CN114478181B - Method for preparing ethylbenzene by gas phase method, catalyst and preparation method of catalyst - Google Patents

Method for preparing ethylbenzene by gas phase method, catalyst and preparation method of catalyst Download PDF

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CN114478181B
CN114478181B CN202011146487.6A CN202011146487A CN114478181B CN 114478181 B CN114478181 B CN 114478181B CN 202011146487 A CN202011146487 A CN 202011146487A CN 114478181 B CN114478181 B CN 114478181B
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molecular sieve
aluminum
silicon
catalyst
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CN114478181A (en
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谢明观
翟云平
王幼驹
王永睿
慕旭宏
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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China Petroleum and Chemical Corp
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
    • C07C2/54—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition of unsaturated hydrocarbons to saturated hydrocarbons or to hydrocarbons containing a six-membered aromatic ring with no unsaturation outside the aromatic ring
    • C07C2/64—Addition to a carbon atom of a six-membered aromatic ring
    • C07C2/66—Catalytic processes
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/041—Mesoporous materials having base exchange properties, e.g. Si/Al-MCM-41
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/082—Decomposition and pyrolysis
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/30—Ion-exchange
    • 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
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/40—Special temperature treatment, i.e. other than just for template removal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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Abstract

The invention discloses a method for preparing ethylbenzene by a gas phase method, a catalyst and a preparation method of the catalyst. The method for preparing ethylbenzene uses a supported catalyst of a super macroporous molecular sieve, thereby remarkably reducing the impurity xylene content in the reaction product of preparing ethylbenzene by a gas phase method. The catalyst of the invention comprises a molecular sieve with intragranular mesopores. The catalyst is used for catalyzing the reaction of ethylene and benzene gas phase alkylation to prepare ethylbenzene, the ethylene conversion rate is high, the selectivity of ethylbenzene and other ethylated products in the product is high, and the xylene impurities are less.

Description

Method for preparing ethylbenzene by gas phase method, catalyst and preparation method of catalyst
Technical Field
The invention relates to a method for preparing ethylbenzene by a gas phase method, a catalyst and a preparation method of the catalyst.
Background
Ethylbenzene is an important chemical raw material and is mainly used for producing important chemical intermediates such as styrene, acetophenone, ethyl anthraquinone, p-nitroacetophenone and the like. Ethylbenzene manufacturing technologies mainly include benzene and ethylene alkylation technologies, and separation technologies of C8 aromatic hydrocarbon fractions from refineries, the former accounting for about 90% of the total ethylbenzene production. Early ethylbenzene production was carried out in AlCl 3 Is produced by a liquid phase alkylation process. However, this process has problems of equipment corrosion, serious environmental pollution, high maintenance cost, etc., and is gradually replaced by a molecular sieve catalyst in seventies of the twentieth century. The unique pore canal structure of the molecular sieve can improve the selectivity of ethylbenzene, inhibit the generation of byproducts, can be recycled and lighten the reaction to a certain extentCorrosion and pollution problems are solved. ZSM-5 molecular sieve and Beta molecular sieve were successfully applied in ethylbenzene production in succession, and gas phase alkylation and liquid phase alkylation processes were developed. Compared with the liquid phase alkylation process using Beta molecular sieve as the catalyst active component, the gas phase alkylation process using ZSM-5 molecular sieve as the catalyst active component has more flexibility and economy, can produce raw materials such as pure ethylene, dilute ethylene, ethanol and ethane, and has been applied to 35 sets of global ethylbenzene production devices, and the yield of the process is about half of the world ethylbenzene yield. However, the vapor phase alkylation reaction product using ZSM-5 molecular sieve as the catalyst active component has a relatively high xylene content. Because of the difficulty in separating the xylenes from the ethylbenzene, more xylenes impurities have an adverse effect on the quality of the subsequent product polystyrene. US3751506 discloses a process for preparing ethylbenzene by gas phase alkylation of pure ethylene and benzene using a ZSM-5 molecular sieve as catalyst, wherein the xylene content is higher than 2000ppm; US4107224 reports a method for preparing ethylbenzene by gas phase alkylation of dilute ethylene and benzene with a ZSM-5 molecular sieve as a catalyst, wherein the reaction temperature is 370 ℃, and the reaction raw materials need to be strictly refined to remove impurities such as hydrogen sulfide and water, and the operation is complex; CN106881146A reports a method for preparing ethylbenzene from dry gas and phenylalkyl by using F-ZSM-11 molecular sieve, and xylene content >750ppm. In summary, the prior art generally has the problem of high xylene content.
Molecular sieves are widely used and different applications often place different demands on the framework pore structure of the molecular sieve. The molecular sieve has four skeleton pore structure types of small pores, medium pores, large pores and ultra-large pores: small pore molecular sieves have a molecular sieve structure selected from the group consisting ofTo->Is a pore size of (2); mesoporous molecular sieves have a molecular weight of->To->Is a pore size of (2); the macroporous molecular sieve has->Is a pore size of (2); super macroporous molecular sieves have a molecular weight greater thanIs a pore size of the polymer. In the framework pore structure of the 232 molecular sieves at present, the ultra-large pore molecular sieves only occupy more than 10 kinds. CN108238610a discloses an ultra-large pore molecular sieve, which has a unique X-ray diffraction pattern and a primary crystal morphology from flat prism shape to flat cylinder shape, and although the molecular sieve has a great potential and application prospect in catalyzing macromolecular reactions, for certain catalytic reactions, the catalytic effect of the molecular sieve has a room for further improvement.
For porous materials, pore size can be divided into three stages: pores with a pore diameter of less than 2nm are called micropores; pores with the pore diameter between 2 and 50nm are called mesopores (also called mesopores); pores with a pore size of greater than 50nm to 1000nm are referred to as macropores.
The information disclosed in the foregoing background section is only for enhancement of understanding of the background of the invention and may include information that is not already known to those of ordinary skill in the art.
Disclosure of Invention
The first object of the invention is to greatly reduce the content of xylene impurities in the reaction for preparing ethylbenzene by gas phase alkylation of benzene and ethylene under the premise of maintaining or improving the conversion rate and selectivity. A second object of the present invention is to increase the conversion and selectivity and further reduce the xylene impurity content in the reaction of gas phase alkylation of benzene and ethylene to ethylbenzene in addition to the previous object.
1. A method for preparing ethylbenzene by a gas phase process, comprising: contacting ethylene with benzene in the presence of a catalyst and under vapor phase alkylation reaction conditions; the catalyst comprises a aluminosilicate molecular sieve having an X-ray diffraction pattern substantially as shown in the following table,
2. a process according to any one of the preceding claims, wherein the aluminosilicate molecular sieve has intra-crystalline mesopores.
3. The method according to any of the preceding claims, wherein the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
4. the method according to any of the preceding claims, wherein the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
5. the method according to any one of the preceding claims, characterized in that the aluminosilicate molecular sieve has a schematic chemical composition represented by the formula "silica-alumina" or by the formula "silica-alumina-organic templating agent-water"; the molar ratio of silica to alumina is 15 to 300, preferably 20 to 50.
6. A method according to any of the preceding claims, characterized in that the individual crystals of the aluminosilicate molecular sieve have a particle size of between 200nm and 1000nm, preferably between 250nm and 800nm, as seen by transmission electron microscopy.
7. The method according to any of the preceding claims, characterized in that the mesoporous pore volume of the aluminosilicate molecular sieve is more than 25% of the total pore volume, which may be 25% to 50% or 30% to 40%.
8. A process according to any of the preceding claims, characterized in that the ethylene feedstock used is one or more of pure ethylene, ethylene-containing refinery catalytic cracking dry gas (preferably ethylene volume fraction of 10% to 60%) and ethylene-containing refinery catalytic cracking dry gas (preferably ethylene volume fraction of 10% to 60%).
