CN117654587A - Metal modified molecular sieve, preparation method thereof and long-chain olefin alkylation method - Google Patents
Metal modified molecular sieve, preparation method thereof and long-chain olefin alkylation method Download PDFInfo
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- CN117654587A CN117654587A CN202211033764.1A CN202211033764A CN117654587A CN 117654587 A CN117654587 A CN 117654587A CN 202211033764 A CN202211033764 A CN 202211033764A CN 117654587 A CN117654587 A CN 117654587A
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- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical class [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 title claims abstract description 275
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 166
- 239000002184 metal Substances 0.000 title claims abstract description 166
- 238000000034 method Methods 0.000 title claims abstract description 43
- 150000001336 alkenes Chemical class 0.000 title claims abstract description 38
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 title claims abstract description 33
- 238000005804 alkylation reaction Methods 0.000 title claims abstract description 30
- 238000002360 preparation method Methods 0.000 title claims abstract description 12
- 230000029936 alkylation Effects 0.000 title abstract description 11
- 239000002808 molecular sieve Substances 0.000 claims abstract description 200
- 238000012360 testing method Methods 0.000 claims abstract description 46
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 39
- 238000005342 ion exchange Methods 0.000 claims description 37
- 239000007788 liquid Substances 0.000 claims description 34
- 238000006243 chemical reaction Methods 0.000 claims description 24
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 23
- 238000010304 firing Methods 0.000 claims description 23
- 239000003054 catalyst Substances 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 18
- 150000001875 compounds Chemical class 0.000 claims description 17
- 239000002243 precursor Substances 0.000 claims description 17
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 16
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 15
- 239000011734 sodium Substances 0.000 claims description 14
- 150000002739 metals Chemical class 0.000 claims description 13
- 150000003863 ammonium salts Chemical class 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 11
- 239000001301 oxygen Substances 0.000 claims description 11
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- 239000000377 silicon dioxide Substances 0.000 claims description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 10
- 238000001354 calcination Methods 0.000 claims description 10
- 229910052746 lanthanum Inorganic materials 0.000 claims description 10
- 235000019270 ammonium chloride Nutrition 0.000 claims description 8
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical group C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 6
- 150000007514 bases Chemical class 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 229910021529 ammonia Inorganic materials 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 5
- 150000004945 aromatic hydrocarbons Chemical class 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 5
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 4
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 4
- 150000002500 ions Chemical group 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 230000002152 alkylating effect Effects 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 claims description 2
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 2
- 229910019142 PO4 Inorganic materials 0.000 claims description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 2
- 239000001099 ammonium carbonate Substances 0.000 claims description 2
- 235000012501 ammonium carbonate Nutrition 0.000 claims description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 2
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 2
- 239000004202 carbamide Substances 0.000 claims description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 239000004711 α-olefin Substances 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims 1
- 229910002651 NO3 Inorganic materials 0.000 claims 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims 1
- 239000010452 phosphate Substances 0.000 claims 1
- 150000004996 alkyl benzenes Chemical class 0.000 abstract description 19
- 230000004048 modification Effects 0.000 abstract description 7
- 238000012986 modification Methods 0.000 abstract description 7
- 238000003442 catalytic alkylation reaction Methods 0.000 abstract description 6
- 230000002035 prolonged effect Effects 0.000 abstract description 5
- 239000000047 product Substances 0.000 description 27
- 239000000243 solution Substances 0.000 description 20
- 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 description 17
- 239000012071 phase Substances 0.000 description 16
- CRSBERNSMYQZNG-UHFFFAOYSA-N 1-dodecene Chemical compound CCCCCCCCCCC=C CRSBERNSMYQZNG-UHFFFAOYSA-N 0.000 description 14
- 230000003197 catalytic effect Effects 0.000 description 12
- 238000001035 drying Methods 0.000 description 10
- 238000004364 calculation method Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000009826 distribution Methods 0.000 description 7
- 229940069096 dodecene Drugs 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 6
- 239000010457 zeolite Substances 0.000 description 6
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 5
- 229910021536 Zeolite Inorganic materials 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-O ammonium group Chemical group [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 5
- 235000011114 ammonium hydroxide Nutrition 0.000 description 5
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 238000006555 catalytic reaction Methods 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000006317 isomerization reaction Methods 0.000 description 3
- -1 monocyclic aromatic hydrocarbon Chemical class 0.000 description 3
- 239000011973 solid acid Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical group [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 239000010948 rhodium Substances 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical group [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- DHEQXMRUPNDRPG-UHFFFAOYSA-N strontium nitrate Chemical group [Sr+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O DHEQXMRUPNDRPG-UHFFFAOYSA-N 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000013077 target material Substances 0.000 description 2
- 238000004876 x-ray fluorescence Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 150000001768 cations Chemical group 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 238000010960 commercial process Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000006384 oligomerization reaction Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 239000000271 synthetic detergent Substances 0.000 description 1
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- Catalysts (AREA)
Abstract
The invention relates to the field of molecular sieves, and discloses a metal modified molecular sieve, a preparation method thereof and a long-chain olefin alkylation method, wherein the metal modified molecular sieve comprises a molecular sieve and metal outside a molecular sieve framework; the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve; in the metal modified molecular sieve, the ratio of the mass fraction of the surface phase metal measured by XPS to the mass fraction of the bulk phase metal measured by XRF test is not more than 1.45 in terms of the mass fraction of the elements. Through the modification of a certain amount of extra-framework metal, the proportion of bulk phase metal and surface phase metal is controlled, so that the skeletal isomerism of alkylbenzene products can be well inhibited, the linearity of the products is improved, and meanwhile, the catalytic alkylation cycle life of the alkylbenzene products is greatly prolonged. The method is used for alkylation reaction of C8-C28 long-chain olefins, the selectivity of monoalkylbenzene is more than 99%, and the linear chain degree of alkylbenzene is more than 94%.
Description
Technical Field
The invention relates to the field of molecular sieves, in particular to a metal modified molecular sieve, a preparation method thereof and a long-chain olefin alkylation method.
