation. Specifically, the steps for preparing parahydroxyben-zaldehyde by catalytic oxidation are as follows:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, p-cresol (10 g) and sodium hydroxide (10 g) were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, controlling the temperature of a bed layer at 65 ℃, controlling the pressure of the bed layer at normal pressure, stopping the raw material solution for 3.3 hours through a fixed bed reactor, flowing out, detecting the reaction solution by a liquid chromatograph, wherein the conversion rate of the raw material is 98.7%, the yield of the reaction solution to the hydroxybenzaldehyde is 90.4%, and obtaining the hydroxybenzaldehyde product by continuous acid precipitation, filtration and drying of the reaction solution, the purity is 98.6%, and the yield is 80.1%.
Example 20
Which is different from example 1 in the step of preparing p-hydroxybenzaldehyde by catalytic oxidation. Specifically, the steps for preparing parahydroxyben-zaldehyde by catalytic oxidation are as follows:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, p-cresol (10 g) and sodium hydroxide (11 g) were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, the raw material solution is stopped for 3.3 hours through a fixed bed reactor and flows out, the reaction solution is detected by a liquid chromatographic instrument, the raw material conversion rate is 98.2%, the temperature of a bed layer is controlled at 65 ℃, the pressure of the bed layer is controlled at normal pressure, the yield of the reaction solution to the hydroxybenzaldehyde is 90.1%, the reaction solution is subjected to continuous acid precipitation and filtration, and the reaction solution is dried to obtain the hydroxybenzaldehyde product with the purity of 98.5% and the yield of 79.4%.
Example 21
Which is different from example 1 in the step of preparing p-hydroxybenzaldehyde by catalytic oxidation. Specifically, the steps for preparing parahydroxyben-zaldehyde by catalytic oxidation are as follows:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, p-cresol (10 g) and sodium hydroxide (10 g) were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, the temperature of a bed layer is controlled at 73 ℃, the pressure of the bed layer is controlled at normal pressure, a raw material solution flows out after staying for 3.3 hours through a fixed bed reactor, a liquid chromatographic instrument is used for detecting a reaction solution, the conversion rate of the raw material is 98.7%, the yield of the reaction solution to the hydroxybenzaldehyde is 90.8%, and the reaction solution is subjected to continuous acid precipitation, filtration and drying to obtain the hydroxybenzaldehyde product with the purity of 98.1% and the yield of 81.3%.
Example 22
Which is different from example 1 in the step of preparing p-hydroxybenzaldehyde by catalytic oxidation. Specifically, the steps for preparing parahydroxyben-zaldehyde by catalytic oxidation are as follows:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, p-cresol (10 g) and sodium hydroxide (10 g) were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, controlling the temperature of a bed layer at 83 ℃, controlling the pressure of the bed layer at normal pressure, stopping the raw material solution for 3.3 hours through a fixed bed reactor, flowing out, detecting the reaction solution by a liquid chromatograph, wherein the conversion rate of the raw material is 99.3%, the yield of the reaction solution to the hydroxybenzaldehyde is 91.7%, and obtaining the hydroxybenzaldehyde product by continuous acid precipitation, filtration and drying of the reaction solution, the purity is 99.1%, and the yield is 82.8%.
