CN116212905B - A method for continuously synthesizing isoprene based on enal liquid phase method - Google Patents
A method for continuously synthesizing isoprene based on enal liquid phase method Download PDFInfo
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- CN116212905B CN116212905B CN202211179637.2A CN202211179637A CN116212905B CN 116212905 B CN116212905 B CN 116212905B CN 202211179637 A CN202211179637 A CN 202211179637A CN 116212905 B CN116212905 B CN 116212905B
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- catalyst
- nitrate
- reaction
- chloride
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- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 title claims abstract description 188
- 238000000034 method Methods 0.000 title claims abstract description 123
- 239000007791 liquid phase Substances 0.000 title claims abstract description 85
- 230000002194 synthesizing effect Effects 0.000 title claims description 43
- 239000003054 catalyst Substances 0.000 claims abstract description 163
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 159
- 238000006243 chemical reaction Methods 0.000 claims abstract description 137
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 87
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 claims abstract description 79
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 72
- -1 rare earth phosphate Chemical class 0.000 claims abstract description 55
- 239000010452 phosphate Substances 0.000 claims abstract description 54
- 239000012071 phase Substances 0.000 claims abstract description 46
- BZLVMXJERCGZMT-UHFFFAOYSA-N Methyl tert-butyl ether Chemical compound COC(C)(C)C BZLVMXJERCGZMT-UHFFFAOYSA-N 0.000 claims abstract description 45
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 claims abstract description 41
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 38
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 37
- 239000002994 raw material Substances 0.000 claims abstract description 22
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 claims abstract description 12
- 229910004298 SiO 2 Inorganic materials 0.000 claims abstract description 9
- XYJRXVWERLGGKC-UHFFFAOYSA-D pentacalcium;hydroxide;triphosphate Chemical class [OH-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O XYJRXVWERLGGKC-UHFFFAOYSA-D 0.000 claims description 63
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 60
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 claims description 44
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 claims description 42
- 239000000243 solution Substances 0.000 claims description 41
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 38
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 claims description 38
- 229910052751 metal Inorganic materials 0.000 claims description 35
- 239000002184 metal Substances 0.000 claims description 35
- 229910052681 coesite Inorganic materials 0.000 claims description 30
- 229910052906 cristobalite Inorganic materials 0.000 claims description 30
- 239000000377 silicon dioxide Substances 0.000 claims description 30
- 229910052682 stishovite Inorganic materials 0.000 claims description 30
- 229910052905 tridymite Inorganic materials 0.000 claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
- 238000001035 drying Methods 0.000 claims description 23
- 229910052746 lanthanum Inorganic materials 0.000 claims description 22
- 229910052750 molybdenum Inorganic materials 0.000 claims description 22
- 229910052721 tungsten Inorganic materials 0.000 claims description 22
- 230000001105 regulatory effect Effects 0.000 claims description 21
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 claims description 20
- 229910052720 vanadium Inorganic materials 0.000 claims description 20
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 19
- VYLVYHXQOHJDJL-UHFFFAOYSA-K cerium trichloride Chemical compound Cl[Ce](Cl)Cl VYLVYHXQOHJDJL-UHFFFAOYSA-K 0.000 claims description 19
- 150000001875 compounds Chemical class 0.000 claims description 19
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 19
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 19
- 238000001914 filtration Methods 0.000 claims description 19
- 235000005074 zinc chloride Nutrition 0.000 claims description 19
- 239000011592 zinc chloride Substances 0.000 claims description 19
- LJBTWTBUIINKRU-UHFFFAOYSA-K cerium(3+);triperchlorate Chemical compound [Ce+3].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O LJBTWTBUIINKRU-UHFFFAOYSA-K 0.000 claims description 18
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 claims description 18
- 150000002736 metal compounds Chemical class 0.000 claims description 18
- 150000002910 rare earth metals Chemical class 0.000 claims description 18
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 claims description 18
- 229910000368 zinc sulfate Inorganic materials 0.000 claims description 18
- 229960001763 zinc sulfate Drugs 0.000 claims description 18
- OERNJTNJEZOPIA-UHFFFAOYSA-N zirconium nitrate Chemical compound [Zr+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O OERNJTNJEZOPIA-UHFFFAOYSA-N 0.000 claims description 18
- 238000000498 ball milling Methods 0.000 claims description 17
- 229910052588 hydroxylapatite Inorganic materials 0.000 claims description 17
- XPFCZYUVICHKDS-UHFFFAOYSA-N 3-methylbutane-1,3-diol Chemical compound CC(C)(O)CCO XPFCZYUVICHKDS-UHFFFAOYSA-N 0.000 claims description 15
- GDKSTFXHMBGCPG-UHFFFAOYSA-N 4,4-dimethyl-1,3-dioxane Chemical compound CC1(C)CCOCO1 GDKSTFXHMBGCPG-UHFFFAOYSA-N 0.000 claims description 15
- HKVFISRIUUGTIB-UHFFFAOYSA-O azanium;cerium;nitrate Chemical compound [NH4+].[Ce].[O-][N+]([O-])=O HKVFISRIUUGTIB-UHFFFAOYSA-O 0.000 claims description 15
- XNHGKSMNCCTMFO-UHFFFAOYSA-D niobium(5+);oxalate Chemical compound [Nb+5].[Nb+5].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O XNHGKSMNCCTMFO-UHFFFAOYSA-D 0.000 claims description 15
- 239000010949 copper Substances 0.000 claims description 14
- 238000002156 mixing Methods 0.000 claims description 14
- XMPZTFVPEKAKFH-UHFFFAOYSA-P ceric ammonium nitrate Chemical compound [NH4+].[NH4+].[Ce+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O XMPZTFVPEKAKFH-UHFFFAOYSA-P 0.000 claims description 13
- 238000000926 separation method Methods 0.000 claims description 13
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 claims description 12
- 235000018660 ammonium molybdate Nutrition 0.000 claims description 12
- 239000011609 ammonium molybdate Substances 0.000 claims description 12
- 229940010552 ammonium molybdate Drugs 0.000 claims description 12
- 229910052802 copper Inorganic materials 0.000 claims description 12
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 claims description 12
- UJVRJBAUJYZFIX-UHFFFAOYSA-N nitric acid;oxozirconium Chemical compound [Zr]=O.O[N+]([O-])=O.O[N+]([O-])=O UJVRJBAUJYZFIX-UHFFFAOYSA-N 0.000 claims description 12
- 229910052723 transition metal Inorganic materials 0.000 claims description 12
- 150000003624 transition metals Chemical class 0.000 claims description 12
- QYCVHILLJSYYBD-UHFFFAOYSA-L copper;oxalate Chemical compound [Cu+2].[O-]C(=O)C([O-])=O QYCVHILLJSYYBD-UHFFFAOYSA-L 0.000 claims description 11
- 150000002500 ions Chemical class 0.000 claims description 11
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 claims description 11
- CFYGEIAZMVFFDE-UHFFFAOYSA-N neodymium(3+);trinitrate Chemical compound [Nd+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CFYGEIAZMVFFDE-UHFFFAOYSA-N 0.000 claims description 11
- 239000002244 precipitate Substances 0.000 claims description 11
- 229910021591 Copper(I) chloride Inorganic materials 0.000 claims description 10
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 10
- 229910002651 NO3 Inorganic materials 0.000 claims description 10
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 10
- 239000002253 acid Substances 0.000 claims description 10
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 claims description 10
- OXBLHERUFWYNTN-UHFFFAOYSA-M copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 claims description 10
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 claims description 10
- 229940045803 cuprous chloride Drugs 0.000 claims description 10
- MWFSXYMZCVAQCC-UHFFFAOYSA-N gadolinium(iii) nitrate Chemical compound [Gd+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O MWFSXYMZCVAQCC-UHFFFAOYSA-N 0.000 claims description 10
- ICAKDTKJOYSXGC-UHFFFAOYSA-K lanthanum(iii) chloride Chemical compound Cl[La](Cl)Cl ICAKDTKJOYSXGC-UHFFFAOYSA-K 0.000 claims description 10
- DHRLEVQXOMLTIM-UHFFFAOYSA-N phosphoric acid;trioxomolybdenum Chemical compound O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.OP(O)(O)=O DHRLEVQXOMLTIM-UHFFFAOYSA-N 0.000 claims description 10
- IYDGMDWEHDFVQI-UHFFFAOYSA-N phosphoric acid;trioxotungsten Chemical compound O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.OP(O)(O)=O IYDGMDWEHDFVQI-UHFFFAOYSA-N 0.000 claims description 10
- YWECOPREQNXXBZ-UHFFFAOYSA-N praseodymium(3+);trinitrate Chemical compound [Pr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O YWECOPREQNXXBZ-UHFFFAOYSA-N 0.000 claims description 10
- YOUIDGQAIILFBW-UHFFFAOYSA-J tetrachlorotungsten Chemical compound Cl[W](Cl)(Cl)Cl YOUIDGQAIILFBW-UHFFFAOYSA-J 0.000 claims description 10
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 10
- MFXMOUUKFMDYLM-UHFFFAOYSA-L zinc;dihydrogen phosphate Chemical compound [Zn+2].OP(O)([O-])=O.OP(O)([O-])=O MFXMOUUKFMDYLM-UHFFFAOYSA-L 0.000 claims description 10
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 9
- 229910021551 Vanadium(III) chloride Inorganic materials 0.000 claims description 9
- 238000005137 deposition process Methods 0.000 claims description 9
- 229960002089 ferrous chloride Drugs 0.000 claims description 9
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 9
- 239000011790 ferrous sulphate Substances 0.000 claims description 9
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 claims description 9
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 9
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 9
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 9
- PDKHNCYLMVRIFV-UHFFFAOYSA-H molybdenum;hexachloride Chemical compound [Cl-].[Cl-].[Cl-].[Cl-].[Cl-].[Cl-].[Mo] PDKHNCYLMVRIFV-UHFFFAOYSA-H 0.000 claims description 9
- LHBNLZDGIPPZLL-UHFFFAOYSA-K praseodymium(iii) chloride Chemical compound Cl[Pr](Cl)Cl LHBNLZDGIPPZLL-UHFFFAOYSA-K 0.000 claims description 9
- FEONEKOZSGPOFN-UHFFFAOYSA-K tribromoiron Chemical compound Br[Fe](Br)Br FEONEKOZSGPOFN-UHFFFAOYSA-K 0.000 claims description 9
- HQYCOEXWFMFWLR-UHFFFAOYSA-K vanadium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[V+3] HQYCOEXWFMFWLR-UHFFFAOYSA-K 0.000 claims description 9
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 8
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 7
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 7
- 229910052758 niobium Inorganic materials 0.000 claims description 7
- 239000010955 niobium Substances 0.000 claims description 7
- 229910021575 Iron(II) bromide Inorganic materials 0.000 claims description 6
- 229940046149 ferrous bromide Drugs 0.000 claims description 6
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 claims description 6
- 229910000360 iron(III) sulfate Inorganic materials 0.000 claims description 6
- GYCHYNMREWYSKH-UHFFFAOYSA-L iron(ii) bromide Chemical compound [Fe+2].[Br-].[Br-] GYCHYNMREWYSKH-UHFFFAOYSA-L 0.000 claims description 6
- 239000002923 metal particle Substances 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 229910021332 silicide Inorganic materials 0.000 claims description 6