9. A process according to any one of the preceding claims, characterized in that the catalyst consists of a binder (preferably alumina and/or silica) and the aluminosilicate molecular sieve (preferably the molecular sieve has a mass fraction of 15% to 95%, preferably 60% to 90% by mass of the catalyst).
10. A process according to any one of the preceding claims, characterized in that the gas phase alkylation reaction conditions are: the reaction temperature is 285-420 ℃, the reaction pressure is 0.6-1.0 MPa, and the molar ratio of benzene to ethylene is 4:1 to 8:1, ethylene weight space velocity of 0.5h -1 ～5.0h -1 The method comprises the steps of carrying out a first treatment on the surface of the Preferably, the reaction temperature is 320-400 ℃, the reaction pressure is 0.7-0.9 MPa, and the molar ratio of benzene to ethylene is 5:1 to 7:1, ethylene weight space velocity of 0.8h -1 ～4.0h -1 。
11. A catalyst for vapor phase ethylbenzene manufacture comprising a aluminosilicate molecular sieve having an X-ray diffraction pattern substantially as shown in the following table,
the method comprises the steps of carrying out a first treatment on the surface of the Preferably, the aluminosilicate molecular sieve has intra-crystalline mesopores.
12. The catalyst according to any of the preceding claims, characterized in that the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
13. the catalyst according to any of the preceding claims, characterized in that the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
14. the catalyst according to any one of the preceding claims, characterized in that the aluminosilicate molecular sieve has a schematic chemical composition represented by the formula "silica-alumina" or by the formula "silica-alumina-organic templating agent-water"; the molar ratio of the silicon oxide to the aluminum oxide is 20-50.
15. The catalyst according to any of the preceding claims, characterized in that the single crystals of the aluminosilicate molecular sieve have a particle size, as seen by transmission electron microscopy, comprised between 200nm and 1000nm, preferably between 250nm and 800 nm.
16. The catalyst according to any one of the preceding claims, characterized in that the mesoporous volume of the aluminosilicate molecular sieve is more than 25% of the total pore volume, which may be 25% to 50% or 30% to 40%.
17. A process for preparing any of the foregoing catalysts, comprising; mixing and kneading the molecular sieve raw powder, a silicon-containing compound and/or an aluminum-containing compound, nitric acid and deionized water to form, drying, burning out a template agent in air at 450-550 ℃, exchanging in an ammonium salt aqueous solution at 80-90 ℃, and finally roasting and deaminizing at 500-600 ℃ for 1-5 hours to obtain the catalyst.
18. The method for preparing a catalyst according to any one of the preceding claims, characterized in that the silicon-containing compound is selected from one or more of silica sol, methyl orthosilicate and ethyl orthosilicate.
19. The method for preparing a catalyst according to any one of the preceding claims, wherein the aluminum-containing compound is selected from one or more of pseudo-boehmite, SB powder, alumina sol and aluminum isopropoxide.
20. The method for preparing a catalyst according to any one of the preceding claims, characterized in that the ammonium salt is selected from one or more of ammonium nitrate, ammonium chloride and ammonium sulfate.
21. The method for preparing the catalyst according to any one of the preceding claims, wherein a pore-forming agent, such as sesbania powder, may be added, wherein the pore-forming agent accounts for 2% -5% of the total weight of the dry material.
22. The process for preparing a catalyst according to any of the preceding claims, characterized in that the amount of nitric acid is 2 to 8% based on the total weight of the dry material.
23. The method for preparing the catalyst according to any one of the preceding claims, wherein the silicon-aluminum molecular sieve is prepared by the following method:
(1) Providing an initial gel mixture comprising a silicon source, an aluminum source, a first templating agent, water, and an alkali source; the silicon source is SiO 2 The aluminum source is calculated as Al 2 O 3 The molar ratio of the silicon source, the aluminum source, the template agent, the water and the hydroxide of the alkali metal in the initial gel mixture is 1:0-0.02:0.1-0.5:5-25:0-0.5;
(2) Crystallizing the initial gel mixture in step (1);
(3) After crystallization, the following four intermediate products are obtained: (a) a molecular sieve slurry; (b) filtering, washing and drying the molecular sieve raw powder; (c) Ammonium exchange, filtering, washing and drying; (d) Ammonium exchange, filtering, washing, drying and roasting to obtain hydrogen molecular sieve;
(4) Mixing the intermediate product in the step (3) with an aluminum source, an alkali source and a second template agent, wherein the molar ratio of the silicon source to the aluminum source to the template agent to the water to the alkali metal hydroxide is 1:0.02-0.04:0.1-0.5:5-25:0-0.2;
(5) Crystallizing the mixture obtained in the step (4), and performing post-treatment to obtain the silicon-aluminum molecular sieve.
24. The process for producing a catalyst according to any one of the preceding claims, characterized in that, in the process for producing a silica-alumina molecular sieve, the first template and the second template are each independently selected from the compounds represented by the following formula (I),
the radicals R1 and R2 are identical or different from one another and are each independently selected from C3-12 linear or branched alkylene, preferably from C3-12 linear alkylene, particularly preferably one from C3-12 linear alkylene and the other from C4-6 linear alkylene; the plurality of radicals R, equal to or different from each other, are each independently selected from C1-4 linear or branched alkyl radicals, preferably each independently selected from methyl and ethyl radicals, more preferably each methyl radical; x is OH.
CN108238610a discloses an oversized framework pore molecular sieve having a unique X-ray diffraction pattern (XRD) and a unique primary crystal morphology, such as from flat prism to oblate column. The inventor discovers that compared with the prior art that the ZSM-5 molecular sieve is adopted to catalyze benzene and ethylene to produce ethylbenzene, the molecular sieve is adopted to catalyze the benzene and ethylene to produce ethylbenzene under the same reaction condition, and the content of xylene impurities is greatly reduced, thus the invention is primarily completed. Further, although the molecular sieve is excellent in catalytic performance, the molecular sieve generally has a silica-alumina ratio of 60 to 700 and a low aluminum content, which may result in insufficient acid amount of the molecular sieve in the catalytic reaction; meanwhile, the molecular sieve still belongs to a microporous material, has the defect of small pore diameter, and limits the exertion of the catalytic performance of the molecular sieve to a certain extent. The inventors have unexpectedly found that the process of the present invention can be used to produce molecular sieves having the same molecular sieve crystal topology as the document, but with a lower silicon to aluminum ratio than the molecular sieves of the document, particularly with the abundant mesoporous structure within the molecular sieve crystal of the present invention that the molecular sieve of the document does not possess, thereby providing a novel catalytic material that is more suitable for catalyzing the reaction of certain macromolecules. The present inventors have found that the molecular sieve of the present invention is a catalyst for an active component, which has a higher ethylene conversion rate and a higher selectivity for ethylation products such as ethylbenzene, and further significantly reduced xylene impurities, under the same reaction conditions, as compared with the molecular sieve of the aforementioned document for catalyzing benzene to produce ethylbenzene with ethylene, thereby completing the present invention.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
FIG. 1 is a powder X-ray diffraction (XRD) pattern of a molecular sieve raw powder prepared in example 3 of the present invention.
FIG. 2 is a molecular sieve raw powder prepared in example 3 of the present invention 27 Al MAS-NMR spectra.
FIG. 3 is a scanning electron microscope image of the molecular sieve raw powder prepared in example 3 of the present invention.
FIG. 4 is a transmission electron microscope image of the molecular sieve raw powder prepared in example 3 of the present invention.
Figure 5 is an XRD pattern of a molecular sieve raw powder prepared in example 4 of the present invention.