Example 23
Which is different from example 1 in the step of preparing p-hydroxybenzaldehyde by catalytic oxidation. Specifically, the steps for preparing parahydroxyben-zaldehyde by catalytic oxidation are as follows:
50g of a supported cobalt catalyst (XueKai catalyst, cat# CoCAT-3000Q) was charged in a 60ml fixed bed reactor, p-cresol (10 g) and sodium hydroxide (10 g) were dissolved in methanol (70 ml) to prepare a raw material solution, and oxygen was introduced into the fixed bed reactor while pumping the raw material solution at 0.25g/min and the flow rate of the oxygen was controlled so that the molar ratio of the introduced oxygen to the pumped p-cresol was 8:1, controlling the temperature of a bed layer at 83 ℃, controlling the pressure of the bed layer at 0.6MPa, stopping the raw material solution for 3.3 hours through a fixed bed reactor, flowing out, detecting the reaction solution by a liquid chromatograph, wherein the conversion rate of the raw material is 99.2%, the yield of the reaction solution to the hydroxybenzaldehyde is 91.8%, and obtaining the hydroxybenzaldehyde product by continuous acid precipitation, filtration and drying of the reaction solution, wherein the purity is 99.2%, and the yield is 83.6%; wherein, the liquid chromatogram of the raw material solution is shown in fig. 6, the liquid chromatogram of the effluent flowing out after 3.3h of residence is shown in fig. 7, the liquid chromatogram of the p-hydroxybenzaldehyde product is shown in fig. 8, the residence time of about 4.2min corresponds to the peak position of the raw material p-cresol in fig. 6 and 7, and the residence time of 2.7min corresponds to the peak position of the p-hydroxybenzaldehyde in fig. 7 and 8; in FIG. 7, the peak relative specific surface area corresponding to p-toluol is only 1.37%, the peak relative specific surface area of p-hydroxybenzaldehyde is 93.42%, and p-toluol is substantially completely converted into p-hydroxybenzaldehyde, and as can be seen from FIG. 8, the finally obtained p-hydroxybenzaldehyde product has almost no impurity peak, and the p-hydroxybenzaldehyde product has high purity.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A continuous production method of parahydroxyben-zaldehyde, which is characterized by comprising the following steps:
Step S1, mixing concentrated sulfuric acid and water in a seventh continuous flow reactor to obtain a third sulfuric acid aqueous solution, preparing a nitrifying reagent in an eighth continuous flow reactor by the third sulfuric acid aqueous solution and fuming nitric acid, reacting toluene and the nitrifying reagent in a ninth continuous flow reactor, nitrifying the toluene to generate paranitrotoluene, and continuously separating and purifying a system after the nitrifying reaction is completed to obtain the paranitrotoluene;
S2, dissolving the paranitrotoluene in an organic solvent to form a paranitrotoluene solution, and introducing hydrogen into the paranitrotoluene solution in a first continuous flow reactor under the catalysis of a hydrogenation catalyst to perform hydrogenation reaction to generate paratoluidine;
S3, dissolving the p-toluidine in a first sulfuric acid aqueous solution in a second continuous flow reactor to obtain a p-toluidine ammonium salt solution, carrying out diazotization reaction on the sodium nitrite aqueous solution and the p-toluidine ammonium salt solution in a third continuous flow reactor to obtain a p-toluidine diazonium salt solution system, carrying out quenching reaction on the p-toluidine diazonium salt solution system by using a urea aqueous solution in a fourth continuous flow reactor to obtain a diazonium salt quenching system, carrying out diazonium salt Jie Sheng on p-cresol in a mixed solution of the second sulfuric acid aqueous solution and an organic solvent in a fifth continuous flow reactor, and carrying out continuous separation and purification on the diazonium salt solution system after the diazonium salt reaction is completed to obtain p-toluol;
And S4, dissolving the p-cresol and sodium hydroxide in methanol to form a mixed solution of the p-cresol and the sodium hydroxide, conveying the mixed solution of the p-cresol and the sodium hydroxide to a sixth continuous flow reactor, introducing oxygen to perform oxidation reaction under the catalysis of an oxidation catalyst to generate p-hydroxybenzaldehyde, and continuously separating and purifying the system after the oxidation reaction is completed to obtain the p-hydroxybenzaldehyde.
2. The continuous production method of parahydroxyben-zaldehyde according to claim 1, characterized in that in the step S1, paranitrotoluene is obtained by separating liquid, alkaline washing and rectifying the system after the nitration reaction is completed; and/or the number of the groups of groups,
In the step S1, separating the system after the nitration reaction is completed, washing an organic phase after the separation with alkali, washing the organic phase after the alkali washing with water, and rectifying the organic phase after the water washing to obtain paranitrotoluene; and/or the number of the groups of groups,
In the step S2, removing hydrogen and concentrating the system after the hydrogenation reaction is completed to remove a solvent, thereby obtaining the p-toluidine; and/or the number of the groups of groups,
In the step S3, the system after the hydrolysis reaction is subjected to liquid separation, alkali washing and distillation to obtain p-toluene; and/or the number of the groups of groups,
In the step S4, the system after the oxidation reaction is subjected to acid precipitation, filtration and drying to obtain the parahydroxyben-zaldehyde.