Background
Long chain alkylbenzenes are important raw materials for preparing synthetic detergents sodium alkylbenzenesulfonate. The long-chain alkylbenzene is mainly prepared by alkylation reaction of long-chain olefin and monocyclic aromatic hydrocarbon, and the current commercial process technology mainly adopts HF or AlCl 3 As a catalyst, the two catalytic systems have larger hidden safety and environmental protection hazards, and are gradually eliminated along with the gradual increase of the requirements of safety and environmental protection. The development of new solid acid alkylation method without corrosion and pollution is used as an alternative technology and becomes a necessary development trend of long-chain alkylbenzene production technology.
Currently, the commercial solid acid process is used to develop fluorine-containing SiO in cooperation with UOP and Petresa in Spanish 2 -Al 2 O 3 The solid acid catalyst (CN 1092755A) has certain corrosiveness to equipment and certain potential safety hazard due to fluorine contained in the catalyst.
More research is being carried out at home and abroad on catalyst systems of zeolite molecular sieves. Because long-chain alkylbenzene molecules are relatively large, ten-membered rings and pore channels below cannot enter, only molecular sieves such as MOR, Y, beta with pore channels above ten-membered rings have good alkylation reaction catalytic performance of benzene and long-chain olefins (catalyst Surv Asia (2014) 18:1-12; catalyst Today (2017) 298:109-116). On the other hand, the branched alkylbenzene is not easy to degrade, and the national standard has strict requirements on the linearity of the alkylbenzene product. The biggest problems in molecular sieve catalyzed synthesis of long chain alkylbenzenes are shorter service life and lower linearity.
For example, CN107867699a discloses a Y zeolite containing regular oversized micropores, by subjecting selected Y zeolite to a template agent and an acid-base treatment, a Y zeolite having 1-2nm regular oversized micropores is constructed, and higher conversion and selectivity are obtained due to the abundant acid centers and suitable reaction channels provided by the regular oversized micropores.
CN110562995a discloses a synthesis method of nano Y zeolite and its application in synthesis of linear alkylbenzene, and because of the catalyst grain, the diffusion resistance is small, and the activity and stability of long-chain olefine alkylation are improved.
CN102639471a discloses a process for producing linear alkylbenzenes which uses a combination of two zeolites to limit skeletal isomerization to increase the linear character of the product.
However, in the prior art, the catalyst is still short in service life of the long-chain olefin alkylation cycle, low in product linearity, long in preparation flow and high in cost.
Disclosure of Invention
The invention aims to solve the problems of short service life and low product linearity of the long-chain olefin alkylation catalyzed by a molecular sieve in the prior art, and provides a metal modified molecular sieve, a preparation method thereof and a long-chain olefin alkylation method.
In order to achieve the above object, a first aspect of the present invention provides a metal-modified molecular sieve, the metal-modified molecular sieve comprising a molecular sieve and a metal outside a molecular sieve framework; the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve;
in the metal modified molecular sieve, the ratio of the mass fraction of the surface phase metal measured by XPS to the mass fraction of the bulk phase metal measured by XRF test is not more than 1.45 in terms of the mass fraction of elements.
The second aspect of the present invention provides a method for preparing a metal modified molecular sieve, comprising the steps of:
(1) Subjecting the molecular sieve precursor to a first ion exchange with a first exchange liquid comprising a soluble compound of a metal;
(2) Carrying out first roasting on the product of the first ion exchange to obtain a first exchange molecular sieve;
(3) Subjecting the first exchange molecular sieve to a second ion exchange with a second exchange liquid containing a soluble compound of a metal;
(4) Subjecting the second ion exchanged product to a second calcination, optionally repeating the second ion exchange and the second calcination, to obtain a second exchanged molecular sieve;
(5) Carrying out high-temperature treatment on the second exchange molecular sieve in an oxygen-containing atmosphere to obtain the metal modified molecular sieve;
wherein the first firing and/or the second firing is performed under an alkaline atmosphere;
wherein the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve.
The third aspect of the invention provides a metal modified molecular sieve prepared by the preparation method.
In a fourth aspect, the present invention provides a process for alkylating a long chain olefin, the process comprising: under alkylation reaction conditions, long-chain olefin and aromatic hydrocarbon are contacted with a catalyst to carry out alkylation reaction;
wherein the catalyst is the metal modified molecular sieve provided in the first aspect or the third aspect.
According to the metal modified molecular sieve provided by the invention, through modification of a certain amount of metal outside the framework, the mass fraction of the surface phase metal measured by XPS and the mass fraction of the bulk phase metal measured by XRF test are not more than 1.45, so that the skeletal isomerism of alkylbenzene products can be well inhibited, the linearity of the products is improved, and meanwhile, the catalytic alkylation cycle life of the products is greatly prolonged.
According to the preparation method of the metal modified molecular sieve, provided by the invention, the modification of the specific extra-framework metal can be realized through two-to-two baking, meanwhile, the stability of unit cells of the molecular sieve before and after the reaction is ensured, and the molecular sieve structure is prevented from being damaged due to repeated baking.
According to the long-chain olefin alkylation method provided by the invention, the shape of the reaction product is selected after the molecular sieve is modified, so that the linearity of the product is obviously improved, and the selectivity is improved, so that the service life of the catalytic alkylation cycle of the metal modified molecular sieve is obviously prolonged.
Drawings
FIG. 1 is an XRD contrast spectrum of the metal-modified molecular sieve and the HY molecular sieve prepared in example 1;
FIG. 2 is a graph showing the stability of the metal modified molecular sieve prepared in example 1 in a continuous operation for 300 hours in a reaction of benzene with 1-dodecene to prepare linear alkylbenzene.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The first aspect of the invention provides a metal modified molecular sieve, which comprises a molecular sieve and metal outside a molecular sieve framework; the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve;
in the metal modified molecular sieve, the ratio of the mass fraction of the surface phase metal measured by XPS to the mass fraction of the bulk phase metal measured by XRF test is not more than 1.45 in terms of the mass fraction of elements.
Through a great deal of research, the inventor of the invention discovers that the molecular sieve containing a certain amount of extra-framework metal inside the molecular sieve can well inhibit the framework isomerism of alkylbenzene products, improves the linearity of the products, and greatly prolongs the service life of the catalytic alkylation cycle. In the invention, the metal outside the molecular sieve framework refers to the metal which exists in the molecular sieve cation position in the form of ions and/or is loaded on the surface of the molecular sieve in the form of oxides, and the outlet peak position of the characteristic peak of the metal modified molecular sieve is the same as the outlet peak position of the diffraction peak of the unmodified molecular sieve through XRD test, namely, the characteristic peak does not deviate, so that the metal can be proved to be positioned outside the molecular sieve framework.