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 claims description 6
- 239000007790 solid phase Substances 0.000 claims description 6
- 125000005287 vanadyl group Chemical group 0.000 claims description 6
- 235000019353 potassium silicate Nutrition 0.000 claims description 5
- 230000000630 rising effect Effects 0.000 claims description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 5
- 239000011701 zinc Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 229910052725 zinc Inorganic materials 0.000 claims description 4
- 239000002638 heterogeneous catalyst Substances 0.000 claims description 3
- 230000035484 reaction time Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 abstract description 28
- 238000007086 side reaction Methods 0.000 abstract description 20
- 238000004519 manufacturing process Methods 0.000 abstract description 13
- 150000001336 alkenes Chemical class 0.000 abstract description 6
- 230000036571 hydration Effects 0.000 abstract description 5
- 238000006703 hydration reaction Methods 0.000 abstract description 5
- 238000011084 recovery Methods 0.000 abstract description 4
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 abstract description 3
- 230000001276 controlling effect Effects 0.000 description 28
- 239000000047 product Substances 0.000 description 21
- 239000013067 intermediate product Substances 0.000 description 18
- 239000000463 material Substances 0.000 description 16
- 238000011068 loading method Methods 0.000 description 14
- 239000003921 oil Substances 0.000 description 14
- 238000002360 preparation method Methods 0.000 description 12
- 238000003756 stirring Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 5
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- CPJRRXSHAYUTGL-UHFFFAOYSA-N isopentenyl alcohol Chemical compound CC(=C)CCO CPJRRXSHAYUTGL-UHFFFAOYSA-N 0.000 description 4
- 230000001502 supplementing effect Effects 0.000 description 4
- 239000013065 commercial product Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 230000000887 hydrating effect Effects 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- ZHXZNKNQUHUIGN-UHFFFAOYSA-N chloro hypochlorite;vanadium Chemical compound [V].ClOCl ZHXZNKNQUHUIGN-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- ZSWFCLXCOIISFI-UHFFFAOYSA-N cyclopentadiene Chemical compound C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- ASUAYTHWZCLXAN-UHFFFAOYSA-N prenol Chemical compound CC(C)=CCO ASUAYTHWZCLXAN-UHFFFAOYSA-N 0.000 description 2
- NSPPRYXGGYQMPY-UHFFFAOYSA-N 3-Methylbuten-2-ol-1 Natural products CC(C)C(O)=C NSPPRYXGGYQMPY-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910017518 Cu Zn Inorganic materials 0.000 description 1
- 229910017752 Cu-Zn Inorganic materials 0.000 description 1
- 229910017943 Cu—Zn Inorganic materials 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 244000286663 Ficus elastica Species 0.000 description 1
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000001345 alkine derivatives Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229940032950 ferric sulfate Drugs 0.000 description 1
- 229960001781 ferrous sulfate Drugs 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000003205 fragrance Substances 0.000 description 1
- 238000002290 gas chromatography-mass spectrometry Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229920003049 isoprene rubber Polymers 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000001819 mass spectrum Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000012450 pharmaceutical intermediate Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/14—Phosphorus; Compounds thereof
- B01J27/182—Phosphorus; Compounds thereof with silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/14—Phosphorus; Compounds thereof
- B01J27/186—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J27/188—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with chromium, molybdenum, tungsten or polonium
- B01J27/19—Molybdenum
-
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Abstract
本发明提供了催化剂在烯醛液相法合成异戊二烯中的应用；所述催化剂包括改性稀土磷酸盐催化剂；所述改性稀土磷酸盐的通式为AxByPO4·SiO2。本发明以叔丁醇、甲基叔丁基醚和甲醛为原料，两段式连续化反应合成异戊二烯，控制甲醛副反应、开发多相可回收催化剂，特别是一段反应利用该改性稀土磷酸盐催化剂，采用低烯醛比和较低的反应温度减少甲醛副反应，提高烯源利用率和产物生产效率，省去异丁烯回收、水合过程。The present invention provides an application of a catalyst in the synthesis of isoprene by an olefinic aldehyde liquid phase method; the catalyst comprises a modified rare earth phosphate catalyst; the general formula of the modified rare earth phosphate is A x B y PO 4 ·SiO 2 . The present invention uses tert-butyl alcohol, methyl tert-butyl ether and formaldehyde as raw materials, synthesizes isoprene by two-stage continuous reaction, controls the formaldehyde side reaction, develops a multi-phase recyclable catalyst, and particularly utilizes the modified rare earth phosphate catalyst in a one-stage reaction, adopts a low olefinic aldehyde ratio and a relatively low reaction temperature to reduce the formaldehyde side reaction, improves the utilization rate of the olefin source and the production efficiency of the product, and saves the isobutylene recovery and hydration process.
Description
Technical Field
The invention belongs to the technical field of isoprene synthesis by an enal method, relates to application of a catalyst in isoprene synthesis by an enal liquid phase method and a method for synthesizing isoprene by an enal liquid phase method, and particularly relates to a method and a catalyst for continuously synthesizing isoprene by an enal liquid phase method.
Background
Isoprene is a key raw material for synthesizing isoprene rubber, and is also a basic raw material for synthesizing isoprene latex, pharmaceutical intermediates, fragrances, crosslinking agents, and the like. Currently, the main process for producing isoprene is C5 separation, which has low process yield (less than 1.7% of the input raw material), and a rubber plant of 10 ten thousand t/a requires five and six megatons of ethylene plant to satisfy the supply of isoprene raw material, while the enal process for synthesizing isoprene has obvious economic advantages among many chemical synthesis methods. Russian has developed the study of two-step method of olefine aldehyde and one-step method (gas phase) successively, wherein the two-step method for synthesizing isoprene has been industrialized, and although the one-step method of olefine aldehyde has short flow, the product is easy to refine, and each energy consumption is obviously reduced, but no industrialized report exists at present.
The key of the technology for synthesizing isoprene by using the olefine aldehyde method is to control formaldehyde side reaction and olefin (isobutene and isoprene) side reaction, so as to improve the selectivity. The reaction temperature of the one-step method is higher (300 ℃), the formaldehyde side reaction is serious, byproducts are more, the generated high-boiling point compounds are more, the olefin compounds easily participate in the carbon-forming reaction, and the yield is difficult to exceed 70 percent. By adopting the tower reactor and the multi-stage separation device, the advantages of the process can be realized when the device scale is large. In contrast, the enal liquid phase method has the advantages of mild reaction temperature (< 200 ℃) and strong controllability of side reactions, low requirements on equipment and technology, and has the advantages of ① reducing the raw material and energy consumption for isoprene production, ② improving the ecological index of the production process, reducing the emission of waste water, waste gas and the like, ③ having high purity and low impurity content, and being capable of reducing the cost of isoprene polymerization (the purity of isoprene is required to be more than 99.4%, the content of cyclopentadiene is required to be less than 3 mu g/g and the content of alkyne is required to be less than 10 mu g/g in general because the impurity content of polymer grade isoprene is strictly controlled). In 1972, the one-step method developed by Sumitomo chemical company of Japan is used for synthesizing isoprene, isobutene or tertiary butanol and formaldehyde are used as raw materials, the reaction is carried out in a liquid phase at 149-160 ℃, the residence time in a reactor is 30-50 min, the reaction flow is that isobutene and formaldehyde are condensed to generate intermediate products (mainly 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol, 3-methyl-3-buten-1-ol and 3-methyl-2-buten-1-ol), the intermediate products are cracked to generate isoprene, the generation and the cracking of the intermediate products are carried out in the same reactor, and in order to inhibit side reactions, the molar ratio of formaldehyde to isobutene or tertiary butanol is 1:1.2 (Oil & Gas Journal,1972,70 (26)). Japanese colali (EP 83110225.6, US4511751, US 4593145) reports the process in detail, sulfuric acid or boric acid is used as a catalyst, an acidic aqueous solution is firstly introduced into a reaction kettle, the temperature is raised to 170-180 ℃ to form a pressure of about 10atm, tertiary butanol, formaldehyde and water are introduced at a certain rate, the pressure of about 12-20 atm is reached after the system is stabilized, a gas product flows out from the top of the reaction kettle, and the gas product is collected after cooling. When the molar ratio of C4/formaldehyde is >3, the yield of isoprene is reduced, and from the viewpoint of selectivity, the larger the ratio of enal is, the better, but the improvement of the yield of isoprene by the excessive ratio of enal is not obvious, and the heat consumption is obviously increased.
The European company develops a novel environment-friendly enal liquid phase method process (two-stage method), which is slightly different from the process, adopts formaldehyde and tertiary butanol as raw materials to firstly generate DMD, and then the DMD reacts with the tertiary butanol in a liquid phase to generate isoprene, so that the method can effectively improve the formaldehyde selectivity. The Russian Down-Carmstick petrochemical company uses enal liquid phase method to produce isoprene in large scale in 2003, and the technology is used for replacing the original enal two-step method technology, and the productivity reaches 18 ten thousand t/a (petrochemical industry, 1 (2): 103-104, fine petrochemical industry, 2012,29,77-82). The published patent shows (EP 2157072A 1) that the process uses phosphoric acid as the base catalyst, and as a typical result, 9L of phosphoric acid solution (7%) is added into a reactor, the temperature is raised to 110 ℃ and 160 ℃ respectively, 40% formaldehyde (256.6 g/h) and 88% tertiary butanol (860 g/h) are added into the reactor 1, the pressure of the reaction kettle is 22atm, the product of the reaction kettle 1 and tertiary butanol (2015.9 g/h) are mixed into the reaction kettle 2, the pressure of the reaction kettle 2 is 12atm, and the selectivity of formaldehyde and isobutene is 75% and 82% respectively. The intermediate products 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol, 3-methyl-3-buten-1-ol and the like are intermediate products for synthesizing isoprene by a liquid phase method, are also key for limiting the production efficiency of isoprene, reduce the production efficiency of the intermediate products although effectively inhibiting formaldehyde side reaction, and generate more energy consumption for recycling and hydrating a large amount of isobutene.
