CN116410354A - Supported multi-center catalyst and preparation method thereof - Google Patents
Supported multi-center catalyst and preparation method thereof Download PDFInfo
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- CN116410354A CN116410354A CN202111647003.0A CN202111647003A CN116410354A CN 116410354 A CN116410354 A CN 116410354A CN 202111647003 A CN202111647003 A CN 202111647003A CN 116410354 A CN116410354 A CN 116410354A
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- Prior art keywords
- chromium
- vanadium
- inorganic
- temperature
- catalyst
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- 239000003054 catalyst Substances 0.000 title claims abstract description 129
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 239000011651 chromium Substances 0.000 claims abstract description 154
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 111
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 103
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 79
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims abstract description 72
- -1 polyethylene Polymers 0.000 claims abstract description 63
- 238000011068 loading method Methods 0.000 claims abstract description 40
- 230000003213 activating effect Effects 0.000 claims abstract description 13
- 238000001035 drying Methods 0.000 claims description 99
- 238000000034 method Methods 0.000 claims description 66
- 238000006116 polymerization reaction Methods 0.000 claims description 60
- 239000012298 atmosphere Substances 0.000 claims description 57
- 239000011148 porous material Substances 0.000 claims description 44
- 230000009467 reduction Effects 0.000 claims description 39
- WYYQVWLEPYFFLP-UHFFFAOYSA-K chromium(3+);triacetate Chemical compound [Cr+3].CC([O-])=O.CC([O-])=O.CC([O-])=O WYYQVWLEPYFFLP-UHFFFAOYSA-K 0.000 claims description 22
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 claims description 20
- WGLPBDUCMAPZCE-UHFFFAOYSA-N chromium trioxide Inorganic materials O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 14
- 238000005470 impregnation Methods 0.000 claims description 13
- 230000004913 activation Effects 0.000 claims description 12
- PHFQLYPOURZARY-UHFFFAOYSA-N chromium trinitrate Chemical compound [Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O PHFQLYPOURZARY-UHFFFAOYSA-N 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 229910000352 vanadyl sulfate Inorganic materials 0.000 claims description 10
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims description 9
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 8
- 229940117975 chromium trioxide Drugs 0.000 claims description 8
- GAMDZJFZMJECOS-UHFFFAOYSA-N chromium(6+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Cr+6] GAMDZJFZMJECOS-UHFFFAOYSA-N 0.000 claims description 8
- 125000001183 hydrocarbyl group Chemical group 0.000 claims description 8
- 150000001336 alkenes Chemical class 0.000 claims description 7
- MFWFDRBPQDXFRC-LNTINUHCSA-N (z)-4-hydroxypent-3-en-2-one;vanadium Chemical compound [V].C\C(O)=C\C(C)=O.C\C(O)=C\C(C)=O.C\C(O)=C\C(C)=O MFWFDRBPQDXFRC-LNTINUHCSA-N 0.000 claims description 6
- PMJNEQWWZRSFCE-UHFFFAOYSA-N 3-ethoxy-3-oxo-2-(thiophen-2-ylmethyl)propanoic acid Chemical compound CCOC(=O)C(C(O)=O)CC1=CC=CS1 PMJNEQWWZRSFCE-UHFFFAOYSA-N 0.000 claims description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 6
- 229910021555 Chromium Chloride Inorganic materials 0.000 claims description 6
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 6
- AZFUOHYXCLYSQJ-UHFFFAOYSA-N [V+5].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O Chemical compound [V+5].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O AZFUOHYXCLYSQJ-UHFFFAOYSA-N 0.000 claims description 6
- JOSWYUNQBRPBDN-UHFFFAOYSA-P ammonium dichromate Chemical compound [NH4+].[NH4+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O JOSWYUNQBRPBDN-UHFFFAOYSA-P 0.000 claims description 6
- 125000004432 carbon atom Chemical group C* 0.000 claims description 6
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 claims description 6
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 claims description 6
- XEHUIDSUOAGHBW-UHFFFAOYSA-N chromium;pentane-2,4-dione Chemical compound [Cr].CC(=O)CC(C)=O.CC(=O)CC(C)=O.CC(=O)CC(C)=O XEHUIDSUOAGHBW-UHFFFAOYSA-N 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 6
- OGUCKKLSDGRKSH-UHFFFAOYSA-N oxalic acid oxovanadium Chemical compound [V].[O].C(C(=O)O)(=O)O OGUCKKLSDGRKSH-UHFFFAOYSA-N 0.000 claims description 6
- CMZUMMUJMWNLFH-UHFFFAOYSA-N sodium metavanadate Chemical compound [Na+].[O-][V](=O)=O CMZUMMUJMWNLFH-UHFFFAOYSA-N 0.000 claims description 6
- IHIXIJGXTJIKRB-UHFFFAOYSA-N trisodium vanadate Chemical compound [Na+].[Na+].[Na+].[O-][V]([O-])([O-])=O IHIXIJGXTJIKRB-UHFFFAOYSA-N 0.000 claims description 6
- 229910000351 vanadium(III) sulfate Inorganic materials 0.000 claims description 6
- OYCGXLKTCYDJNJ-UHFFFAOYSA-H vanadium;trisulfate Chemical compound [V].[V].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O OYCGXLKTCYDJNJ-UHFFFAOYSA-H 0.000 claims description 6
- 125000005287 vanadyl group Chemical group 0.000 claims description 6
- UUUGYDOQQLOJQA-UHFFFAOYSA-L vanadyl sulfate Chemical compound [V+2]=O.[O-]S([O-])(=O)=O UUUGYDOQQLOJQA-UHFFFAOYSA-L 0.000 claims description 6
- 229940041260 vanadyl sulfate Drugs 0.000 claims description 6
- AMNQGHSNHCPOMO-UHFFFAOYSA-N [O-2].[V+5].CC[O-].CC[O-].CC[O-] Chemical compound [O-2].[V+5].CC[O-].CC[O-].CC[O-] AMNQGHSNHCPOMO-UHFFFAOYSA-N 0.000 claims description 5
- 238000001354 calcination Methods 0.000 claims description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 4
- VKTGMGGBYBQLGR-UHFFFAOYSA-N [Si].[V].[V].[V] Chemical compound [Si].[V].[V].[V] VKTGMGGBYBQLGR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 239000004927 clay Substances 0.000 claims description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 4
- FWFGVMYFCODZRD-UHFFFAOYSA-N oxidanium;hydrogen sulfate Chemical compound O.OS(O)(=O)=O FWFGVMYFCODZRD-UHFFFAOYSA-N 0.000 claims description 4
- 229910000323 aluminium silicate Inorganic materials 0.000 claims description 3
- 229910052810 boron oxide Inorganic materials 0.000 claims description 3
- 239000000292 calcium oxide Substances 0.000 claims description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 3
- 229910052570 clay Inorganic materials 0.000 claims description 3
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 claims description 3
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 3
- 239000000395 magnesium oxide Substances 0.000 claims description 3
- 229910000484 niobium oxide Inorganic materials 0.000 claims description 3
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims description 3
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims description 3
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 3
- 229910001887 tin oxide Inorganic materials 0.000 claims description 3
- 229910001930 tungsten oxide Inorganic materials 0.000 claims description 3
- 239000011787 zinc oxide Substances 0.000 claims description 3
- 229910021551 Vanadium(III) chloride Inorganic materials 0.000 claims description 2
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 2
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 claims description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 2
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- HQYCOEXWFMFWLR-UHFFFAOYSA-K vanadium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[V+3] HQYCOEXWFMFWLR-UHFFFAOYSA-K 0.000 claims description 2
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- 150000002899 organoaluminium compounds Chemical group 0.000 claims 1
- 239000004698 Polyethylene Substances 0.000 abstract description 41
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- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- VOITXYVAKOUIBA-UHFFFAOYSA-N triethylaluminium Chemical compound CC[Al](CC)CC VOITXYVAKOUIBA-UHFFFAOYSA-N 0.000 description 2
- 150000003681 vanadium Chemical class 0.000 description 2
- OCJBOOLMMGQPQU-UHFFFAOYSA-N 1,4-dichlorobenzene Chemical class ClC1=CC=C(Cl)C=C1 OCJBOOLMMGQPQU-UHFFFAOYSA-N 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- WWUVJRULCWHUSA-UHFFFAOYSA-N 2MP Natural products CCCC(C)=C WWUVJRULCWHUSA-UHFFFAOYSA-N 0.000 description 1
- XNDZQQSKSQTQQD-UHFFFAOYSA-N 3-methylcyclohex-2-en-1-ol Chemical compound CC1=CC(O)CCC1 XNDZQQSKSQTQQD-UHFFFAOYSA-N 0.000 description 1
- SUWJESCICIOQHO-UHFFFAOYSA-N 4-methylhex-1-ene Chemical compound CCC(C)CC=C SUWJESCICIOQHO-UHFFFAOYSA-N 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- 239000004705 High-molecular-weight polyethylene Substances 0.000 description 1
- 238000005481 NMR spectroscopy Methods 0.000 description 1
- 206010067482 No adverse event Diseases 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- MGSCVPSSIVOYMY-UHFFFAOYSA-N [V+3].CC[O-].CC[O-].CC[O-] Chemical compound [V+3].CC[O-].CC[O-].CC[O-] MGSCVPSSIVOYMY-UHFFFAOYSA-N 0.000 description 1
- DMTKBDZGHYGKFA-UHFFFAOYSA-N [V].CC(=O)C.CC(=O)C Chemical compound [V].CC(=O)C.CC(=O)C DMTKBDZGHYGKFA-UHFFFAOYSA-N 0.000 description 1
- 125000002723 alicyclic group Chemical group 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 125000005234 alkyl aluminium group Chemical group 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 125000002029 aromatic hydrocarbon group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 238000012662 bulk polymerization Methods 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- ZHXZNKNQUHUIGN-UHFFFAOYSA-N chloro hypochlorite;vanadium Chemical compound [V].ClOCl ZHXZNKNQUHUIGN-UHFFFAOYSA-N 0.000 description 1
- HBXWYZMULLEJSG-UHFFFAOYSA-N chromium vanadium Chemical compound [V][Cr][V][Cr] HBXWYZMULLEJSG-UHFFFAOYSA-N 0.000 description 1
- 239000003426 co-catalyst Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 125000001511 cyclopentyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C1([H])[H] 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 229940069096 dodecene Drugs 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000006353 environmental stress Effects 0.000 description 1
- 229920001038 ethylene copolymer Polymers 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 238000010528 free radical solution polymerization reaction Methods 0.000 description 1
- 239000000499 gel Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical group 0.000 description 1
