CN116037099A - Composite catalyst, preparation method thereof and method for preparing olefin by alcohol dehydration - Google Patents

Composite catalyst, preparation method thereof and method for preparing olefin by alcohol dehydration Download PDF

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CN116037099A
CN116037099A CN202111262363.9A CN202111262363A CN116037099A CN 116037099 A CN116037099 A CN 116037099A CN 202111262363 A CN202111262363 A CN 202111262363A CN 116037099 A CN116037099 A CN 116037099A
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oxide
nitrate
composite catalyst
alkaline earth
catalyst
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张筱榕
田保亮
唐国旗
宋超
彭晖
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/24—Chromium, molybdenum or tungsten
    • B01J23/26—Chromium
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of zinc, cadmium or mercury
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/613—10-100 m2/g
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/64—Pore diameter
    • B01J35/643—Pore diameter less than 2 nm
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/64—Pore diameter
    • B01J35/647—2-50 nm
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
    • C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
    • C07C1/24—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms by elimination of water
    • 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
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
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    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of zinc, cadmium or mercury
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • C07C2523/24—Chromium, molybdenum or tungsten
    • C07C2523/26—Chromium
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
    • C07C2523/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36
    • C07C2523/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36 with alkali- or alkaline earth metals or beryllium
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    • 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 relates to the technical field of alcohol dehydration, in particular to a composite catalyst and a preparation method thereof as well as a method for preparing olefin by alcohol dehydration, wherein the composite catalyst comprises a main component ZrO 2 Alkaline earth metal oxides and transition metal oxides;wherein, in the composite catalyst, the pore volume with the pore diameter within the range of 1.7-2.6nm accounts for more than 60% of the total pore volume of the composite catalyst; relative to 100 parts by weight of ZrO as main component 2 0.05-8 parts by weight of alkaline earth metal oxide; the transition metal oxide is 0.08-10 parts by weight. The invention is implemented by using ZrO 2 The alkaline earth metal oxide and the transition metal oxide are introduced into the base catalyst, so that the ZrO can be improved 2 The basic catalyst forms unbalanced charge sites on the surface of the composite oxide at the same time of alkalinity, thereby forming new catalyst surface acid centers, being beneficial to improving the catalytic performance of the composite catalyst and improving the selectivity of alpha-olefin in alcohol dehydration reaction.

Description

Composite catalyst, preparation method thereof and method for preparing olefin by alcohol dehydration
Technical Field
The invention relates to the technical field of alcohol dehydration, in particular to a composite catalyst, a preparation method thereof and a method for preparing olefin by alcohol dehydration.
Background
The alcohol dehydration method for preparing the alpha-olefin has the advantages of simple process route, mild reaction condition, high product purity, easy separation, cleaner production process and low energy consumption in the rectification process, and is a synthesis route with competitive advantage. Alcohol dehydration catalysts can be divided into two types, namely oxidation-reduction catalysts, wherein the surfaces of the catalysts are provided with metal ions with oxidation-reduction performance, active free radical intermediates are generated in the adsorption and activation process, so that side reactions are more, the selectivity of target products is lower, and the products are difficult to separate. The other type is an acid-base bifunctional catalyst, and the surface of the acid-base bifunctional catalyst has an acid site and an alkaline site, and has a synergistic catalytic effect with reactants, so that the acid-base bifunctional catalyst has better activity, selectivity and longer service life, and has unique catalytic performance in dehydration reaction. The solid oxide acid-base bifunctional catalyst has wide application in the reactions of catalyzing alcohol dehydration, catalytic hydrogenation, olefin isomerization, olefin hydrogenation, polymerization, oxidation and the like.