3. The continuous production method of parahydroxyben-zaldehyde according to claim 1, wherein in the step S2, the hydrogenation catalyst is one or more selected from palladium carbon, platinum carbon, raney nickel and supported nickel-based catalysts; and/or the number of the groups of groups,
In the step S2, the molar ratio of the hydrogen to the paranitrotoluene is 4-10: 1, a step of; and/or the number of the groups of groups,
In the step S2, the reaction temperature of the hydrogenation reaction is 50-90 ℃; and/or the number of the groups of groups,
In the step S2, the reaction pressure of the hydrogenation reaction is 0.1-1 MPa.
4. The continuous production method of parahydroxyben-zaldehyde according to claim 1, characterized in that in the step S3, the temperature of the diazotization reaction is 0-20 ℃; and/or the number of the groups of groups,
In the step S3, the diazotization reaction time is 6-30 min; and/or the number of the groups of groups,
In the step S3, the temperature of the quenching reaction is 0-20 ℃; and/or the number of the groups of groups,
In the step S3, the quenching reaction time is 6-60 min; and/or the number of the groups of groups,
In the step S3, the reaction temperature of the diazonium salt hydrolysis reaction is 50-100 ℃; and/or the number of the groups of groups,
In the step S3, the diazonium salt hydrolysis reaction time is 7-30 min; and/or the number of the groups of groups,
In the step S3, the mass fraction of sulfuric acid in the first sulfuric acid aqueous solution is 20-30%; and/or the number of the groups of groups,
In the step S3, the mass fraction of the para-tolueneammonium salt in the para-tolueneammonium salt solution is 20-30%; and/or the number of the groups of groups,
In the step S3, the mass fraction of sodium nitrite in the sodium nitrite aqueous solution is 20-30%; and/or the number of the groups of groups,
In the step S3, the mass fraction of urine in the urea aqueous solution is 3-8%; and/or the number of the groups of groups,
In the step S3, the mass fraction of sulfuric acid in the second sulfuric acid aqueous solution is 20-30%; and/or the number of the groups of groups,
In the step S3, the organic solvent is selected from one or more of chlorobenzene, 2-methyltetrahydrofuran, toluene and 1, 4-dioxane; and/or the number of the groups of groups,
In the step S3, the mass ratio of the para-tolueneammonium salt in the para-tolueneammonium salt solution, the sodium nitrite in the sodium nitrite aqueous solution and the urea in the urea aqueous solution is 1: (0.2 to 0.8): (0.01 to 0.1).
5. The continuous production method of parahydroxyben-zaldehyde according to claim 1, characterized in that in the step S4, the oxidation catalyst is a transition metal supported catalyst; and/or the number of the groups of groups,
In the transition metal supported catalyst, the carrier is selected from one of active carbon, silicon dioxide and carbon nano tubes, and the transition metal is selected from at least one of cobalt and copper; and/or the number of the groups of groups,
In the step S4, the molar ratio of the oxygen to the p-cresol is (5-15): 1, a step of; and/or the number of the groups of groups,
In the step S4, the mass ratio of the p-cresol to the sodium hydroxide is 1: (0.9 to 1.1); and/or the number of the groups of groups,
In the step S4, the concentration of the p-cresol in the mixed solution of the p-cresol and the sodium hydroxide is 0.08-0.2 g/ml; and/or the number of the groups of groups,
In the step S4, the concentration of sodium hydroxide in the mixed solution of the p-cresol and the sodium hydroxide is 0.08-0.2 g/ml; and/or the number of the groups of groups,
In the step S4, the temperature of the oxidation reaction is 60-90 ℃; and/or the number of the groups of groups,
In the step S4, the pressure of the oxidation reaction is 0.1-0.6 MPa.