- RYPKRALMXUUNKS-UHFFFAOYSA-N hex-2-ene Chemical compound CCCC=CC RYPKRALMXUUNKS-UHFFFAOYSA-N 0.000 description 1
- 238000004742 high temperature nuclear magnetic resonance Methods 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- CPOFMOWDMVWCLF-UHFFFAOYSA-N methyl(oxo)alumane Chemical compound C[Al]=O CPOFMOWDMVWCLF-UHFFFAOYSA-N 0.000 description 1
- NRQNMMBQPIGPTB-UHFFFAOYSA-N methylaluminum Chemical compound [CH3].[Al] NRQNMMBQPIGPTB-UHFFFAOYSA-N 0.000 description 1
- 229910052901 montmorillonite Inorganic materials 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000003136 n-heptyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001280 n-hexyl group Chemical group C(CCCCC)* 0.000 description 1
- 125000000740 n-pentyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001624 naphthyl group Chemical group 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 238000005580 one pot reaction Methods 0.000 description 1
- 125000002524 organometallic group Chemical group 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 125000001147 pentyl group Chemical group C(CCCC)* 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 239000002685 polymerization catalyst Substances 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000010557 suspension polymerization reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000006276 transfer reaction Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F110/02—Ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
Abstract
The invention discloses a supported multi-center catalyst and a preparation method thereof, wherein the catalyst comprises a carrier and an active component, the active component is supported on the carrier, and the active component comprises an organic chromium active component, an inorganic chromium active component and an inorganic vanadium active component; wherein, the inorganic chromium active component is obtained by carrying a chromium source on the carrier, roasting, reducing CO and activating a cocatalyst; the inorganic vanadium active component is obtained by loading a vanadium source on the carrier, roasting, reducing CO and activating a cocatalyst. The catalyst has high polymerization activity, good hydrogen regulation sensitivity and copolymerization performance, and can be applied to the preparation of polyethylene products with wide molecular weight distribution and trimodal or multimodal distribution.
Description
Technical Field
The invention belongs to the field of olefin polymerization catalysts, and particularly relates to a supported multi-center catalyst, a preparation method and application thereof.
Background
Polyethylene is widely used in various fields of human production and life at present, including household appliances, automobiles, furniture, toys, packages, containers, pipes and the like, and the annual average consumption of polyethylene is continuously increased by more than 1 hundred million tons each year, so that polyethylene becomes a synthetic resin material with the largest human consumption.
The key to the regulation of the mechanical and processing properties of polyethylene products is the regulation of the molecular weight distribution. At the same time, for some applications, such as high performance pipes and films, the distribution of the short chain branching content along the polymer molecular weight is also important. For the last thirty years, a double-kettle serial process is widely used in industry to enhance the adjustability of the molecular weight and the distribution of short-chain branches of polyethylene products, namely, two reaction kettles are operated in series, and the polyethylene products with larger difference of the molecular weight and the short-chain branches content are formed in the two reaction kettles by mainly adjusting the concentration of chain transfer agent hydrogen and comonomer (such as 1-butene, 1-hexene and 1-octene) in the two reaction kettles and the stay time of the catalyst in the two reaction kettles. From the polymer molecular weight distribution curve, the molecular weight of the polyethylene synthesized by the double-kettle serial connection process generally shows bimodal distribution, wherein the higher molecular weight component has excellent toughness, but the processability is poorer, the lower molecular weight component has better rigidity, and the higher molecular weight component can serve as a lubricant to improve the processability of the higher molecular weight component, so that the synthesized bimodal polyethylene product has better processing and mechanical properties, and the market application range of the polyethylene product is greatly expanded. On the other hand, it should be noted that although the control range of the molecular weight distribution of polyethylene can be improved by connecting two reaction kettles in series, it correspondingly increases the complexity and operation difficulty of the reaction process, and at the same time, the investment cost of equipment, the energy consumption and the like are obviously increased compared with those of a single reaction kettle.
Therefore, it is hoped to realize the synthesis of polyethylene with bimodal molecular weight distribution in a single reaction kettle through the innovation of the catalyst technology, and the main research thought is to screen active components with different chain growth and chain transfer characteristics to be co-supported on the same carrier surface, and simultaneously synthesize polyethylene components with obvious difference in molecular weight on the catalyst surface through different active components so as to achieve the purpose of synthesizing bimodal polyethylene.
However, the technology is generally faced with the problem that the poisoning effect between different active components is difficult to realize effective control of the relative content of high and low molecular weight polyethylene components. TiCl is prepared by Lu and Ahmadi et al 4 /Cp 2 ZrCl 2 /MgCl 2 It can be used for synthesizing bimodal polyethylene, but has polymerization activity of TiCl only due to poisoning effect between active centers of Zr and Ti 4 /MgCl 2 About half of (a) the number of (b). Yang Yongrong et al use a polymer layer coated on the surface of a catalyst carrier to physically separate two active components, thereby preventing poisoning of the two components and obtaining a double active center bimodal polyethylene catalyst with higher activity. Zhao et al also prepared Cr/VO x /SiO 2 Bimetallic center catalystIt is found that Cr and V have no toxic effect and may be used in preparing polyethylene with obviously bimodal molecular weight distribution.
In recent years, the company of the chemical industry of the Nordic in Germany and the like successively develops a three-kettle series process, and compared with the double-kettle series process, the three-kettle series process has the advantages that the molecular weight of a polyethylene product and the regulation range of the distribution of short branched chains can be further widened by regulating the operation condition of a third series reaction kettle, so that the active species on the surface of the same catalyst particle can synthesize polyethylene components with lower molecular weight, higher molecular weight and ultrahigh molecular weight in different reaction kettles, the molecular weight of the polymer is in trimodal distribution (namely multimodal distribution), and the corresponding mechanical property is obviously improved on the basis of bimodal polyethylene. On the other hand, compared with the double-kettle serial process, the three-kettle serial process obviously has further improvement in the aspects of operation difficulty, investment, production cost, energy consumption and the like.
Therefore, there have been continuous reports in recent years on techniques for synthesizing multimodal polyethylene using a multi-centered catalyst one pot process. Warzelhan et al (DE 3242150A 1) report a co-supported TiCl on silica gel 3 /VCl 3 /ZrCl 4 The method for synthesizing trimodal polyethylene by using three active components has the defects that the molecular weight distribution of the polymer is difficult to accurately regulate and control and a polymer product with stable performance cannot be obtained because the three active components of the catalyst have serious interaction. Mulhaupt et al use the metallocene/iminate/quinoline chromium three ethylene polymerization active components loaded on the surface of silica gel or graphene to synthesize polyethylene with a trimodal molecular weight distribution, and the molecular weight distribution of the polymer can be regulated and controlled by the loading amounts of different active components on the surface of the catalyst, but the three active components still show obvious poisoning effect, so that the polymerization activity is obviously reduced after the loading.
Thus, there is still a need in the art for further research into multi-active site catalysts for ethylene polymerization.
Disclosure of Invention
The invention mainly aims to provide a supported multi-center catalyst and a preparation method thereof, which are used for overcoming the defects of low catalytic activity, poor long-term mechanical property and the like of the multi-center catalyst for ethylene polymerization in the prior art.
In order to achieve the above object, the present invention provides a supported multicenter catalyst comprising a support and an active component, the active component being supported on the support, the active component comprising an organic chromium active component, an inorganic chromium active component and an inorganic vanadium active component;
wherein, the inorganic chromium active component is obtained by carrying a chromium source on the carrier, roasting, reducing CO and activating a cocatalyst;
the inorganic vanadium active component is obtained by carrying a vanadium source on the carrier, roasting, reducing CO and activating a cocatalyst.
The supported multi-center catalyst provided by the invention is characterized in that the organic chromium active component is obtained by carrying bis-trihydrocarbylsilane chromate on the carrier and activating the catalyst promoter.