FIG. 6 is a molecular sieve raw powder prepared in example 4 of the present invention 27 Al MAS-NMR spectra.
FIG. 7 is a scanning electron microscope image of the molecular sieve raw powder prepared in example 4 of the present invention.
FIG. 8 is a transmission electron microscope image of the molecular sieve raw powder prepared in example 4 of the present invention.
Figure 9 is an XRD pattern of a molecular sieve raw powder prepared in example 5 of the present invention.
FIG. 10 is a molecular sieve raw powder prepared in example 5 of the present invention 27 Al MAS-NMR chart.
FIG. 11 is a scanning electron microscope image of the molecular sieve raw powder prepared in example 5 of the present invention.
FIG. 12 is a transmission electron microscope image of the molecular sieve raw powder prepared in example 5 of the present invention.
FIG. 13 is a transmission electron microscope image of the molecular sieve raw powder prepared in example 6 of the present invention.
FIG. 14 is a transmission electron microscope image of the molecular sieve raw powder prepared in example 7 of the present invention.
FIG. 15 is a NH value of a hydrogen molecular sieve prepared in example 1 and example 8 of the present invention 3 -TPD profile.
FIG. 16 is a transmission electron microscope image of the molecular sieve raw powder prepared in example 8 of the present invention.
Detailed Description
The invention is described in detail below in connection with the embodiments, but it should be noted that the scope of the invention is not limited by these embodiments and the principle explanation, but is defined by the claims.
The disclosure of CN108238610a is incorporated herein in its entirety.
Technical and scientific terms used in the present invention are defined to have their meanings, and are not defined to have their ordinary meanings in the art.
In the present invention, any matters or matters not mentioned are directly applicable to those known in the art without modification except for those explicitly stated. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or ideas thus formed are all considered as part of the original disclosure or original description of the present invention, and should not be considered as new matters not disclosed or contemplated herein unless such combination would obviously be unreasonable to one skilled in the art.
All of the features disclosed in this invention may be combined in any combination which is known or described in the present invention and should be interpreted as specifically disclosed and described in the present invention unless the combination is obviously unreasonable by those skilled in the art. The numerical points disclosed in the present specification include not only the numerical points specifically disclosed in the embodiments but also the end points of each numerical range in the specification, and any combination of these numerical points should be considered as a disclosed or described range of the present invention.
In the context of the present specification, so-called organic templating agents are sometimes also referred to in the art as structure directing agents or organic directing agents.
In the context of the present specification, a so-called silicon source is sometimes referred to in the art as a silicon oxide source. The silicon source described in other cases does not contain molecular sieves except where it may be uniquely determined in accordance with the context of the present specification or by definition itself.
In the context of the present specification, the so-called aluminium source is sometimes also referred to in the art as alumina source.
In the context of the present specification, the total specific surface area refers to the total area of the molecular sieve per unit mass, and includes the inner surface area and the outer surface area. The non-porous material has only an outer surface area, such as portland cement, some clay mineral particles, etc., while the porous material has an outer surface area and an inner surface area, such as asbestos fibers, diatomaceous earth, molecular sieves, etc.
In the context of the present specification, the pore volume, also referred to as pore volume, refers to the volume of pores that a molecular sieve has per unit mass. The micropore volume is the volume of all micropores (i.e., pores having a pore diameter of less than 2 nm) of a molecular sieve per unit mass.
In the context of the present specification, w, m, s, vs in the XRD data of the molecular sieve represents the diffraction peak intensity, w is weak, m is medium, s is strong, vs is very strong, as is well known to those skilled in the art. In general, w is less than 20%; m is 20% -40%; s is 40% -70%; vs is greater than 70%, calculated as 100% of the intensity of the diffraction peak of the strongest peak.
Unless explicitly indicated, all percentages, parts, ratios, etc. mentioned in this specification are by weight unless otherwise clear to the routine knowledge of a person skilled in the art.
In the present invention, "optional" means optional and may be understood as comprising or not comprising.
The invention provides a method for preparing ethylbenzene by a gas phase method, which comprises the following steps: contacting ethylene with benzene in the presence of a catalyst and under vapor phase alkylation reaction conditions; the catalyst comprises a aluminosilicate molecular sieve having an X-ray diffraction pattern substantially as shown in the following table,
According to the method for producing ethylbenzene of the present invention, the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
according to the method for producing ethylbenzene of the present invention, the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
according to the process for preparing ethylbenzene of the present invention, the aluminosilicate molecular sieve has a schematic chemical composition represented by the formula "silica-alumina" or the formula "silica-alumina-organic templating agent-water"; the molar ratio of silica to alumina is 15 to 300, preferably 20 to 50. It is known that molecular sieves sometimes, especially immediately after synthesis, contain some amount of moisture, but the present invention recognizes that it is not necessary to specify the amount of moisture, since the presence or absence of this moisture does not substantially affect the XRD pattern of the molecular sieve and this moisture will be removed during the calcination of the catalyst. In view of this, the schematic chemical composition is in fact representative of the anhydrous chemical composition of the molecular sieve. Moreover, it is evident that this schematic chemical composition represents the framework chemical composition of the molecular sieve. The molecular sieve may further generally contain, in its composition, an organic template agent, water, etc., such as those filled in its pore channels, immediately after synthesis. Thus, the molecular sieve may sometimes also have a schematic chemical composition represented by the formula "silica-alumina-organic templating agent-water". Here, the molecular sieve having the schematic chemical composition represented by the formula "silica-alumina-organic templating agent-water" can be obtained by calcining the molecular sieve having the schematic chemical composition represented by the formula "silica-alumina-organic templating agent-water" so as to remove any organic templating agent, water, etc. present in the pores thereof.
In the method for producing ethylbenzene according to the present invention, among the aforementioned schematic chemical compositions, as the organic template, for example, any organic template used in the preparation of the molecular sieve may be cited, and in particular, the organic template used in the preparation of the molecular sieve of the present embodiment may be cited (see the detailed description below). These organic templates may be used alone or in combination of plural kinds in an arbitrary ratio. Specifically, the organic template may be, for example, a compound represented by the following formula (I).
In formula (I), the radical R 1 And R is 2 Are identical or different from each other and are each independently selected from C 3-12 A linear or branched alkylene group, a plurality of radicals R being identical to or different from one another and each independently selected from C 1-4 Straight or branched alkyl, and X is OH.
According to the method for preparing ethylbenzene, the ethylene raw material is one or more of pure ethylene, ethylene-containing refinery catalytic cracking dry gas (preferably, ethylene volume fraction is 10% -60%) and ethylene-containing refinery catalytic cracking dry gas (preferably, ethylene volume fraction is 10% -60%).
According to the method for preparing ethylbenzene of the present invention, the catalyst consists of a binder (preferably alumina and/or silica) and the aluminosilicate molecular sieve (preferably, the molecular sieve has a mass fraction of 15% to 95%, preferably 60% to 90%, based on the mass of the catalyst).
According to the method for preparing ethylbenzene of the invention, the gas phase alkylation reaction conditions are as follows: the reaction temperature is 285-420 ℃, the reaction pressure is 0.6-1.0 MPa, and the molar ratio of benzene to ethylene is 4:1 to 8:1, ethylene weight space velocity of 0.5h -1 ～5.0h -1 The method comprises the steps of carrying out a first treatment on the surface of the Preferably, the reaction temperature is 320-400 ℃, the reaction pressure is 0.7-0.9 MPa, and the molar ratio of benzene to ethylene is 5:1 to 7:1, ethylene weight space velocity of 0.8h -1 ～4.0h -1 。
As a preferred embodiment, the ethylbenzene production method of the present invention employs a molecular sieve having a relatively low silica-alumina ratio (e.g., 20-50) and having intra-crystalline mesopores. In the molecular sieve, aluminum enters a molecular sieve framework and mainly exists in the form of four-coordination framework aluminum, so that the acid quantity of the molecular sieve is greatly improved, and the application of the molecular sieve in acid catalytic reaction is facilitated to be enlarged; in addition, the silicon-aluminum molecular sieve crystal contains abundant mesoporous structures, so that the diffusion of reaction molecules in a molecular sieve pore canal is greatly promoted.