6. The continuous production method of parahydroxyben-zaldehyde according to any one of claims 1 to 5, characterized in that in the step S1, the mass fraction of sulfuric acid in the third sulfuric acid aqueous solution is 60-80%; and/or the number of the groups of groups,
In the step S1, the molar ratio of nitric acid to toluene is 1-1.5: 1 feeding the nitration reagent and the toluene into the ninth continuous flow reactor; and/or the number of the groups of groups,
In the step S1, the molar ratio of sulfuric acid to toluene is 3-5: 1 feeding the nitration reagent and the toluene into the ninth continuous flow reactor; and/or the number of the groups of groups,
In the step S1, the reaction temperature of the nitration reaction is 55-70 ℃; and/or the number of the groups of groups,
In the step S1, the reaction time of the nitration reaction is 10-90 min.
7. A continuous production system employed in the continuous production method of parahydroxyben-zaldehyde according to any one of claims 1 to 6, characterized by comprising: the device comprises a nitration reaction unit, a first continuous separation and purification unit, a catalytic hydrogenation reaction unit, a second continuous separation and purification unit, a diazotization and hydrolysis unit, a third continuous separation and purification unit, a catalytic oxidation unit and a fourth continuous separation and purification unit;
The nitration reaction unit includes:
The seventh continuous flow reactor is provided with a concentrated sulfuric acid feeding pipe, a water inlet pipe and a third sulfuric acid aqueous solution discharging port;
the eighth continuous flow reactor is provided with a third sulfuric acid aqueous solution feeding pipe, a fuming nitric acid feeding pipe and a nitrifying reagent discharging port, and the third sulfuric acid aqueous solution feeding pipe is connected with the third sulfuric acid aqueous solution discharging port;
The ninth continuous flow reactor is provided with a nitrifying reagent feeding pipe, a toluene feeding pipe and a system discharge port after the nitrifying reaction is finished, and the nitrifying reagent feeding pipe is connected with the nitrifying reagent discharge port; the system discharge port after the nitration reaction is completed is connected with the feed inlet of the first continuous separation and purification unit;
The catalytic hydrogenation reaction unit includes:
A first charging tank for preparing paranitrotoluene solution, wherein a charging port of the first charging tank is connected with a paranitrotoluene discharging port of the first continuous separation and purification unit;
The first continuous flow reactor is provided with a hydrogen feeding pipe, a paranitrotoluene solution feeding pipe and a discharge hole of a hydrogenation reaction system, and is connected with a hydrogen cylinder through the hydrogen feeding pipe; the first continuous flow reactor is connected with the discharge port of the first charging bucket through the paranitrotoluene solution feeding pipe; the discharge port of the hydrogenation reaction system is connected with the feed port of the second continuous separation and purification unit;
The diazotisation and hydrolysis unit comprises:
the second continuous flow reactor is provided with a first sulfuric acid water solution feeding pipe, a p-toluidine feeding pipe and a p-toluidine ammonium salt solution discharging port, and the p-toluidine feeding pipe is connected with the discharging port of the second continuous separation and purification unit;
The third continuous flow reactor is provided with a sodium nitrite water solution feeding pipe, a para-toluidine ammonium salt solution feeding pipe and a para-toluidine diazonium salt solution discharging port, and the para-toluidine ammonium salt solution feeding pipe is connected with the para-toluidine ammonium salt solution discharging port;
The fourth continuous flow reactor is provided with a urea water solution feeding pipe, a p-toluidine diazonium salt solution feeding pipe and a diazonium salt quenching system discharge port, and the p-toluidine diazonium salt solution feeding pipe is connected with the toluidine diazonium salt solution discharge port;
the fifth continuous flow reactor is provided with a diazonium salt quenching system feeding pipe, a second sulfuric acid water solution feeding pipe, an organic solvent feeding pipe and a hydrolysate discharging port, and the p-toluidine diazonium salt solution feeding pipe is connected with the diazonium salt quenching system discharging port; the hydrolysate discharge port is connected with the feed port of the third continuous separation and purification unit;
The catalytic oxidation unit includes:
the second charging bucket is used for preparing the mixed solution of the p-cresol and the sodium hydroxide, and a discharge port of the mixed solution of the p-cresol and the sodium hydroxide is arranged on the second charging bucket;
The system comprises a sixth continuous flow reactor, a first reactor and a second reactor, wherein the sixth continuous flow reactor is provided with an oxygen conveying pipeline, a p-toluene phenol conveying pipeline and a system discharge port after the oxidation reaction is finished, and the sixth continuous flow reactor is connected with an oxygen bottle through the oxygen conveying pipeline; the sixth continuous flow reactor is connected with a discharge port of the mixed solution of the cresol and the sodium hydroxide through the p-cresol conveying pipeline; and a system discharge port after the oxidation reaction is finished is connected with a feed inlet of the fourth continuous separation and purification unit.