The supported multicenter catalyst of the invention, wherein the chromium source is supported on the carrier, the chromium source has the structure shown in the formula a after roasting, the vanadium source is supported on the carrier, the vanadium source has the structure shown in the formula b after roasting, the bis-trihydrocarbylsilane chromate is supported on the carrier, the chromium source has the structure shown in the formula c after roasting,
Wherein R is a hydrocarbon group;
the chromium source is loaded on the carrier, the structure of the formula d is shown after roasting and CO reduction, the vanadium source is loaded on the carrier, the structure of the formula e is shown after roasting and CO reduction,
the supported multi-center catalyst of the invention, wherein the carrier is an inorganic carrier, and the specific surface area of the carrier is 100-1000 m 2 Per g, pore volume of0.5～5.0cm 3 And/g, the average pore diameter is 1-100 nm.
The supported multi-center catalyst provided by the invention, wherein the content of the organic chromium active component is 0.05-5wt% calculated by Cr, the content of the inorganic chromium active component is 0.05-5wt% calculated by Cr, and the content of the inorganic vanadium active component is 0.05-10wt% calculated by V based on the total mass of the supported multi-center catalyst.
The supported multi-center catalyst disclosed by the invention, wherein the chromium source comprises at least one of chromium trioxide, chromium nitrate, chromium acetate, chromium chloride, chromium sulfate, ammonium chromate, ammonium dichromate, basic chromium acetate and chromium acetylacetonate; the vanadium source comprises at least one of ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadyl (IV) sulfate hydrate, vanadium (III) sulfate, vanadium trichlorooxide, sodium orthovanadate, sodium metavanadate, vanadium diacetylacetonate oxide, vanadyl triisopropoxide, vanadium tripropanol oxide, vanadium acetylacetonate, triethoxy vanadium oxide, vanadyl chloride and vanadium silicide; the cocatalyst is an organoaluminum compound.
In order to achieve the above purpose, the present invention also provides a preparation method of the supported multi-center catalyst, comprising the following steps:
step 1, loading an inorganic chromium source and an inorganic vanadium source on an inorganic carrier, roasting, and reducing CO to obtain a catalyst intermediate loaded with inorganic chromium and inorganic vanadium;
and 2, loading an organic chromium source on the catalyst intermediate loaded with inorganic chromium and inorganic vanadium, drying, and activating a cocatalyst to obtain the supported multi-center catalyst.
The invention relates to a preparation method of a supported multi-center catalyst, wherein the inorganic chromium source comprises at least one of chromium trioxide, chromium nitrate, chromium acetate, chromium chloride, chromium sulfate, ammonium chromate, ammonium dichromate, basic chromium acetate and chromium acetylacetonate; the inorganic vanadium source comprises at least one of ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadyl (IV) sulfate hydrate, vanadium (III) sulfate, vanadium trichloride oxide, sodium orthovanadate, sodium metavanadate, vanadium diacetylacetone oxide, vanadyl triisopropoxide, vanadium tripropanol oxide, vanadium acetylacetonate, triethoxy vanadium oxide, vanadyl chloride and vanadium silicide; the organochromium source is a bis-trihydrocarbylsilane chromate.
The invention relates to a preparation method of a supported multi-center catalyst, wherein the organic chromium source has the following structural formula:
wherein R is a hydrocarbon group of 1 to 20 carbon atoms.
The preparation method of the supported multi-center catalyst is characterized in that the roasting temperature is 400-950 ℃ and the roasting time is 2-24 hours; the CO reduction is: reducing the roasted catalyst in CO atmosphere at 150-600 deg.c for 2-24 hr; the cocatalyst is an organic aluminum compound, the product obtained after the drying in the step 2 is calculated by chromium, and the molar ratio of the cocatalyst to the product obtained after the drying in the step 2 is 0.01-200; the activation temperature is 20-120 ℃, and the activation time is 0.5-5 h.
The invention relates to a preparation method of a supported multi-center catalyst, wherein the method for supporting an inorganic chromium source and an inorganic vanadium source on an inorganic carrier is impregnation, and the method for supporting an organic chromium source on a catalyst intermediate of the supported inorganic chromium and inorganic vanadium is impregnation; the inorganic carrier is at least one of silicon oxide, aluminum oxide, aluminosilicate, inorganic clay, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, ferric oxide, tin oxide, zinc oxide, boron oxide, tungsten oxide and niobium oxide.
The invention has the beneficial effects that:
the three-active center catalyst is used for olefin polymerization, can obtain polyethylene with broad or three-peak molecular weight distribution, and is more economical, green and efficient compared with a three-kettle series process.
The ethylene and alpha olefin copolymer synthesized by the supported multi-center catalyst of the invention has the comonomer mainly distributed in the higher molecular weight component, so that a multimodal polyethylene product with short-chain branches in inverse distribution can be synthesized by a single kettle method, and the long-term mechanical properties, such as slow crack growth resistance, of the product are more excellent than those of a polyethylene product with short-chain branches mainly concentrated in the low molecular weight component.
Drawings
FIG. 1 is a high temperature GPC curve of the synthetic polymer of comparative example 14;
FIG. 2 is a high temperature GPC curve of the synthetic polymer of comparative example 15;
FIG. 3 is a high temperature GPC curve of the synthetic polymer of comparative example 16;
FIG. 4 is a high temperature GPC curve of the synthetic polymer of example 22;
FIG. 5 is a high temperature GPC curve of the synthetic polymer of example 34;
FIG. 6 is a high temperature GPC curve of the synthetic polymer of example 38;
FIGS. 7-9 are high temperature GPC curves for the synthetic polymers of examples 50-52;
FIGS. 10 to 12 are high temperature GPC curves of the synthetic polymers of comparative examples 19 to 21;
FIG. 13 is a high temperature GPC-FTIR curve of the synthetic polymer of example 47.
Detailed Description
The following describes the present invention in detail, and the present examples are implemented on the premise of the technical solution of the present invention, and detailed embodiments and processes are given, but the scope of protection of the present invention is not limited to the following examples, in which the experimental methods of specific conditions are not noted, and generally according to conventional conditions.
The invention provides a supported multi-center catalyst, which comprises a carrier and an active component, wherein the active component is supported on the carrier and comprises an organic chromium active component, an inorganic chromium active component and an inorganic vanadium active component;
wherein, the inorganic chromium active component is obtained by carrying a chromium source on the carrier, roasting, reducing CO and activating a cocatalyst;
the inorganic vanadium active component is obtained by loading a vanadium source on the carrier, roasting, reducing CO and activating a cocatalyst.
After the chromium source is loaded on the carrier, the roasted product and the vanadium source are loaded on the carrier, and the roasted product is subjected to CO reduction, the valence states of chromium and vanadium are reduced, so that the inorganic chromium active component becomes more sensitive to hydrogen chain transfer in the polymerization process, the sensitivity of the inorganic vanadium active component to hydrogen chain transfer in the polymerization process is not obviously changed, and the three-peak or multi-peak polyethylene is easy to synthesize by the catalyst due to the difference change of the sensitivity of the inorganic chromium active component and the inorganic vanadium active component to hydrogen.
In one embodiment, the chromium source is supported on a carrier and the calcined product has the structure of formula a below, and the calcined, CO reduced product has the structure of formula d below:
wherein the two vertical stubs in formula a represent the connection between the chromium oxide and the support and the two vertical stubs in formula d represent the connection between the chromium oxide and the support after CO reduction. The connection may be a chemical bond or a physical action, and the present invention is not particularly limited.
In one embodiment, the vanadium source is supported on a carrier and the calcined product has the structure of formula b, and the vanadium source is supported on a carrier and the calcined, CO reduced product has the structure of formula e:
wherein the three vertical stubs in formula b represent the connection between the vanadium oxide and the support, and the three vertical stubs in formula e represent the connection between the vanadium oxide and the support after CO reduction. The connection may be a chemical bond or a physical action, and the present invention is not particularly limited.
Wherein the chromium oxide (formula a) is obtained by loading a chromium source on a carrier and roasting. The chromium source is not particularly limited, and is, for example, at least one of a soluble chromium salt, chromium trioxide, chromium nitrate, chromium acetate, chromium chloride, chromium sulfate, ammonium chromate, ammonium dichromate, basic chromium acetate, and chromium acetylacetonate. The vanadium oxide (formula b) is obtained by loading a vanadium source on a carrier and roasting. The vanadium source of the present invention is not particularly limited, and is, for example, at least one of soluble vanadium salt, ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadium (IV) sulfate hydrate, vanadium (III) sulfate, vanadium oxychloride, sodium orthovanadate, sodium metavanadate, vanadium diacetone oxide, vanadyl triisopropoxide, vanadium tripropaxide, vanadium acetylacetonate, vanadium triethoxide, vanadyl chloride, and vanadyl silicide.
The temperature of the firing is not particularly limited, and is, for example, 400 to 950 ℃. The CO reduction process is carried out in CO atmosphere, the reduction temperature is 150-600 ℃, preferably 250-450 ℃, and the reduction time is 2-24 hours, preferably 4-8 hours.
In one embodiment, the organochromium active component is a bis-trihydrocarbylsilane chromate supported on a support and activated by a cocatalyst. For example, a bis-trihydrocarbylsilane chromate has the structure of formula I below, and after being supported on a carrier, has the structure of formula c below:
wherein the vertical short line in formula c represents the connection between the organochromium active component and the support, which may be a chemical bond or a physical effect, and the present invention is not particularly limited.
Wherein R is a hydrocarbon group. In one embodiment, R is a hydrocarbyl group of 1 to 20 carbon atoms which may be a saturated or unsaturated hydrocarbyl group including aliphatic, alicyclic, and aromatic hydrocarbyl groups such as methyl, ethyl, propyl, butyl, pentyl, cyclopentyl, allyl, phenyl, naphthyl, and the like. In another embodiment, R is an aromatic hydrocarbon group, in which case the organochromium active component is relatively stable.