Therefore, how to find a more suitable method for synthesizing isoprene by using an enal method, further inhibit the occurrence of side reactions, improve the production efficiency, and become one of the focuses of prospective researchers in the industry.
Disclosure of Invention
In view of the above, the technical problem to be solved by the invention is to provide an application of a catalyst in synthesizing isoprene by an enal liquid phase method and a method for synthesizing isoprene by an enal liquid phase method, in particular to a method for continuously synthesizing isoprene by an enal liquid phase method. The invention designs the modified rare earth phosphate catalyst with specific composition for synthesizing isoprene by using an enal liquid phase method, which not only reduces formaldehyde side reaction and improves isoprene production efficiency, but also has the advantages of easier recovery of solid phase catalyst for liquid phase method process, mild reaction condition, simple operation and large-scale synthesis prospect.
The invention provides an application of a catalyst in synthesizing isoprene by an enal liquid phase method;
the catalyst comprises a modified rare earth phosphate catalyst;
The general formula of the modified rare earth phosphate is A xByPO4·SiO2;
Wherein x is 0.7-1.4, and y is 0.02-0.3;
A is one or more of La, ce, pr, nd and Gd;
B is one or more of Mo, zr, cu, zn, W, V and Nb.
Preferably, the catalyst is a heterogeneous catalyst;
The catalyst also comprises a metal modified hydroxyapatite catalyst;
The metal comprises one or more of Cu, ce, fe and Zn;
The mass content of the metal in the metal modified hydroxyapatite is 2-20wt%;
the size of the metal particles in the metal modified hydroxyapatite is 10-50 nm.
Preferably, in the modified rare earth phosphate, the mass content of SiO 2 is 15-45 wt%;
The synthesis includes continuous synthesis;
The synthesis is specifically two-stage synthesis;
the modified rare earth phosphate catalyst is a catalyst for one-stage synthesis;
The metal modified hydroxyapatite catalyst is a catalyst for two-stage synthesis.
The invention also provides a method for synthesizing isoprene by using the enal liquid phase method, which comprises the following steps:
1) Tertiary butyl alcohol and/or methyl tertiary butyl ether, a modified rare earth phosphate catalyst and formaldehyde are sent into a first reaction device for reaction, and then a liquid phase reaction system is obtained;
2) And (3) sending the tertiary butyl alcohol and/or methyl tertiary butyl ether, the metal modified hydroxyapatite catalyst and the liquid phase reaction system obtained in the steps into a second reaction device for re-reaction to obtain isoprene.
Preferably, the ratio of olefine to aldehyde of the raw materials in the step 1) is (0.2-1.6): 1;
The reaction temperature is 120-145 ℃;
the reaction time is 10-60 minutes;
the pressure of the reaction is less than or equal to 10atm;
the feeding rate fed in the step 1) is 5-50 ml/min;
Filtering the solid phase catalyst after the reaction to obtain a liquid phase reaction system;
The liquid phase reaction system comprises 4, 4-dimethyl-1, 3-dioxane and 3-methyl-1, 3-butanediol.
Preferably, the molar equivalent ratio of the tertiary butanol and/or methyl tertiary butyl ether in the step 2) to the formaldehyde in the step 1) is (2-10): 1;
The feeding rate fed in the step 2) is 5-50 ml/min;
The temperature of the re-reaction is 145-165 ℃;
The time of the re-reaction is 10-60 minutes;
the pressure of the re-reaction is 16atm or less.
Preferably, the reaction further comprises a catalyst separation step after the re-reaction;
The separated liquid phase comprises an oil phase and a water phase;
The height of the water phase is not more than one half of the height of the reaction area of the reactor and not less than one quarter of the height of the reaction area of the reactor;
The height of the oil phase is not more than one half of the height of the reaction area of the reactor and not less than one quarter of the height of the reaction area of the reactor;
In the method, the generated isobutene is hydrated to obtain tertiary butanol, and the tertiary butanol returns to the step 1).
Preferably, the preparation method of the modified rare earth phosphate catalyst comprises the following steps:
Mixing the mixed solution of the rare earth metal soluble compound and the transition metal soluble compound with silicide, regulating the pH value to obtain precipitate, drying, carrying out stepped temperature rise ball milling with phosphoric acid solution, and roasting to obtain the modified rare earth phosphate catalyst;
The rare earth metal soluble compound comprises one or more of lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate and gadolinium nitrate;
The transition metal soluble compound comprises one or more of ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadyl trichloride, niobic acid, niobium oxalate and niobium oxalate complex;
The total concentration of the metal compounds in the mixed solution is 10-80 g/L;
The silicide comprises one or more of tetraethoxysilane, water glass and silica sol;
The temperature of the mixing is 50-80 ℃.
Preferably, the pH value is 8-10;
the temperature of the drying is 50-80 ℃;
the drying time is 3-10 hours;
The concentration of the phosphoric acid solution is 3-30 g/L;
the start-stop temperature of the step heating ball milling is 15-200 ℃;
The temperature rising rate of the step temperature rising ball milling is 1-20 ℃;
the residence time of the steps is 0.5-3.5 hours;
the roasting temperature is 400-600 ℃;
and the roasting time is 3-10 hours.
Preferably, the preparation method of the metal modified hydroxyapatite catalyst comprises the following steps:
roasting the hydroxyapatite, placing the hydroxyapatite into a modified metal compound solution, and roasting the hydroxyapatite again after the exchange-adsorption-deposition process to obtain a metal modified hydroxyapatite catalyst;
the roasting temperature is 800-1500 ℃;
the roasting time is 2-8 hours;
The modified metal compound solution comprises one or more of copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous bromide, ferric sulfate, ferrous sulfate, cerium nitrate, cerium chloride, ceric ammonium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate and zinc dihydrogen phosphate;
The ion concentration of the modified metal in the modified metal compound solution is 0.02-1.2 g/ml;
the pH value of the system in the exchange-adsorption-deposition process is 5-8;
the time of the exchange-adsorption-deposition process is 2-24 hours;
the temperature of the re-roasting is 600-1300 ℃;
And the re-roasting time is 2-8 hours.
The invention provides application of a catalyst in synthesizing isoprene by an enal liquid phase method, wherein the catalyst comprises a modified rare earth phosphate catalyst, and the general formula of the modified rare earth phosphate is A xByPO4·SiO2, wherein x is 0.7-1.4, y is 0.02-0.3, A is one or more of La, ce, pr, nd and Gd, and B is one or more of Mo, zr, cu, zn, W, V and Nb. Compared with the prior art, the invention designs a modified rare earth phosphate catalyst which is particularly used in the reaction process aiming at the defects existing in the existing liquid-phase method for synthesizing isoprene by using olefine aldehyde, and the catalyst is a solid-phase catalyst which is easier to recycle in the liquid-phase method synthesis process. The modified rare earth phosphate catalyst provided by the invention is further combined with the modified hydroxyapatite catalyst in the two-stage continuous reaction synthesis process, so that formaldehyde side reaction is reduced, isoprene production efficiency is improved, and the catalyst is easy to recycle.
The invention takes tert-butyl alcohol, methyl tert-butyl ether and formaldehyde as raw materials, synthesizes isoprene by two-section continuous reaction, controls formaldehyde side reaction and develops a multiphase recoverable catalyst. The method comprises the steps of adopting modified rare earth phosphate (A xByPO4·SiO2) as a catalyst to catalyze formaldehyde, tertiary butanol and methyl tertiary butyl ether to synthesize intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like at a low olefine-aldehyde ratio of 120-145 ℃, controlling the liquid phase product to be a uniform phase, controlling the reaction pressure to be less than 10atm, controlling the conversion rate and selectivity of the tertiary butanol and the methyl tertiary butyl ether to be more than 92%, and the second step of keeping the alkene source excess of the intermediate products, the tertiary butanol and the methyl tertiary butyl ether at 145-165 ℃ and adopting a modified hydroxyapatite catalyst to convert and synthesize isoprene, wherein the reaction pressure is less than 16atm, and the yield can reach 80%. The first-stage reaction adopts low olefine-aldehyde ratio and lower reaction temperature to reduce formaldehyde side reaction, improve olefine source utilization rate and product production efficiency, and omit isobutene recovery and hydration processes.
Experimental results show that the catalyst and the two-stage continuous reaction synthesis mode provided by the invention have the advantages that in the one-stage reaction, the conversion rate and the selectivity of raw materials of tertiary butanol and methyl tertiary butyl ether are both more than 92%, and in the two-stage reaction, the yield can reach 80% by adopting the modified hydroxyapatite catalyst.
Drawings
FIG. 1 is a schematic diagram of a reaction scheme for continuously synthesizing isoprene by using an enal liquid phase method;
FIG. 2 shows the product distribution and regulation 1 of the continuous isoprene synthesis process based on the enal liquid phase method provided by the invention;
FIG. 3 shows the product distribution and control 2 of the process of synthesizing isoprene continuously by using the enal liquid phase method;
FIG. 4 is a diagram of a gas chromatograph-mass spectrum full-component analysis of the process of synthesizing isoprene continuously by using an enal liquid phase method.
Detailed Description
For a further understanding of the present invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further features and advantages of the invention and are not limiting of the invention claims.
All the raw materials of the present invention are not particularly limited in their sources, and may be purchased on the market or prepared according to conventional methods well known to those skilled in the art.
The purity of all the raw materials of the invention is not particularly limited, and the invention preferably adopts the conventional purity requirement in the field of synthesizing isoprene by using an analytically pure or enal liquid phase method.
All raw materials and processes of the invention, the brands or abbreviations of which belong to the conventional brands or abbreviations in the field of the related application are clear and definite, and according to the brands, abbreviations and the corresponding application, the raw materials and processes can be purchased from the market or prepared by the conventional method or realized by adopting the corresponding equipment.