8. The continuous production system of claim 7, wherein the first continuous separation and purification unit comprises: the second liquid separating device, the second alkali washing device, the water washing device and the second rectifying device; the feeding pipe of the second liquid separation device is connected with the system discharge port after the nitration reaction is finished, the organic phase outlet of the second liquid separation device is connected with the feeding pipe of the second alkaline washing device, and the feeding pipe of the water washing device is connected with the organic phase discharge port of the second alkaline washing device; the feeding pipe of the second rectifying device is connected with the organic phase discharge port of the water washing device, and the p-nitrotoluene discharge port of the second rectifying device is connected with the feeding port of the first charging tank; and/or the number of the groups of groups,
The second continuous separation and purification unit comprises: the device comprises a first gas-liquid separation tank, a first receiving tank, a third buffer tank, a falling film evaporator, a second receiving tank, a condenser, a light phase tank, a second liquid delivery pump, a heavy phase tank and a first buffer tank for containing p-toluidine, wherein a gas-liquid feeding pipe of the first gas-liquid separation tank is connected with a discharge port of a hydrogenation reaction system, a back pressure valve is arranged on the gas-liquid feeding pipe of the first gas-liquid separation tank, and the discharge port of the first gas-liquid separation tank is connected with the feeding pipe of the first receiving tank; the material inlet of the third buffer tank is connected with the material outlet of the first receiving tank through a third liquid delivery pump; the material inlet of the falling film evaporator is connected with the material outlet of the third buffer tank, and the material outlet of the falling film evaporator is connected with the material inlet of the second receiving tank; the gas phase outlet of the second receiving tank is connected with the condenser, the discharge port of the condenser is connected with the light phase tank, and the outlet of the light phase tank is connected with the solvent recovery device; the liquid phase outlet of the second receiving tank is connected with the feed inlet of the heavy phase tank through the second liquid delivery pump; the discharge port of the heavy phase tank is connected with the feeding pipe of the first buffer tank; the discharge port of the first buffer tank is connected with the toluidine feeding pipe; and/or the number of the groups of groups,
The third continuous separation and purification unit comprises: the organic phase outlet of the first liquid separating device is connected with the feeding pipe of the first alkaline washing device; the discharge port of the first alkaline washing device is connected with the feeding pipe of the first distillation device; the p-toluidine fraction outlet of the first distillation device is connected with a second buffer tank for containing p-cresol; and/or the number of the groups of groups,
The fourth continuous separation and purification unit comprises:
The device comprises a second gas-liquid separation tank, a third receiving tank, an acid precipitation device and a filtering device, wherein a gas-liquid feeding pipe of the second gas-liquid separation tank is connected with a discharge port of a system after oxidation reaction, and a liquid phase outlet of the second gas-liquid separation tank is connected with a feed port of the third receiving tank; a second back pressure valve is arranged at a gas outlet of the second gas-liquid separation tank; the feeding pipe of the acid precipitation device is connected with the discharge port of the third receiving tank, and the discharge port of the acid precipitation device is connected with the feeding port of the filtering device; the feeding pipe of the acid precipitation device is provided with a first liquid conveying pump and a fifth mass flow controller, and the acid liquid inlet of the acid precipitation device is connected with an acid liquid storage device.
