SG185374A1 - Process for preparing tolylenediamine by hydrogenation of dinitrotoluene - Google Patents
Process for preparing tolylenediamine by hydrogenation of dinitrotoluene Download PDFInfo
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- SG185374A1 SG185374A1 SG2012079281A SG2012079281A SG185374A1 SG 185374 A1 SG185374 A1 SG 185374A1 SG 2012079281 A SG2012079281 A SG 2012079281A SG 2012079281 A SG2012079281 A SG 2012079281A SG 185374 A1 SG185374 A1 SG 185374A1
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- reactor
- catalyst
- process according
- dinitrotoluene
- weight
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- DYSXLQBUUOPLBB-UHFFFAOYSA-N 2,3-dinitrotoluene Chemical compound CC1=CC=CC([N+]([O-])=O)=C1[N+]([O-])=O DYSXLQBUUOPLBB-UHFFFAOYSA-N 0.000 title claims abstract description 80
- 238000005984 hydrogenation reaction Methods 0.000 title claims abstract description 49
- VOZKAJLKRJDJLL-UHFFFAOYSA-N tolylenediamine group Chemical group CC1=C(C=C(C=C1)N)N VOZKAJLKRJDJLL-UHFFFAOYSA-N 0.000 title claims abstract description 35
- 238000004519 manufacturing process Methods 0.000 title description 7
- 239000003054 catalyst Substances 0.000 claims abstract description 107
- 238000000034 method Methods 0.000 claims abstract description 50
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 49
- 230000008569 process Effects 0.000 claims abstract description 40
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000001257 hydrogen Substances 0.000 claims abstract description 21
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 21
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 18
- 239000007791 liquid phase Substances 0.000 claims abstract description 17
- 238000002360 preparation method Methods 0.000 claims abstract description 6
- 239000000047 product Substances 0.000 claims description 49
- 239000000203 mixture Substances 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
- 238000006243 chemical reaction Methods 0.000 claims description 23
- 229910052751 metal Inorganic materials 0.000 claims description 17
- 239000002184 metal Substances 0.000 claims description 17
- 238000002955 isolation Methods 0.000 claims description 15
- 239000012263 liquid product Substances 0.000 claims description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 12
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 11
- 239000007789 gas Substances 0.000 claims description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 9
- VDCZKCIEXGXCDJ-UHFFFAOYSA-N 3-methyl-2-nitroaniline Chemical compound CC1=CC=CC(N)=C1[N+]([O-])=O VDCZKCIEXGXCDJ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 229910052763 palladium Inorganic materials 0.000 claims description 6
- 239000012071 phase Substances 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 5
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 230000000737 periodic effect Effects 0.000 claims description 3
- 239000011541 reaction mixture Substances 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 230000003068 static effect Effects 0.000 claims description 2
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 24
- 239000000725 suspension Substances 0.000 description 22
- 230000015572 biosynthetic process Effects 0.000 description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 12
- 239000007788 liquid Substances 0.000 description 12
- 238000004817 gas chromatography Methods 0.000 description 9
- 238000003969 polarography Methods 0.000 description 9
- 230000009467 reduction Effects 0.000 description 9
- 230000002829 reductive effect Effects 0.000 description 9
- 150000003839 salts Chemical class 0.000 description 8
- 239000002904 solvent Substances 0.000 description 8
- 230000001476 alcoholic effect Effects 0.000 description 7
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 6
- 239000007900 aqueous suspension Substances 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 6
- 230000009849 deactivation Effects 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- 238000004128 high performance liquid chromatography Methods 0.000 description 6
- 150000002739 metals Chemical class 0.000 description 6
- 238000010626 work up procedure Methods 0.000 description 6
- XTRDKALNCIHHNI-UHFFFAOYSA-N 2,6-dinitrotoluene Chemical compound CC1=C([N+]([O-])=O)C=CC=C1[N+]([O-])=O XTRDKALNCIHHNI-UHFFFAOYSA-N 0.000 description 5
- 229910018661 Ni(OH) Inorganic materials 0.000 description 5
- 239000000654 additive Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000001590 oxidative effect Effects 0.000 description 5
- 231100000572 poisoning Toxicity 0.000 description 5
- 230000000607 poisoning effect Effects 0.000 description 5
- RMBFBMJGBANMMK-UHFFFAOYSA-N 2,4-dinitrotoluene Chemical compound CC1=CC=C([N+]([O-])=O)C=C1[N+]([O-])=O RMBFBMJGBANMMK-UHFFFAOYSA-N 0.000 description 4
- -1 40 ZrO Chemical class 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 150000004982 aromatic amines Chemical class 0.000 description 4
- 238000004821 distillation Methods 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 150000002823 nitrates Chemical class 0.000 description 4
- 150000002828 nitro derivatives Chemical class 0.000 description 4
- 238000000634 powder X-ray diffraction Methods 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 229910052720 vanadium Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- 229910052797 bismuth Inorganic materials 0.000 description 3
- 239000006229 carbon black Substances 0.000 description 3
- 235000019241 carbon black Nutrition 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 150000002815 nickel Chemical class 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 3
- ZPTVNYMJQHSSEA-UHFFFAOYSA-N 4-nitrotoluene Chemical compound CC1=CC=C([N+]([O-])=O)C=C1 ZPTVNYMJQHSSEA-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000003480 eluent Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- CJNBYAVZURUTKZ-UHFFFAOYSA-N hafnium(iv) oxide Chemical compound O=[Hf]=O CJNBYAVZURUTKZ-UHFFFAOYSA-N 0.000 description 2
- 238000000265 homogenisation Methods 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000001603 reducing effect Effects 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 239000010948 rhodium Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- RUIFULUFLANOCI-UHFFFAOYSA-N 3,5-Dinitrotoluene Chemical compound CC1=CC([N+]([O-])=O)=CC([N+]([O-])=O)=C1 RUIFULUFLANOCI-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- USFZMSVCRYTOJT-UHFFFAOYSA-N Ammonium acetate Chemical compound N.CC(O)=O USFZMSVCRYTOJT-UHFFFAOYSA-N 0.000 description 1
- 239000005695 Ammonium acetate Substances 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910021607 Silver chloride Inorganic materials 0.000 description 1
- 239000004280 Sodium formate Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- GEIAQOFPUVMAGM-UHFFFAOYSA-N ZrO Inorganic materials [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- 229940043376 ammonium acetate Drugs 0.000 description 1
- 235000019257 ammonium acetate Nutrition 0.000 description 1
- VZTDIZULWFCMLS-UHFFFAOYSA-N ammonium formate Chemical compound [NH4+].[O-]C=O VZTDIZULWFCMLS-UHFFFAOYSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 239000000010 aprotic solvent Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- XTEGARKTQYYJKE-UHFFFAOYSA-N chloric acid Chemical compound OCl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-N 0.000 description 1