In one embodiment, the cocatalyst is an organoaluminum compound, the cocatalyst has an activation temperature of 20-120 ℃ and an activation time of 0.5-5 hours.
In one embodiment, the support is an inorganic support; in another embodiment, the support is a porous inorganic support having a specific surface area of 100 to 1000m 2 Per gram, pore volume of 0.5-5.0 cm 3 And/g, the average pore diameter is 1-100 nm. In yet another embodiment, the support is at least one of silica, alumina, aluminosilicate, inorganic clay, titania, zirconia, magnesia, calcia, iron oxide, tin oxide, zinc oxide, boron oxide, tungsten oxide, niobium oxide. Among them, the inorganic clay is preferably montmorillonite, and the silica is preferably amorphous porous silica gel.
In one embodiment, the content of the organic chromium active component is 0.05 to 5wt% based on the total mass of the supported multi-center catalyst, the content of the inorganic chromium active component is 0.05 to 5wt% based on Cr, and the content of the inorganic vanadium active component is 0.05 to 10wt% based on V.
In one embodiment, the invention also provides a method for preparing the supported multi-center catalyst, and the catalyst can be prepared by the method. The preparation method comprises the following steps:
step 1, loading an inorganic chromium source and an inorganic vanadium source on an inorganic carrier, roasting, and reducing CO to obtain a catalyst intermediate loaded with inorganic chromium and inorganic vanadium;
And 2, loading an organic chromium source on the catalyst intermediate loaded with inorganic chromium and inorganic vanadium, drying, and activating a cocatalyst to obtain the supported multi-center catalyst.
In one embodiment, the inorganic chromium source is, for example, at least one of a soluble chromium salt, chromium trioxide, chromium nitrate, chromium acetate, chromium chloride, chromium sulfate, ammonium chromate, ammonium dichromate, basic chromium acetate, chromium acetylacetonate. The inorganic vanadium source is, for example, at least one of soluble vanadium salt, ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadium (IV) sulfate hydrate, vanadium (III) sulfate, vanadium trichlorooxide, sodium orthovanadate, sodium metavanadate, vanadium diacetylacetone oxide, vanadyl triisopropoxide, vanadium tripropanol oxide, vanadium acetylacetonate, triethoxy vanadium oxide, vanadyl chloride, and vanadyl silicide.
The present invention is not particularly limited in the manner in which the inorganic chromium source and the inorganic vanadium source are supported on the carrier, and is, for example, impregnation. The order in which the inorganic chromium source and the inorganic vanadium source are supported on the carrier is not particularly limited, and for example, the inorganic chromium source may be supported on the carrier and then calcined, and then the inorganic vanadium source may be supported and calcined; or loading inorganic vanadium source on the carrier, roasting, loading inorganic chromium source, and roasting; the inorganic chromium source and the inorganic vanadium source can be simultaneously loaded on the carrier and then baked.
The method is not particularly limited to the sequence of CO reduction of chromium and vanadium, and chromium oxide and vanadium oxide can be subjected to CO reduction respectively, for example, CO reduction is carried out after chromium source loading and roasting, and then vanadium source loading, roasting and CO reduction are carried out; or the chromium source and the vanadium source are both loaded on the carrier, and CO reduction is carried out simultaneously after roasting.
The present invention is not particularly limited to the manner in which the organic chromium source is supported on the above-mentioned inorganic chromium-and inorganic vanadium-supported catalyst intermediate, and is, for example, impregnation. The organochromium source is a bis-trihydrocarbylsilane chromate, which is described in detail above and will not be described again here.
In one embodiment, the solvent medium used in the impregnation process of step 1 is at least one of water, methanol, ethanol, n-hexane, n-heptane, n-octane, benzene, toluene, xylene, etc.; the dipping temperature is 20-120 ℃, preferably 45-90 ℃, and the dipping time is 1-24 hours, preferably 4-12 hours; the step 1 also comprises a drying step after dipping, wherein the drying temperature is 60-150 ℃, preferably 80-130 ℃, and the drying time is 2-24 hours, preferably 6-16 hours; the roasting process of the inorganic chromium source and the inorganic vanadium source on the surface of the inorganic carrier is carried out in inert gas or oxygen-containing atmosphere, preferably oxygen and air atmosphere; the roasting temperature is 400-950 ℃, preferably 600-900 ℃, the heating rate of the roasting process is 0.1-5 ℃/min, preferably 0.5-2 ℃/min, and the roasting time is 2-24 hours, preferably 4-12 hours. In the roasting process, before the temperature is raised to 150 ℃, roasting is performed under nitrogen or inert atmosphere such as argon and helium, after the roasting temperature exceeds 150 ℃, roasting is performed in oxygen-containing atmosphere such as oxygen or dry air, and after the roasting is finished and the temperature is lowered to 300-400 ℃, the oxygen-containing atmosphere is replaced by inert atmosphere.
The calcination process described in step 1 can be generally carried out in a fluidized state or a non-fluidized state, but is preferably carried out in a fluidized state, and the calcination is mainly divided into four stages, wherein the first stage is at room temperature to 150 ℃, and the stage mainly removes water components physically adsorbed on the surface of the inorganic carrier; the second stage is 150 ℃ to roasting temperature, and the stage mainly condenses hydroxyl groups on the surface of the inorganic carrier, removes the formed water and simultaneously partially decomposes chromium sources and vanadium sources which are impregnated and adsorbed on the surface of the inorganic carrier; the third stage is a roasting temperature, which almost completely decomposes the chromium source and the vanadium source and forms chromium oxide and vanadium oxide, respectively; the fourth stage is a cooling stage in which chromium oxide and vanadium oxide have formed on the surface of the inorganic support, but the catalyst needs to be cooled to room temperature with continued gas introduction for collection. Wherein the first stage is carried out in an inert gas so that the water content is sufficiently removed, the second and third stages are carried out in an oxygen-containing atmosphere, and the fourth stage switches the working atmosphere from the oxygen-containing atmosphere to the inert gas when the temperature is lowered to 300 to 400 ℃.
The CO reduction process is carried out in CO atmosphere, the reduction temperature is 150-600 ℃, preferably 250-450 ℃, and the reduction time is 2-24 hours, preferably 4-8 hours. In one embodiment, the CO reduction process is generally performed in a fluidized state or a non-fluidized state, but preferably in a fluidized state, and the reduction process is mainly divided into three stages, wherein the first stage is a temperature raising process, namely, raising the temperature of the roasted product from room temperature to a target temperature under a CO atmosphere, the target temperature is 150-600 ℃, preferably 250-450 ℃, the temperature raising rate of the temperature raising process is 0.1-3 ℃/min, preferably 0.5-2 ℃/min, and the reduction time is 2-24 h, preferably 4-8 h; the second stage is a constant temperature reduction process, namely, the roasting product is reacted for 0.5 to 10 hours, preferably 2 to 6 hours at the target temperature under the CO atmosphere; the third stage is a cooling and purging stage, and the general cooling process is natural cooling After the temperature is reduced to 150 ℃, the CO atmosphere is switched into an inert gas atmosphere, such as N 2 Ar, etc., and purging is continued for 0.5 to 4 hours, preferably 1 to 2 hours, to replace CO in the system with an inert gas.
The impregnation process of the step 2 is carried out in an inert organic solvent, wherein the inert organic solvent can be at least one of common organic hydrocarbon compounds such as n-hexane, n-heptane, n-octane, benzene, toluene and xylene; the dipping temperature is 20-120 ℃, preferably 45-80 ℃, and the dipping time is 1-24 hours, preferably 4-8 hours; evaporating and removing the organic solvent in the system at a high temperature after the impregnation is finished to achieve the aim of drying, wherein the drying temperature is 60-150 ℃, preferably 80-130 ℃, and the drying time is 2-24 hours, preferably 6-16 hours; in another embodiment, the entire process is carried out under nitrogen or an inert gas such as argon and helium. In the process, an organic chromium source takes an inert organic solvent as a medium, and reacts with the residual hydroxyl on the surface of the porous inorganic carrier by a dipping and stirring method so as to be loaded on the surface of the porous inorganic carrier, wherein the dosage of the organic chromium source is as follows: the content of Cr in the organic chromium active component is 0.05-5 wt% (based on the weight of Cr) of the total weight of the catalyst.
In one embodiment, the method for preparing the supported multi-center catalyst of the present invention comprises the steps of:
step A, respectively converting an inorganic chromium source and an inorganic vanadium source into an inorganic chromium active component precursor and an inorganic vanadium active component precursor which are loaded on the surface of an inorganic carrier through dipping, drying, roasting and CO reduction procedures to obtain a chromium-vanadium-loaded two-center catalyst intermediate, wherein the loading sequence of the inorganic chromium active component precursor and the inorganic vanadium active component precursor is arbitrary;
step B, loading an organic chromium source on the surface of the product obtained in the step A through impregnation and drying procedures to form an organic chromium active component precursor, thus obtaining a loaded three-center catalyst precursor;
adding a cocatalyst into the supported three-center catalyst precursor to perform pretreatment activation, and then drying to obtain a target catalyst; or taking the supported three-center catalyst precursor, and placing the supported three-center catalyst precursor in a reaction kettle before polymerization to react with an organometallic cocatalyst to form a target catalyst in situ.