The testing conditions of the XRD include: the instrument used was an X-ray powder diffractometer from PANalytical, netherlands; the test conditions included: tube voltage 40kV, tube current 40ma, cu target ka radiation, scan speed 2 °/min, scan range 2θ=5° -35 °.
In the present invention, the mass fraction of the surface phase metal means the mass fraction of the metal element obtained by XPS test, and the mass fraction of the bulk phase metal means the mass fraction of the metal element obtained by XRF test and calculation. It will be appreciated that XRF testing first yields the mass fraction of bulk metal in terms of oxide, and then calculates the mass fraction of the corresponding element.
In the present invention, XPS test was performed using an esclab 250 type X-ray photoelectron spectrometer (Thermo Fisher Scientific company), and test conditions include: monochromatic AlK alpha X-rays, energy 1486.6eV, power 150W, are used to correct charge displacement by C1s peak (284.8 eV) of polluted carbon.
In the present invention, XRF test was performed using an X-ray fluorescence spectrometer of Nippon Motor industry Co., ltd 3271; the test conditions included: the anode target material of the X-ray tube is rhodium target; the laser voltage is 50kV; the laser current was 50mA.
The inventor creatively discovers that the distribution of bulk phase metals and surface phase metals has key influence on the catalytic performance in the alkylation reaction of the metal modified molecular sieve, and under the condition of the distribution, the generation and deactivation of byproducts caused by olefin isomerization, polyalkylation reaction and the like can be effectively inhibited, and the shape selective catalysis is realized, so that the linearity of the product and the cycle life of the molecular sieve are improved.
According to the invention, preferably, the ratio of the mass fraction of the surface phase metal measured by XPS to the mass fraction of the bulk phase metal measured by XRF test, expressed as mass fraction of the element, is not more than 1.35, preferably 0.9 to 1.35, and may be, for example, a value of 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35 or between two points. Under the above preferred distribution conditions, the service life of the molecular sieve and the linearity of the product are improved, and the ratio of the mass fraction of the surface phase metal to the mass fraction of the bulk phase metal is too high, which may result in shortening of the catalytic life of the molecular sieve, and too low ratio may result in lowering of the linearity of the product.
In the present invention, it is preferable that the metal is contained in an amount of 12 to 23% by weight on an elemental basis based on the total amount of the metal-modified molecular sieve. For example, the metal may be present in an amount of 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt% or a value between any two points on an elemental basis. Under the preferable condition, the metal distribution is ensured to be in the optimal position, so that shape selective catalysis is realized, and the service life of the catalyst and the linearity of the product are improved.
In the present invention, the metal preferably has an atomic radius of 120 to 270pm, preferably 160 to 240pm. Preferably, the metal is selected from at least one of alkaline earth metals, group IIIB metals, and group IIIA metals; preferably at least one of Mg, ca, sr, ba, la, ce, pr, rd, sm, eu, yb, sc, Y, al, ga, in; further preferably at least one of La, ce, sr and Y. The adoption of the preferable metal is favorable for realizing matching with a molecular sieve pore passage, achieves the optimal shape-selective catalytic effect, protects a molecular sieve structure, and improves the catalytic life and the product linearity.
In the present invention, preferably, the metal modified molecular sieve is a silica-alumina molecular sieve.
Preferably, the molar ratio of silica/alumina in the metal modified molecular sieve is 1-100:1, further preferably 3 to 20:1.
according to the present invention, preferably, the metal modified molecular sieve is selected from at least one of an X-type molecular sieve, a Y-type molecular sieve, an MCM-22-type molecular sieve, a Beta-type molecular sieve and a MOR-type molecular sieve, and preferably is an X-type molecular sieve and/or a Y-type molecular sieve. The adoption of the preferable molecular sieve type is beneficial to further improving the catalytic activity of the molecular sieve.
The second aspect of the present invention provides a method for preparing a metal modified molecular sieve, comprising the steps of:
(1) Subjecting the molecular sieve precursor to a first ion exchange with a first exchange liquid comprising a soluble compound of a metal;
(2) Carrying out first roasting on the product of the first ion exchange to obtain a first exchange molecular sieve;
(3) Subjecting the first exchange molecular sieve to a second ion exchange with a second exchange liquid containing a soluble compound of a metal;
(4) Subjecting the second ion exchanged product to a second calcination, optionally repeating the second ion exchange and the second calcination, to obtain a second exchanged molecular sieve;
(5) Carrying out high-temperature treatment on the second exchange molecular sieve in an oxygen-containing atmosphere to obtain the metal modified molecular sieve;
wherein the first firing and/or the second firing is performed under an alkaline atmosphere;
wherein the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve.
According to the preparation method of the metal modified molecular sieve, provided by the invention, the modification of the metal outside the specific framework can be realized through at least two-to-two baking, meanwhile, the stability of the unit cell size of the molecular sieve before and after the reaction is ensured, and the molecular sieve structure can be prevented from being damaged due to repeated baking.
In the present invention, the number of repetition of the second ion exchange and the second calcination is not particularly limited, and may be determined according to the effect of the ion exchange in order that the metal content in the molecular sieve satisfies the above range requirement, and may be repeated 1 to 3 times, for example.
According to the present invention, preferably, the molecular sieve precursor is a silica-alumina molecular sieve, and the molar ratio of silica/alumina in the molecular sieve is preferably 1 to 100:1, further preferably 3 to 20:1.
in the invention, the mole ratio of the silicon oxide and the aluminum oxide of the molecular sieve before and after metal modification is basically kept unchanged, and the requirements of the mole ratio range are met.
According to the present invention, preferably, the molecular sieve precursor is selected from at least one of an X-type molecular sieve, a Y-type molecular sieve, an MCM-22-type molecular sieve, a Beta-type molecular sieve and a MOR-type molecular sieve, preferably an X-type molecular sieve and/or a Y-type molecular sieve.
According to the present invention, preferably, the molecular sieve precursor is a molecular sieve in the hydrogen form or the sodium form.
Preferably, the molecular sieve precursor is a sodium type molecular sieve, and the first exchange liquid and/or the second exchange liquid further comprise an ammonium salt, for example, the first exchange liquid further comprises an ammonium salt. In this case, step (1) comprises ion-co-exchanging the sodium molecular sieve with a first exchange liquid comprising a soluble compound of a metal and an ammonium salt.