- 229940005991 chloric acid Drugs 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 238000002356 laser light scattering Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical class [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- OCAAQQIPYFCKIK-UHFFFAOYSA-N nitro(phenyl)methanamine Chemical class [O-][N+](=O)C(N)C1=CC=CC=C1 OCAAQQIPYFCKIK-UHFFFAOYSA-N 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 229910052762 osmium Inorganic materials 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 238000002459 porosimetry Methods 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 239000011669 selenium Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000010944 silver (metal) Substances 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- HLBBKKJFGFRGMU-UHFFFAOYSA-M sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 description 1
- 235000019254 sodium formate Nutrition 0.000 description 1
- 239000011877 solvent mixture Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010414 supernatant solution Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
- C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
- C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
- C07C211/49—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring having at least two amino groups bound to the carbon skeleton
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
20 AbstractPROCESS FOR PREPARING TOLYLENEDIAMINE BY HYDROGENATION OF DINITROTOLUENEThe invention relates to a process for continuous preparation of tolylenediamine by liquid phase hydrogenation of dinitrotoluene with hydrogen in the presence of a suspended nickel-containing catalyst in a reactor with a product removal unit connected downstream of the reactor to obtain a product output from the reactor comprising a liquid phase containing tolylenediamine and dinitrotoluene in which the nickel-containing catalyst is suspended, wherein the concentration of dinitrotoluene in the liquid phase of the product output from the reactor in the region between the reactor and the downstream product removal unit is adjusted to a value in the range from 1 to 200 ppm by weight, based on the total weight of the liquid phase of the product output from the reactor.No suitable figure
Description
Process for preparing tolylenediamine by hydrogenation of dinitrotoluene
The invention relates to a process for preparing toluenediamine by hydrogenation of dinitrotoluene.
Toluenediamine, hereinafter referred to as TDA, is an aromatic amine which is frequently used in industry; it is, in particular, processed further to give tolylene diisocyanate which is predominantly used in polyurethane production. TDA is prepared industrially by catalytic hydrogenation of dinitrotoluene, hereinafter referred to as DNT.
Many catalysts have been developed for the above reaction in order to achieve a very 16 high yield and selectivity in the reaction and also to discover catalysts which are stable at relatively high reaction temperatures.
The hydrogenation of DNT is strongly exothermic. It has therefore always been an aim to utilize the heat of reaction, for example in the form of steam.
As a reactor which is particularly suitable for removing the heat of reaction,
WO 00/35852 A1 has proposed a reactor which has internal and external loop motion and is configured as a vertically upright apparatus having a driving jet nozzle at its upper end, via which the reaction mixture taken off from the reaction bottoms is injected via an exothermic loop into the upper region of the reactor and subsequently flows into a central plug-in tube which is arranged in the longitudinal direction of the reactor, flows through this tube from the top downward, is there deflected by an impingement plate and again flows upward in an internal loop motion outside the plug- in tube. To remove the heat of reaction, heat exchangers, in particular field tubes, i.e. double tubes which are arranged vertically in the longitudinal direction of the reactor and in which the inner tube is open at the lower end to the outer tube and the outer tube is closed off at the bottom from the reaction space and in which a heat transfer medium, in particular water, flows and removes the heat of reaction, are provided in the interior of the reactor. In addition to the removal of heat via heat exchangers arranged in the interior of the reactor, a heat exchanger can also be provided in the external loop flow. In the process described in WO 00/35852 A1, aromatic amines are said to be produced in a high space-time yield and with significant suppression of secondary reactions.
However, it has been found that increased contents of nitroaromatics occasionally occur in the reactor, in particular at the position at which DNT is introduced and in the downward-directed flow, especially when low catalyst contents are used.
DE 198 44 901 C1 describes a process for preparing aromatic amines by the liquid- phase process, in which the nitroaromatics are fed via a ring conduit provided with holes into the reactor. The ring conduit can also be cooled by means of an external heat exchanger in order to rule out the risk of overheating and thus thermal decomposition of the nitroaromatics. In this process, particularly good distribution of the nitroaromatics in the reaction mixture is said to be achieved. Reactors described as suitable are, for example, loop reactors, bubble columns, preferably stirred vessels.
The advantages of the process described in DE 198 44 901 C1 is said to be that both catalyst deactivation and by-product formation are significantly reduced.
The challenge in the above processes for preparing TDA is to provide processes in which catalyst deactivation and by-product formation are reduced. It is therefore an object of the present invention to provide an economically attractive process for the catalytic hydrogenation of DNT to TDA which ensures an increased operating life of the catalyst and selectivity of the conversion of DNT into TDA.
The present invention accordingly provides a process for the continuous preparation of toluenediamine by liquid-phase hydrogenation of dinitrotoluene by means of hydrogen in the presence of a suspended, nickel-comprising catalyst in a reactor with a product isolation unit downstream of the reactor to give a product output from the reactor comprising a liquid phase comprising toluenediamine and dinitrotoluene, in which the nickel-comprising catalyst is suspended, wherein the concentration of dinitrotoluene in the liquid phase of the product output from the reactor in the region between the reactor and the downstream product isolation unit is set to a value in the range from 1 to 200 ppm by weight, based on the total weight of the liquid phase of the product output from the reactor.
It has been found that ensuring a minimum DNT concentration of at least 1 ppm, for example by lowering the reaction temperature, the hydrogen partial pressure, the residence time, the catalyst concentration or catalyst activity or by increasing the amount of dinitrotoluene fed in enables by-product formation to be considerably reduced.
Furthermore, it has been found that limiting the DNT concentration to not more than 200 ppm enables catalyst deactivation to be largely avoided.
In summary, it has thus been found that by-product formation can be reduced and at the same time catalyst deactivation can be largely avoided by setting the dinitrotoluene concentration to a value in the range from 1 to 200 ppm.