The invention provides an application of a catalyst in synthesizing isoprene by an enal liquid phase method;
the catalyst comprises a modified rare earth phosphate catalyst;
The general formula of the modified rare earth phosphate is A xByPO4·SiO2;
Wherein x is 0.7-1.4, and y is 0.02-0.3;
A is one or more of La, ce, pr, nd and Gd;
B is one or more of Mo, zr, cu, zn, W, V and Nb.
In the invention, the general formula of the modified rare earth phosphate is A xByPO4·SiO2;
Wherein x is 0.7 to 1.4, may be 0.8 to 1.3, preferably 0.9 to 1.2, and more preferably 1.0 to 1.1.y is 0.02 to 0.3, may be 0.05 to 0.25, and is preferably 0.1 to 0.2.
In the present invention, a is one or more of La, ce, pr, nd and Gd, which may be La, ce, pr, nd or Gd.
In the present invention, B is one or more of Mo, zr, cu, zn, W, V and Nb, and may be Mo, zr, cu, zn, W, V or Nb.
In the present invention, the catalyst is preferably a heterogeneous catalyst.
In the present invention, the catalyst also preferably includes a metal-modified hydroxyapatite catalyst.
In the present invention, the metal preferably includes one or more of Cu, ce, fe, and Zn, more preferably Cu, ce, fe, or Zn.
In the invention, the mass content of the metal in the metal-modified hydroxyapatite is preferably 2-20 wt%, more preferably 5-17 wt%, and even more preferably 8-14 wt%.
In the present invention, the size of the metal particles in the metal-modified hydroxyapatite is preferably 10 to 50nm, more preferably 15 to 45nm, still more preferably 20 to 40nm, and still more preferably 25 to 35nm.
In the modified rare earth phosphate, the mass content of SiO 2 is preferably 15-45 wt%, more preferably 20-40 wt%, and even more preferably 25-35 wt%.
In the present invention, the synthesis preferably includes a continuous synthesis.
In the present invention, the synthesis is specifically preferably a two-stage synthesis.
In the present invention, the modified rare earth phosphate catalyst is preferably a catalyst for one-stage synthesis.
In the present invention, the metal-modified hydroxyapatite catalyst is preferably a catalyst for two-stage synthesis.
The invention provides a method for synthesizing isoprene by an enal liquid phase method, which comprises the following steps:
1) Tertiary butyl alcohol and/or methyl tertiary butyl ether, a modified rare earth phosphate catalyst and formaldehyde are sent into a first reaction device for reaction, and then a liquid phase reaction system is obtained;
2) And (3) sending the tertiary butyl alcohol and/or methyl tertiary butyl ether, the metal modified hydroxyapatite catalyst and the liquid phase reaction system obtained in the steps into a second reaction device for re-reaction to obtain isoprene.
The invention firstly sends tertiary butanol and/or methyl tertiary butyl ether, a modified rare earth phosphate catalyst and formaldehyde into a first reaction device for reaction to obtain a liquid phase reaction system.
In the present invention, the ratio of the olefine aldehyde to the aldehyde in the raw material in the step 1) is preferably (0.2 to 1.6): 1, more preferably (0.4 to 1.4): 1, still more preferably (0.6 to 1.2): 1, and still more preferably (0.8 to 1.2): 1.
In the present invention, the reaction temperature is preferably 120 to 145 ℃, more preferably 125 to 140 ℃, and even more preferably 130 to 135 ℃.
In the present invention, the reaction time is preferably 10 to 60 minutes, more preferably 20 to 50 minutes, and still more preferably 30 to 40 minutes.
In the present invention, the pressure of the reaction is preferably 10atm or less, more preferably 9atm or less, and still more preferably 8atm or less.
In the present invention, the feeding rate of the material in the step 1) is preferably 5 to 50ml/min, more preferably 15 to 40ml/min, and even more preferably 25 to 30ml/min.
In the present invention, it is preferable to obtain a liquid-phase reaction system after filtering the solid-phase catalyst after the reaction.
In the present invention, the liquid-phase reaction system preferably includes 4, 4-dimethyl-1, 3-dioxane and 3-methyl-1, 3-butanediol.
The invention finally sends the tertiary butanol and/or methyl tertiary butyl ether, the metal modified hydroxyapatite catalyst and the liquid phase reaction system obtained in the steps into a second reaction device to react again, and then isoprene is obtained.
In the present invention, the molar equivalent ratio of the tertiary butanol and/or methyl tertiary butyl ether in the step 2) to the formaldehyde in the step 1) is preferably (2 to 10): 1, more preferably (3 to 9): 1, still more preferably (4 to 8): 1, still more preferably (5 to 7): 1.
In the present invention, the feeding rate of the material fed in the step 2) is preferably 5 to 50ml/min, more preferably 15 to 40ml/min, and even more preferably 25 to 30ml/min.
In the present invention, the temperature of the re-reaction is preferably 145 to 165 ℃, more preferably 149 to 161 ℃, and even more preferably 153 to 157 ℃.
In the present invention, the time for the re-reaction is preferably 10 to 60 minutes, more preferably 20 to 50 minutes, and still more preferably 30 to 40 minutes.
In the present invention, the pressure of the re-reaction is preferably 16atm or less, more preferably 15atm or less, and still more preferably 14atm or less.
In the present invention, the re-reaction is preferably followed by a catalyst separation step.
In the present invention, the separated liquid phase preferably includes an oil phase and an aqueous phase.
In the present invention, the height of the aqueous phase is preferably not more than one half, more preferably one third, preferably not less than one fourth, more preferably not less than one fifth of the height of the reaction zone of the reactor.
In the present invention, the height of the oil phase is preferably not more than one half, more preferably one third, preferably not less than one fourth, more preferably not less than one fifth of the height of the reaction zone of the reactor.
In the process according to the invention, the isobutene produced is hydrated to give tert-butanol, preferably back to step 1).
In the present invention, the preparation method of the modified rare earth phosphate catalyst preferably comprises the following steps:
mixing the mixed solution of the rare earth metal soluble compound and the transition metal soluble compound with silicide, regulating the pH value to obtain precipitate, drying, carrying out stepped temperature rise ball milling with phosphoric acid solution, and roasting to obtain the modified rare earth phosphate catalyst.
In the present invention, the rare earth metal-soluble compound preferably includes one or more of lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, cerium ammonium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate, and gadolinium nitrate, more preferably lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, cerium ammonium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate, or gadolinium nitrate.
In the present invention, the transition metal soluble compound preferably includes one or more of ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadyl trichloride, niobic acid, niobium oxalate, and niobium oxalate complex, more preferably ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, niobic acid, niobium oxalate, or niobium oxalate complex.
In the invention, the total concentration of the metal compounds in the mixed solution is preferably 10-80 g/L, more preferably 25-65 g/L, and even more preferably 40-50 g/L.
In the present invention, the silicide preferably includes one or more of ethyl orthosilicate, water glass, and silica sol, more preferably ethyl orthosilicate, water glass, or silica sol.
In the present invention, the temperature of the mixing is preferably 50 to 80 ℃, more preferably 55 to 75 ℃, and still more preferably 60 to 70 ℃.
In the present invention, the pH is preferably 8 to 10, more preferably 8.4 to 9.6, and even more preferably 8.8 to 9.2.
In the present invention, the temperature of the drying is preferably 50 to 80 ℃, more preferably 55 to 75 ℃, and still more preferably 60 to 70 ℃.
In the invention, the drying time is 3 to 10 hours, preferably 4.5 to 8.5 hours, and more preferably 6 to 7 hours.
In the present invention, the concentration of the phosphoric acid solution is preferably 3 to 30g/L, more preferably 8 to 25g/L, and even more preferably 13 to 20g/L.
In the invention, the start-stop temperature of the step-heating ball milling is preferably 15-200 ℃, more preferably 50-160 ℃, and even more preferably 90-120 ℃.
In the invention, the temperature rising rate of the step-heating ball milling is preferably 1-20 ℃, more preferably 5-16 ℃, and even more preferably 9-12 ℃.
In the present invention, the residence time of the step is preferably 0.5 to 3.5 hours, more preferably 1.0 to 3.0 hours, and still more preferably 1.5 to 2.5 hours.
In the present invention, the temperature of the firing is preferably 400 ℃ to 600 ℃, more preferably 440 ℃ to 560 ℃, and still more preferably 480 ℃ to 520 ℃.
In the present invention, the baking time is preferably 3 to 10 hours, more preferably 4 to 9 hours, still more preferably 5 to 8 hours, and still more preferably 6 to 7 hours.
In the present invention, the preparation method of the metal-modified hydroxyapatite catalyst preferably comprises the following steps:
And (3) roasting the hydroxyapatite, placing the hydroxyapatite into a modified metal compound solution, and roasting the hydroxyapatite again after the exchange-adsorption-deposition process to obtain the metal modified hydroxyapatite catalyst.
In the present invention, the temperature of the baking is preferably 800 to 1500 ℃, more preferably 950 to 1350 ℃, and even more preferably 1100 to 1200 ℃.
In the present invention, the baking time is preferably 2 to 8 hours, more preferably 3 to 7 hours, and still more preferably 4 to 6 hours.
In the present invention, the modified metal compound solution preferably includes one or more of copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous sulfate, cerium nitrate, cerium chloride, ceric ammonium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate, and zinc dihydrogen phosphate, more preferably copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous bromide, ferric sulfate, ferrous sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate, or zinc dihydrogen phosphate.
In the present invention, the ion concentration of the modifying metal in the modifying metal compound solution is preferably 0.02 to 1.2g/ml, more preferably 0.1 to 1.0g/ml, still more preferably 0.3 to 0.8g/ml, still more preferably 0.5 to 0.6g/ml.
In the invention, the pH value of the system in the exchange-adsorption-deposition process is preferably 5-8, more preferably 5.5-7.5, and even more preferably 6-7.
In the present invention, the time of the exchange-adsorption-deposition process is preferably 2 to 24 hours, more preferably 6 to 20 hours, and still more preferably 10 to 16 hours.
In the present invention, the temperature of the re-baking is preferably 600 to 1300 ℃, more preferably 750 to 1150 ℃, and even more preferably 900 to 1000 ℃.