According to the embodiment, the silica-alumina molecular sieve in this embodiment, 27 analysis of the Al MAS NMR results showed that the aluminum was basicIn the form of tetra-coordinated framework aluminum.
According to the embodiment, the silica-alumina molecular sieve in this embodiment has a particle diameter of a single crystal of 200nm to 1000nm, preferably 250nm to 800nm, as observed by a transmission electron microscope.
According to the embodiment, the mesoporous pore volume of the silicon-aluminum molecular sieve in the embodiment accounts for more than 25% of the total pore volume, and can be 25% -50% or 30% -40%.
According to the described embodiments, the aluminosilicate molecular sieves in this embodiment have intra-crystalline mesopores. For example, the molecular sieve can see uniformly distributed mesopores when viewed at 20000 to 500000 x magnification with a transmission electron microscope; the molecular sieve is not seen to have distributed pores when viewed under a scanning electron microscope at 20000 to 200000 times magnification.
The present invention provides a catalyst for the vapor phase production of ethylbenzene comprising a aluminosilicate molecular sieve having an X-ray diffraction pattern substantially as shown in the following table,
preferably, the aluminosilicate molecular sieve has intra-crystalline mesopores.
The catalyst for preparing ethylbenzene according to the invention consists of a binder (preferably alumina and/or silica) and a molecular sieve (preferably, the mass fraction of the molecular sieve is 15-95%, preferably 60-90% based on the mass of the catalyst).
The catalyst for ethylbenzene production according to the present invention, the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
The catalyst for ethylbenzene production according to the present invention, the X-ray diffraction pattern further comprises X-ray diffraction peaks substantially as shown in the following table,
the catalyst for preparing ethylbenzene according to the present invention has a schematic chemical composition represented by the formula "silica-alumina" or "silica-alumina-organic templating agent-water"; the molar ratio of silica to alumina may be 15 to 300, generally 20 to 120, preferably 20 to 50.
According to the catalyst for preparing ethylbenzene, the particle size of the single crystal of the silicon-aluminum molecular sieve is between 200nm and 1000nm, preferably between 250nm and 800nm, as observed by a transmission electron microscope.
According to the catalyst for preparing ethylbenzene, the mesoporous pore volume of the silicon-aluminum molecular sieve accounts for more than 25% of the total pore volume, and can be 25% -50% or 30% -40%.
The invention provides a preparation method of the catalyst, which comprises the following steps of; mixing and kneading the molecular sieve raw powder, a silicon-containing compound and/or an aluminum-containing compound, nitric acid and deionized water to form, drying, burning out a template agent in air at 450-550 ℃, exchanging in an ammonium salt aqueous solution at 80-90 ℃, and finally roasting and deaminizing at 500-600 ℃ for 1-5 hours to obtain the catalyst.
According to the preparation method of the catalyst, the silicon-containing compound is selected from one or more of silica sol, methyl orthosilicate and ethyl orthosilicate.
According to the preparation method of the catalyst, the aluminum-containing compound is selected from one or more of pseudo-boehmite, SB powder, aluminum sol and aluminum isopropoxide.
According to the preparation method of the catalyst, the ammonium salt is selected from one or more of ammonium nitrate, ammonium chloride and ammonium sulfate.
According to the preparation method of the catalyst, sesbania powder can be added, and the dosage of the sesbania powder is 2-5% based on the total weight of dry materials.
According to the preparation method of the catalyst, the usage amount of nitric acid is 2-8% based on the total weight of dry materials.
According to the preparation method of the catalyst, the silicon-aluminum molecular sieve is prepared by the following steps:
(1) Providing an initial gel mixture comprising a silicon source, an aluminum source, a first templating agent, water, and an alkali source; the silicon source is SiO 2 The aluminum source is calculated as Al 2 O 3 The molar ratio of the silicon source, the aluminum source, the template agent, the water and the hydroxide of the alkali metal in the initial gel mixture is 1:0-0.02:0.1-0.5:5-25:0-0.5;
(2) Crystallizing the initial gel mixture in step (1);
(3) After crystallization, the following four intermediate products are obtained: (a) a molecular sieve slurry; (b) filtering, washing and drying the molecular sieve raw powder; (c) Ammonium exchange, filtering, washing and drying; (d) Ammonium exchange, filtering, washing, drying and roasting to obtain hydrogen molecular sieve;
(4) Mixing the intermediate product in the step (3) with an aluminum source, an alkali source and a second template agent, wherein the molar ratio of the silicon source to the aluminum source to the template agent to the water to the alkali metal hydroxide is 1:0.02-0.04:0.1-0.5:5-25:0-0.2;
(5) Crystallizing the mixture obtained in the step (4), and performing post-treatment to obtain the silicon-aluminum molecular sieve.
According to the method for preparing the catalyst of the present invention, in the method for preparing the silicon-aluminum molecular sieve, the first template agent and the second template agent are each independently selected from the compounds represented by the following formula (I),
the radicals R1 and R2 are identical or different from one another and are each independently selected from C3-12 linear or branched alkylene, preferably from C3-12 linear alkylene, particularly preferably one from C3-12 linear alkylene and the other from C4-6 linear alkylene; the plurality of radicals R, equal to or different from each other, are each independently selected from C1-4 linear or branched alkyl radicals, preferably each independently selected from methyl and ethyl radicals, more preferably each methyl radical; x is OH.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, in the step (1), the molar ratio of the silicon source to the aluminum source to the template agent to the water to the alkali metal hydroxide is preferably 1:0.00142-0.016:0.1-0.25:6.5-20:0-0.4.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, in the step (4), the molar ratio of the silicon source to the aluminum source to the template agent to the water to the alkali metal hydroxide is preferably 1:0.02-0.04:0.1-0.15:6.5-20:0-0.15.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, the crystallization conditions in the step (2) are as follows: the crystallization temperature can be 80-200 ℃, and the crystallization time can be 1-8 days; preferably, it is: crystallizing at 100-140 deg.c for 0-2 days, and crystallizing at 140-170 deg.c for 3-7 days; more preferably: crystallizing at 110-120 deg.c for 0.5-1 day and then crystallizing at 140-160 deg.c for 4-6 days.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, the crystallization conditions in the step (5) are as follows: crystallizing at 120 deg.c for 0-2 days, and crystallizing at 150 deg.c for 3-7 days; preferably, it is: crystallizing at 120 deg.c for 0.5-1 day and then crystallizing at 150 deg.c for 4-6 days.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, if the temperature needs to be raised, the temperature raising mode and the speed in any step are not particularly limited. In any step of the preparation method, a temperature programming mode can be adopted, and each step independently adopts a temperature rising rate of 0.5-5 ℃/min.
According to the preparation method of the catalyst, the pressure of any crystallization process is not particularly limited in the preparation method of the silicon-aluminum molecular sieve. Any crystallization process of the invention can be the autogenous pressure of a crystallization system.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, the crystallization process is carried out in a closed environment, and the reaction vessel for crystallization can be a stainless steel reaction kettle with a polytetrafluoroethylene lining. The dynamic crystallization can be performed in a rotary oven provided with a crystallization kettle.