The dinitrotcluene concentration in the liquid product output from the reactor is preferably set to a value in the range from 1 to 100 ppm by weight, based on the total weight of the liquid product output from the reactor, more preferably to a value of from 2 to 50 ppm by weight, based on the total weight of the liquid product output from the reactor, and particularly preferably to a value in the range from 3 to 30 ppm by weight, based on the total weight of the liquid product output from the reactor.
For the purposes of the invention, “liquid product output in the region between the reactor and the product isolation unit” means a liquid stream or a plurality of liquid streams via which the product output is discharged from the reactor. The product output is preferably discharged at a place of low DNT concentration, i.e. typically at a position facing away from the DNT inlet via a catalyst removal unit. In the case of stirred tank reactors, a simple overflow is frequently utilized as catalyst removal unit for this purpose. In the case of loop reactors, on the other hand, the product output is usually discharged from the external loop.
Ensuring a DNT concentration in the range from 1 to 200 ppm in precisely this “liquid product output in the region between the reactor and the product isolation unit” thus at the same time serves as a final control on the mixing and reaction processes in the preceding reactors. Reference is explicitly made at this point to the technically very much more complicated task of ensuring suitable DNT concentrations at various points directly in the reactor. The concentration ranges to be set would in this case increase considerably with increasing vicinity to the point at which the DNT is introduced (and/or to regions in the reactor in which flow is relatively poor).
The product isolation unit or catalyst removal unit is generally a filter (e.g. a membrane filter/crossflow filter), a static decanter (e.g. a gravity separator or settler, frequently a lamellar clarifier) or a dynamic decanter (e.g. a centrifuge or a jet separator). The catalyst is separated off from the product and is subsequently recirculated (generally as a thickened suspension) to the reactor. The product output is particularly preferably discharged with retention of the catalyst. The amine can then be purified by conventional and known methods, for example by distillation or extraction.
The setting of the DNT concentration in the liquid product output from the reactor in the region between the reactor and the downstream product isolation unit on the basis of a 40 repeated measurement of the dinitrotoluene concentration in the liquid product output from the reactor is carried out at time intervals of <24 hours. The measurement is preferably repeated continually at time intervals of <12 hours, particularly preferably =4 hours and very particularly preferably <1 hour. The time intervals employed for monitoring should be selected so that changes in the DNT concentration in the region between the reactor and product isolation unit can be reacted to quickly. The samples to be taken for monitoring are usually taken upstream of the product isolation unit (for example when a settler is used) or downstream of the product isolation unit (for example when a filter is used). The measurement of the DNT concentration can be carried out in-line, on-line or off-line.
As reactors in which the process of the invention can be carried out, it is in principle possible to use all reactors suitable for the continuous hydrogenation of nitroaromatics.
Suitable reactors for the process of the invention are continuously operated stirred tank reactors, and circular flow reactors or loop reactors and also bubble columns are likewise suitable. In the process of the invention, preference is given to using stirred tank reactors, loop reactors, bubble columns or jet loop reactors having internal and external circulation, as described, for example, in WO 00/35852 A1. in the process of the invention, DNT is hydrogenated to TDA. Particularly low by- product formation and catalyst deactivation are observed.
The hydrogenation is carried out in the process of the invention under a pressure in the range from 5 to 50 bar, preferably at a pressure in the range from 10 to 40 bar, particularly preferably at a pressure in the range from 20 to 30 bar. The operating temperature at which the hydrogenation of dinitrotoluene to toluenediamine is carried out is generally in the range from 50 to 250°C, preferably in the range from 80 to 200°C, preferably in the range from 105 fo 130°C.
In a further preferred embodiment of the invention, the process of the invention is operated in such a way that the concentration of the partially hydrogenated intermediate aminonifrotoluene, hereinafter referred to as ANT for short, is also controlled and is set in the region between the reactor and the product isolation unit to an ANT concentration in the range from 0 to 2000 ppm, preferably to an ANT concentration in the range from 0.5 to 1000 ppm, particularly preferably to an ANT concentration in the range from 1 to 200 ppm. Setting of the concentration of this partially hydrogenated intermediate in the ranges mentioned firstly allows a further reduction in catalyst deactivation and secondly a further reduction in by-product formation. In general, the concentrations of DNT and ANT run largely parallel.
Many catalysts are possible for the preparation of TDA.
In a first general embodiment of the invention, the process of the invention is, as indicated above, carried out in the presence of a catalyst, in particular in the presence of a supported catalyst comprising, as active component, nickel either alone or together with at least one metal of transition groups |., V., VI. and/or VIII. of the Periodic Table. 5 The catalysts used according to the invention can be produced industrially by applying nickel and optionally at least one of the abovementioned additional metals to a suitable support.
In a preferred embodiment of the invention, the catalyst has a nickel content in the range from 0.1 to 99% by weight, preferably from 1 to 90% by weight, particularly preferably from 25 to 85% by weight and very particularly preferably from 60 to 80% by weight, based on the total weight of the catalyst.
As metals of transition groups |, Ii, V., VI. and/or VIII. of the Periodic Table, preference 156 is given to using palladium, platinum, rhodium, iron, cobalt, zinc, chromium, vanadium, copper, silver or a mixture of two or more thereof.
In a preferred embodiment of the invention, the catalyst comprises Ni and platinum. In a further preferred embodiment of the invention, the catalyst comprises Ni and Al; in a further particularly preferred embodiment, the catalyst comprises nickel, palladium and iron.
As support materials, preference is given to using activated carbon, carbon black, graphite or oxidic support components such as silicon dioxide, silicon carbide, kieselguhr, aluminum oxide, magnesium oxide, titanium dioxide, zirconium dioxide and/or hafnium dioxide or a mixture of two or more thereof, particularly preferably zirconium dioxide, ZrO», HO, and/or SiO,, ZrQ, and/or SiQ,, ZrO,, HfO,.
The supports used are preferably mesoporous and have an average pore diameter of from 35 to 50 nm and a specific surface area of from 50 to 250 m?%g. The surface area of the support is determined by the BET process by means of N; adsorption, in particular in accordance with DIN 66131. The average pore diameter and the pore size distribution are determined by Hg porosimetry, in particular in accordance with
DIN 66133.