CN 108126704 A discloses a cerium-iron-zirconium composite oxide catalyst, a preparation method and application thereof. The cerium-iron-zirconium composite oxide catalyst is a solid solution catalyst composed of cerium oxide, iron oxide and zirconium oxide, wherein the molar ratio of various metals is as follows: ce: fe: zr=1-30:30-70:30-70%. The invention describes that the cerium-iron-zirconium composite oxide can be used as the catalyst for CO 2 And CH (CH) 3 Direct synthesis of dimethyl carbonate by OH; however, in the reaction of preparing dimethyl carbonate by using methanol as a catalyst, the conversion rate of the methanol is only 0.12-2.88%.
US20210039077A1 discloses a bimetallic doped mesoporous silicate catalyst and alcohol dehydration applications. The silicate is doped with a first transition metal M and a second transition metal M ', wherein M and M ' are selected from Zr, nb and W, such that M and M ' replace Si atoms. The pore diameter of the catalyst is in the range of 7nm to 10 nm. The alcohol dehydration reaction in the invention adopts mild conditions (low temperature and normal pressure), and the bimetallic silicate catalyst is environment-friendly (nontoxic and non-corrosive); the catalyst is used for dehydration research on ethanol, propanol, butanol, nonanol, glycerin and sugar alcohols such as sorbitol and xylitol, various dehydration products such as olefin, ether, ketone and enol are generated by the reaction, namely, the selectivity of alpha-olefin is low, and side reactions such as dehydrogenation exist in the catalytic reaction process.
In summary, the alcohol dehydration catalyst in the prior art has the defects of short service life, low product selectivity, multiple side reactions, easy carbon deposition deactivation, complex preparation method and the like, so that the catalytic activity is reduced, and the application of the catalyst in industrial production is limited.
Disclosure of Invention
The invention aims to solve the problems of short service life, low product selectivity, multiple side reactions, easy carbon deposition deactivation and complex preparation method of the alcohol dehydration catalyst in the prior art, and provides a composite catalyst and a preparation method thereof as well as a method for preparing olefin by alcohol dehydration.
In order to achieve the above object, a first aspect of the present invention provides a composite catalyst comprising a main component ZrO 2 Alkaline earth metal oxides and transition metal oxidesThe pore volume of the pore diameter in the range of 1.7-2.6nm in the composite catalyst accounts for more than 60% of the total pore volume of the composite catalyst;
relative to 100 parts by weight of ZrO as main component 2 0.05-8 parts by weight of alkaline earth metal oxide; 0.08-10 parts by weight of transition metal oxide; wherein the transition metal oxide is selected from one of VIB, VIII, IB, IIB group metal oxides.
In a second aspect, the present invention provides a method of preparing a composite catalyst, the method comprising: zirconium source, alkaline earth metal salt and transition metal salt are mixed according to the mole ratio of 1:0.0003-0.2: mixing 0.0001-0.02 in solvent to obtain mixed solution; adding a precipitant into the mixed solution for coprecipitation reaction, and then aging; roasting the aged product;
wherein the transition metal salt is selected from one of a group VIB metal salt, a group VIII metal salt, a group IB metal salt and a group IIB metal salt.
In a third aspect, the present invention provides a composite catalyst prepared according to the method of the second aspect.
In a fourth aspect, the present invention provides a process for the preparation of olefins by dehydration of alcohols, the process comprising: the dehydration reaction is carried out by contacting the alcohol with the catalyst of the first aspect or the second aspect described above in the presence or absence of a carrier gas.
Through the technical scheme, the invention is realized by the method that the method comprises the following steps of 2 The alkaline earth metal oxide and the transition metal oxide are introduced into the base catalyst, so that the ZrO can be improved 2 The basic catalyst forms unbalanced charge sites on the surface of the composite oxide at the same time of alkalinity, thereby forming new catalyst surface acid centers, being beneficial to improving the catalytic performance of the composite catalyst and improving the selectivity of alpha-olefin in alcohol dehydration reaction.
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.