In the present invention, the time for the re-baking is preferably 2 to 8 hours, more preferably 3 to 7 hours, and still more preferably 4 to 6 hours.
Referring to fig. 1, fig. 1 is a schematic and schematic diagram of a reaction flow for continuously synthesizing isoprene by using an enal liquid phase method.
The invention is a complete and refined integral technical scheme, and better reduces formaldehyde side reaction, further improves the utilization rate of an alkene source and the production efficiency of products for synthesizing isoprene by an alkene-aldehyde liquid phase method, and the method for continuously synthesizing isoprene by the alkene-aldehyde liquid phase method specifically and preferably comprises the following steps:
a method for synthesizing isoprene continuously by using an enal liquid phase method comprises the steps of taking formaldehyde, tertiary butanol and methyl tertiary butyl ether as raw materials, and carrying out two-stage reaction;
(1) The first-stage reaction is carried out at 120-145 ℃, the olefine-aldehyde ratio is controlled to be 0.2-1.6, the feeding rate is controlled to be 5-50 ml/min, the residence time of materials in the reactor is 10-60 minutes, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase products are in a uniform phase, the reaction pressure is controlled to be less than 10atm, the catalyst is reserved in the first-stage reactor through a filter, and the materials enter the second-stage reactor.
(2) Supplementing tert-butyl alcohol and methyl tert-butyl ether, keeping the equivalent ratio of the tert-butyl alcohol and formaldehyde at 2-10, keeping the feeding rate at 5-50 ml/min, keeping the reaction temperature at 145-165 ℃, keeping the material residence time at 10-60 min, regulating the reaction pressure to be less than 16atm, separating to obtain isoprene, separating a liquid phase into oil-water two phases, controlling the water phase to be not more than one half of a reactor and not less than one fourth, controlling the oil phase to be not more than one half of a reactor and not less than one fourth, and returning the separated isobutene to the first-stage reactor through hydration.
Specifically, the catalyst adopted by the first-stage reactor is modified rare earth phosphate (A xByPO4·SiO2), A is rare earth La, ce, pr, nd, gd and the like. From lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate, gadolinium nitrate, etc., and B is a transition metal Mo, zr, cu, zn, W, V, nb, etc., from ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadyl trichloride, niobic acid, niobium oxalate complex, etc.
Specifically, the modified rare earth phosphate catalyst can be expressed as A xByPO4·SiO2, and is characterized in that A is one or more of rare earth metals La, ce, pr, nd, gd and the like, the atomic ratio x of the A to P is 0.7-1.4, B is one or more of transition metals Mo, zr, cu, zn, W, V, nb and the like, the atomic ratio y of the B to P is 0.02-0.3, and the content of A xByPO4 in A xByPO4·SiO2 is 15-45wt%.
Specifically, the preparation process comprises the following steps:
(1) Dissolving a soluble compound containing La, ce, pr, nd, gd and other rare earth metals in water, adding the soluble compound containing Mo, zr, cu, zn, W, V, nb and other rare earth metals, wherein the total concentration of the metal compounds in the solution is 10-80 g/L, and adding silicon-containing compounds such as tetraethoxysilane, water glass, silica sol and the like;
(2) Stirring and mixing at 50-80 ℃, adjusting the pH to 8-10, filtering out precipitate, and drying at 50-80 ℃ for 3-10 hours;
(3) Adding a phosphoric acid solution with the concentration of 3-30 g/L, adopting a temperature programming-ball milling mode, controlling the temperature programming to be between room temperature and 200 ℃, controlling the temperature programming rate to be between 1 and 20 ℃, and roasting for 3-10 hours at 400 to 600 ℃ to obtain A xByPO4·SiO2, wherein the residence time is between 0.5 and 3.5 hours.
Specifically, the catalyst adopted by the second-stage reactor is metal modified hydroxyapatite, one or more of the modified metals is Cu, ce, fe, zn, the loading amount is 2-20wt%, and the size of metal particles in the catalyst is 10-50 nm.
The modified hydroxyapatite catalyst is prepared by taking hydroxyapatite as a commodity, roasting the hydroxyapatite at 800-1500 ℃ for 2-8 hours before using the hydroxyapatite, adopting a solution containing Cu, ce, fe, zn for 'exchange-adsorption-deposition' for 2-24 hours, wherein the ion concentration is 0.02-1.2 g/ml, cu, ce, fe, zn is from copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferrous bromide, ferric sulfate, ferrous sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate and the like, adjusting the pH of the system to be=5-8, drying the system at 100 ℃ for 3-8 hours after filtering, and roasting the system at 600-1300 ℃ for 2-8 hours.
Further, the method and the catalyst for synthesizing isoprene continuously by using the enal liquid phase method provided by the invention more preferably comprise the following steps:
The liquid-phase method for synthesizing isoprene from formaldehyde, tertiary butanol and methyl tertiary butyl ether is used as raw materials, and the two-stage reaction is carried out,
(1) The first-stage reaction is carried out at 120-145 ℃, preferably 125-140 ℃, the olefine-aldehyde ratio is controlled to be 0.2-1.6, preferably 0.3-1.5, the feeding rate is controlled to be 5-50 ml/min, preferably 10-50 ml/min, the residence time of materials in a reactor is 10-60 minutes, preferably 15-50 minutes, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase products are uniform phases, and the reaction pressure is regulated to be less than 10atm, preferably <9atm. The catalyst was left in the first stage reactor through the filter and the material was fed into the second stage reactor.
(2) The method comprises the steps of supplementing tert-butyl alcohol and methyl tert-butyl ether, keeping the equivalent ratio of the tert-butyl alcohol and methyl tert-butyl ether to formaldehyde to be 2-10, preferably 2.5-9.5, the feeding rate to be 5-50 ml/min, preferably 10-50 ml/min, the reaction temperature to be 145-165 ℃ and preferably 150-160 ℃, the residence time of materials to be 10-60 min, preferably 15-50 min, regulating the reaction pressure to be less than 16atm, preferably <14atm, separating to obtain isoprene, separating a liquid phase into oil phase and water phase, controlling the oil phase to be not more than one half of a reactor and not less than one fourth of a reactor, and returning isobutene to a first-stage reactor after separation through hydration.
The catalyst adopted by the first-stage reactor is modified rare earth phosphate (A xByPO4·SiO2), wherein A is rare earth metal La, ce, pr, nd, gd and the like, preferably La, ce, pr, nd, gd, and is selected from lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate, gadolinium nitrate and the like, preferably lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate and gadolinium nitrate. B is a transition metal Mo, zr, cu, zn, W, V, nb or the like, preferably Mo, zr, cu, zn, W, V, nb, and is derived from ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadyl trichloride, niobic acid, niobium oxalate complex or the like, preferably ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadyl trichloride, niobic acid, niobium oxalate complex or the like.
The modified rare earth phosphate catalyst can be expressed as A xByPO4·SiO2, wherein A is one or more of rare earth metals La, ce, pr, nd, gd and the like, preferably one or more of La, ce, pr, nd, gd, the atomic ratio x of the catalyst to P is 0.7-1.4, preferably 0.8-1.3, B is one or more of transition metals Mo, zr, cu, zn, W, V, nb and the like, preferably one or more of Mo, zr, cu, zn, W, V, nb, the atomic ratio y of the catalyst to P is 0.02-0.3, preferably 0.03-0.28, and the content of A xByPO4 in A xByPO4·SiO2 is 15-45 wt%, preferably 18-40 wt%.
The preparation process of the modified rare earth phosphate catalyst comprises the following steps:
(1) Dissolving a soluble compound containing La, ce, pr, nd, gd and other rare earth metals in water, adding the soluble compound containing Mo, zr, cu, zn, W, V, nb and other rare earth metals, wherein the total concentration of the metal compounds in the solution is 10-80 g/L, preferably 15-75 g/L;
(2) Stirring and mixing at 50-80 ℃, preferably 55-75 ℃, adjusting the pH to 8-10, filtering out the precipitate, and drying at 50-80 ℃ for 3-10 hours, preferably 55-75 ℃ for 5-10 hours;
(3) Adding 3-30 g/L phosphoric acid solution, preferably 5-25 g/L phosphoric acid solution, adopting a temperature programming-ball milling mode, controlling the temperature programming to be between room temperature and 200 ℃, preferably between 50 and 170 ℃, the temperature programming rate to be between 1 and 20 ℃, preferably between 2 and 15 ℃, the residence time to be between 0.5 and 3.5 hours, preferably between 1 and 3 hours, and roasting at 400 and 600 ℃ for 3 to 10 hours to obtain A xByPO4·SiO2, wherein the roasting temperature is preferably between 450 and 550 ℃, and the roasting time is preferably between 4 and 8 hours.
The catalyst adopted by the second-stage reactor is metal modified hydroxyapatite, the modified metal is one or more of Cu, ce, fe, zn, the loading amount is 2-20wt%, preferably 4-18wt%, and the size of metal particles in the catalyst is 10-50 nm, preferably 15-45 nm.
The metal modified hydroxyapatite is used as a commodity, and is roasted for 2-8 hours at 800-1500 ℃ before being used, the roasting temperature is preferably 850-1400 ℃, and the roasting time is preferably 3-7 hours;
(1) The method comprises the steps of carrying out exchange-adsorption-deposition on a solution containing Cu, ce, fe, zn for 2-24 hours, preferably 3-20 hours, wherein the ion concentration is 0.02-1.2 g/ml, preferably 0.04-1.0 g/ml, cu, ce, fe, zn is from copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate and the like, preferably copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate and zinc dihydrogen phosphate;
(2) The pH value of the system is regulated to be 5-8, the system is dried for 3-8 hours, preferably 4-7 hours, at 100 ℃ after filtration, and the modified hydroxyapatite catalyst is obtained by roasting for 2-8 hours at 600-1300 ℃, wherein the roasting temperature is preferably 650-1200 ℃, and the roasting time is preferably 3-7 hours.