The application of nickel! and optionally the at least one further metal can be achieved by the customary suitable methods which are known to a person skilled in the field of catalyst technology. The supports which have been coated, coated by coprecipitation or impregnated with the metal or metal salts are subsequently dried and calcined by 40 known methods. The coated supports are subsequently activated by treating them in a gas stream which comprises free hydrogen. This activation usually takes place at temperatures in the range from 30 to 600°C, preferably in the range from 80 to 150°C and particularly preferably at 100°C. The gas stream preferably comprises from 50 io 100% by volume of hydrogen and from 0 to 50% by volume of nitrogen. The catalyst produced for use according to the invention has a degree of reduction of at least 70% after reduction for one hour at 100°C.
The supported catalysts obtained in this way generally have a nickel metal surface area of from about 10 to about 50 m?g, preferably from about 20 to about 60 m?/g. The nickel content of the catalysts used in the process of the invention is generally in the range from 0.1 to 99% by weight, preferably in the range from 1 to 90% by weight, particularly preferably in the range from 25 to 85% by weight, based on the total weight of the catalysts used.
Suitable catalysts of this embodiment are described, for example, in the publications
EP 1161297 A1and EP 1 165 231 A1.
In a second embodiment of the invention, activated nickel catalysts as described, for example, in WO 2008/145179 A1 are used in the process of the invention. Accordingly, in a preferred embadiment of the invention, activated nickel catalysts based on an Ni/Al alloy, which can comprise one or more metals selected from the group consisting of
Mg, Ce, Ti, V, Nb, Cr, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Pt, Cu, Ag, Au and Bi, are used.
The degree of doping is in the range from 0.05% by weight to 20% by weight for each doping element. The average particle size of the catalysts used is < 25 um.
In a third embodiment of the invention, catalysts as are described, for example, in
WO 2008/138784 A1 are used in the process of the invention. The invention thus further provides, in a preferred embodiment of the invention, for the use of hydrogenation catalysts comprising, as active component, a mixture of nickel, palladium and an additional element selected from the group consisting of cobalt, iron, vanadium, manganese, chromium, platinum, iridium, gold, bismuth, molybdenum, selenium, tellurium, tin and antimony on a support for preparing aromatic amines by catalytic hydrogenation of the corresponding nitro compounds, in particular for preparing toluenediamine by hydrogenation of dinitrotoluene. The additional element is preferably selected from the group consisting of cobalt, iron, vanadium, bismuth and tin.
As supports for the catalysts, it is possible to use the materials which are customary and known for this purpose. Preference is given to using activated carbon, carbon black, graphite or metal oxides, preferably hydrothermally stable metal oxides such as 40 ZrO, TiO, Al, Os. In the case of graphite, HSAG (high surface area graphite) having a surface area of from 50 to 300 m%g is particularly preferred. Particular preference is given to activated carbons, in particular physically or chemically activated carbons, or carbon blacks such as acetylene black.
The catalysts according to the invention are produced, for example, by initially charging the support and bringing it into contact with an aqueous solution of the palladium and nickel salts together with the additional element. Here, the amount of the water used for dissolving the salts should be such that a kneadable paste is formed. The water is preferably used in an amount of from 100 to 200% by weight of the mass of the support. As metal salts, use is made, in particular, of nitrates or chiorides, with nitrates being preferred because they are less corrosive. The paste is mixed and the water is then evaporated under reduced pressure at temperatures in the range from 50 to 100°C, for example in a rotary evaporator or in an oven. For safety reasons, the evaporation can be carried out in a stream of nitrogen. Fixing of the metals to the support can be effected when using chlorides as metal salts by reduction by means of hydrogen. However, corrosion can occur here. The metals are therefore preferably fixed under alkaline conditions. This is carried out, in particular, by addition of an aqueous solution of alkali metal carbonates and subsequent washing of the support until it is free of anions. As an alternative, the metals can also be precipitated from a supernatant solution on to the support under alkaline conditions, in particular at a pH in the range from 8 to 9. The support is then dried, preferably as described above, and reduced by means of hydrogen. This can be affected, for example, in a rotary sphere oven. Before removal of the catalyst from the oven, the catalyst is passivated, for example under an inert gas such as nitrogen containing traces of air, preferably not more than 10% by volume.
The hydrogenation catalysts according to the invention produced by this method preferably comprise from 0.5 to 5% by weight of palladium, from 10 to 20% by weight of nickel and from 0.5 to 5% by weight of the additional element.
In a further embodiment of the production of the hydrogenation catalysts used according to the invention, the reduction of the catalysts is effected by addition of salts having a reducing action, e.g. ammonium carboxylates or alkali metal carboxylates, for example ammonium formate or sodium formate. For this purpose, the support is suspended in water and the solutions of the metal salts are added simultaneously with or after suspension. As metal salts, use is made, in particular, of nitrates or chlorides, with nitrates being preferred because they are less corrosive. The salts having a reducing action are added to this solution and the suspension is heated, for example by boiling under reflux. The catalysts are subsequently washed free of anions and filtered, for example by means of a filter press or a centrifuge, and used as moist paste. Further 40 examples of the production of the catalysts which are preferably used may be found in
WO 2005/037768 A1.
In the process of the invention, 2,4-DNT or industrial mixtures thereof which further comprise 2,6-DNT, with these mixtures preferably comprising up to 35% by weight, based on the total weight, of 2,6-DNT with proportions of from 1 to 4% of vicinal DNT and from 0.5 to 1.5% of 2,5- and 3,5-DNT, are hydrogenated to the corresponding amine. The DNT isomers are frequently used in the isomer ratio obtained in the dinitration of toluene.
In the process of the invention, the 2,4-DNT or the 2,4-DNT/2,6-DNT mixture can be used in pure form, as a mixture with water, as a mixture with water and an alcoholic solvent or as a mixture with water, an alcoholic solvent and a catalyst-reactivating additive. It is likewise possible for catalysts, water and/or alcoholic solvents or mixtures thereof to be introduced together or separately in addition to and separately from the
DNT.
As can be derived from what has been said above, the hydrogenation in the process of the invention can be carried out in the absence or presence of an alcoholic solvent and a catalyst-activating additive.
If an alcoholic solvent and a catalyst-reactivating additive are used, it is of course also possible to add mixtures of two or more thereof.
Alcoholic solvents used are lower aliphatic alcohols having from 1 to 6 carbon atoms, preferably methanol, ethanol or propanol or a mixture of two or more thereof.