In one embodiment, the resulting supported three-centered catalyst precursor has the following structure:
wherein d is an inorganic chromium active component precursor, e is an inorganic vanadium active component precursor, and c is an organic chromium active component precursor.
In one embodiment, the inorganic chromium source, inorganic vanadium source and organic chromium source are used in amounts such that the resulting catalyst meets the following levels: based on the total mass of the supported multi-center catalyst, the content of the organic chromium active component is 0.05 to 5 weight percent based on Cr, the content of the inorganic chromium active component is 0.05 to 5 weight percent based on Cr, and the content of the inorganic vanadium active component is 0.05 to 10 weight percent based on V.
The inorganic carrier of the present invention is described in detail above and will not be described herein.
According to the application of the supported multi-center catalyst in catalyzing olefin polymerization, an organic metal cocatalyst can be added to activate the catalyst before or during polymerization according to requirements. The cocatalyst is an organoaluminum compound, preferably the organoaluminum compound is a trialkylaluminum AlR 3 Dialkylaluminum alkoxide AlR 2 OR, dialkyl aluminum halide AlR 2 At least one of X, aluminoxane, ethyl sesquialuminum chloride, wherein R is an alkyl group, such as an alkyl group having 1 to 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-dodecyl, and the like, and X is a halogen, such as fluorine, chlorine, bromine, and iodine, preferably chlorine. Among them, aluminoxane may include all aluminum alkyls such as methylaluminum and water reactants. As a specific example, the organoaluminum compound may be at least one of triethylaluminum, triisobutylaluminum, diethylaluminum ethoxide, diethylaluminum monochloride, methylaluminoxane and the like.
Wherein the molar ratio of the cocatalyst to the supported multi-center catalyst precursor is 0.01-200 based on chromium; the solvent used in the activation reaction is at least one selected from isopentane, n-pentane, n-hexane, isohexane, n-heptane, n-octane, toluene and xylene, preferably at least one selected from isopentane, n-hexane, isohexane and n-heptane, the activation temperature is 20-120 ℃, preferably room temperature-100 ℃, more preferably room temperature-60 ℃, the activation time is 0.5-20 h, preferably 0.5-10 h, more preferably 0.5-5 h, and the reduction activation treatment adopts a stirring mode, preferably continuous stirring. Drying is carried out after the treatment is finished under nitrogen or inert gas atmosphere, for example, under nitrogen, helium, argon and the like, preferably under nitrogen atmosphere, the drying process can also be carried out under vacuum condition, and the obtained supported three-active-center catalyst subjected to pre-reduction activation is preserved for standby under inert gas atmosphere, and the drying temperature is for example, 60-120 ℃ and the drying time is 2-8 hours.
The activated catalyst can be used for olefin polymerization, further, can be used for ethylene homo-or copolymerization, and the comonomer is alpha-olefin with 3-20 carbon atoms, including any combination of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-methyl-1-pentene, 4-methyl-1-hexene. The comonomer is preferably at least one of 1-butene, 1-hexene and 1-octene; when present, the amount of comonomer is generally from 0.01 to 20% by volume, preferably from 0.01 to 10% by volume, based on the volume concentration of the comonomer relative to the solvent at the time of polymerization.
When the supported multi-center catalyst is used for catalyzing the homopolymerization of ethylene or the copolymerization of ethylene and alpha-olefin, the produced polyethylene product has the following characteristics: the molecular weight distribution is wider when ethylene homopolymerization is carried out, and part of the molecular weight distribution is multimodal; when the copolymerization of ethylene and alpha-olefin is carried out, the molecular weight distribution is wider, part of the copolymer is multimodal, the insertion rate of the comonomer in the lower molecular weight polymer component is lower, and the insertion rate of the comonomer in the higher molecular weight polymer component is higher.
Molecular weight regulators may also be optionally added during the polymerization; wherein the molecular weight regulator is hydrogen, and the partial pressure of the added hydrogen is 0.01-2 MPa.
The supported multi-center catalyst of the present invention is not particularly limited in its method of polymerization when catalyzing olefin polymerization, and when used for catalyzing ethylene homo-polymerization or copolymerization of ethylene and α -olefin, the polymerization method may include a gas phase polymerization process, a slurry polymerization process, a suspension polymerization process, a bulk polymerization process, a solution polymerization process, etc., which are carried out under conventional embodiments and polymerization conditions, preferably a gas phase polymerization process and a slurry polymerization process.
Preferably, when the polymerization is carried out using a slurry polymerization process, the polymerization is initiated by adding ethylene to the reaction vessel, then adding the solvent and the organoaluminum cocatalyst, and optionally hydrogen and comonomer, and finally adding the supported dual-site catalyst of the invention. The solvent used therein is generally any solvent known in the art for olefin polymerization and may be an alkane having 3 to 20 carbon atoms such as propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, cyclohexane, n-heptane, n-octane, etc.; these solvents may be used singly or in combination of two or more. The solvent used is preferably isobutane, isopentane, n-hexane, cyclohexane, n-heptane or the like.
The supported multi-center catalyst is applied to ethylene homopolymerization and copolymerization of ethylene and alpha-olefin, and the synthesized polymer has wider molecular weight distribution and part of the polymer is in trimodal distribution. Ethylene homopolymers, particularly lower, medium and high or ultra-high molecular weight ethylene homopolymers, and ethylene copolymers, particularly lower, medium and high or ultra-high molecular weight ethylene homopolymers, catalyzed ethylene polymerization. In one embodiment, the supported multicenter catalysts of the invention are used in ethylene homo-and ethylene co-polymerization with alpha-olefins, the synthesized polymers have a trimodal or multimodal molecular weight distribution and comprise lower molecular weights (100 to 10000 g.mol -1 ) Component, medium molecular weight (10000 ultra-high)100000g·mol -1 ) Component, high molecular weight (100000 ～ 1000000 g.mol) -1 ) And/or ultra-high molecular weight (greater than 1000000 g.mol) -1 ) Any three of the components in combination, wherein the molecular weight range of each component can be given by the peak value of its corresponding signal peak in the high temperature GPC curve.
The supported multi-center catalyst of the invention has good catalytic synergistic effect of each catalytic component, namely, the catalytic activity is higher than the addition of the activities of each single active component, and the molecular weight distribution of the multimodal polyethylene product can be regulated more effectively by regulating the load quantity or polymerization condition of each active component, especially the hydrogen partial pressure, so that the supported multi-center catalyst is beneficial to developing polyethylene products with different processing and mechanical properties. The ethylene and alpha olefin copolymer synthesized by the supported multi-center catalyst of the invention has the comonomer mainly distributed in the higher molecular weight component, so that a multimodal polyethylene product with short-chain branches in inverse distribution can be synthesized by a single kettle method, and the long-term mechanical properties, such as slow crack growth resistance, of the product are more excellent compared with the polyethylene product with the short-chain branches mainly concentrated in the low molecular weight component.
The technical scheme of the present invention will be described in further detail with reference to examples, but embodiments of the present invention are not limited thereto.
The reagents used in the examples are commercially available as usual unless otherwise specified.
The various polymer properties in the examples were determined according to the following methods:
high temperature gel chromatography (HT-GPC)
Weight average molecular weight and molecular weight distribution were determined by high temperature gel chromatography: the molecular weight and molecular weight distribution of polyethylene were measured in this experiment using a PL-220 type high temperature gel permeation chromatograph (Polymer Laboratories company). For the case where the short chain branching distribution needs to be analyzed, an infrared detector (IR 4, polymer Char Co.) will be used in combination with HT-GPC. In the experiment, 1,2, 4-trichlorobenzene was used as a solvent and was measured at 160 ℃. And processing data by adopting a universal correction method with narrow-distribution polystyrene as a standard sample.
13 C high temperature nuclear magnetic resonance spectrum [ ]HT- 13 CNMR)
The short chain branch content of the polymer was determined using a high Wen Heci carbon spectrum: the experiment adopts Bruker Avance III 500 type nuclear magnetic resonance apparatus to measure the short branched chain content of polyethylene. In the experiment, deuterated paradichlorobenzene is used as a solvent, and the short-chain branch content is calculated by taking a carbon signal (displacement is 30.00 ppm) on a polyethylene main chain as an internal standard in measurement at 110 ℃.
The polymerization experiments in the examples were carried out as follows: firstly, carrying out vacuum heating and impurity removal on a polymerization reaction kettle, then replacing the polymerization reaction kettle with high-purity nitrogen, repeatedly operating for three times, replacing the polymerization reaction kettle with a small amount of ethylene monomer once, and finally filling ethylene into the reaction kettle to micro positive pressure (0.1 MPa); adding a dehydrated and deoxidized refined solvent such as n-heptane and a certain amount of alkyl aluminum as a cocatalyst into a reaction kettle, respectively adding a certain amount of hydrogen and a comonomer into a hydrogen blending copolymerization experiment, adjusting the ethylene pressure to 1MPa, and finally adding the catalyst to start polymerization reaction; the instantaneous consumption of monomer ethylene is collected online in the reaction process and recorded by a computer, and after the reaction is carried out for a certain time (for example, 1 hour) at a certain temperature (for example, 50-100 ℃), the hydrochloric acid/ethanol mixed solution is added to terminate the reaction; the polymer was washed, dried in vacuo, weighed and analyzed.