Still further, the method and the catalyst for continuously synthesizing isoprene by using the olefine aldehyde liquid phase method provided by the invention can effectively reduce formaldehyde side reaction, improve isoprene production efficiency, and simultaneously develop and easily recycle the catalyst, and can further comprise the following steps:
The liquid-phase method for synthesizing isoprene from formaldehyde, tertiary butanol and methyl tertiary butyl ether is used as raw materials, and the two-stage reaction is carried out,
(1) The first stage reaction is carried out at 120-145 ℃, preferably 125-140 ℃, more preferably 130-140 ℃, the olefine-aldehyde ratio is controlled to be 0.2-1.6, preferably 0.3-1.5, the feeding rate is controlled to be 5-50 ml/min, preferably 10-50 ml/min, more preferably 10-45 ml/min, the residence time of materials in the reactor is 10-60 minutes, preferably 15-50 minutes, more preferably 15-40 minutes, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid phase product is a uniform phase, and the regulated reaction pressure is less than 10atm, preferably <9atm, more preferably <8atm. The catalyst was left in the first stage reactor through the filter and the material was fed into the second stage reactor.
(2) The method comprises the steps of supplementing tert-butyl alcohol and methyl tert-butyl ether, keeping the equivalent ratio of the tert-butyl alcohol and formaldehyde to be 2-10, preferably 2.5-9.5, more preferably 2.8-9.0, feeding the mixture at a rate of 5-50 ml/min, preferably 10-50 ml/min, more preferably 12-45 ml/min, reacting at 145-165 ℃, preferably 150-160 ℃, more preferably 155-160 ℃, staying time of the materials at 10-60 minutes, preferably 15-50 minutes, more preferably 15-40 minutes, regulating the reaction pressure to be less than 16atm, preferably <14atm, more preferably <12atm, separating to obtain isoprene, separating the liquid phase into oil-water two phases, controlling the water phase to be not more than one half of the reactor, controlling the oil phase to be not more than one half of the reactor, and controlling the isobutene to be separated and then hydrating and returning the isobutene to the first-stage reactor.
The catalyst adopted by the first-stage reactor is modified rare earth phosphate (A xByPO4·SiO2), wherein A is rare earth La, ce, pr, nd, gd and the like, preferably La, ce, pr, nd, gd, and more preferably La, ce, nd, gd; lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate, gadolinium nitrate, etc., preferably lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate, gadolinium nitrate, more preferably lanthanum nitrate, cerium nitrate, ammonium cerium nitrate, neodymium nitrate, gadolinium nitrate, etc. B is a transition metal Mo, zr, cu, zn, W, V, nb or the like, preferably Mo, zr, cu, zn, W, V, nb, more preferably Mo, zr, cu, W, nb, and is derived from ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadium oxychloride, niobic acid, niobium oxalate complex or the like, preferably ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadium oxychloride, niobic acid, niobium oxalate complex, more preferably ammonium molybdate, phosphomolybdic acid, zirconyl nitrate, copper acetate, phosphotungstic acid, ammonium tungstate, tungsten chloride, niobic acid, niobium oxalate.
The modified rare earth phosphate catalyst is expressed as A xByPO4·SiO2, and is characterized in that A is one or more of rare earth metals La, ce, pr, nd, gd, and the like, preferably one or more of La, ce, pr, nd, gd, more preferably one or two of La, ce, nd, gd, the atomic ratio x of the catalyst to P is 0.7-1.4, preferably 0.8-1.3, more preferably 0.9-1.2, one or more of transition metals Mo, zr, cu, zn, W, V, nb, and the like, preferably one or more of Mo, zr, cu, zn, W, V, nb, more preferably one or two of Mo, zr, cu, W, nb, the atomic ratio y of the catalyst to P is 0.02-0.3, preferably 0.03-0.28, more preferably 0.05-0.25, and the content of A xByPO4 in A xByPO4·SiO2 is 15-45 wt%, preferably 18-40 wt%, and more preferably 20-35 wt%.
The preparation process of the modified rare earth phosphate catalyst comprises the following steps:
(1) Dissolving a soluble compound containing La, ce, pr, nd, gd and other rare earth metals in water, adding the soluble compound containing Mo, zr, cu, zn, W, V, nb and other rare earth metals, wherein the total concentration of the metal compounds in the solution is 10-80 g/L, preferably 15-75 g/L, more preferably 18-70 g/L;
(2) Stirring and mixing at 50-80 ℃, preferably at 55-75 ℃, more preferably at 60-70 ℃, adjusting the pH to 8-10, filtering out the precipitate, and drying at 50-80 ℃ for 3-10 hours, preferably at 55-75 ℃ for 5-10 hours, more preferably at 60-70 ℃ for 6-9 hours;
(3) Adding 3-30 g/L phosphoric acid solution, preferably 5-25 g/L phosphoric acid solution, more preferably 8-20 g/L phosphoric acid solution, adopting a temperature programming-ball milling mode, controlling a temperature programming process to be between room temperature and 200 ℃, preferably between 50 and 170 ℃, more preferably between 50 and 160 ℃, a temperature programming rate to be between 1 and 20 ℃, preferably between 2 and 15 ℃, more preferably between 2 and 10 ℃, a residence time to be between 0.5 and 3.5 hours, preferably between 1 and 3 hours, more preferably between 1.5 and 2.5 hours, and roasting at 400 and 600 ℃ for 3 to 10 hours to obtain A xByPO4·SiO2, wherein the roasting temperature is preferably between 450 and 550 ℃, more preferably between 460 and 520 ℃, and the roasting time is preferably between 4 and 8 hours, more preferably between 4.5 and 7 hours.
The catalyst adopted by the second-stage reactor is metal modified hydroxyapatite, the modified metal is one or more of Cu, ce, fe, zn, the loading amount is 2-20wt%, preferably 4-18wt%, more preferably 5-16wt%, and the size of metal particles in the catalyst is 10-50 nm, preferably 15-45 nm, more preferably 20-40 nm.
The metal modified hydroxyapatite is used as a commodity, and is roasted for 2-8 hours at 800-1500 ℃ before being used, wherein the roasting temperature is preferably 850-1400 ℃, more preferably 900-1350 ℃, and the roasting time is preferably 3-7 hours, more preferably 3.5-6.5 hours;
(1) The solution containing Cu, ce, fe, zn is used for 'exchange-adsorption-deposition' for 2 to 24 hours, preferably 3 to 20 hours, more preferably 4 to 16 hours; the ion concentration is 0.02-1.2 g/ml, preferably 0.04-1.0 g/ml, more preferably 0.05-1.0 g/ml; cu, ce, fe, zn is derived from copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate, etc., preferably copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous bromide, ferric sulfate, ferrous sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate, more preferably copper nitrate, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferrous nitrate, ferric bromide, ferrous bromide, ferric sulfate, cerium nitrate, cerium chloride, ammonium cerium nitrate, zinc chloride, zinc nitrate, zinc dihydrogen phosphate;
(2) The pH=5-8 of the system is regulated, the system is dried for 3-8 hours, preferably 4-7 hours, more preferably 4.5-6.5 hours at 100 ℃ after filtration, and the modified hydroxyapatite catalyst is obtained by roasting for 2-8 hours at 600-1300 ℃, wherein the roasting temperature is preferably 650-1200 ℃, more preferably 700-1150 ℃, and the roasting time is preferably 3-7 hours, more preferably 3.5-6.5 hours.
The process and parameters for continuously synthesizing isoprene based on the enal liquid phase method provided by the invention are analyzed.
Referring to fig. 2, fig. 2 shows the product distribution and regulation 1 of the continuous isoprene synthesis process based on the enal liquid phase method.
As can be seen from fig. 2, when the reaction temperature is high, formaldehyde is excessive, side reactions are aggravated, and dark byproducts, even solids, are formed.
Referring to fig. 3, fig. 3 shows the distribution and control 2 of products in the process of synthesizing isoprene continuously by using an enal liquid phase method.
As can be seen from fig. 3, when the reaction temperature is low, the excess formaldehyde can increase the utilization rate of the alkene source, and simultaneously inhibit the side reaction of formaldehyde.
The reaction process for continuously synthesizing isoprene by using the enal liquid phase method provided by the invention is characterized.
Referring to fig. 4, fig. 4 is a diagram of a gas chromatography-mass spectrometry full component analysis of an enal liquid phase method continuous isoprene synthesis process provided by the invention.
The invention provides a method and a catalyst for continuously synthesizing isoprene based on an enal liquid phase method. The invention provides a modified rare earth phosphate catalyst which is particularly used in the reaction process of synthesizing isoprene by an enal liquid phase method, and the catalyst is a solid phase catalyst which is easier to recycle in the liquid phase method synthesis process. The modified rare earth phosphate catalyst provided by the invention is further combined with the modified hydroxyapatite catalyst in the two-stage continuous reaction synthesis process, so that formaldehyde side reaction is reduced, isoprene production efficiency is improved, and the catalyst is easy to recycle.
The invention takes tert-butyl alcohol, methyl tert-butyl ether and formaldehyde as raw materials, synthesizes isoprene by two-section continuous reaction, controls formaldehyde side reaction and develops a multiphase recoverable catalyst. The method comprises the steps of adopting modified rare earth phosphate (A xByPO4·SiO2) as a catalyst to catalyze formaldehyde, tertiary butanol and methyl tertiary butyl ether to synthesize intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like at a low olefine-aldehyde ratio of 120-145 ℃, controlling the liquid phase product to be a uniform phase, controlling the reaction pressure to be less than 10atm, controlling the conversion rate and selectivity of the tertiary butanol and the methyl tertiary butyl ether to be more than 92%, and the second step of keeping the alkene source excess of the intermediate products, the tertiary butanol and the methyl tertiary butyl ether at 145-165 ℃ and adopting a modified hydroxyapatite catalyst to convert and synthesize isoprene, wherein the reaction pressure is less than 16atm, and the yield can reach 80%. The first-stage reaction adopts low olefine-aldehyde ratio and lower reaction temperature to reduce formaldehyde side reaction, improve olefine source utilization rate and product production efficiency, and omit isobutene recovery and hydration processes.
Experimental results show that the catalyst and the two-stage continuous reaction synthesis mode provided by the invention have the advantages that in the one-stage reaction, the conversion rate and the selectivity of raw materials of tertiary butanol and methyl tertiary butyl ether are both more than 92%, and in the two-stage reaction, the yield can reach 80% by adopting the modified hydroxyapatite catalyst.
For further explanation of the present invention, the application of a catalyst in synthesizing isoprene by an enal liquid phase method and a method for synthesizing isoprene by an enal liquid phase method provided by the present invention are described in detail below with reference to examples, but it should be understood that these examples are implemented on the premise of the technical scheme of the present invention, and detailed implementation and specific operation procedures are given only for further explanation of the features and advantages of the present invention, and not limitation of the claims of the present invention, and the scope of protection of the present invention is not limited to the examples described below.