As catalyst-activating additives, preference is given to using aprotic solvents, in particular acetone, dimethylformamide, dioxane or tetrahydrofuran or a mixture of two or more thereof.
The amount of the alcoholic solvents used and of the catalyst-reactivating additives is not restricted in any particular way for the purposes of the process of the invention and can be chosen freely by a person skilled in the art in accordance with requirements.
In a preferred embodiment of the invention, the hydrogenation is carried out in a three- phase mixture of hydrogen-comprising gas phase, suspended catalyst and liquid phase comprising from 0 to 40% by volume of an alcohol, from 10 to 60% by volume of water and from 20 to 70% by volume of TDA, as defined above. The catalyst content is from about 0.1 to 15% by weight, preferably from 2 to 8% by weight, based on the total weight of the three-phase mixture used. 40 The invention is illustrated by the following examples.
Example 1
A cylindrical loop reactor having a driving jet nozzle which is driven by two centrifugal pumps connected in series and is arranged centrally at the top of the reactor and opens into an external circuit, a concentric plug-in tube and an impingement plate in the lower part of the reactor for deflecting the loop flow (internal circuit) (for the functional principle, cf. WO 2000/35852 A1) was used. The reaction volume of the reactor was about 14 m°. The reactor was provided with a bundle of field tubes connected in parallel to remove the heat of reaction. The amount of cooling water fed info the field tubes was set so that the temperature in the reactor was maintained at about 120°C. To maintain the loop flow, a volume flow of 600 m*/h was circulated in the external product circuit, as a result of which a pressure drop of about 2.5 bar was established over the driving jet nozzle. The reactor comprised about 12 m® of a liquid hydrogenation bath. This consisted essentially of a mixture of TDA and water in a mass ratio of 0.58 : 0.42 in which about 5% by weight of a metallic Ni catalyst supported on
SiO; and ZrO; (produced as described in example 2 of EP 1 161 297 and comminuted by means of a stirred mill; here, 10% by volume of the catalyst consisted of particles having a diameter of <about 5 um, 50% by volume are <about 10 um and 90% by volume are <about 15 um, measured by laser light scattering (Malvern Mastersizer S) after stirring in water) were suspended and, in addition, hydrogen was dissolved. The liquid surface was just below the opening of the driving jet nozzle. Above this there were about 2 m® of a gas atmosphere whose hydrogen content was set to from 90 to 95% by volume (in addition to inert gases such as N;) by continuous discharge of a small offgas stream. 7.5 t/h of molten DNT heated to about 80°C, which comprised a mixture of the 2,4- and 2,6-DNT isomers in a ratio of about 80 : 20 and about 5% of the remaining DNT isomers and traces of mononitrotoluene, was injected into the gas space of the reactor by means of a diaphragm metering pump. A pressure of 25 bar was set in the reactor by simultaneous introduction of about 0.5 t/h of hydrogen (diluted with about 2 kg/h Ny). 95% of the hydrogen was metered into the hydrogenation bath via a nozzle ring above the impingement plate and 5% was metered in at the reactor outlet. The reaction proceeded under largely isothermal conditions: the reaction temperature remained in the range from 116 to 126°C in the overall reactor. in addition, 625 kg/h of a suspension of the abovementioned catalyst in water (partly separated off from the hydrogenation product in the work-up section) were metered in, likewise continuously, by means of a diaphragm pump. The amount of catalyst comprised in this suspension was varied in a targeted manner in the range from 0 to 5 kg/h in order to set the DNT concentration and was on average about 1 kg/h.
To keep the liquid level in the reactor constant, an appropriate amount of hydrogenation product was taken off continuously from the external product circuit on the pressure side of the 2nd centrifugal pump and fed into a lamellar clarifier having a liquid volume of about 50 m*® and a gas volume of about 10 m®. The catalyst could concentrate in the lower region of the clarifier. 18 standard m*h of an appropriately thickened suspension were then recirculated to the suction side of the 1st centrifugal pump. At the same time, about 8.6 t/h of hydrogenation product were taken from the lamellar clarifier via an overflow. This product comprised about 4.9 t/h of TDA (with an isomer distribution corresponding to that of the DNT used), about 0.1 t/h of low and high boilers (in a ratio of about 20 : 80) and about 3.6 t/h of water and up to about 1 kg/h of catalyst (mostly fines). The hydrogenation product was conveyed via a pressure reduction like the hydrogenation products of other reactors into a joint intermediate vessel and was from this conveyed continuously to the work-up by distillation. The parts in contact with the product were partly made of standard steel (in general S137) and partly of stainless steel (1.4571).
To determine the content of DNT and ANT in the hydrogenation bath, samples of suspension were taken at intervals of not more than 4 hours from the line from the external product circuit of the loop reactor fo the lamellar clarifier. These were freed of suspended solid by filtration and the concentration of the nitro compounds comprised was determined by means of polarography. The DNT concentration was set fo from 3 to 30 ppm (on average: 10 ppm) and the ANT concentration was set to from 1 to 200 ppm (on average: 3 ppm) by adjusting the catalyst concentration in the aqueous suspension fed to the reactor (see above).
The reactor was operated under the conditions mentioned for 3 months without significant interruptions. During this time, the crystallite size determined by means of
X-ray powder diffraction of the Ni catalyst filtered off in each case from the above samples of suspension increased from 9 nm to 14 nm as a result of sintering. During a further three months under these conditions, the crystallite size increased further to 15 nm. An appreciable change in the stoichiometric composition of the catalyst or its catalytic performance was not observed over the entire 6 months, nor was formation of oxidized Ni species (for example formation of Ni(OH), by oxidative poisoning).
Example 2
A stirred tank reactor (diameter: 2.8 m, height: 4.7 m, volume: 23 mS, material: St37) having cooling coils fastened by means of fine supports in the interior in the region of the reactor wall and a double inclined blade stirrer was used: the larger upper set of 40 inclined blades pushed the hydrogenation bath downward in the interior of the reactor, and the bath then flowed upward again along the cooling coils; the lower set of inclined blades, on the other hand, sucked in the thickened suspension flowing back from the lamellar clarifier which was likewise used here and pushed it upward into the flow generated by the upper set of blades. The amount of cooling water fed into the cooling coils was set so that the temperature in the reactor was maintained in the range from 116 to 126°C. The reactor comprised about 18 m® of a liquid hydrogenation bath. This consisted essentially of a mixture of TDA and water in a mass ratio of 0.58 : 0.42 in which about 5% by weight of the metallic Ni catalyst supported on SiO, and ZrO», as mentioned in example 1, was suspended and, in addition, hydrogen was dissolved.