Examples 1-3: (silica gel Structure)
EXAMPLE 1 corresponding SiO 2 The physical structure of the carrier is as follows: specific surface area 270m 2 Per g, pore volume 1.7mL/g, pore diameter 21nm; example 2 the physical structure of the corresponding silica gel support is as follows: specific surface area 530m 2 3.1mL/g pore volume and 31nm pore diameter; EXAMPLE 3 corresponding SiO 2 The physical structure of the carrier is as follows: specific surface area 800m 2 Per g, pore volume 1.3mL/g, pore diameter 11nm; for examples 1-3, 10g of SiO was taken 2 Immersing in aqueous solution of ammonium metavanadate and basic chromium acetate (the loading of V and Cr is 0.25wt% and 0.3wt% respectively relative to the total weight of the catalyst), continuously stirring and immersing for about 4 hours, wherein the immersing temperature is 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8 hours. Placing the dried mixture in a fluidized bed, heating and roasting from room temperature at a heating rate of 1 ℃/min, keeping constant temperature for 4 hours when reaching 800 ℃, and ending roastingAnd then naturally cooling to room temperature, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Examples 4-6: (modification of Carrier)
The physical structure of the supports used in examples 4-6 is generally as follows: specific surface area 490m 2 Per g, pore volume 2.9mL/g, pore diameter 28nm; the main component of the carrier used in examples 4-6 is SiO 2 Further, it contains 5wt% of Al, 5wt% of Ti and 5wt% of Zr in this order. For examples 4-6, 10g of the corresponding support was immersed in an aqueous solution of ammonium metavanadate and basic chromium acetate (the loadings of V and Cr were 0.25wt% and 0.3wt%, respectively, relative to the total weight of the catalyst) in sequence, continuously stirred for about 4 hours at a temperature of 60 ℃, then warmed to 120 ℃, and dried with continued stirring for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Producing the above-mentioned baked productPlacing the material in the fluidized bed again, heating from room temperature to 300 deg.C at a heating rate of 1 deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150 deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Examples 7 to 9: (baking temperature)
Taking 10g of SiO 2 (specific surface area 530m 2 And/g, soaking in aqueous solution of ammonium metavanadate and basic chromium acetate (the loading of V and Cr is 0.25wt% and 0.3wt% respectively relative to the total weight of the catalyst) with pore volume of 3.1mL/g and pore diameter of 31nm, continuously stirring and soaking for about 4h, wherein the soaking temperature is 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8h. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein for examples 7-9, the corresponding constant-temperature roasting temperatures, namely the target temperatures are 500 ℃, 700 and 900 ℃, the heating rate is 1 ℃/min, constant temperature is kept for 4 hours when the target temperature is reached, and after roasting is finished, the mixture starts to be naturally cooled to room temperature, and is transferred to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-target temperature, dry air atmosphere is adopted in the constant temperature stage of reaching the target temperature, the dry air atmosphere is adopted when the target temperature is reduced to 300 ℃ during natural cooling, and the nitrogen atmosphere is switched to when the target temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in a normal hexane solution of bis-triphenylsilane chromate (Cr loading is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃ and the immersion time isAnd 6h, then heating and drying, wherein the drying temperature is 80 ℃, the drying time is 4h, stirring is applied during the soaking and drying processes, and after the drying is finished, the catalyst precursor is transferred to an anhydrous and anaerobic condition for preservation under the protection of nitrogen.
Examples 10 to 12: (reduction temperature)
Taking 10g of SiO 2 (specific surface area 530m 2 And/g, soaking in aqueous solution of ammonium metavanadate and basic chromium acetate (the loading of V and Cr is 0.25wt% and 0.3wt% respectively relative to the total weight of the catalyst) with pore volume of 3.1mL/g and pore diameter of 31nm, continuously stirring and soaking for about 4h, wherein the soaking temperature is 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8h. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to target reduction temperature at heating rate of 1 deg.C/min under CO gas condition, for examples 10-12, respectively reducing at constant temperature of 200, 400 and 500 deg.C for 4 hr at target reduction temperature, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Examples 13 to 15: (inorganic Cr Supports)
Taking 10g of SiO 2 (specific surface area 530m 2 Per gram, pore volume 3.1mL/g, pore diameter 31 nm) is impregnated with ammonium metavanadate andin the aqueous solution of chromium trioxide, for examples 13 to 15, the loading of V was fixed at 0.25wt% with respect to the total weight of the catalyst, but the loading of Cr was sequentially 0.1wt%, 0.5wt% and 1wt% with respect to the total weight of the catalyst, the impregnated material was continuously stirred for about 4 hours, the impregnation temperature was 60 ℃, and then the temperature was raised to 120 ℃, and stirring and drying were continued for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Examples 16 to 18: (inorganic V Supports)
Taking 10g of SiO 2 (specific surface area 530m 2 Per gram, pore volume 3.1mL/g, pore diameter 31 nm) was immersed in an aqueous solution of ammonium metavanadate and chromium trioxide, the loading of cr was fixed at 0.3wt% with respect to the total weight of the catalyst, but the loading of V was 0.1wt%, 0.5wt% and 1wt% with respect to the total weight of the catalyst in this order for example 16-18, the immersed object was continuously stirred for about 4 hours, the immersing temperature was 60 ℃, then the temperature was raised to 120 ℃, and stirring and drying were continued for 8 hours. Placing the dried mixture in a fluidized bed, heating and roasting from room temperature at a heating rate of 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃,and after the roasting is finished, naturally cooling to room temperature, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Example 19: (step-by-step calcination)
Taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) in an aqueous solution of ammonium metavanadate (V loading of 0.25 wt.% relative to the total weight of the catalyst), continuously stirring and impregnating for about 4 hours, impregnating at 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. The above calcined product was immersed in an aqueous solution of basic chromium acetate (the amount of Cr supported was 0.3wt% relative to the total weight of the catalyst), continuously stirred and immersed for about 4 hours at a temperature of 60 ℃, then heated to 120 ℃, and continuously stirred and dried for 8 hours. Placing the dried mixture And (3) heating and roasting in a fluidized bed from room temperature, wherein the heating rate is 1 ℃/min, the temperature is kept constant for 4 hours when the temperature reaches 800 ℃, the roasting is naturally cooled to the room temperature after the roasting is finished, and the roasting is stored under anhydrous and anaerobic conditions. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Example 20: (prereduction)
Taking 10g of SiO 2 (specific surface area 530m 2 And/g, soaking in aqueous solution of ammonium metavanadate and basic chromium acetate (the loading of V and Cr is 0.25wt% and 0.3wt% respectively relative to the total weight of the catalyst) with pore volume of 3.1mL/g and pore diameter of 31nm, continuously stirring and soaking for about 4h, wherein the soaking temperature is 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8h. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, and heating at 1 deg.C/min under the condition of introducing CO gasThe temperature rises from room temperature to 300 ℃, the temperature is reduced for 4 hours, then the temperature is naturally cooled to 150 ℃, and then the gas is introduced to switch from CO to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen. Transferring the prepared catalyst precursor into a clean three-neck flask which is dehydrated and deoxidized under the protection of nitrogen, simultaneously adding triisobutylaluminum and normal hexane solvent which can permeate the catalyst precursor according to the molar ratio of Al/metal center (namely Cr to V) of 3/1, stirring and activating for 1h at 45 ℃, heating to 80 ℃, introducing nitrogen and drying for 4h, and transferring the pre-reduced catalyst into an anhydrous and anaerobic condition under the protection of nitrogen after the drying is finished.