Example 1
(1) Catalyst preparation
The modified rare earth phosphate catalyst is prepared into a catalyst La 0.9Cu0.2PO4·SiO2 according to the metering ratio, wherein the SiO 2 content is 65wt%. Dissolving lanthanum nitrate in water, adding copper nitrate, adding tetraethoxysilane, stirring and mixing at 60 ℃, adjusting the pH to 9, filtering out precipitate, drying at 70 ℃ for 8 hours, adding phosphoric acid solution with the concentration of 23g/L, transferring to ball milling, controlling the temperature rise program to be between room temperature and 200 ℃, controlling the temperature rise rate to be 5 ℃, staying at 100 ℃ for 2 hours, staying at 200 ℃ for 2.5 hours, and roasting the obtained sample at 550 ℃ for 5 hours to obtain La 0.9Cu0.2PO4·SiO2 hours.
The modified hydroxyapatite catalyst is prepared by taking 50g of commercial product hydroxyapatite, roasting at 1100 ℃ for 3 hours, adopting a solution of copper nitrate and cerium nitrate for 'exchange-adsorption-deposition' for 18 hours, adjusting the pH value of a system to be 7, wherein the ion concentration is 1.0g/ml, drying at 100 ℃ for 5 hours after filtering, roasting at 1100 ℃ for 3 hours, wherein the loading amount of CuO x in the obtained catalyst is about 7wt% and the loading amount of CeO x is about 14wt%.
(2) Isoprene synthesis
10G of the prepared modified rare earth phosphate catalyst is added into a first-stage reactor, formaldehyde and tertiary butanol are added, the olefine-aldehyde ratio is controlled to be 1, the feeding rate is 30ml/min, the retention time is 25 minutes, the reaction temperature is 135 ℃, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase product is a uniform phase, the reaction pressure is controlled to be less than 9atm, the catalyst is left in the first-stage reactor through a filter, and the materials enter a second-stage reactor.
10G of the prepared modified hydroxyapatite catalyst is added into a second section reactor, tertiary butanol is supplemented, the equivalent ratio of the tertiary butanol to formaldehyde is kept to be 8, the feeding rate is 36ml/min, the reaction temperature is 165 ℃, the residence time is 36 minutes, the reaction pressure is regulated and controlled to be less than 12atm, isoprene is obtained through separation, the liquid phase is divided into oil-water two phases, the water phase is not more than one half of the reactor and not less than one fourth of the reactor, the oil phase is not more than one half of the reactor and not less than one fourth of the reactor, and isobutene is generated and then is hydrated to return to the first section reactor after separation.
At equilibrium, 80% isoprene yield, 88% formaldehyde selectivity and 92% t-butanol selectivity were calculated.
Example 2
(1) Catalyst preparation
The catalyst Ce 1.2Zr0.1PO4·SiO2 is prepared by the modified rare earth phosphate catalyst according to the metering ratio, wherein the SiO 2 content is 60wt%. Dissolving ceric ammonium nitrate in water, adding zirconyl nitrate, adding silica sol, stirring and mixing at 55 ℃, adjusting the pH to 9, filtering out precipitate, drying at 80 ℃ for 6 hours, adding phosphoric acid solution with the concentration of 18g/L, transferring to ball milling, controlling the temperature rise program to be between room temperature and 200 ℃, controlling the temperature rise rate to be 10 ℃, staying at 100 ℃ for 3 hours, staying at 200 ℃ for 1.5 hours, and roasting at 500 ℃ for 8 hours to obtain Ce 1.2Zr0.1PO4·SiO2.
The modified hydroxyapatite catalyst is prepared by taking 50g of commercial product hydroxyapatite, roasting at 800 ℃ for 5 hours, adopting a Cu-Zn-containing solution for 'exchange-adsorption-deposition' for 15 hours, adjusting the pH value of a system to be 7, wherein the ion concentration is 0.6g/ml, drying at 100 ℃ for 6 hours after filtering, roasting at 800 ℃ for 5 hours, wherein the loading amount of CuO x in the obtained catalyst is 6wt% and the loading amount of ZnO x is 12wt%.
(2) Isoprene synthesis
10G of the prepared modified rare earth phosphate catalyst is added into a first-stage reactor, formaldehyde and methyl tertiary butyl ether are added, the olefine-aldehyde ratio is controlled to be 0.4, the feeding rate is 40ml/min, the residence time is 24 minutes, the reaction temperature is 125 ℃, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase product is a uniform phase, the reaction pressure is regulated to be less than 10atm, the catalyst is left in the first-stage reactor through a filter, and the materials enter a second-stage reactor.
10G of the prepared modified hydroxyapatite catalyst is added into a second section reactor, methyl tertiary butyl ether is supplemented, the equivalent ratio of methyl tertiary butyl ether to formaldehyde is kept to be 4, the feeding rate is 25ml/min, the reaction temperature is 155 ℃, the residence time is 39 minutes, the reaction pressure is regulated to be less than 12atm, isoprene is obtained through separation, the liquid phase is divided into oil-water two phases, the water phase is not more than one half of the reactor and not less than one fourth of the reactor, the oil phase is not more than one half of the reactor and not less than one fourth of the reactor, and isobutene is generated and then is hydrated to return to the first section reactor after separation.
At equilibrium, the isoprene yield was calculated to be 74%, the formaldehyde selectivity was 86%, and the methyl tert-butyl ether selectivity was 90%.
Example 3
(1) Catalyst preparation
The modified rare earth phosphate catalyst is prepared into a catalyst LaPr 0.9Mo0.08PO4·SiO2 according to the metering ratio, wherein the SiO 2 content is 70wt%. Dissolving lanthanum chloride and praseodymium nitrate in water, adding ammonium molybdate, wherein the total concentration of metal compounds in the solution is 56g/L, adding silica sol, stirring and mixing at 65 ℃, adjusting the pH to 9, filtering out precipitate, drying at 60 ℃ for 5 hours, adding phosphoric acid solution with the concentration of 18g/L, transferring to ball milling, controlling the temperature raising program to be between room temperature and 200 ℃, controlling the temperature raising rate to be 15 ℃, staying at 100 ℃ for 2.5 hours, staying at 200 ℃ for 2 hours, and roasting at 500 ℃ for 6 hours to obtain LaPr 0.9Mo0.08PO4·SiO2.
The modified hydroxyapatite catalyst is prepared by taking 50g of commercial product hydroxyapatite, roasting at 900 ℃ for 5 hours, adopting a solution containing Cu and Ce for 'exchange-adsorption-deposition' for 20 hours, adjusting the pH value of a system to be 7, wherein the ion concentration is 0.5g/ml, drying at 100 ℃ for 6 hours after filtering, roasting at 900 ℃ for 5 hours, wherein the loading amount of CuO x in the obtained catalyst is 5wt% and the loading amount of CeO x is 16wt%.
(2) Isoprene synthesis
10G of the prepared modified rare earth phosphate catalyst is added into a first-stage reactor, formaldehyde and tertiary butanol are added, the olefine-aldehyde ratio is controlled to be 0.3, the feeding rate is 25ml/min, the residence time is 46 minutes, the reaction temperature is 125 ℃, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase product is a uniform phase, the reaction pressure is regulated to be less than 10atm, the catalyst is left in the first-stage reactor through a filter, and the materials enter a second-stage reactor.
10G of the prepared modified hydroxyapatite catalyst is added into a second-stage reactor, the equivalent ratio of tertiary butyl alcohol to methyl tertiary butyl ether (volume ratio is 1:1) is kept to be 6, the feeding rate is 36ml/min, the reaction temperature is 165 ℃, the residence time is 54 minutes, the reaction pressure is regulated and controlled to be less than 10atm, isoprene is obtained by separation, a liquid phase is divided into oil-water two phases, a water phase is not more than one half of the reactor and not less than one fourth of the reactor, an oil phase is not more than one half of the reactor and not less than one fourth of the reactor is controlled, and isobutene is generated and then is separated and hydrated to return to the first-stage reactor.
At equilibrium, the isoprene yield was calculated to be 70%, the formaldehyde selectivity was 82%, and the t-butanol/methyl t-butyl ether selectivity was 93%.
Example 4
(1) Catalyst preparation
The catalyst Ce 0.8ZrV0.06PO4·SiO2 is prepared by the modified rare earth phosphate catalyst according to the metering ratio, wherein the content of SiO 2 is 62wt%. Dissolving ceric ammonium nitrate in water, adding zirconyl nitrate and ammonium metavanadate, wherein the total concentration of metal compounds in the solution is 52g/L, adding silica sol, stirring and mixing at 70 ℃, adjusting the pH to 9, filtering out precipitate, drying at 80 ℃ for 10 hours, adding phosphoric acid solution with the concentration of 23g/L, transferring to ball milling, controlling the temperature rise program to be between room temperature and 200 ℃, controlling the temperature rise rate to be 5 ℃, staying at 100 ℃ for 3 hours, staying at 200 ℃ for 3 hours, and roasting at 450 ℃ for 8 hours to obtain Ce 0.8ZrV0.06PO4·SiO2.
The modified hydroxyapatite catalyst is prepared by taking 50g of commercial hydroxyapatite, roasting for 5 hours at 800 ℃ before use, adding cerium ammonium nitrate and zinc nitrate solution (the ion concentration is 1.0 g/ml), carrying out 'exchange-adsorption-deposition' for 2-24 hours, regulating the pH value of a system to be 7, drying for 5 hours at 100 ℃ after filtering, and roasting for 5 hours at 800 ℃, wherein the loading of ZnO x in the obtained catalyst is 6wt% and the loading of CeO x is 12wt%.
(2) Isoprene synthesis
10G of the prepared modified rare earth phosphate catalyst is added into a first-stage reactor, formaldehyde and methyl tertiary butyl ether are added, the olefine-aldehyde ratio is controlled to be 0.4, the feeding rate is 25ml/min, the residence time is 46 minutes, the reaction temperature is 120 ℃, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase product is a uniform phase, the reaction pressure is regulated to be less than 10atm, the catalyst is left in the first-stage reactor through a filter, and the materials enter a second-stage reactor.