In the present invention, the ammonium salt may be selected conventionally in the art. Preferably, the ammonium salt is selected from at least one of ammonium nitrate, ammonium chloride and ammonium sulfate.
In the present invention, the concentration of the ammonium salt is preferably 50 to 200g/L, and preferably 70 to 150g/L.
According to the present invention, when the molecular sieve precursor is a sodium type molecular sieve, preferably, the production method further comprises subjecting the second exchange molecular sieve to ammonium exchange with a third exchange liquid containing an ammonium salt, and then subjecting the second exchange molecular sieve to the high temperature treatment.
In the present invention, the ammonium exchange and drying may be performed using methods and conditions conventional in the art, for example, subjecting the second exchange molecular sieve to ammonium exchange, followed by filtration and drying, and the ammonium exchange process may be optionally repeated 1 to 3 times as one ammonium exchange process, so that the Na mass fraction in the molecular sieve is less than 0.2%.
In the present invention, the concentration of the ammonium salt in the third exchange liquid may be the same as the concentration range in the first exchange liquid or the second exchange liquid, and will not be described herein.
In the present invention, the specific kind of the soluble compound of the metal is not particularly limited as long as a metal source can be provided, and can be selected according to actual needs. Preferably, the soluble compound of a metal is selected from at least one of the group consisting of chlorides, nitrates, phosphates and sulphates of metals.
According to the present invention, the concentration of the soluble compound of the metal in the first exchange liquid and/or the second exchange liquid is not particularly limited as long as the content of the metal element in the metal-modified molecular sieve satisfies the above-mentioned range requirements, and a person skilled in the art can make routine adjustments. Preferably, the concentration of the soluble compounds of the metals in the first exchange liquid and the second exchange liquid is 100 to 500g/L each independently, more preferably 130 to 400g/L, and the above preferred embodiment can shorten the preparation flow on the basis of meeting the above content requirements.
Preferably, the first exchange liquid and the second exchange liquid each independently comprise a solvent, and the solvent is preferably water.
In the present invention, the metal preferably has an atomic radius of 120 to 270pm, preferably 160 to 240pm. Preferably, the metal is selected from at least one of alkaline earth metals, group IIIB metals, and group IIIA metals; preferably at least one of Mg, ca, sr, ba, la, ce, pr, rd, sm, eu, yb, sc, Y, al, ga, in; further preferably at least one of La, ce, sr and Y. The adoption of the preferable metal is favorable for realizing matching with a molecular sieve pore passage, achieves the optimal shape-selective catalytic effect, protects a molecular sieve structure, prolongs the service life of a catalyst and improves the linear degree of a product.
According to the present invention, for the first ion exchange to be more sufficient, it is preferable that the mass ratio of the first exchange liquid to the molecular sieve precursor is 2 to 8:1, further preferably 3 to 6:1.
preferably, the mass ratio of the second exchange liquid to the first exchange molecular sieve is 3-6:1, further preferably 3 to 5:1.
in the present invention, preferably, the conditions of the first ion exchange include: the exchange temperature is 50-90 ℃, preferably 70-90 ℃; the exchange time is 0.5-2h, preferably 0.8-1.5h.
In the present invention, the conditions of the second ion exchange may be the same as or different from those of the first ion exchange, and preferably the conditions of the second ion exchange include: the exchange temperature is 50-120 ℃, preferably 70-100 ℃; the exchange time is 0.5-2h, preferably 0.8-1.5h. Preferably, the exchange temperature of the second ion exchange is 0-15 ℃, preferably 1-10 ℃, higher than the exchange temperature of the first exchange. The adoption of the preferred embodiment is beneficial to optimizing the metal distribution and further improving the catalytic activity of the molecular sieve.
According to the present invention, it is preferable that the metal is contained in an amount of 12 to 23% by weight on an elemental basis based on the total amount of the metal-modified molecular sieve. For example, the metal may be present in an amount of 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt% or a value between any two points on an elemental basis. The adoption of the preferable metal content is beneficial to ensuring that the metal distribution is at the optimal position, thereby realizing shape selective catalysis and prolonging the service life of the molecular sieve and the linearity of the product.
In the present invention, in order to be able to further regulate the distribution of the metal, the first firing and/or the second firing are performed under an alkaline atmosphere, and preferably, both the first firing and the second firing are performed under an alkaline atmosphere. The adoption of the preferred embodiment is beneficial to protecting the molecular sieve structure and further improving the catalytic life of the metal modified molecular sieve.
According to the present invention, preferably, the alkaline atmosphere is provided by an aqueous solution of an alkaline compound. It is understood that the aqueous solution of the basic compound rapidly vaporizes at the firing temperature to provide an alkaline atmosphere for the firing process.
In the present invention, the selection range for the basic compound is wide. Preferably, the basic compound is selected from at least one of ammonia, ammonium carbonate and urea, preferably ammonia.
In the present invention, preferably, the concentration of the basic compound in the aqueous solution of the basic compound is 0.01 to 2mol/L, preferably 0.01 to 0.5mol/L, further preferably 0.05 to 0.3mol/L, and in the above preferred case, the stability of the molecular sieve structure is facilitated and the cycle life of the catalytic alkylation of the molecular sieve is prolonged.
According to the present invention, the basic atmosphere is preferably introduced at a rate of 0.01 to 0.5mL/min, more preferably 0.05 to 0.2mL/min, relative to 50g of the molecular sieve precursor. It is understood that the rate of introduction of the basic atmosphere may be increased proportionally as the throughput of molecular sieve precursors increases.
Preferably, the conditions of the first firing include: the roasting temperature is 400-600 ℃, the roasting time is 0.5-3h, the pressure is 0.01-0.1MPa, and the pressure is gauge pressure.
Preferably, the conditions of the second firing include: the roasting temperature is 400-600 ℃, the roasting time is 0.5-3h, the pressure is 0.01-0.1MPa, and the pressure is gauge pressure.
In the present invention, the first firing and the second firing do not refer to an operation sequence, and are used only to distinguish firing conditions in different steps. The conditions of the first firing and the second firing may be the same or different as long as the above-described condition requirements are satisfied.