According to the process for the preparation of the catalyst of the invention, the product of the invention can be obtained in step (5) by any post-treatment means conventionally known, such as filtration, washing and drying of the crystallized mixture, and optionally calcination. The filtration, washing and drying may be performed in any manner conventionally known in the art. As a specific example, as the filtration, for example, the obtained reaction mixture may be simply suction-filtered. The washing may be performed, for example, by washing with deionized water until the pH of the filtrate reaches 7 to 9, preferably 8 to 9. The drying temperature may be, for example, 40 to 250 ℃, preferably 90 to 120 ℃, and the drying time may be, for example, 4 to 30 hours, preferably 6 to 14 hours. The drying may be performed under normal pressure or under reduced pressure. If necessary, a calcination step (hereinafter referred to as a calcination step) may be further included to remove the organic template agent and moisture or the like which may be present, thereby obtaining a calcined molecular sieve. In the context of this specification, the molecular sieve before or after calcination, the molecular sieve with or without ammonium exchange, and the four combinations between them, are collectively referred to as the molecular sieve of the present invention or the molecular sieve according to the present invention. The calcination may be carried out in any manner conventionally known in the art, such as a calcination temperature generally ranging from 300 ℃ to 750 ℃, preferably from 400 ℃ to 700 ℃, and a calcination time generally ranging from 1 hour to 10 hours, preferably from 3 hours to 6 hours. In addition, the calcination is typically performed under an oxygen-containing atmosphere, such as air or an oxygen atmosphere.
In the method for producing the catalyst according to the present invention, there is no particular limitation on the silicon source, and any conventionally known silicon source for producing a molecular sieve may be used in the present invention. For example, the silicon source can be one or more selected from silica sol, solid silica gel, tetraethoxysilane, white carbon black and water glass.
According to the method for preparing the catalyst of the present invention, there is no particular limitation on the aluminum source, and any conventionally known aluminum source for preparing a molecular sieve may be used in the present invention. For example, the aluminum sources in the step (1) and the step (4) may be the same or different, and may be one or more selected from aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum hydroxide, sodium metaaluminate and aluminum sol.
According to the preparation method of the catalyst, in the preparation method of the silicon-aluminum molecular sieve, the alkali sources in the step (1) and the step (4) can be the same or different, and each alkali source is independently selected from one or more of sodium hydroxide and potassium hydroxide.
Reagents, instruments and tests
Unless otherwise specified, all reagents used in the present invention are analytically pure and commercially available.
The analysis and test in the invention are all carried out by the following instruments and methods.
In the following examples, X-ray powder diffraction phase analysis (XRD) employed an Empyrean diffractometer of the family pananaceae, netherlands, equipped with a PIXcel3D detector. Test conditions: cu target, K alpha radiation, ni filter, tube voltage 40kV, tube current 40mA and scanning range 5-50 degrees.
In the following examples, scanning electron microscope topography analysis (SEM) was performed using a japanese scanning electron microscope type S4800. Test conditions: after the sample is dried and ground, it is stuck on the conductive adhesive. The accelerating voltage of the analysis electron microscope is 5.0kV, and the magnification is 20-200000 times.
In the following examples, a transmission electron microscope scanning method (TEM) was carried out using a TECNAIG2F20 (200 kv) type transmission electron microscope from FEI company, a suspension method was used, 0.01g of a sample was put into a 2mL glass bottle, absolute ethanol was added to disperse the sample, after shaking uniformly, a drop of liquid was taken with a dropper, dropped onto a sample net having a diameter of 3mm, after drying the liquid, the sample was put into a sample injector, and then was observed by an electron microscope.
In the following examples, nuclear magnetic resonance spectroscopy was used in the United states of America Varian UNITY INOVA MHz. TestingConditions are as follows: adopts a solid double-resonance probe, and the diameter of the solid double-resonance probe is 4mm ZrO 2 A rotor. Experimental parameters: the test temperature is room temperature, the scanning times nt=5000, the pulse width pw=3.9 μs, the spectral width sw=31300 Hz, the resonance frequency sfrq= 125.64MHz of the observed nuclei, the sampling time at=0.5 s, the chemical shift scaling δtms=0, the delay time d1=4.0 s, the decoupling mode dm= nny (reverse gating decoupling), and the deuterated chloroform locking.
In the following examples, an X-ray fluorescence spectrometer of Nippon electric machine Co.Ltd 3013 was used as the bulk composition. Test conditions: tungsten target, excitation voltage 40kV and excitation current 50mA. The experimental process comprises the following steps: after the catalyst sample is pressed into tablets, the tablets are arranged on an X-ray fluorescence spectrometer, and fluorescent light is emitted under the irradiation of X rays, and the following relationship exists between the fluorescent wavelength lambda and the atomic number Z of the element: λ=k (Z-S) -2,K is a constant, and this element can be determined by measuring the wavelength λ of fluorescence. And measuring the intensity of each element characteristic spectral line by using a scintillation counter and a proportional counter, and carrying out element quantitative or semi-quantitative analysis.
In the following examples, the total specific surface area and pore volume of the molecular sieves were measured according to the following analytical methods.
The device comprises: micromeritic ASAP2010 static nitrogen adsorption instrument
Measurement conditions: placing the sample in a sample processing system, and vacuumizing to 1.33X10 at 350deg.C -2 Pa, maintaining the temperature and the pressure for 15h, and purifying the sample. Measuring the P/P of the purified sample at different specific pressures at the temperature of liquid nitrogen of-196 DEG C 0 And (3) obtaining an adsorption-desorption isothermal curve for the adsorption quantity and the desorption quantity of the nitrogen under the condition. Then calculating the total specific surface area by using a two-parameter BET formula, and taking the specific pressure P/P 0 The adsorption amount of about 0.98 or less is the pore volume of the sample.
By NH 3 The temperature programmed desorption analysis measures the total acid content of the sample. The analytical instrument was a Micro-meric Autochem II 2920. Weighing 0.215g of 20-40 mesh sample, filling the sample into a sample tube, placing the sample tube into a heating furnace of a thermal conductivity cell, using helium gas as carrier gas (20 mL/min), heating to 600 ℃ at a heating rate of 20 ℃/min, and keeping for 60min to remove impurities adsorbed on the surface of the sample. Then cooling to 100deg.C, maintaining for 10min, and switching to ammonia-helium gas mixture (10.02% ammonia +89.98% helium) for 30min, then switched to helium, and purged continuously for 90min to baseline plateau to desorb the physically adsorbed ammonia from the sample. Heating to 600 ℃ at a heating rate of 10 ℃/min, and keeping for 30min, so that the desorption of the sample is finished. Detecting the change of the gas component in the sample tube by using a TCD detector to obtain NH 3 And (5) an adsorption and desorption curve, and automatically integrating to obtain the total acid quantity.
In the following examples, the reaction was carried out in a continuous flow fixed bed stainless steel tube reactor having an inner diameter of 12mm, a catalyst loading of 2g, and N 2 The catalyst bed is activated for 2 hours after being heated to 400 ℃ under the atmosphere, and then is treated by N 2 The atmosphere is reduced to the required reaction temperature, and the reaction of synthesizing ethylbenzene by the gas phase of the ethylene-containing gas and benzene is carried out. The reaction products were analyzed on-line for composition using an Agilent7890A chromatograph, an HP-Innovax column, and a hydrogen ion flame detector.
Ethylene conversion and ethylbenzene selectivity were calculated from the following formulas:
ethylene conversion xe= (mass fraction of ethylene feed-mass fraction of unreacted ethylene)/mass fraction of ethylene feed x 100%;
ethylation selectivity sebs= (ethylbenzene + diethylbenzene) mass fraction/(mass fraction of 1-benzene-mass fraction of ethylene) ×100%
Ethylbenzene selectivity seb=mass fraction of ethylbenzene/(mass fraction of 1-benzene-mass fraction of ethylene) ×100%
In an embodiment, the templating agent R1 is a 1, 8-tetramethyl-1, 8-diazaseventeen-membered ring-1, 8-diquaternary ammonium base.