As described above, the first aspect of the present invention provides a composite catalyst comprising a main component ZrO 2 Alkaline earth metal oxides and transition metal oxides; wherein, in the composite catalyst, the pore volume with the pore diameter within the range of 1.7-2.6nm accounts for more than 60% of the total pore volume of the composite catalyst;
relative to 100 parts by weight of ZrO as main component 2 0.05-8 parts by weight of alkaline earth metal oxide; 0.08-10 parts by weight of transition metal oxide;
wherein the transition metal oxide is selected from one of VIB, VIII, IB, IIB group metal oxides.
According to the present invention, preferably, the alkaline earth metal oxide is at least one selected from the group consisting of magnesium oxide, calcium oxide, strontium oxide and barium oxide; more preferably magnesium oxide and/or calcium oxide.
According to the present invention, preferably, the transition metal oxide is selected from one of chromium oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, and zinc oxide; preferably nickel oxide or copper oxide.
In the present invention, in order to further optimize the selectivity of the composite catalyst to alpha-olefins, it is preferable that the catalyst is used in a state where the catalyst is used in an amount of 100 parts by weight of ZrO 2 The alkaline earth metal oxide is 0.1 to 5 parts by weight, more preferably 0.5 to 1.4 parts by weight, and may be, for example, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1 parts by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, or any value in the range consisting of any two of the above values.
In the present invention, in order to further optimize the selectivity of the composite catalyst to alpha-olefins, it is preferable that the catalyst is used in a state where the catalyst is used in an amount of 100 parts by weight of ZrO 2 The transition metal oxide is 0.1 to 4.5 parts by weight, preferably 0.25 to 1.1 parts by weight may be, for example, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, 0.75 parts by weight, 0.8 parts by weight, 0.85 parts by weight, 0.9 parts by weight, 0.95 parts by weight, 1.0 parts by weight, 1.05 parts by weight, 1.1 parts by weight, or any value in the range of any two of the above.
According to the invention, it is further preferred that the weight ratio of the alkaline earth metal oxide to the transition metal oxide is 0.1-62.5:1, preferably 0.75-14:1.
In the present invention, the carbon dioxide adsorption amount of the composite catalyst is preferably 0.17 to 0.3 mmol.g -1 The method comprises the steps of carrying out a first treatment on the surface of the The amount of the middle strong alkaline center of the composite catalyst is 0.09-0.24 mmol.g -1 Under the above preferred conditions, the selectivity of the composite catalyst to α -olefin in the alcohol dehydration reaction can be further improved.
In the present invention, in order to further improve the catalytic performance of the composite catalyst, it is preferable that the specific surface area of the composite catalyst is 50 to 130m 2 ·g -1 The method comprises the steps of carrying out a first treatment on the surface of the Further preferably, in the composite catalyst, the pore volume with the pore diameter in the range of 1.7-2.6nm accounts for 65-90%, preferably 65-70% of the total pore volume of the composite catalyst; the pore volume with the pore diameter smaller than 1.7nm accounts for 0-6%, preferably 2-4% of the total pore volume of the composite catalyst.
The present invention is not particularly limited in the manner of compounding the main component and the alkaline earth metal oxide and the transition metal oxide, and the alkaline earth metal oxide and the rare earth metal oxide may be supported on the main component or may be dispersed in the main component; in the present invention, it is preferable to disperse in the main component, that is, the catalyst is a composite metal oxide catalyst. In the present invention, the dispersion or loading of the alkaline earth metal oxide and the transition metal oxide has little influence on the microstructure of the catalyst, and therefore, the resulting catalyst has a similar pore structure to that of the main component structure.
In the invention, the catalyst can be prepared by adopting the existing method that the pore diameter content meets the range.
In a second aspect, the present invention provides a process for preparing the catalyst comprising: zirconium source, alkaline earth metal salt and transition metal salt are mixed according to the mole ratio of 1:0.0003-0.2: mixing 0.0001-0.02 in solvent to obtain mixed solution; adding a precipitant into the mixed solution for coprecipitation reaction, and then aging; roasting the aged product;
wherein the transition metal salt is selected from one of a group VIB metal salt, a group VIII metal salt, a group IB metal salt and a group IIB metal salt.