In the present invention, before the first roasting or the second roasting, solid-liquid separation and drying of the first ion-exchanged product or the second ion-exchanged product are further included, and the solid-liquid separation and drying may be performed by using conventional operations in the art, which are not described herein.
According to the present invention, preferably, the oxygen-containing atmosphere is air or a mixture of oxygen and an inert gas; the inert gas is preferably nitrogen.
In the present invention, preferably, the oxygen-containing atmosphere has an oxygen content of 16 to 30vol%, preferably 18 to 25vol%.
Preferably, the temperature of the high temperature treatment is 50-100 ℃ higher than the second firing temperature.
According to the present invention, preferably, the conditions of the high temperature treatment include: the temperature is 500-700 ℃, preferably 550-650 ℃, and the treatment time is 2-12h, preferably 4-8h.
The third aspect of the invention provides a metal modified molecular sieve prepared by the preparation method.
In a fourth aspect, the present invention provides a process for alkylating a long chain olefin, the process comprising: under alkylation reaction conditions, long-chain olefin and aromatic hydrocarbon are contacted with a catalyst to carry out alkylation reaction;
wherein the catalyst is the metal modified molecular sieve of the first aspect or the third aspect.
In the invention, the linear chain degree of the product is obviously improved due to the shape selection of the reaction product after the modification of the molecular sieve, and the service life of the catalytic alkylation cycle of the metal modified molecular sieve is obviously prolonged due to the improvement of the selectivity.
In the present invention, the source of the long-chain olefin is not particularly limited, and long-chain olefins obtained by, for example, paraffin dehydrogenation, cracking, and oligomerization of small-molecular olefins can be used in the present invention. Preferably, the long-chain olefin is a long-chain olefin having a double bond at both the terminal and internal positions, and/or a long-chain alpha olefin having a double bond at the terminal position.
Preferably, the long-chain olefin is a C8-C28 long-chain olefin, more preferably a C8-C15 long-chain olefin, and even more preferably a C10-C14 long-chain olefin.
According to the present invention, preferably, the aromatic hydrocarbon is selected from at least one of benzene, toluene and ethylbenzene, preferably benzene.
In the present invention, the alkylation reaction conditions may be carried out using conditions conventional in the art, preferably ensuring that the alkylation reaction is carried out in the liquid phase and that the pressure is always sufficient to ensure that the reaction is carried out in a single liquid phase. In the invention, the single liquid phase means that all reactants are liquid phase, and the reaction conditions meet that the reactants are not vaporized in the reaction process.
In the present invention, the advantages areOptionally, the alkylation reaction conditions include: the reaction temperature is 50-250 ℃, preferably 70-200 ℃; the reaction pressure is 0.1-7MPa, preferably 2-4MPa; the mole ratio of the benzene is 3-70:1, preferably 4-60:1, a step of; space velocity of long-chain olefin is 0.1-5h -1 Preferably 0.3-3h -1 . The preferred reaction conditions described above are employed to help reduce isomerization of alkyl groups and minimize polyalkylation of benzene (or aromatic moieties of other aryl compounds) while maximizing consumption of olefins to maximize product.
Preferably, the alkylation reaction is carried out in a slurry bed reactor.
The present invention will be described in detail by examples.
In the following examples, various raw materials used were obtained from commercial sources without particular explanation.
In the examples below, the mass fraction of bulk metal was tested by XRF. The mass fraction of the gauge phase metal was measured by XPS testing.
In the present invention, XPS test was performed using an esclab 250 type X-ray photoelectron spectrometer (Thermo Fisher Scientific company), and test conditions include: monochromatic AlK alpha X-rays, energy 1486.6eV, power 150W, are used to correct charge displacement by C1s peak (284.8 eV) of polluted carbon.
In the present invention, XRF test was performed using an X-ray fluorescence spectrometer of Nippon Motor industry Co., ltd 3271; the test conditions included: the anode target material of the X-ray tube is rhodium target; the laser voltage is 50kV; the laser current was 50mA.
The testing conditions of the XRD include: the instrument used was an X-ray powder diffractometer from PANalytical, netherlands; the test conditions included: tube voltage 40kV, tube current 40ma, cu target ka radiation, scan speed 2 °/min, scan range 2θ=5° -35 °.
The molecular sieves used in the examples below were all purchased from chinese petrochemical catalysts.
Example 1
(1) 50g of HY molecular sieve (molar ratio of silica/alumina 6,w (Na 2 O) =0.0628%), usingThe lanthanum nitrate solution carries out first ion exchange on the HY molecular sieve, the concentration of lanthanum nitrate is 300g/L, the exchange temperature is 80 ℃, the exchange time is 1h, and the mass ratio of the lanthanum nitrate solution to the HY molecular sieve is 3:1, filtering and drying the exchanged molecular sieve, performing first roasting at 550 ℃ for 1h under the pressure of 0.02MPa, and introducing 0.1M ammonia water at the concentration of 0.1mL/min in the roasting process; and roasting to obtain the first exchange molecular sieve, and obtaining the lanthanum metal with the mass fraction of 10.65% through XRF detection and calculation.
(2) And (3) carrying out second ion exchange and second roasting on the first exchange molecular sieve to obtain a second exchange molecular sieve, wherein the conditions are the same as those of the step (1), and the second exchange molecular sieve is subjected to XRF detection and calculation to obtain the lanthanum metal with the mass fraction of 17.33%.
(3) And roasting the second exchange molecular sieve in the atmosphere of air in a muffle furnace at 600 ℃ for 4 hours to obtain the finished molecular sieve, wherein the number of the finished molecular sieve is Y1.
According to XRD test, as shown in figure 1, characteristic peaks at 11.9 degrees and 12.4 degrees are attributed to metal ions at cation positions, characteristic peaks at 29.0 degrees are attributed to metal oxides on the surface of the molecular sieve, meanwhile, the peak positions of the characteristic peaks of the metal modified molecular sieve are identical with the peak positions of the diffraction peaks of the HY molecular sieve, namely no offset is generated, and therefore, the metal is proved to be located outside the molecular sieve framework.
The physicochemical properties of the molecular sieve Y1 obtained by the test are shown in Table 1.
Example 2
According to the method in example 1, except that the HY type molecular sieve in (1) was replaced with an equal mass of H.beta.type molecular sieve (molar ratio of silica/alumina was 19, w (Na 2 O) =0.0171%). The number of the prepared metal modified molecular sieve is Y2.