Examples 21 to 40:
examples 21 to 40 correspond in sequence to the ethylene polymerization experiments performed using the catalysts prepared in examples 1 to 20, 50mg of the corresponding catalyst precursor was weighed and mixed in 10mL of purified n-heptane solution to form a catalyst precursor suspension, and the polymerization experiments were performed. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then 900mL of refined n-heptane solvent is added into the reaction kettle in sequence, triisobutylaluminum (TIBA) with the dosage of Al/Cr (Cr is the total chromium molar quantity) =20 is added as a cocatalyst, and then 100mL of dehydrated and deoxidized refined n-heptane solvent is added. And (3) regulating the ethylene pressure to 1MPa, and after the temperature in the reactor is constant at 80 ℃, utilizing high-pressure nitrogen to press the catalyst precursor suspension into the polymerization reactor to start the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Examples 41 to 43:
50mg of the catalyst precursor prepared in example 2 was weighed and mixed in 10mL of a purified n-heptane solution to form a catalyst precursor suspension, and polymerization experiments were conducted. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then 900mL of purified n-heptane solvent was added sequentially to the reactor, a certain amount of Triisobutylaluminum (TIBA) as a cocatalyst was added thereto, the addition amount of TIBA was 10, 20 and 50 in the molar ratio of Al/Cr (Cr is the total chromium molar amount) for examples 41 to 43, and then 100mL of dehydrated and deoxidized purified n-heptane solvent was added thereto. And (3) regulating the ethylene pressure to 1MPa, and after the temperature in the reactor is constant at 80 ℃, utilizing high-pressure nitrogen to press the catalyst precursor suspension into the polymerization reactor to start the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Examples 44 to 46:
50mg of the catalyst precursor prepared in example 2 was weighed and mixed in 10mL of a purified n-heptane solution to form a catalyst precursor suspension, and polymerization experiments were conducted. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then 900mL of refined n-heptane solvent was added sequentially to the reaction vessel, a certain amount of co-catalyst was added so that the Al/Cr (Cr is the total chromium molar amount) ratio was 20, and for examples 44-46, triethylaluminum, ethoxydiethylaluminum and diethylaluminum chloride were added sequentially, followed by 100mL of dehydrated and deoxidized refined n-heptane solvent. And (3) regulating the ethylene pressure to 1MPa, and after the temperature in the reactor is constant at 80 ℃, utilizing high-pressure nitrogen to press the catalyst precursor suspension into the polymerization reactor to start the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Examples 47 to 49:
50mg of the catalyst precursor prepared in example 2 was weighed and mixed in 10mL of a purified n-heptane solution to form a catalyst precursor suspension, and polymerization experiments were conducted. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then, a certain amount of 1-hexene comonomer and 900mL of purified n-heptane solvent were sequentially added into the reaction vessel, the addition amounts of the 1-hexene for examples 47 to 49,1 were 10mL, 30mL and 50mL, respectively, and then Triisobutylaluminum (TIBA) was added as a cocatalyst in an amount of Al/Cr (Cr is the total chromium molar amount) =20, and further 100mL of dehydrated and deoxidized purified n-heptane solvent was added. And (3) regulating the ethylene pressure to 1MPa, and after the temperature in the reactor is constant at 80 ℃, utilizing high-pressure nitrogen to press the catalyst precursor suspension into the polymerization reactor to start the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Examples 50 to 52:
50mg of the catalyst precursor prepared in example 2 was weighed and mixed in 10mL of a purified n-heptane solution to form a catalyst precursor suspension, and polymerization experiments were conducted. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then 900mL of refined n-heptane solvent is added into the reaction kettle in sequence, triisobutylaluminum (TIBA) with the dosage of Al/Cr (Cr is the total chromium molar quantity) =20 is added as a cocatalyst, and then 100mL of dehydrated and deoxidized refined n-heptane solvent is added. For examples 50-52, hydrogen chain transfer agents of 0.05MPa, 0.1MPa and 0.2MPa were sequentially introduced into the reaction kettle, then the ethylene pressure was adjusted to 1MPa, and after the temperature in the kettle was constant at 80 ℃, the catalyst precursor suspension was hydraulically pressed into the polymerization kettle by high-pressure nitrogen to begin the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Comparative example 1:
taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) is immersed in an aqueous solution of basic chromium acetate (Cr loading is 0.3wt% relative to the total weight of the catalyst), the mixture is continuously stirred and immersed for about 4 hours, the immersion temperature is 60 ℃, then the mixture is heated to 120 ℃, and stirring and drying are continued for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. The catalyst precursor is then transferred to anhydrous and anaerobic conditions for storage under nitrogen protection.
Comparative example 2:
taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) in an aqueous solution of ammonium metavanadate (V loading of 0.25 wt.% relative to the total weight of the catalyst), continuously stirring and impregnating for about 4 hours, impregnating at 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the above process, nitrogen atmosphere is adopted at room temperature to 150 ℃, dry air atmosphere is adopted at the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted at the constant temperature stage of 800 ℃, and the temperature is reduced from 800 ℃ to 300 ℃ when naturally cooled, and is lower than 30 DEG CAt 0 c, the atmosphere was switched to a nitrogen atmosphere. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. The catalyst precursor is then transferred to anhydrous and anaerobic conditions for storage under nitrogen protection.
Comparative example 3:
taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) in an aqueous solution of aluminum nitrate nonahydrate (Al loading 3wt% relative to the total weight of the catalyst), continuously stirring and impregnating for about 4 hours, at room temperature, then heating to 120 ℃, and continuously stirring and drying for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, and when the temperature reaches 500 ℃, the temperature is kept for 4 hours, and after roasting, naturally cooling to room temperature. Mixing the above calcined product with ammonium metavanadate and H 2 SO 4 In the aqueous solution (V and sulfur loadings of 0.25wt% and 2wt%, respectively, relative to the total weight of the catalyst), the impregnation was continued with stirring for about 4 hours, the impregnation temperature was room temperature, then the temperature was raised to 120℃and the stirring and drying was continued for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃.
Comparative example 4:
taking 10g of SiO 2 (specific surface area 530m 2 Per gram, pore volume 3.1mL/g, pore diameter 31 nm) was immersed in deionized water with continuous stirring for about 4 hours at 60℃and then heated to 120℃and dried with continuous stirring for 8 hours. Placing the dried mixture in a fluidized bed, heating from room temperature to 1 deg.C/min, and baking at 800 deg.C for 4 hrAnd after the burning is finished, the material starts to naturally cool to room temperature, and is transferred to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. The CO-treated SiO is treated with 2 Immersing in n-hexane solution of bis-triphenylsilane chromate (Cr loading is 0.25wt% relative to the total weight of the catalyst), immersing at 45 ℃ for 6h, heating and drying at 80 ℃ for 4h, stirring during immersing and drying, and transferring the catalyst precursor to anhydrous and anaerobic condition for preservation under nitrogen protection after drying.
Comparative example 5:
taking 10g of SiO 2 (specific surface area 530m 2 And/g, soaking in aqueous solution of ammonium metavanadate and basic chromium acetate (the loading of V and Cr is 0.25wt% and 0.3wt% respectively relative to the total weight of the catalyst) with pore volume of 3.1mL/g and pore diameter of 31nm, continuously stirring and soaking for about 4h, wherein the soaking temperature is 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8h. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under CO gas condition, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching by CO gasIs N 2 And cooling to room temperature was continued. The catalyst precursor is then transferred to anhydrous and anaerobic conditions for storage under nitrogen protection.
Comparative example 6:
taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) is immersed in an aqueous solution of basic chromium acetate (Cr loading is 0.3wt% relative to the total weight of the catalyst), the mixture is continuously stirred and immersed for about 4 hours, the immersion temperature is 60 ℃, then the mixture is heated to 120 ℃, and stirring and drying are continued for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Comparative example 7:
taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) in an aqueous solution of ammonium metavanadate (V loading of 0.25 wt.% relative to the total weight of the catalyst), continuously stirring and impregnating for about 4 hours, impregnating at 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8 hours. Placing the dried mixture in a fluidized bed, and roasting at a temperature rising rate of 1 ℃/min from room temperatureKeeping the temperature at 800 ℃ for 4 hours, naturally cooling to room temperature after roasting, and transferring to a water-free and oxygen-free condition for preservation. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Placing the above baked product in fluidized bed again, heating from room temperature to 300deg.C at heating rate of 1deg.C/min under the condition of introducing CO gas, reducing at constant temperature for 4 hr, naturally cooling to 150deg.C, and switching from CO gas to N 2 And cooling to room temperature was continued. Immersing the CO reduction product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to anhydrous and anaerobic conditions for preservation under the protection of nitrogen.
Comparative example 8:
taking 10g of SiO 2 (specific surface area 530m 2 Per g, pore volume 3.1mL/g, pore diameter 31 nm) in an aqueous solution of ammonium metavanadate (V loading of 0.25 wt.% relative to the total weight of the catalyst), continuously stirring and impregnating for about 4 hours, impregnating at 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8 hours. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Immersing the above calcined product in n-hexane solution of bis-triphenylsilane chromate (Cr loading of 0.25wt% relative to the total weight of the catalyst) at 45deg.C for 6h, and drying at 80Stirring is applied in the soaking and drying processes, and after the drying is finished, the catalyst precursor is transferred to an anhydrous and anaerobic condition for preservation under the protection of nitrogen.
Comparative example 9:
taking 10g of SiO 2 (specific surface area 530m 2 And/g, soaking in aqueous solution of ammonium metavanadate and basic chromium acetate (the loading of V and Cr is 0.25wt% and 0.3wt% respectively relative to the total weight of the catalyst) with pore volume of 3.1mL/g and pore diameter of 31nm, continuously stirring and soaking for about 4h, wherein the soaking temperature is 60 ℃, then heating to 120 ℃, and continuously stirring and drying for 8h. And (3) placing the dried mixture in a fluidized bed, heating and roasting from room temperature, wherein the heating rate is 1 ℃/min, keeping the temperature constant for 4 hours when the temperature reaches 800 ℃, naturally cooling to room temperature after roasting is finished, and transferring to an anhydrous and anaerobic condition for storage. In the process, nitrogen atmosphere is adopted from room temperature to 150 ℃, dry air atmosphere is adopted in the temperature rising stage of 150-800 ℃, dry air atmosphere is adopted in the constant temperature stage of 800 ℃, the temperature is reduced from 800 ℃ to 300 ℃ when the temperature is naturally cooled, and the temperature is switched to nitrogen atmosphere when the temperature is lower than 300 ℃. Immersing the baked product in n-hexane solution of bis-triphenylsilane chromate (the load of Cr is 0.25wt% relative to the total weight of the catalyst), wherein the immersion temperature is 45 ℃, the immersion time is 6 hours, then heating and drying are carried out, the drying temperature is 80 ℃, the drying time is 4 hours, stirring is applied in the immersion and drying processes, and after the drying is finished, the catalyst precursor is transferred to an anhydrous and anaerobic condition for preservation under the protection of nitrogen.