Adding 10g of the prepared modified hydroxyapatite catalyst into a second section reactor, supplementing tertiary butanol, keeping the equivalent ratio of tertiary butanol to formaldehyde at 8, keeping the feeding rate at 40ml/min, reacting at 150 ℃ for 34 minutes, regulating the reaction pressure to be less than 10atm, separating to obtain isoprene, separating a liquid phase into oil-water two phases, controlling the water phase to be not more than one half of the reactor and not less than one fourth, controlling the oil phase to be not more than one half of the reactor and not less than one fourth, and separating generated isobutene and then hydrating and returning to the first section reactor.
At equilibrium, the isoprene yield was calculated to be 78%, the formaldehyde selectivity was 85%, and the tert-butanol/methyl tert-butyl ether selectivity was 88%.
Example 5
(1) Catalyst preparation
The modified rare earth phosphate catalyst is prepared into a catalyst Nd 0.9MoNb0.06PO4·SiO2 according to the metering ratio, wherein the content of SiO 2 is 63wt%. Dissolving neodymium nitrate in water, adding ammonium molybdate and niobium oxalate, wherein the total concentration of metal compounds in the solution is 66g/L, adding tetraethoxysilane, stirring and mixing at 75 ℃, adjusting the pH to 9, filtering out precipitate, drying at 70 ℃ for 8 hours, adding phosphoric acid solution with the concentration of 18g/L, transferring to ball milling, controlling the temperature rise program to be between room temperature and 200 ℃, controlling the temperature rise rate to be 10 ℃, staying at 100 ℃ for 3 hours, staying at 200 ℃ for 2 hours, and roasting at 550 ℃ for 8 hours to obtain Nd 0.9MoNb0.06PO4·SiO2.
The modified hydroxyapatite catalyst is prepared by taking 50g of commercial hydroxyapatite, roasting for 5 hours at 1000 ℃ before use, adding copper oxalate, cerium nitrate and zinc nitrate solution (the ion concentration is 0.9 g/ml), carrying out 'exchange-adsorption-deposition' for 18 hours, regulating the pH value of a system to be 7, drying for 7 hours at 100 ℃ after filtering, roasting for 3 hours at 1100 ℃, wherein the loading of CuO x in the obtained catalyst is 5wt%, the loading of CeO x is 11wt% and the loading of ZnO x is 5wt%.
(2) Isoprene synthesis
10G of the prepared modified rare earth phosphate catalyst is added into a first-stage reactor, formaldehyde and tertiary butanol are added, the olefine-aldehyde ratio is controlled to be 0.4, the feeding rate is 36ml/min, the residence time is 30 minutes, the reaction temperature is 140 ℃, intermediate products such as 4, 4-dimethyl-1, 3-dioxane, 3-methyl-1, 3-butanediol and the like are synthesized, the liquid-phase product is a uniform phase, the reaction pressure is regulated to be less than 10atm, the catalyst is left in the first-stage reactor through a filter, and the materials enter a second-stage reactor.
10G of the prepared modified hydroxyapatite catalyst is added into a second section reactor, tertiary butanol is supplemented, the equivalent ratio of the tertiary butanol to formaldehyde is kept to be 5, the feeding rate is 53ml/min, the reaction temperature is 155 ℃, the residence time is 32 minutes, the reaction pressure is regulated and controlled to be less than 12atm, isoprene is obtained through separation, the liquid phase is divided into oil-water two phases, the water phase is not more than one half of the reactor and not less than one fourth of the reactor, the oil phase is not more than one half of the reactor and not less than one fourth of the reactor, and isobutene is generated and then is hydrated to return to the first section reactor after separation.
At equilibrium, the isoprene yield was calculated to be 76%, the formaldehyde selectivity was 81%, and the t-butanol selectivity was 92%.
The foregoing has outlined rather broadly the principles and embodiments of the present invention by providing a method and catalyst for the continuous synthesis of isoprene based on the liquid phase process of enal, wherein specific examples are provided herein to facilitate an understanding of the method and core concepts of the present invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems, and performing any incorporated methods. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims. The scope of the patent protection is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
Claims (10)
1. The catalyst is applied to synthesizing isoprene by an enal liquid phase method;
the catalyst comprises a modified rare earth phosphate catalyst;
The general formula of the modified rare earth phosphate is A xByPO4·SiO2;
Wherein x is 0.7-1.4, and y is 0.02-0.3;
a is one or more of La, ce, pr, nd and Gd;
b is one or more of Mo, zr, cu, zn, W, V and Nb;
The synthesis is specifically two-stage synthesis;
the modified rare earth phosphate catalyst is a catalyst for one-stage synthesis;
The catalyst also comprises a metal modified hydroxyapatite catalyst;
The metal comprises one or more of Cu, ce, fe and Zn;
The metal modified hydroxyapatite catalyst is a catalyst for two-stage synthesis.
2. The use according to claim 1, wherein the catalyst is a heterogeneous catalyst;
The mass content of the metal in the metal modified hydroxyapatite is 2-20wt%;
the size of the metal particles in the metal modified hydroxyapatite is 10-50 nm.
3. The use according to claim 2, characterized in that the mass content of SiO 2 in the modified rare earth phosphate is 15-wt-45 wt%;
The synthesis includes a continuous synthesis.
4. The method for synthesizing isoprene by using an enal liquid phase method is characterized by comprising the following steps of:
1) Tertiary butyl alcohol and/or methyl tertiary butyl ether, a modified rare earth phosphate catalyst and formaldehyde are sent into a first reaction device for reaction, and then a liquid phase reaction system is obtained;
The general formula of the modified rare earth phosphate is A xByPO4·SiO2;
Wherein x is 0.7-1.4, and y is 0.02-0.3;
a is one or more of La, ce, pr, nd and Gd;
b is one or more of Mo, zr, cu, zn, W, V and Nb;
2) Sending the liquid phase reaction system obtained in the steps into a second reaction device for re-reaction to obtain isoprene;
the metal in the metal modified hydroxyapatite catalyst comprises one or more of Cu, ce, fe and Zn.
5. The method according to claim 4, wherein the ratio of olefine to aldehyde in the raw material in the step 1) is (0.2-1.6): 1;
The reaction temperature is 120-145 ℃;
the reaction time is 10-60 minutes;
the pressure of the reaction is less than or equal to 10atm;
the feeding rate fed in the step 1) is 5-50 ml/min;
Filtering the solid phase catalyst after the reaction to obtain a liquid phase reaction system;
The liquid phase reaction system comprises 4, 4-dimethyl-1, 3-dioxane and 3-methyl-1, 3-butanediol.
6. The method according to claim 4, wherein the molar equivalent ratio of the tertiary butanol and/or methyl tertiary butyl ether in the step 2) to formaldehyde in the step 1) is (2-10): 1;
The feeding rate fed in the step 2) is 5-50 ml/min;
The temperature of the re-reaction is 145-165 ℃;
The time of the re-reaction is 10-60 minutes;
the pressure of the re-reaction is 16atm or less.
7. The method of claim 4, further comprising a catalyst separation step after the re-reacting;
the separated liquid phase comprises an oil phase and a water phase;
The height of the water phase is not more than one half of the height of the reaction area of the reactor and not less than one quarter of the height of the reaction area of the reactor;
The height of the oil phase is not more than one half of the height of the reaction area of the reactor and not less than one quarter of the height of the reaction area of the reactor;
In the method, the generated isobutene is hydrated to obtain tertiary butanol, and the tertiary butanol returns to the step 1).
8. The method of claim 4, wherein the method of preparing the modified rare earth phosphate catalyst comprises the steps of:
Mixing the mixed solution of the rare earth metal soluble compound and the transition metal soluble compound with silicide, regulating the pH value to obtain precipitate, drying, carrying out stepped temperature rise ball milling with phosphoric acid solution, and roasting to obtain the modified rare earth phosphate catalyst;
The rare earth metal soluble compound comprises one or more of lanthanum nitrate, lanthanum chloride, cerium nitrate, cerium chloride, ammonium cerium nitrate, cerium perchlorate, praseodymium nitrate, praseodymium chloride, neodymium nitrate and gadolinium nitrate;
The transition metal soluble compound comprises one or more of ammonium molybdate, molybdenum chloride, phosphomolybdic acid, zirconium nitrate, zirconyl nitrate, copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc sulfate, zinc chloride, phosphotungstic acid, ammonium tungstate, tungsten chloride, ammonium metavanadate, vanadium trichloride, vanadyl trichloride, niobic acid, niobium oxalate and niobium oxalate complex;
The total concentration of the metal compounds in the mixed solution is 10-80 g/L;
The silicide comprises one or more of tetraethoxysilane, water glass and silica sol;
The temperature of the mixing is 50-80 ℃.
9. The method of claim 8, wherein the pH is 8-10;
the temperature of the drying is 50-80 ℃;
the drying time is 3-10 hours;
The concentration of the phosphoric acid solution is 3-30 g/L;
the start-stop temperature of the step heating ball milling is 15-200 ℃;
The temperature rising rate of the step temperature rising ball milling is 1-20 ℃;
the residence time of the steps is 0.5-3.5 hours;
the roasting temperature is 400-600 ℃;
and the roasting time is 3-10 hours.
10. The method according to claim 4, wherein the method for preparing the metal modified hydroxyapatite catalyst comprises the steps of:
roasting the hydroxyapatite, placing the hydroxyapatite into a modified metal compound solution, and roasting the hydroxyapatite again after the exchange-adsorption-deposition process to obtain a metal modified hydroxyapatite catalyst;
the roasting temperature is 800-1500 ℃;
the roasting time is 2-8 hours;
The modified metal compound solution comprises one or more of copper nitrate, copper chloride, cuprous chloride, copper sulfate, copper oxalate, ferric nitrate, ferric chloride, ferrous nitrate, ferrous chloride, ferric bromide, ferrous bromide, ferric sulfate, ferrous sulfate, cerium nitrate, cerium chloride, ceric ammonium nitrate, cerium perchlorate, zinc chloride, zinc sulfate, zinc nitrate and zinc dihydrogen phosphate;
The ion concentration of the modified metal in the modified metal compound solution is 0.02-1.2 g/ml;
the pH value of the system in the exchange-adsorption-deposition process is 5-8;
the time of the exchange-adsorption-deposition process is 2-24 hours;
the temperature of the re-roasting is 600-1300 ℃;
And the re-roasting time is 2-8 hours.
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