Above the surface of the liquid there was about 5 m® of a gas atmosphere whose hydrogen content was set to from 90 to 99% by volume (in addition to inert gases such as Ny) by continuously discharging a small offgas stream. 5 t/h of molten DNT heated to about 80°C, which consisted of a mixture of the 2,4- and 2,6-DNT isomers in a ratio of about 80 : 20 and about 5% of the other DNT isomers and traces of mononitrotoluene, were metered by means of a diaphragm metering pump into a funnel which was open in the direction of the gas space and conveyed the
DNT downward via a line into the hydrogenation bath between the sets of inclined blades. A pressure of 25 bar was set in the reactor by simultaneous introduction of about 330 kg/h of hydrogen (diluted with about 2 kg/h of N,). The hydrogen was metered into the hydrogenation bath via a nozzle ring which was installed centrally between the two sets of inclined stirrer blades and fastened there by means of frame supports. The reaction proceeded under largely isothermal conditions. In addition, 435 kg/h of a suspension of the abovementioned catalyst in water (partly separated off from the hydrogenation product in the work-up section) were metered in, likewise continuously, by means of a diaphragm pump. The amount of the catalyst comprised in the suspension was varied in a targeted manner in the range from 0 to 5 kg/h to set the
DNT concentration and was on average just under 1 kg/h.
To keep the liquid level of the reactor constant, an appropriate amount of hydrogenation product was taken off continuously via an overflow and fed into a lamellar clarifier having a liquid volume of about 16 m® and a gas volume of about 4 m®.
The catalyst could concentrate in the lower region of the clarifier. About 30 standard mh of an appropriately thickened suspension were then sucked back into the stirred tank by means of the lower set of blades of the inclined blade stirrer. At the same time, about 5.8 th of hydrogenation product were taken from the lamellar clarifier via an overflow. This product comprised about 3.3 t/h of TDA (with an isomer distribution corresponding to that of the DNT used), about 0.07 t/h of low and high boilers (in a ratio of about 10 : 60) and about 2.4 t/h of water and up to 1 kg/h of catalyst (mostly fines).
The hydrogenation product was conveyed via a pressure reduction like the 40 hydrogenation products of other reactors into a joint intermediate vessel and from this was fed continuously to the work-up by distillation.
To determine the content of DNT and ANT in the hydrogenation bath, samples of suspension were taken at intervals of not more than 4 hours from the line from the stirred tank reactor to the lamellar clarifier. These were freed of suspended solid by filtration and the concentration of the nitro compounds comprised was determined by means of polarography. The DNT concentration was set to from 3 to 30 ppm (on average: 10 ppm) and the aminonitrotoluene concentration was set to from 1 to 200 ppm (on average: 3 ppm) by adjusting the catalyst concentration in the aqueous suspension fed to the reactor (see above).
The reactor was operated under the conditions mentioned for 3 months without significant interruptions. During this time, the crystallite size determined by means of
X-ray powder diffraction of the Ni catalyst filtered off in each case from the above samples of suspension increased from 15 nm to 16 nm as a result of sintering. An appreciable change in the stoichiometric composition of the catalyst or its catalytic performance was not observed, nor was formation of oxidized Ni species (for example formation of Ni(OH), by oxidative poisoning).
Example 3
The stirred tank reactor described in example 2 was used and the procedure described there was employed. To achieve better separation of the reaction products from the catalyst, to make oxidative poisoning more difficult and achieve optimal homogeneity of the hydrogenation bath even at a lower reaction temperature of from 100 to 105°C, ethanol was used as additional solubilizer. The catalyst was accordingly not introduced in aqueous suspension but instead in the form of 0.5 t/h of an ethanolic suspension {ethanol recovered from the hydrogenation product in the work-up section was mostly used here). The amount of the catalyst comprised in this suspension was varied in a targeted manner in the range from 0 to 5 kg/h as in example 2 in order to set the DNT concentration and was on average just under 1kg/h. The other flows were as described in example 2.
The about 5.9 t/h of hydrogenation product taken from the lamellar clarifier via the overflow comprised a good 3.3 t/h of TDA (with an isomer distribution corresponding to that of the DNT used), about 0.05 t/h of low and high boilers (in a ratio of about 10 : 40) and about 2 t/h of water, about 0.5 t/h of ethanol and up to 1 kg/h of catalyst (mostly fines). The hydrogenation product was conveyed via a pressure reduction like the hydrogenation products of other reactors into a joint intermediate vessel and was fed continuously from this to the work-up by distillation. To determine the content of DNT and ANT in the hydrogenation bath, samples of suspension were taken at intervals of 40 not more than 4 hours from the line from the stirred tank reactor to the lamellar clarifier.
These were freed of suspended solid by filtration and the concentration of the nitro compounds comprised was determined by means of polarography. The DNT concentration was set to from 3 to 30 ppm (on average: 10 ppm) and the ANT concentration was set to from 1 to 200 ppm (on average: 3 ppm) by adjusting the catalyst concentration in the aqueous suspension fed to the reactor (see above).
The reactor was operated under the conditions mentioned for 3 months without significant interruptions. During this time, the crystallite size determined by means of
X-ray powder diffraction of the Ni catalyst filtered off in each case from the above samples of suspension increased from 14 nm to 15 nm as a result of sintering. An appreciable change in the stoichiometric composition of the catalyst or its catalytic performance was not observed, nor was formation of oxidized Ni species (for example formation of Ni(OH), by oxidative poisoning).
Example 4
As in example 2, a stirred tank reactor (diameter: 2.8 m, height: 4.7 m, volume: 23 m®, material: St37) having cooling coils fastened in the interior in the region of the reactor wall and a double inclined blade stirrer was used. However, the fastenings of the cooling coils and the nozzle ring for distribution of hydrogen were made very much more solid and thus resulted in slightly poorer mixing of the hydrogenation bath.
Otherwise, the reaction was carried out as described in example 2.