In an embodiment, the templating agent R2 is 1, 6-tetramethyl-1, 6-diazadecabicyclo-1, 6-diquaternary ammonium base.
In an embodiment, the templating agent R3 is 1, 6-tetramethyl-1, 6-diazadeca-ring-1, 6-diquaternary ammonium base.
Example 1
This example illustrates the preparation of intermediate A.
Uniformly mixing a template agent R1, crude silica gel, aluminum nitrate, sodium hydroxide and deionized water to obtain an initial gel mixture, wherein the molar ratio of reactants is SiO 2 ：Al 2 O 3 ：R:H 2 O naoh=1:0.015:0.15:9.82:0.1. The above mixture was put into 45mL steel autoclave with polytetrafluoroethylene liner, capped and sealed, the autoclave was placed in a rotary oven at 20rpm, reacted at 120℃for 1 day, and then heated to 150℃for 4 days. And taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain an intermediate product A.
Example 2
This example illustrates the preparation of intermediate B.
Uniformly mixing a template agent R2, crude silica gel, sodium metaaluminate, sodium hydroxide and deionized water to obtain a gel mixture, wherein the molar ratio of reactants is SiO 2 ：Al 2 O 3 ：R:H 2 O naoh=1:0.011:0.15:9.82:0.1. The above mixture was put into 45mL steel autoclave with polytetrafluoroethylene liner, capped and sealed, the autoclave was placed in a rotary oven at 40rpm, reacted at 120℃for 1 day, and then heated to 150℃for 5 days. And taking out the autoclave after cooling, washing with deionized water, filtering, and drying at 120 ℃ for 12 hours after ammonium exchange to obtain an intermediate product B.
Example 3
This example illustrates the preparation of the molecular sieves of the present invention.
Uniformly mixing a template agent R2, an intermediate product A, sodium metaaluminate, sodium hydroxide and deionized water to obtain a gel mixture, wherein the molar ratio of reactants is as follows: siO (SiO) 2 ：Al 2 O 3 ：R:H 2 O naoh=1:0.033:0.1:10:0.15 the above mixture was put into 45mL steel autoclave lined with polytetrafluoroethylene and capped and sealed, the autoclave was placed in a rotary oven at 30rpm, reacted at 120 ℃ for 1 day, and then heated to 160 ℃ for 5 days. Taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain molecular sieve raw powder.
And carrying out X-ray diffraction analysis on the obtained molecular sieve raw powder, wherein an XRD spectrum is shown in figure 1.XRF results indicated a sample silicon to aluminum ratio of 28.4. 27 The Al MAS-NMR spectrum is shown in FIG. 2, and the characteristic peak at 50ppm is attributed toFour-coordination framework aluminum, and aluminum in the molecular sieve mainly exists in the form of four-coordination framework aluminum. Performing ammonium exchange, drying and roasting on molecular sieve raw powder to obtain a hydrogen type molecular sieve, wherein the total specific surface area of the molecular sieve is 565.6m by adopting BET analysis 2 /g, wherein the micropore area is 519.3m 2 Per g, mesoporous area of 46.3m 2 /g; the total pore volume is 0.36ml/g, the micropore volume is 0.24ml/g, and the mesopore volume is 0.12ml/g. NH treatment of molecular sieves with hydrogen 3 TPD analysis was characterized, as shown in FIG. 15, by an acid amount substantially higher than that of the sample obtained in example 8. The morphology of the molecular sieve is observed by adopting SEM, a scanning electron microscope image is shown in figure 3, the molecular sieve is in a disc shape, the grain size is about 400 nm-600 nm, and no pore distribution is found on the surface of the crystal. The molecular sieve is observed by TEM, and a transmission electron microscope image is shown in fig. 4, which shows that the molecular sieve crystal has a uniformly distributed mesoporous structure.
90g of the molecular sieve raw powder obtained in the example is mixed with 11g of alumina, added with 2.1g of sesbania powder, 5.2g of nitric acid and 5.2g of deionized water, kneaded, extruded and molded, and dried at 120 ℃ for 4 hours. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-A is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature is 320 ℃, the reaction pressure is 0.7MPa, the benzene/ethylene mole ratio is 5.0, and the ethylene weight space velocity (WHSV) =0.8 h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
Example 4
This example illustrates the preparation of the molecular sieves of the present invention.
Uniformly mixing a template agent R2, an intermediate product B, sodium metaaluminate, sodium hydroxide and deionized water to obtain a gel mixture, wherein the molar ratio of reactants is as follows: siO (SiO) 2 ：Al 2 O 3 ：R:H 2 O naoh=1:0.033:0.12:6.5:0.12, the above mixture was charged into a 45mL steel autoclave lined with polytetrafluoroethylene, capped and sealed, and the autoclave was placed inThe reaction was carried out in a rotary oven at a speed of 40rpm at 120℃for 1 day and at a temperature of 150℃for 6 days. Taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain molecular sieve raw powder.
And carrying out X-ray diffraction analysis on the obtained molecular sieve raw powder, wherein an XRD spectrum is shown in figure 5.XRF results indicated a sample silicon to aluminum ratio of 32.1. 27 The Al MAS-NMR spectrum is shown in FIG. 6, the characteristic peak at 50ppm is attributed to four-coordinate framework aluminum, and the aluminum in the molecular sieve exists mainly in the form of four-coordinate framework aluminum. Performing ammonium exchange, drying and roasting on molecular sieve raw powder to obtain a hydrogen type molecular sieve, wherein the total specific surface area of the molecular sieve is 568.9m by adopting BET analysis 2 /g, wherein the micropore area is 527m 2 /g, mesoporous area of 41.9m 2 /g; the total pore volume is 0.35ml/g, the micropore volume is 0.244, and the mesopore volume is 0.106ml/g. The morphology of the molecular sieve is observed by adopting SEM, a scanning electron microscope image is shown in figure 7, the molecular sieve is in a disc shape, and the grain size is about 400 nm-600 nm. The molecular sieve is observed by TEM, and a transmission electron microscope image is shown in fig. 8, which shows that the molecular sieve crystal has a uniformly distributed mesoporous structure.
80g of the molecular sieve raw powder obtained in the example is mixed with 20g of alumina, 3.1g of sesbania powder, 8.2g of nitric acid and 10g of deionized water are added, and then the mixture is kneaded, extruded and molded, and dried for 4 hours at 120 ℃. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-B is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature was 360 ℃, the reaction pressure was 0.8MPa, the benzene/ethylene molar ratio was 5.0, and the ethylene weight space velocity (WHSV) =1h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
Example 5
This example illustrates the preparation of the molecular sieves of the present invention.
Uniformly mixing a template agent R3, an intermediate product A, sodium metaaluminate, sodium hydroxide and deionized water to obtain a gel mixture,the molar ratio of the reactants is as follows: siO (SiO) 2 ：Al 2 O 3 ：R:H 2 O naoh=1:0.04:0.15:20:0.12, the above mixture was put into 45mL steel autoclave lined with polytetrafluoroethylene and capped and sealed, the autoclave was placed in a rotary oven at 20rpm, reacted at 120 ℃ for 0.5 days, and then heated to 150 ℃ for 5 days. Taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain molecular sieve raw powder.