The physicochemical properties of the molecular sieve Y2 obtained by the test are shown in Table 1.
Example 3
The procedure of example 1 was followed except that the lanthanum nitrate solution was replaced with cerium nitrate solution. The number of the prepared metal modified molecular sieve is Y3.
The physicochemical properties of the molecular sieve Y3 obtained by the test are shown in Table 1.
Example 4
The procedure of example 1 was followed except that the lanthanum nitrate solution was replaced with a strontium nitrate solution. The number of the prepared metal modified molecular sieve is Y4.
The physicochemical properties of the molecular sieve Y4 obtained by the test are shown in Table 1.
Example 5
The procedure of example 1 was followed, except that in both the first and second ion exchanges, the mass ratio of lanthanum nitrate solution to HY molecular sieve was 2.5:1. the number of the prepared metal modified molecular sieve is Y5.
The physicochemical properties of the molecular sieve Y5 obtained by the test are shown in Table 1.
Example 6
The procedure of example 1 was followed, except that in both the first and second ion exchanges, the mass ratio of lanthanum nitrate solution to HY molecular sieve was 3.8:1. the number of the prepared metal modified molecular sieve is Y6.
The physicochemical properties of the molecular sieve Y6 obtained by the test are shown in Table 1.
Example 7
The procedure of example 1 was followed except that the rate of ammonia was replaced with 0.03mL/min. The number of the prepared metal modified molecular sieve is Y7.
The physicochemical properties of the molecular sieve Y7 obtained by the test are shown in Table 1.
Example 8
(1) 50g of NaY molecular sieve (molar ratio of silica/alumina 5,w (Na 2 O) =12.8%), the NaY molecular sieve is subjected to a first ion exchange with a mixed solution of ammonium chloride and lanthanum nitrate, the concentration of ammonium chloride is 120g/L (calculated alone), the concentration of lanthanum nitrate is 300g/L (calculated alone), the exchange temperature is 80 ℃, the exchange time is 1h, and the mass ratio of the mixed solution to the molecular sieve is 3:1, filtering and drying the exchanged molecular sieve, performing first roasting at 550 ℃ for 1h under the pressure of 0.02MPa, and introducing 0.1M ammonia water at the concentration of 0.1mL/min in the roasting process; and roasting to obtain the first exchange molecular sieve.
(2) And (3) carrying out second ion exchange and second roasting on the first exchange molecular sieve to obtain a second exchange molecular sieve, wherein the conditions are the same as those of the step (1).
(3) And exchanging the second exchange molecular sieve by adopting an ammonium chloride solution, wherein the concentration of ammonium chloride is 120g/L, the exchange temperature is 80 ℃, the exchange time is 1h, and the mass ratio of the ammonium chloride solution to the molecular sieve is 3: and 1, filtering and drying the exchanged molecular sieve, then exchanging ammonium chloride solution again, repeating the process for 2 times under the same conditions as the above, so that the Na mass fraction in the molecular sieve is lower than 0.2%, and roasting the second exchanged molecular sieve in a muffle furnace at 600 ℃ for 4 hours in the air atmosphere.
The finished molecular sieve is the molecular sieve with the number of Y8. The physicochemical properties of the molecular sieve Y8 obtained by the test are shown in Table 1.
Example 9
The procedure of example 1 was followed, except that the concentration of the lanthanum nitrate solution was 400g/L. The number of the prepared metal modified molecular sieve is Y9.
The physicochemical properties of the molecular sieve Y9 obtained by the test are shown in the following Table 1.
Example 10
The procedure of example 1 was followed, except that the concentration of the lanthanum nitrate solution was 200g/L. The number of the prepared metal modified molecular sieve is Y10.
The physicochemical properties of the molecular sieve Y10 obtained by the test are shown in the following Table 1.
Example 11
According to the method in example 1, except that the HY type molecular sieve in (1) was replaced with an HX type molecular sieve of equal mass (molar ratio of silica/alumina is 2,w (Na 2 O) =0.0156%). The number of the prepared metal modified molecular sieve is Y11.
The physicochemical properties of the molecular sieve Y11 obtained by the test are shown in the following Table 1.
Example 12
(1) 50g of HY molecular sieve (molar ratio of silica/alumina 6,w (Na 2 O) =0.0628%), the first ion exchange is performed on the HY molecular sieve by using a lanthanum nitrate solution, the concentration of lanthanum nitrate is 300g/L, the exchange temperature is 80 ℃, the exchange time is 1h, and the mass ratio of the lanthanum nitrate solution to the HY molecular sieve is 3:1, exchangeFiltering and drying the rear molecular sieve, and then performing first roasting at 550 ℃ for 1h under the pressure of 0.02MPa, and introducing 0.1M ammonia water at the concentration of 0.1mL/min in the roasting process to obtain a first exchange molecular sieve;
(2) Performing a second ion exchange on the first exchange molecular sieve, the second ion exchange temperature being 90 ℃ different from the first ion exchange; and roasting to obtain the second exchange molecular sieve.
(3) And roasting the second exchange molecular sieve in the atmosphere of air in a muffle furnace at 600 ℃ for 4 hours to obtain the finished molecular sieve, wherein the number of the finished molecular sieve is Y12.
The physicochemical properties of the molecular sieve Y12 obtained by the test are shown in the following Table 1.
Comparative example 1
The untreated HY molecular sieve of example 1 was used and was numbered DY1. The physicochemical properties of the molecular sieve DY1 obtained by the test are shown in the following Table 1.
Comparative example 2
(1) 50g of HY molecular sieve (molar ratio of silica/alumina 6,w (Na 2 O) =0.0628%), first ion exchange is performed on the HY molecular sieve by using a lanthanum nitrate solution, the concentration of lanthanum nitrate is 150g/L, the exchange temperature is 80 ℃, the exchange time is 1h, and the mass ratio of the solution to the molecular sieve is 3:1, filtering and drying the exchanged molecular sieve, roasting at 550 ℃ for 1h under the pressure of 0.02MPa, and simultaneously introducing 0.1M ammonia water at the concentration of 0.1mL/min in the roasting process; and roasting to obtain the first exchange molecular sieve, and obtaining the lanthanum metal with the mass fraction of 5.83% through XRF detection and calculation.