9. The continuous production system of claim 7, wherein the first continuous flow reactor is one of a fixed bed reactor, a continuous tank reactor; and/or the number of the groups of groups,
The second continuous flow reactor is one of a micro-channel reactor and a tubular reactor; and/or the number of the groups of groups,
The third continuous flow reactor is one of a micro-channel reactor and a tubular reactor; and/or the number of the groups of groups,
The fourth continuous flow reactor is one of a micro-channel reactor and a tubular reactor; and/or the number of the groups of groups,
The fifth continuous flow reactor is one of a micro-channel reactor, a tubular reactor, a columnar stirring reactor and a continuous kettle reactor; and/or the number of the groups of groups,
The sixth continuous flow reactor is one of a fixed bed reactor and a continuous kettle reactor; and/or the number of the groups of groups,
The seventh continuous flow reactor, the eighth continuous flow reactor and the ninth continuous flow reactor are respectively and independently selected from one of a micro-channel reactor and a tubular reactor.
10. The continuous production system of any one of claims 7 to 9, wherein a nitrating material preheater is provided on the toluene feed pipe and the nitrating agent feed pipe; and/or the number of the groups of groups,
The hydrogen feeding pipe is sequentially provided with a regulating valve, a hydrogen buffer tank, a first mass flow controller and a hydrogen preheater, wherein the regulating valve is arranged close to the hydrogen cylinder, and the hydrogen preheater is arranged close to the first continuous flow reactor; and/or the number of the groups of groups,
A fourth liquid delivery pump, a third mass flow controller and a raw material preheater are sequentially arranged on the paranitrotoluene solution feeding pipe, the fourth liquid delivery pump is arranged close to the first charging bucket, and the raw material preheater is arranged close to the first continuous flow reactor; and/or the number of the groups of groups,
The oxygen transmission pipeline is sequentially provided with a second mass flow controller and an oxygen buffer tank, the second mass flow controller is arranged close to an oxygen bottle, and the oxygen buffer tank is arranged close to the sixth continuous flow reactor; and/or the number of the groups of groups,
A fifth liquid delivery pump and a fourth mass flow controller are sequentially arranged on the p-cresol delivery pipeline, the fifth liquid delivery pump is arranged close to the second charging bucket, and the fourth mass flow controller is arranged close to the sixth continuous flow reactor; and/or the number of the groups of groups,
The diazotisation and hydrolysis unit further comprises: the device comprises a sodium nitrate aqueous solution tank, a urea solution tank and an organic solvent tank, wherein the sodium nitrate aqueous solution tank is connected with a sodium nitrate aqueous solution feeding pipe, the urea aqueous solution tank is connected with a urea aqueous solution feeding pipe, and the organic solvent tank is connected with an organic solvent feeding pipe; and/or the number of the groups of groups,
The diazotisation and hydrolysis unit further comprises: the device comprises a third water storage tank, a first concentrated sulfuric acid tank and a tenth continuous flow reactor, wherein a concentrated sulfuric acid inlet of the tenth continuous flow reactor is connected with the first concentrated sulfuric acid tank, a water inlet pipe of the tenth continuous flow reactor is connected with the third water storage tank, and a discharge port of the tenth continuous flow reactor is connected with a first sulfuric acid aqueous solution feeding pipe; and/or the number of the groups of groups,
The diazotisation and hydrolysis unit further comprises: the device comprises a fourth water storage tank, a third concentrated sulfuric acid tank and an eleventh continuous flow reactor, wherein a concentrated sulfuric acid inlet of the eleventh continuous flow reactor is connected with the third concentrated sulfuric acid tank, a water body inlet of the eleventh continuous flow reactor is connected with the fourth water storage tank, and a discharge port of the eleventh continuous flow reactor is connected with a second sulfuric acid aqueous solution feeding pipe.
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