And carrying out X-ray diffraction analysis on the obtained molecular sieve raw powder, wherein an XRD spectrum is shown in figure 9. 27 The Al MAS-NMR spectrum is shown in FIG. 10, the characteristic peak at 50ppm is attributed to four-coordinate framework aluminum, and the aluminum in the molecular sieve exists mainly in the form of four-coordinate framework aluminum. XRF results indicated a sample silicon to aluminum ratio of 23.4. The morphology of the molecular sieve is observed by adopting SEM, and a scanning electron microscope image is shown in figure 11, which shows that the molecular sieve is in a disc shape, and the grain size is about 550nm. The molecular sieve is observed by TEM, and a transmission electron microscope image is shown in fig. 12, which shows that the molecular sieve crystal has a uniformly distributed mesoporous structure.
65g of the molecular sieve raw powder obtained in the example is mixed with 35g of alumina, 5.3g of sesbania powder, 6.3g of nitric acid and 7g of deionized water are added, and then the mixture is kneaded, extruded and molded, and dried for 4 hours at 120 ℃. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-C is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature was 400 ℃, the reaction pressure was 0.7MPa, the benzene/ethylene molar ratio was 7.0, and the ethylene weight space velocity (WHSV) =4h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
Example 6
This example illustrates the preparation of the molecular sieves of the present invention.
Uniformly mixing a template agent R3, an intermediate product B, sodium metaaluminate, sodium hydroxide and deionized water to obtain a gel mixture, wherein the molar ratio of reactants is as follows: siO (SiO) 2 ：Al 2 O 3 ：R:H 2 O naoh=1:0.029:0.15:10:0.15, the above mixture was put into 45mL steel autoclave lined with polytetrafluoroethylene and capped and sealed, the autoclave was placed in a rotary oven at 40rpm, reacted at 120 ℃ for 1 day, and then heated to 150 ℃ for 5 days. Taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain molecular sieve raw powder.
XRF results indicated a sample silicon to aluminum ratio of 26.75. The molecular sieve is observed by adopting a TEM, a transmission electron microscope image is shown in fig. 13, the molecular sieve is in a disc shape, and the molecular sieve crystal has a uniformly distributed mesoporous structure.
90g of the molecular sieve raw powder obtained in the example is mixed with 11g of alumina, added with 2.1g of sesbania powder, 2.06g of nitric acid and 2.06g of deionized water, kneaded, extruded and molded, and dried for 4 hours at 120 ℃. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-D is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature was 360 ℃, the reaction pressure was 0.9MPa, the benzene/ethylene molar ratio was 7.0, and the ethylene weight space velocity (WHSV) =2h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
Example 7
This example illustrates the preparation of the molecular sieves of the present invention.
Uniformly mixing a template agent R3, an intermediate product A, sodium metaaluminate and deionized water to obtain a gel mixture, wherein the molar ratio of reactants is as follows: siO (SiO) 2 ：Al 2 O 3 ：R:H 2 O=1:0.033:0.1:10, the above mixture was put into 45mL of a steel autoclave lined with polytetrafluoroethylene, capped and sealed, the autoclave was placed in a rotary oven at 20rpm, reacted at 120 ℃ for 1 day, and then heated to 150 ℃ for 5 days. Taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain molecular sieve raw powder.
XRF results indicated a sample silicon to aluminum ratio of 35.1. The molecular sieve is observed by adopting a TEM, and a transmission electron microscope image is shown in fig. 14, which shows that the molecular sieve is in a disc shape, and mesoporous structures which are uniformly distributed in a molecular sieve crystal are formed.
80g of the molecular sieve raw powder obtained in the example is mixed with 20g of alumina, 3.1g of sesbania powder, 5.2g of nitric acid and 5.2g of deionized water are added, and then the mixture is kneaded, extruded and molded, and dried for 4 hours at 120 ℃. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-E is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature was 380 ℃, the reaction pressure was 0.7MPa, the benzene/ethylene molar ratio was 6.0, and the ethylene weight space velocity (WHSV) =1h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
Example 8
Uniformly mixing a template agent R2, crude silica gel, sodium metaaluminate, sodium hydroxide and deionized water to obtain a gel mixture, wherein the molar ratio of reactants is SiO 2 ：Al 2 O 3 ：R:H 2 O=1:0.011:0.15:9.82:0.1. The above mixture was put into 45mL steel autoclave with polytetrafluoroethylene liner, capped and sealed, the autoclave was placed in a rotary oven at 40rpm, reacted at 120℃for 1 day, and then heated to 150℃for 5 days. Taking out the autoclave after cooling, washing and filtering the autoclave by deionized water, and drying the autoclave at 120 ℃ for 12 hours to obtain molecular sieve raw powder.
XRF results indicated a sample silicon to aluminum ratio of 92. Performing ammonium exchange, drying and roasting on molecular sieve raw powder to obtain a hydrogen type molecular sieve, wherein the total specific surface area of the molecular sieve is 578.8m by adopting BET analysis 2 /g, wherein the micropore area is 556.4m 2 /g, mesoporous area of 22.4m 2 /g; the total pore volume is 0.294ml/g, the micropore volume is 0.256, and the mesopore volume is 0.038ml/g. NH treatment of molecular sieves with hydrogen 3 TPD analysis was characterized, as shown in FIG. 15, by an acid amount substantially lower than that of the sample obtained in example 1. TEM is adopted to observe the molecular sieve, and electricity is projectedThe mirror image is shown in fig. 16, which shows that the molecular sieve crystals have no mesopores inside.
80g of the molecular sieve raw powder obtained in the example is mixed with 20g of alumina, 3.1g of sesbania powder, 8.2g of nitric acid and 10g of deionized water are added, and then the mixture is kneaded, extruded and molded, and dried for 4 hours at 120 ℃. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-F is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature was 360 ℃, the reaction pressure was 0.8MPa, the benzene/ethylene molar ratio was 5.0, and the ethylene weight space velocity (WHSV) =1h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
Comparative example 1
This comparative example illustrates the preparation of a catalyst having a ZSM-5 molecular sieve as the active component.
Taking Si/Al 2 O 3 80g of Na-ZSM-5 molecular sieve (commercially available from medium petrochemical long-term catalyst factory) with a molar ratio of 25 is mixed with 20g of alumina, 3.1g of sesbania powder, 8.2g of nitric acid and 10g of deionized water are added, and then the mixture is kneaded, extruded and molded, and dried at 120 ℃ for 4 hours. The sample is baked at 550 ℃, then exchanged with 0.5mol/L ammonium nitrate solution at 80 ℃ for 2 times, each time for 2 hours, washed with water, dried at 90 ℃ for 12 hours and baked at 550 ℃ for 3 hours, and the catalyst Cat-X1 is prepared.
On a continuous flow pressurized fixed bed reaction unit, the reaction conditions: the reaction temperature was 360 ℃, the reaction pressure was 0.8MPa, the benzene/ethylene molar ratio was 5.0, and the ethylene weight space velocity (WHSV) =1h -1 . After the reaction was stabilized, the reaction raw materials and the products were analyzed by on-line chromatography, and the reaction results are shown in table 1.
TABLE 1
As can be seen from the data in Table 1, the method for synthesizing ethylbenzene from the ethylene-containing gas provided by the invention has high ethylene conversion rate, and the obtained ethylation products such as ethylbenzene have high selectivity and few xylene impurities.