(2) And (3) carrying out second ion exchange and second roasting on the first exchange molecular sieve to obtain a second exchange molecular sieve, wherein the conditions are the same as those of the step (1), and the second exchange molecular sieve is subjected to XRF detection and calculation to obtain the lanthanum metal with the mass fraction of 6.97%.
(3) And roasting the second exchange molecular sieve in the muffle furnace at 600 ℃ for 4 hours in the air atmosphere to obtain the finished molecular sieve with the number DY2.
The physicochemical properties of the molecular sieve DY2 obtained by the test are shown in the following Table 1.
Comparative example 3
(1) 50g of HY molecular sieve (molar ratio of silica/alumina 6,w (Na 2 O)＝0.0628％) Carrying out first ion exchange on the HY molecular sieve by adopting a lanthanum nitrate solution, wherein the concentration is 900g/L, the exchange temperature is 80 ℃, the exchange time is 1h, and the mass ratio of the solution to the molecular sieve is 3:1, evaporating the molecular sieve after exchange to remove water, drying, roasting at 550 ℃ for 1h under the pressure of 0.02MPa, and simultaneously introducing 0.1M ammonia water at the concentration of 0.1mL/min in the roasting process; after roasting, the molecular sieve is subjected to XRF detection and calculation to obtain the lanthanum metal with the mass fraction of 19.06%.
(2) And (3) carrying out second ion exchange and second roasting on the first exchange molecular sieve to obtain a second exchange molecular sieve, wherein the method is the same as that of the step (1), and the second exchange molecular sieve is subjected to XRF detection and calculation to obtain the lanthanum metal with the mass fraction of 31.80%.
(3) And roasting the second exchange molecular sieve in the muffle furnace at 600 ℃ for 4 hours in the air atmosphere to obtain the finished molecular sieve with the number DY3.
The physicochemical properties of the molecular sieve DY3 obtained by the test are shown in the following Table 1.
Comparative example 4
The procedure of example 1 was followed except that the ammonia was replaced with an equal amount of water during both the first and second calcination, the molecular sieve obtained was designated DY4, and the physicochemical properties of the molecular sieve DY4 obtained by the test were as shown in Table 1.
TABLE 1
Table 1, below
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Test example 1
The molecular sieve sample Y1 of example 1 was subjected to alkylation of benzene with 1-dodecene at 120℃and 2.5MPa with an olefin feed space velocity of 0.354h -1 The molar ratio of the benzene was 60. The conversion and product selectivity results under this reaction condition are shown in Table 2.
The stability of the molecular sieve of example 1 was evaluated, and the results are shown in fig. 2, and it can be seen from fig. 2 that the catalytic performance of the molecular sieve prepared by example 1 in the alkylation reaction of 1-dodecene and benzene was stable, and the selectivity of monoalkylbenzene was always close to 100% and the linearity of alkylbenzene was always above 94% in 300h of evaluation.
Conversion (%) = (amount of substance of 1-dodecene before reaction-amount of substance of 1-dodecene after reaction)/amount of substance of 1-dodecene before reaction×100%;
monoalkylbenzene selectivity (%) = amount of monoalkylbenzene material after reaction/amount of total reaction product material x 100%;
linear degree (%) =amount of substance of linear alkylbenzene after reaction/amount of substance of monoalkylbenzene after reaction×100%.
Test examples 2 to 12
Y1 was replaced by the molecular sieves of examples 2 to 12, respectively, according to the method of test example 1. The alkylation reaction results are shown in Table 2 and the following Table 2.
Comparative test examples 1 to 4
Y1 was replaced with the molecular sieves of comparative examples 1-4, respectively, in the same manner as in test example 1. The alkylation reaction results are shown in Table 2 below.
TABLE 2
Continuous table 2
As can be seen from the results in Table 2 and subsequent Table 2, the metal modified molecular sieve prepared in the embodiment of the invention has high activity, stability and selectivity in catalyzing alkylation reaction of 1-dodecene and benzene, wherein the selectivity of monoalkylbenzene is more than 98%, and the linear chain degree of alkylbenzene is more than 94%.
As can be seen from the comparison of example 1 and comparative examples 1 to 3, when the metal modification is not performed and the metal content is too high or too low, it is disadvantageous in that the catalyst life and the product linearity are improved, and particularly when the metal content exceeds 30wt%, the conversion of olefin is greatly reduced and the selectivity of monoalkylbenzene is poor. It can be seen from examples 1 and 4 that when neither the first calcination nor the second calcination uses an alkaline atmosphere, the mass fraction of the surface phase metal is higher, the activity of the catalyst is lowered, the linearity of alkylbenzene is lowered, and at the same time, the catalytic effect is rapidly attenuated as the reaction proceeds, and the catalyst life is short.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (12)
1. A metal modified molecular sieve, characterized in that the metal modified molecular sieve comprises a molecular sieve and a metal outside a molecular sieve framework; the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve;
in the metal modified molecular sieve, the ratio of the mass fraction of the surface phase metal measured by XPS to the mass fraction of the bulk phase metal measured by XRF test is not more than 1.45 in terms of the mass fraction of elements.
2. The metal modified molecular sieve according to claim 1, wherein the ratio of the mass fraction of the surface phase metal measured by XPS to the mass fraction of the bulk phase metal measured by XRF test in the metal modified molecular sieve is not more than 1.35, preferably 0.9-1.35, in terms of mass fraction of the elements;
preferably, the metal is contained in an amount of 12 to 23wt% in terms of elements based on the total amount of the metal-modified molecular sieve;
preferably, the metal has an atomic radius of 120-270pm, preferably 160-240pm;
preferably, the metal is selected from at least one of alkaline earth metals, group IIIB metals, and group IIIA metals; further preferably at least one of La, ce, sr and Y.
3. The metal modified molecular sieve of claim 1 or 2, wherein the metal modified molecular sieve is a silica-alumina molecular sieve;
preferably, the molar ratio of silica/alumina in the metal modified molecular sieve is 1-100:1, preferably 3-20:1, a step of;
preferably, the metal modified molecular sieve is selected from at least one of an X-type molecular sieve, a Y-type molecular sieve, an MCM-22 type molecular sieve, a Beta-type molecular sieve and a MOR-type molecular sieve, preferably an X-type molecular sieve and/or a Y-type molecular sieve.