In the above catalyst preparation method, those skilled in the art will understand that: if the zirconium source is provided to already contain the alkaline earth metal element and the transition metal element in the desired amounts, molding is carried out using only such a raw material (zirconium source), and if the raw material for providing the main component source does not contain the alkaline earth metal element and the transition metal element or the content of the element is low (insufficient), the alkaline earth metal element and the transition metal element may be additionally introduced.
In the present invention, since the alkaline earth metal salt and the transition metal salt are contained in the main component (ZrO 2 ) Is introduced during the preparation of (a), and therefore, the alkaline earth metal oxide and the transition metal oxide are mainly dispersed in the main component.
According to the present invention, preferably, the zirconium source is selected from at least one of zirconium oxychloride, zirconium nitrate, zirconyl nitrate, and zirconyl sulfate.
According to the present invention, preferably, the precipitant is at least one selected from the group consisting of ammonia, urea, sodium carbonate and sodium hydroxide.
In the present invention, the alkaline earth metal salt is present in the form of a solution of an alkaline earth metal salt (hereinafter referred to as solution a) selected from at least one of an alkaline earth metal nitrate, an alkaline earth metal formate, an alkaline earth metal oxalate and an alkaline earth metal lactate; preferably an alkaline earth metal nitrate; further preferably, the alkaline earth metal nitrate is selected from at least one of magnesium nitrate, calcium nitrate, strontium nitrate and barium nitrate, preferably magnesium nitrate and/or calcium nitrate; the solvent in the solution is selected from water and/or ethanol, preferably water.
In the present invention, the transition metal salt is present in the form of a solution of a transition metal salt (hereinafter referred to as solution B) selected from at least one of a transition metal nitrate, a transition metal formate, a transition metal oxalate and a transition metal lactate; preferably a transition metal nitrate; further preferably, the transition metal nitrate is selected from one of chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate and zinc nitrate, preferably nickel nitrate or copper nitrate; the solvent in the solution is selected from water and/or ethanol, preferably water.
In the invention, the solution A and the solution B can be added into the system containing the zirconium source at the same time or can be added into the system containing the zirconium source separately; when added separately, the order of addition of the solution A and the solution B is not particularly limited.
In one embodiment, the aging may be performed by standing the product of the coprecipitation reaction at a constant temperature, preferably at a temperature of 60 to 90 ℃, preferably 65 to 85 ℃, for example 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, or any value in the range of any two values; more preferably, the aging time is 0.5 to 9 hours, and may be, for example, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, or any value in the range of the constitution of any two values mentioned above.
According to the present invention, preferably, the method further comprises: and centrifuging, washing and drying the aged product. The drying time can be reasonably selected according to the drying temperature, the amount of materials and the type of drying equipment, and the condition that the water content of the dried materials does not influence the subsequent roasting is taken into account. Preferably, the drying temperature is 65 to 140 ℃, for example, 65, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, or any value in the range of any two values, preferably 80 to 130 ℃; the drying time is 4 to 18 hours, and may be, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours, 14 hours, 14.5 hours, 15 hours, 15.5 hours, 16 hours, 16.5 hours, 17 hours, 17.5 hours, 18 hours, or any value in the range of the constitution of any two of the above values.
According to the present invention, the calcination is capable of removing crystal water in the salt and decomposing the salt to form an oxide, and in order to optimize the catalytic activity of the catalyst, preferably, the calcination conditions include: at 1-5deg.C for min -1 Heating to 400-800 ℃ at the heating rate, and roasting for 1-18h at 400-800 ℃; illustratively, the firing temperature may be 400 ℃, 450 ℃, 500 ℃, 525 ℃, 550 ℃, 600 ℃, 625 ℃, 650 ℃, 675 ℃, 700 ℃, 750 ℃, 800 ℃, or any value in the range of any two values mentioned above, preferably 400-600 ℃; the calcination time may be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 7h, 8h, 9h, 9.5h, 10h, 10.5h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h or any value in the range of any two values mentioned above, preferably 1 to 6h.