Comparative examples 10 to 17:
comparative examples 10 to 17 correspond in sequence to ethylene polymerization experiments conducted using the catalysts prepared in comparative examples 1 to 8, 50mg of the corresponding catalyst precursor was weighed and mixed in 10mL of purified n-heptane solution to form a catalyst precursor suspension, and polymerization experiments were conducted. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then 900mL of refined n-heptane solvent is added into the reaction kettle in sequence, triisobutylaluminum (TIBA) with the dosage of Al/Cr (Cr is the total chromium molar quantity) =20 is added as a cocatalyst, and then 100mL of dehydrated and deoxidized refined n-heptane solvent is added. And (3) regulating the ethylene pressure to 1MPa, and after the temperature in the reactor is constant at 80 ℃, utilizing high-pressure nitrogen to press the catalyst precursor suspension into the polymerization reactor to start the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Comparative examples 18 to 21:
50mg of the catalyst precursor prepared in comparative example 9 was weighed and mixed in 10mL of a purified n-heptane solution to form a catalyst precursor suspension, and polymerization experiments were conducted. And (3) carrying out vacuum heating and impurity removal on a 2L stainless steel high-pressure polymerization reaction kettle, pumping and discharging with high-purity nitrogen for three times, and finally filling trace refined ethylene into the reaction kettle to 0.12MPa. Then 900mL of refined n-heptane solvent is added into the reaction kettle in sequence, triisobutylaluminum (TIBA) with the dosage of Al/Cr (Cr is the total chromium molar quantity) =20 is added as a cocatalyst, and then 100mL of dehydrated and deoxidized refined n-heptane solvent is added. For comparative examples 18-21, hydrogen chain transfer agents of 0MPa, 0.05MPa, 0.1MPa and 0.2MPa were sequentially introduced into the reaction kettle, then the ethylene pressure was adjusted to 1MPa, and after the temperature in the kettle was constant at 80 ℃, the catalyst precursor suspension was hydraulically pressed into the polymerization kettle by high-pressure nitrogen to start the reaction. The instantaneous consumption of monomer ethylene is collected on line in the reaction process and recorded by a computer. After 1h, the reaction was terminated by adding a hydrochloric acid/ethanol mixed solution. After filtration the resulting polymer was dried in a vacuum oven at 60 ℃ for 4 hours, weighed and analyzed.
Table 1 example aggregate results summary table
Table 1, below
The polymers synthesized in comparative examples 14-16 were significantly bimodal (as in FIGS. 1-3), which is characteristic of a dual site catalyst catalyzed polymerization. The polymers synthesized in examples 22, 34 and 38 (as in FIGS. 4-6) are significantly trimodal, which is characteristic of the three-site catalysts of the present invention for catalyzing polymerization. However, rather than simply superimposing an active site on the catalyst, a trimodal or multimodal polymer can be produced; the three active centers cannot poison each other, and have to have a synergistic effect, and then the trimodal or multimodal polymer product can be obtained by means of hydrogen regulation and the like. As can be seen from a comparison of the high temperature GPC curves of examples 50-52 (FIGS. 7-9) with comparative examples 19-21 (FIGS. 10-12), the polymerization products of the catalyst without CO reduction have significantly less one low molecular weight polyethylene peak under the same reaction conditions, because the inorganic chromium, organic chromium, inorganic vanadium catalyst precursors would normally be used for ethylene polymerization to synthesize medium, medium and high molecular weight polyethylenes respectively, and the hydrogen sensitivity of the three would be poor and would not pass H 2 The chain transfer agent regulates and controls the polymer molecular weight of the three, so that medium and high molecular weight bimodal polyethylene is formed; inorganic chromium species formed after reduction of CO are more prone to react with H during polymerization 2 Chain transfer reactions (higher hydrogen transfer sensitivity) occur, so that the inorganic chromium active center will synthesize a lower molecular weight polyethylene component; meanwhile, the hydrogen regulation sensitivity of the inorganic vanadium species formed after CO reduction is not changed obviously in the polymerization activity, and the inorganic vanadium species still synthesizes high molecular weight polyethylene, so that the catalyst after CO reduction can more easily synthesize polyethylene products with the molecular weight distributed in a three-peak mode. From the data of example 47 of Table 1 and FIG. 13, it can be seen that the short chain branches of the polymerization product prepared with the catalyst of the present invention are mainly concentrated in the high molecular weight fraction, which is beneficial for improving the environmental stress cracking resistance of the product.
Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (12)
1. A supported multicenter catalyst comprising a support and an active component, the active component being supported on the support, the active component comprising an organochromium active component, an inorganic chromium active component and an inorganic vanadium active component;
Wherein, the inorganic chromium active component is obtained by carrying a chromium source on the carrier, roasting, reducing CO and activating a cocatalyst;
the inorganic vanadium active component is obtained by carrying a vanadium source on the carrier, roasting, reducing CO and activating a cocatalyst.
2. The supported multicenter catalyst according to claim 1, wherein the organochromium active component is a bis-trihydrocarbylsilane chromate supported on the support and activated by a cocatalyst.
3. The supported multicenter catalyst according to claim 2, wherein the chromium source is supported on the carrier, having a structure of formula a after calcination, the vanadium source is supported on the carrier, having a structure of formula b after calcination, the bis-trialkylsilyl chromate is supported on the carrier, having a structure of formula c,
wherein R is a hydrocarbon group;
the chromium source is loaded on the carrier, the structure of the formula d is shown after roasting and CO reduction, the vanadium source is loaded on the carrier, the structure of the formula e is shown after roasting and CO reduction,
4. the supported multicenter catalyst according to claim 1, wherein the support is an inorganic support having a specific surface area of 100-1000 m 2 Per gram, pore volume of 0.5-5.0 cm 3 And/g, the average pore diameter is 1-100 nm.
5. The supported multicenter catalyst according to claim 1, wherein the content of the organic chromium active component is 0.05 to 5wt% in terms of Cr, the content of the inorganic chromium active component is 0.05 to 5wt% in terms of Cr, and the content of the inorganic vanadium active component is 0.05 to 10wt% in terms of V, based on the total mass of the supported multicenter catalyst.
6. The supported multicentric catalyst of claim 1 wherein said chromium source comprises at least one of chromium trioxide, chromium nitrate, chromium acetate, chromium chloride, chromium sulfate, ammonium chromate, ammonium dichromate, basic chromium acetate, chromium acetylacetonate; the vanadium source comprises at least one of ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadyl (IV) sulfate hydrate, vanadium (III) sulfate, vanadium trichlorooxide, sodium orthovanadate, sodium metavanadate, vanadium diacetylacetonate oxide, vanadyl triisopropoxide, vanadium tripropanol oxide, vanadium acetylacetonate, triethoxy vanadium oxide, vanadyl chloride and vanadium silicide; the cocatalyst is an organoaluminum compound.
7. The preparation method of the supported multi-center catalyst is characterized by comprising the following steps:
Step 1, loading an inorganic chromium source and an inorganic vanadium source on an inorganic carrier, roasting, and reducing CO to obtain a catalyst intermediate loaded with inorganic chromium and inorganic vanadium;
and 2, loading an organic chromium source on the catalyst intermediate loaded with inorganic chromium and inorganic vanadium, drying, and activating a cocatalyst to obtain the supported multi-center catalyst.
8. The method of preparing a supported multicenter catalyst according to claim 7, wherein the inorganic chromium source comprises at least one of chromium trioxide, chromium nitrate, chromium acetate, chromium chloride, chromium sulfate, ammonium chromate, ammonium dichromate, basic chromium acetate, chromium acetylacetonate; the inorganic vanadium source comprises at least one of ammonium hexafluorovanadate, vanadium nitrate, vanadyl oxalate, ammonium metavanadate, vanadyl sulfate, vanadyl (IV) sulfate hydrate, vanadium (III) sulfate, vanadium trichloride oxide, sodium orthovanadate, sodium metavanadate, vanadium diacetylacetone oxide, vanadyl triisopropoxide, vanadium tripropanol oxide, vanadium acetylacetonate, triethoxy vanadium oxide, vanadyl chloride and vanadium silicide; the organochromium source is a bis-trihydrocarbylsilane chromate.
9. The method of preparing a supported multicenter catalyst according to claim 8, wherein the organochromium source has the following structural formula:
Wherein R is a hydrocarbon group of 1 to 20 carbon atoms.
10. The method for preparing a supported multicenter catalyst according to claim 7, wherein the roasting temperature is 400-950 ℃ and the roasting time is 2-24 hours; the CO reduction is: reducing the roasted catalyst in CO atmosphere at 150-600 deg.c for 2-24 hr; the cocatalyst is an organic aluminum compound, the product obtained after the drying in the step 2 is calculated by chromium, and the molar ratio of the cocatalyst to the product obtained after the drying in the step 2 is 0.01-200; the activation temperature is 20-120 ℃, and the activation time is 0.5-5 h.
11. The method for preparing the supported multi-center catalyst according to claim 7, wherein the method for supporting the inorganic chromium source and the inorganic vanadium source on the inorganic carrier is impregnation in the step 1, and the method for supporting the organic chromium source on the catalyst intermediate for supporting the inorganic chromium and the inorganic vanadium is impregnation in the step 2; the inorganic carrier is at least one of silicon oxide, aluminum oxide, aluminosilicate, inorganic clay, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, ferric oxide, tin oxide, zinc oxide, boron oxide, tungsten oxide and niobium oxide.
12. The method for preparing a supported multicenter catalyst according to claim 7, wherein the cocatalyst is an organoaluminium compound; the mole ratio of the cocatalyst to the chromium in the inorganic chromium source and the organic chromium source is 0.01-200; the supported multi-center catalyst is added with a molecular weight regulator when being used for olefin polymerization.
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