Claims (12)

1. A method for preparing ethylbenzene by a gas phase process, comprising: contacting ethylene with benzene in the presence of a catalyst and under vapor phase alkylation reaction conditions; the catalyst comprises a aluminosilicate molecular sieve having an X-ray diffraction pattern substantially as shown in the following table,
；
the silicon aluminum molecular sieve has a schematic chemical composition represented by the formula of silicon oxide-aluminum oxide or silicon oxide-aluminum oxide-organic template agent-water; the molar ratio of the silicon oxide to the aluminum oxide is 20-50; the silicon-aluminum molecular sieve is provided with intragranular mesopores, and the mesopore volume accounts for more than 25% of the total pore volume of the silicon-aluminum molecular sieve; the silicon-aluminum molecular sieve is prepared by the following method:
(1) Providing an initial gel mixture comprising a silicon source, an aluminum source, a first templating agent, water, and an alkali source; the silicon source is SiO 2 The aluminum source is calculated as Al 2 O 3 The molar ratio of the silicon source, the aluminum source, the template agent, the water and the hydroxide of the alkali metal in the initial gel mixture is 1:0-0.02:0.1-0.5:5-25:0-0.5;
(2) Crystallizing the initial gel mixture in step (1);
(3) After crystallization, the following four intermediate products are obtained: (a) a molecular sieve slurry; (b) filtering, washing and drying the molecular sieve raw powder; (c) Ammonium exchange, filtering, washing and drying; (d) Ammonium exchange, filtering, washing, drying and roasting to obtain hydrogen molecular sieve;
(4) Mixing the intermediate product in the step (3) with an aluminum source, an alkali source and a second template agent, wherein the molar ratio of the silicon source to the aluminum source to the template agent to the water to the alkali metal hydroxide is 1:0.02-0.04:0.1-0.5:5-25:0-0.2;
(5) Crystallizing the mixture obtained in the step (4), and performing post-treatment to obtain the silicon-aluminum molecular sieve;
in the preparation method of the silicon-aluminum molecular sieve, the first template agent and the second template agent are respectively and independently selected from compounds represented by the following formula (I),
The radicals R1 and R2, equal to or different from each other, are each independently selected from C3-12 linear or branched alkylene; the groups R are the same or different from each other and are each independently selected from C1-4 linear or branched alkyl; x is OH.
2. The method for producing ethylbenzene by the vapor phase process according to claim 1, wherein the silicon-aluminum molecular sieve is produced in such a manner that the groups R1 and R2 are the same or different from each other, one is selected from the group consisting of C3-12 linear alkylene groups and the other is selected from the group consisting of C4-6 linear alkylene groups; the plurality of groups R are the same or different from each other and are each independently selected from methyl and ethyl.
3. The method for producing ethylbenzene by the vapor phase method according to claim 1, wherein the ethylene raw material used is one or more of pure ethylene, ethylene-containing refinery catalytic cracking dry gas and ethylene-containing refinery catalytic cracking dry gas.
4. A process for the vapor phase production of ethylbenzene as claimed in claim 3, wherein the ethylene volume fraction in the ethylene-containing refinery catalytic cracking dry gas is 10% to 60%; in the ethylene-containing refinery catalytic cracking dry gas, the volume fraction of ethylene is 10% -60%.
5. The method for preparing ethylbenzene by gas phase method according to claim 1, wherein the gas phase alkylation reaction conditions are: the reaction temperature is 285-420 ℃, the reaction pressure is 0.6-1.0 MPa, and the molar ratio of benzene to ethylene is 4:1 to 8:1, ethylene weight space velocity of 0.5h -1 ～5.0h -1 。
6. The method for preparing ethylbenzene by gas phase process according to claim 1, wherein the catalyst consists of a binder and the silicon-aluminum molecular sieve.
7. The method for preparing ethylbenzene by gas phase process according to claim 1, wherein the particle size of the single crystals of the silicon-aluminum molecular sieve is 200nm to 1000nm.
8. A catalyst for vapor phase ethylbenzene manufacture comprising a aluminosilicate molecular sieve having an X-ray diffraction pattern substantially as shown in the following table,
；
the silicon aluminum molecular sieve has a schematic chemical composition represented by the formula of silicon oxide-aluminum oxide or silicon oxide-aluminum oxide-organic template agent-water; the molar ratio of the silicon oxide to the aluminum oxide is 20-50; the silicon-aluminum molecular sieve is provided with intragranular mesopores, and the mesopore volume accounts for more than 25% of the total pore volume of the silicon-aluminum molecular sieve; the silicon-aluminum molecular sieve is prepared by the following method:
(1) Providing an initial gel mixture comprising a silicon source, an aluminum source, a first templating agent, water, and an alkali source; the silicon source is SiO 2 The aluminum source is calculated as Al 2 O 3 The molar ratio of the silicon source, the aluminum source, the template agent, the water and the hydroxide of the alkali metal in the initial gel mixture is 1:0-0.02:0.1-0.5:5-25:0-0.5;
(2) Crystallizing the initial gel mixture in step (1);
(3) After crystallization, the following four intermediate products are obtained: (a) a molecular sieve slurry; (b) filtering, washing and drying the molecular sieve raw powder; (c) Ammonium exchange, filtering, washing and drying; (d) Ammonium exchange, filtering, washing, drying and roasting to obtain hydrogen molecular sieve;
(4) Mixing the intermediate product in the step (3) with an aluminum source, an alkali source and a second template agent, wherein the molar ratio of the silicon source to the aluminum source to the template agent to the water to the alkali metal hydroxide is 1:0.02-0.04:0.1-0.5:5-25:0-0.2;
(5) Crystallizing the mixture obtained in the step (4), and performing post-treatment to obtain the silicon-aluminum molecular sieve;
in the preparation method of the silicon-aluminum molecular sieve, the first template agent and the second template agent are respectively and independently selected from compounds represented by the following formula (I),
the radicals R1 and R2, equal to or different from each other, are each independently selected from C3-12 linear or branched alkylene; the groups R are the same or different from each other and are each independently selected from C1-4 linear or branched alkyl; x is OH.
9. The catalyst according to claim 8, wherein the silicon-aluminum molecular sieve is prepared by a process wherein the groups R1 and R2 are the same or different from each other, one is selected from the group consisting of C3-12 linear alkylene groups and the other is selected from the group consisting of C4-6 linear alkylene groups; the plurality of groups R are the same or different from each other and are each independently selected from methyl and ethyl.
10. The catalyst according to claim 8, wherein the catalyst consists of a binder and the aluminosilicate molecular sieve, and the molecular sieve is 15-95% by mass based on the mass of the catalyst.
11. The catalyst according to claim 10, wherein the catalyst consists of a binder and the aluminosilicate molecular sieve, and the molecular sieve is 60-90% by mass based on the mass of the catalyst.
12. A method of preparing the catalyst of claim 8, comprising; mixing and kneading the molecular sieve raw powder, a silicon-containing compound and/or an aluminum-containing compound, nitric acid and deionized water to form, drying, burning out a template agent in air at 450-550 ℃, exchanging in an ammonium salt aqueous solution at 80-90 ℃, and finally roasting and deaminizing at 500-600 ℃ for 1-5 hours to obtain the catalyst.
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CN108238610A (en) * 2016-12-23 2018-07-03 中国石油化工股份有限公司 A kind of molecular sieve, its manufacturing method and its application
CN109384637A (en) * 2017-08-04 2019-02-26 中国石油化工股份有限公司 The method of benzene and preparing ethylbenzene by liquid phase alkylation of ethylene

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Publication number Priority date Publication date Assignee Title
CN1169338A (en) * 1996-06-24 1998-01-07 中国石油化工总公司 Alkyl catalyst and application thereof
CN108238610A (en) * 2016-12-23 2018-07-03 中国石油化工股份有限公司 A kind of molecular sieve, its manufacturing method and its application
CN107159306A (en) * 2017-05-18 2017-09-15 中国科学院大连化学物理研究所 A kind of preparation method of dense ethene and benzene liquid-phase alkylation FAU/MWW molecular sieve catalysts
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