Despite an average concentration of the fresh catalyst added to the aqueous suspension which was doubled compared to example 2, viz. 2 instead of 1 kg/h, i.e. introduction of twice as much fresh catalyst, the average aminonitrotoluene concentration in the filtered samples of suspension taken between the reactor and the lamellar clarifier increased, compared to example 2, from 3 to 25 ppm, and values up to 300 ppm were sometimes measured, The average DNT concentration was also slightly increased at 15 instead of 10 ppm, and values up to 50 ppm were sometimes measured.
The reactor was operated under the conditions mentioned for three months, likewise without significant interruptions. During this time, the crystallite size determined by means of X-ray powder diffraction of the Ni catalyst which was in each case filtered off from the above samples of suspension increased very greatly from 8 nm to 17 nm as a result of sintering. An appreciable change in its stoichometric composition or formation of oxidized Ni species (e.g. formation of Ni(OH), by oxidative poisoning) did not occur here either. However, the amount of DNT fed in had to be reduced stepwise after these three months in order to prevent a further increase in the concentration of DNT and 40 aminonitrotoluene. After a further two months, replacement of the entire catalyst was unavoidable.
Comparative example 1
The stirred tank reactor described in example 4 was used and the procedure described there was employed. In contrast to example 4, the hydrogenation bath here consisted of a mixture of toluenediamine (TDA) and water in a ratio of 0.3 : 0.7, which apart from the dissolved hydrogen comprised only about 1.5% by weight of the metallic Ni catalyst supported on SiO; and ZrO, which was mentioned in example 1 in suspended form.
The amount of the fresh catalyst comprised in the aqueous suspension fed in was on average only just under 0.5 kg/h.
The reactor could be operated under these conditions for only about one hour. The reaction then had fo be stopped because of a decreasing uptake of hydrogen. The polarographic determination of the content of DNT and aminonitrotoluenes in the filtered sample of the suspension taken from the line from the stirred tank reactor to the lamellar clarifier 30 minutes after commencement of the reaction indicated a DNT concentration of 842 ppm and an aminonitrotoluene concentration of 2050 ppm.
Subsequent examination of the Ni catalyst filtered off from a sample of suspension taken after the reaction had been stopped did indicate an unchanged Ni crystallite size and stoichiometric composition within measurement accuracy, but a considerable part of the nickel was present in oxidized form (mostly as catalytically inactive Ni(OH),).
Replacement of the entire catalyst was unavoidable.
Example 5
The hydrogenation of DNT to TDA was carried out in a 180 ml continuous stirred tank, and the catalyst was mechanically held back in the reactor. A 2.8% Pt-0.7% Ni on
Norit® SX activated carbon support catalyst (WO 2005/037768) was suspended in water and introduced into the reactor (amount of catalyst = 0.5% by weight of the liquid volume of the reactor); the reactor was maintained at a temperature of 125°C. Under a hydrogen pressure of 24 bar, DNT was metered in continuously as a melt in such an amount that a space velocity over the catalyst of 180 kgpnr/kgeah was set. Samples were analyzed by means of gas chromatography: the DNT and ANT concentration and the TDA yield were monitored.
Example 6
Same as example 5 but with a space velocity over the catalyst of 229 kgpnr/kgeach.
Comparative example 2 40
Same as example 5 but with a space velocity over the catalyst of 45 kgont/KQearh.
Comparative example 3
Same as example 5 but with a space velocity over the catalyst of 284 kgpnr/kgeah. [ _TDAyed(% | DNT(pm | ANT (em)
Examples | een | 20 | 600
Comparative example? | 987 | 0 | 0
Example 7
The hydrogenation of DNT to TDA was carried out in a 180 ml continuous stirred tank, and the catalyst was mechanically held back in the reactor. A catalyst as described in example 1 was suspended in water and introduced into the reactor (amount of catalyst = 2.5% by weight of the liquid volume of the reactor), and the reactor was maintained at a temperature of 125°C. Under a hydrogen pressure of 24 bar, DNT was metered in continuously as a melt in such an amount that a space velocity over the catalyst of 17 kgonr/kgeah was set. Samples were analyzed by means of gas chromatography: the DNT and ANT concentration and the TDA yield were monitored.
Comparative example 4
Same as example 6 but with a space velocity over the catalyst of 12 kgpni/KQearh.
TDAyield(%) | DNT(ppm) | ANT (ppm)
Comparatveexample4 | 983 ~~ | 0 [| 0
Comparison of different analytical methods for determining DNT and ANT:
Three methods for the analysis of DNT and ANT in the hydrogenation bath are, by way of example, described and compared below. For this purpose, a series of experiments was set up and the analytical methods were compared. The examples described are intended to show that it is possible to analyze the hydrogenation bath using conventional analytical methods and that the same results are obtained regardless of the method of analysis. The three methods gas chromatography (GC), high-pressure liquid chromatography (HPLC) and polarography are only examples of the large number of different possible spectroscopic, chromatographic, electrochemical and other methods. Ili can be seen from the following results that, for example, the use of polarography is possible in principle but it has to be ensured that the samples are measured promptly (at the latest 4 hours, better 1 hour, even better 30 minutes or
15 minutes, after sampling). Otherwise, DNT and ANT values which are erroneously too high are obtained. GC and HPLC enable the substances to be identified and quantified without erroneously positive results being obtained.
The analytical methods are preferably carried out as follows:
Polarography is carried out in a solvent mixture consisting of equal parts of dimethylformamide and 1 mol/l chloric acid solution.