In a third aspect, the present invention provides a composite catalyst prepared according to the method of the second aspect.
Preferably, the composite catalyst comprises a main component ZrO 2 Alkaline earth metal oxides and transition metal oxides; wherein, in the composite catalyst, the pore volume with the pore diameter within the range of 1.7-2.6nm accounts for more than 60% of the total pore volume of the composite catalyst.
Preferably, relative to 100 parts by weight of the main component ZrO 2 The alkaline earth metal oxide is 0.05 to 8 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 1.4 parts by weight;
the transition metal oxide is 0.08 to 10 parts by weight, preferably 0.1 to 4.5 parts by weight, more preferably 0.25 to 1.1 parts by weight; wherein the transition metal oxide is selected from one of VIB, VIII, IB, IIB group metal oxides.
Preferably, the carbon dioxide adsorption amount of the composite catalyst is 0.17-0.3 mmol.g -1 The method comprises the steps of carrying out a first treatment on the surface of the The amount of the middle strong alkaline center of the composite catalyst is 0.09-0.24 mmol.g -1 。
Preferably, the specific surface area of the composite catalyst is 50-130m 2 ·g -1 The method comprises the steps of carrying out a first treatment on the surface of the Further preferably, in the composite catalyst, the pore volume with the pore diameter in the range of 1.7-2.6nm accounts for 65-90% of the total pore volume of the composite catalyst, and the pore volume with the pore diameter smaller than 1.7nm accounts for 0-6% of the total pore volume of the composite catalyst.
In a fourth aspect, the present invention provides a process for the preparation of olefins by dehydration of alcohols, the process comprising: contacting an alcohol with the catalyst of the first aspect or the third aspect in the presence or absence of a carrier gas to effect dehydration;
preferably, the conditions of the dehydration reaction include: the temperature is 250-380deg.C, preferably 260-340 deg.C, more preferably 255-330 deg.C; the pressure is 0.08-0.3MPa; the volume space velocity of the liquid phase is 0.05 to 0.8h -1 Preferably 0.15-0.55h -1 。
According to the present invention, preferably, the carrier gas, when present, has a flow rate of 15 to 45mL min -1 Preferably 20-40mL min -1 。
According to the invention, preferably the alcohol is selected from C 3 -C 18 An alcohol of (a); further preferably, the alcohol is selected from the group consisting of 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 2-propanol, 2-butanol, 2-pentanol, 2-hexanol, 2-heptanol, 2-octanol, 2-nonanol, 2-decanol, 2-undecanol, 2-dodecanol, 2-tridecanol, 2-tetradecanol, 2-hexadecanol, 2-heptadecanol, 2-octadecanol, methyl isobutyl carbinol, diacetone alcohol, phenethyl alcohol, 1-phenyl-2-propanol, 4-phenyl-2-butanol, 5-phenyl-2-propanol, phenethyl propanol, 4-phenyl butanol, 2-methyl-2-pentanol, 2-methyl-2-pentanolAt least one of the group-2-hexanol, 2-methyl-2-heptanol, 2-methyl-2-octanol, 2-methyl-2-nonanol and 5-methyl-2-hexanol.
In the present invention, room temperature means a temperature of 25.+ -. 5 ℃.