4. The preparation method of the metal modified molecular sieve is characterized by comprising the following steps of:
(1) Subjecting the molecular sieve precursor to a first ion exchange with a first exchange liquid comprising a soluble compound of a metal;
(2) Carrying out first roasting on the product of the first ion exchange to obtain a first exchange molecular sieve;
(3) Subjecting the first exchange molecular sieve to a second ion exchange with a second exchange liquid containing a soluble compound of a metal;
(4) Subjecting the second ion exchanged product to a second calcination, optionally repeating the second ion exchange and the second calcination, to obtain a second exchanged molecular sieve;
(5) Carrying out high-temperature treatment on the second exchange molecular sieve in an oxygen-containing atmosphere to obtain the metal modified molecular sieve;
wherein the first firing and/or the second firing is performed under an alkaline atmosphere;
wherein the content of the metal is 8-30wt% based on the total amount of the metal modified molecular sieve.
5. The process according to claim 4, wherein the metal is contained in an amount of 12 to 23% by weight on an elemental basis based on the total amount of the metal-modified molecular sieve.
6. The production process according to claim 4 or 5, wherein the molecular sieve precursor is a molecular sieve in hydrogen form or sodium form;
preferably, the molecular sieve precursor is a silica-alumina molecular sieve, and the molar ratio of silica/alumina in the molecular sieve is preferably 1 to 100:1, preferably 3-20:1, a step of;
preferably, the molecular sieve precursor is selected from at least one of an X-type molecular sieve, a Y-type molecular sieve, an MCM-22-type molecular sieve, a Beta-type molecular sieve, and a MOR-type molecular sieve, preferably an X-type molecular sieve and/or a Y-type molecular sieve;
preferably, the molecular sieve precursor is sodium molecular sieve, and the first exchange liquid and/or the second exchange liquid further comprise ammonium salt;
preferably, the ammonium salt is selected from at least one of ammonium nitrate, ammonium chloride and ammonium sulfate;
preferably, the concentration of ammonium salt in the first exchange liquid and/or the second exchange liquid is 50-200g/L independently.
7. The production method according to any one of claims 4 to 6, wherein the soluble compound of a metal is selected from at least one of a chloride, a nitrate, a phosphate and a sulfate of a metal;
preferably, the concentration of the soluble compounds of the metals in the first exchange liquid and/or the second exchange liquid is 100-500g/L independently;
preferably, the first exchange liquid and the second exchange liquid each independently comprise a solvent, and the solvent is preferably water;
preferably, the metal has an atomic radius of 120-270pm, preferably 160-240pm;
preferably, the metal is selected from at least one of alkaline earth metals, group IIIB metals, and group IIIA metals; further preferably at least one of La, ce, sr and Y;
preferably, the mass ratio of the first exchange liquid to the molecular sieve precursor is 2-8:1, a step of;
preferably, the mass ratio of the second exchange liquid to the first exchange molecular sieve is 3-6:1, a step of;
preferably, the conditions of the first ion exchange include: the exchange temperature is 50-90 ℃, preferably 70-90 ℃; the exchange time is 0.5-2h, preferably 0.5-1.5h;
preferably, the exchange temperature of the second ion exchange is 0-15 ℃, preferably 1-10 ℃, higher than the exchange temperature of the first ion exchange.
8. The production method according to any one of claims 4 to 7, wherein the alkaline atmosphere is provided by an aqueous solution of an alkaline compound;
preferably, the basic compound is selected from at least one of ammonia, ammonium carbonate and urea;
preferably, the concentration of the alkaline compound in the aqueous solution of the alkaline compound is 0.01-2mol/L;
preferably, the basic atmosphere is introduced at a rate of 0.01 to 0.5mL/min relative to 50g of molecular sieve precursor;
preferably, the conditions of the first firing include: the roasting temperature is 400-600 ℃, the roasting time is 0.5-3h, the pressure is 0.01-0.1MPa, and the pressure is gauge pressure;
preferably, the conditions of the second firing include: the roasting temperature is 400-600 ℃, the roasting time is 0.5-3h, the pressure is 0.01-0.1MPa, and the pressure is gauge pressure.
9. The production method according to any one of claims 4 to 8, wherein the oxygen-containing atmosphere is air or a mixture of oxygen and an inert gas;
preferably, the oxygen content in the oxygen-containing atmosphere is 16 to 30vol%, preferably 18 to 25vol%;
preferably, the temperature of the high temperature treatment is 50-100 ℃ higher than the second firing temperature;
preferably, the conditions of the high temperature treatment include: the temperature is 500-700 ℃, preferably 550-650 ℃, and the treatment time is 2-12h, preferably 4-8h.
10. A metal modified molecular sieve made by the method of any one of claims 4-9.
11. A process for alkylating a long chain olefin, the process comprising: under alkylation reaction conditions, long-chain olefin and aromatic hydrocarbon are contacted with a catalyst to carry out alkylation reaction;
characterized in that the catalyst is a metal modified molecular sieve according to any one of claims 1 to 3 and 10.
12. The method according to claim 11, wherein the long-chain olefin is a long-chain olefin having a double bond at both terminal and internal positions, and/or a long-chain alpha olefin having a double bond at a terminal position;
preferably, the long-chain olefin is a C8-C28 long-chain olefin, more preferably a C8-C15 long-chain olefin, and even more preferably a C10-C14 long-chain olefin;
preferably, the aromatic hydrocarbon is at least one of benzene, toluene and ethylbenzene, preferably benzene;
preferably, the alkylation reaction conditions include: the reaction temperature is 50-250 ℃, preferably 70-200 ℃; the reaction pressure is 0.1-7MPa, preferably 2-4MPa; the mole ratio of the benzene is 3-70:1, preferably 4-60:1, a step of; the mass space velocity of the long-chain olefin is 0.1 to 5h -1 Preferably 0.3-3h -1 。
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| CN202211033764.1A CN117654587A (en) | 2022-08-26 | 2022-08-26 | Metal modified molecular sieve, preparation method thereof and long-chain olefin alkylation method |
| PCT/CN2023/114925 WO2024041636A1 (en) | 2022-08-26 | 2023-08-25 | Metal-modified molecular sieve, and preparation and use thereof |
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| CN202211033764.1A CN117654587A (en) | 2022-08-26 | 2022-08-26 | Metal modified molecular sieve, preparation method thereof and long-chain olefin alkylation method |
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