In the electrolyte indicated, dinitrotoluene (DNT) is reduced at about 330 mV and aminonitrotoluene is reduced at about 550 mV. A change in the isomer ratio does not influence the height of the polarographic step. >» VA-processor 746 or 693 polarograph with VA stand (from Metrohm) » Dropping mercury electrode, DME, ¥» Reference electrode, Ag/AgCl, » Electrolyte key, saturated LiCl in ethanol, > Volumetric flasks 100 ml, 50 ml and 25 ml, » Analytical balance (reading precision 0.001 g or better), e.g. Sartorius RC 250 » Pipette 5 mi, » Titration vessels
Gas chromatography (GC) is preferably carried out as indicated below:
Column: Varian — Factor Four CP 8977 (10 mx 0.10 mm ID x 0.20 ym FT)
Carrier gas: helium
Pressure: 41.8 psi
Split flow: 15.2 ml/min
Temperature (ECD): 300°C
Temperature (injector): 250°C
Oven : initial temp.: ~~ 75°C — 20.0°C/min => 250°C — 4.0 min
Injection volume: 0.2 pi
Sample preparation: sample weight: about 500 mg + 5 m| of MeOH
High-pressure liquid chromatography (HPLC) is preferably carried out as follows:
Column: Agilent Lichrosorb RP-18 (4.6 x 200 mm, 5 um)
Eluent 1: water + 1 g/l of ammonium acetate
Eluent 2: methanol 40 Gradient: 0 min 70% of water/30% of methanol 18 min 10% of water/90% of methanol
25 min 10% of water/90% of methanol 30 min 70% of water/30% of methanol
Flow: 0.5 ml/min
Oven temp.: 38°C
Wavelength: 254 nm/bandwidth 4 nm, reference 550 nm/bandwidith 100 nm
Inj. volume: 25 ul
Sample preparation: weight of sample: about 500 mg + 5 ml of MeOH
Series of experiments:
Mixtures of precisely 60.00 g of freshly distilled TDA (2,4- and 2,6-isomer) and 40.00 g of water were produced in a 250 ml conical flask and mixed well at 85°C. As soon as the samples were homogeneous, various amounts of a DNT isomer mixture were added and the samples were homogenized again. The content of the 2,4-DNT isomer was then determined by means of GC and HPLC and the total content of all DNT isomers was determined by means of GC and polarography. The determination by means of polarography was carried out 15 minutes after the renewed homogenization and a second time 4 hours after the renewed homogenization.
Results (measured values in ppm}:
Sample [Method | | 24DNT | Tow DNT cc [1 oo 1 0
Hee | 0 [oo |]
Emr
After 4 h 45
Gc | 48 | =
Hee | [wm
Emer
After 4 h 34 2 Gc | ss | a
Eee pee en | | &
After 4 h 69 3 6c | 1 wm |e [i
Polarography After 15 min 60
EE AE
Claims (16)
1. A process for the continuous preparation of toluenediamine by liquid-phase hydrogenation of dinitrotoluene by means of hydrogen in the presence of a suspended, nickel-comprising catalyst in a reactor with a product isolation unit downstream of the reactor to give a product output from the reactor comprising a liquid phase comprising toluenediamine and dinitrotoluene, in which the nickel-comprising catalyst is suspended, wherein the concentration of dinitrotoluene in the liquid phase of the product output from the reactor in the region between the reactor and the downstream product isolation unit is set to a value in the range from 1 to 200 ppm by weight, based on the total weight of the liquid phase of the product output from the reactor.
2. The process according to claim 1, wherein the concentration of dinitrotoluene in the liquid product output from the reactor is set to a value in the range from 1 to 100 ppm by weight, based on the total weight of the liquid product output from the reactor, preferably to a value of from 2 to 50 ppm by weight, based on the total weight of the liquid product output from the reactor, more preferably to a value in the range from 3 to 30 ppm by weight, based on the total weight of the liquid product output from the reactor.
3. The process according to claim 1 or 2, wherein the hydrogenation of dinitrotoluene to toluenediamine is carried out at a temperature in the range from 50 to 250°C.
4. The process according to any of claims 1 to 3, wherein the hydrogenation of dinitrotoluene to toluenediamine is carried out at a pressure in the range from 5 to 50 bar.
5. The process according to any of claims 1 to 4, wherein the liguid phase of the product output comprises aminonitrotoluene and the concentration of amincnitrotoluene in the liquid phase of the product output from the reactor in the region between the reactor and the product isolation unit is set to a value in the range from 0 to 2000 ppm by weight, based on the total weight of the liquid phase of the product output.
6. The process according to any of claims 1 to 5, wherein the reactor is selected from the group consisting of a stirred tank reactor, a loop reactor and a bubble column.
7. The process according to any of claims 1 to 6, wherein the reactor is a jet loop reactor having external and internal circulation.
8. The process according to any of claims 1 to 7, wherein the product isolation unit is selected from the group consisting of a filter, a static decanter and a dynamic decanter.
a. The process according to any of claims 1 to 8, wherein the suspended catalyst comprises at least one metal of transition groups |, Il., V., VI. and/or VIII. of the Periodic Table in addition to nickel as catalytically active metal..
10. The process according to any of claims 1 to 9, wherein the catalyst has a nickel content in the range from 0.1 to 99% by weight, based on the total weight of the catalyst.
11. The process according to any of claims 1 to 10, wherein the catalyst comprises at least one oxidic support component.
12. The process according to any of claims 1 to 11, wherein the catalyst comprises platinum and nickel.
13. The process according to any of claims 1 fo 11, wherein the catalyst comprises palladium, nickel and iron.
14. The process according to any of claims 1 to 13, wherein the catalyst is used in an amount of from 0.1 to 15% by weight, based on the total weight of the reaction mixture in the reactor.
15. The process according to any of claims 1 to 14, wherein the reaction is carried out in a three-phase mixture composed of hydrogen-comprising gas phase, suspended catalyst and liquid phase comprising from 0 to 40% by volume of an alcohol, from 10 to 60% by volume of water and from 20 to 70% by volume of toluenediamine.
16. The process according to any of claims 1 to 15, wherein the setting of the dinitrotoluene concentration in the liquid product output from the reactor in the region between the reactor and the downstream product isolation unit is carried out on the basis of a repeated measurement of the dinitrotoluene concentration in the liquid product output from the reactor at time intervals of <24 hours.
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US8835688B2 (en) | 2011-03-16 | 2014-09-16 | Basf Se | Optimized introduction of the starting materials for a process for preparing aromatic amines by hydrogenation of nitroaromatics |
US8895783B2 (en) | 2012-02-07 | 2014-11-25 | Basf Se | Monitoring of the stoichiometric ratio in the reaction of nitroaromatics with hydrogen |
BR112014019503A8 (en) * | 2012-02-07 | 2017-07-11 | Basf Se | CONTINUOUS PROCESS TO PREPARE AT LEAST ONE AROMATIC AMINE |
US9302237B2 (en) | 2013-01-11 | 2016-04-05 | Basf Se | Apparatus and process for the continuous reaction of liquids with gases |
WO2014108351A1 (en) | 2013-01-11 | 2014-07-17 | Basf Se | Device and method for the continuous reaction of liquids with gases |
US9295971B2 (en) | 2013-01-11 | 2016-03-29 | Basf Se | Apparatus and process for the continuous reaction of liquids with gases |
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