In the following examples, the elemental composition of the catalyst was analyzed by a plasma emission spectrometer;
the specific surface area and pore volume of the catalyst are measured by a nitrogen adsorption-desorption method (BET), and the test conditions are as follows: experimental gas: n (N) 2 (purity 99.999%); degassing conditions: at 10 ℃ for min -1 Raising the temperature to 350 ℃ and vacuumizing for 4 hours; instrument name: full-automatic materialized adsorption analyzer (Automatic Micropore)&Chemisorption Analyzer); instrument model: ASAP2420, MICromeritcs, U.S. A.;
CO of catalyst 2 The adsorption quantity adopts CO 2 -TPD test, desorption temperature 100-600 ℃, test conditions: accurately weighing about 0.1g of sample, placing into a sample tube, and purging with He gas at 10deg.C for min -1 Heating to 600deg.C, standing for 1 hr, cooling to 120deg.C, and changing gas into 10% CO 2 The mixture of He and the catalyst is adsorbed for 60min, then the mixture is changed into He and purged for 1h, counting is started after the baseline is stabilized, and the temperature is 10 ℃ for min -1 And (5) heating to 600 ℃, keeping for 30min, stopping recording, and completing the experiment. Integrating and calculating the peak area to obtain CO 2 Desorption amount (basic site of catalyst); test instrument: a full-automatic chemical adsorption instrument (Automated Catalyst Characterization System); instrument model: autochem 2920, MICROMERITICS, inc. of America;
the amount of the medium-strong alkaline center of the catalyst adopts CO 2 TPD test, desorption temperature of 230-600 ℃, and specific test method is the same as alkaline position test method.
The carbon deposition amount of the catalyst adopts O 2 -TPO test, test conditions are: accurately weighing 0.2g of sample, taking argon with the flow rate of 40mL/min as carrier gas, pretreating the sample at 150 ℃ for 60min, cooling to 100 ℃, and under the condition that the mixed gas of oxygen and argon with the flow rate of 40mL/min (the oxygen volume fraction is 20%) is taken as analysis gas, programming to 900 ℃ at the speed of 10 ℃/min for programmingOxidation process, detection of CO during temperature programming 2 Signals of gases such as CO. Test instrument: a full-automatic programmed temperature chemical adsorption instrument; instrument model: autochem II 2920, micromeritics Inc. of America.
Example 1
1.59mol of zirconyl nitrate, 0.045mol of calcium nitrate tetrahydrate and 0.0009mol of chromium nitrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Ca 2+ The concentration is 0.015mol L -1 、Cr 3+ The concentration is 0.0003mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of water bath at 82 ℃ and vigorous stirring, and adjusting the pH to 10.2 to obtain a precipitate system; standing the precipitate system in a beaker for 2.5h; then, centrifugal separation is performed, and the obtained precipitate is washed with deionized water to ph=6.5, and then dried at 75 ℃ for 2 hours, and further dried at 130 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating the mixture from 25 ℃ to 400 ℃ at a heating rate, and roasting the mixture for 2 hours at the temperature to obtain a sample ZrO 2 /CaO/Cr 2 O 3 The catalyst was designated as catalyst A-1, and the test results are shown in Table 1.
Example 2
1.59mol of zirconyl nitrate, 0.036mol of calcium nitrate tetrahydrate and 0.0042mol of ferric nitrate nonahydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Ca 2+ The concentration is 0.012mol L -1 、Fe 3+ The concentration is 0.014mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of water bath at 85 ℃ and vigorous stirring, and adjusting the pH to 9.9 to obtain a precipitate system; standing the sediment system in a beaker for 2.6 hours; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed by drying at 85 ℃ for 2 hours and further drying at 115 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25 ℃ to 600 ℃ at a heating rate, and roasting for 2 hours at the temperature to obtain a sample ZrO 2 /CaO/Fe 2 O 3 Catalyst A-2 was identified and the test results are shown in Table 1.
Example 3
1.62mol of zirconyl nitrate, 0.177mol of calcium nitrate tetrahydrate and 0.018mol of cobalt nitrate hexahydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.54mol L -1 、Ca 2+ At a concentration of 0.059mol L -1 、Co 2+ The concentration is 0.006mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of water bath at 60 ℃ and vigorous stirring, and regulating the pH to 10.2 to obtain a precipitate system; standing the sediment system in a beaker for 2.4 hours; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed by drying at 76 ℃ for 2 hours, and further drying at 130 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25 ℃ to 700 ℃ at a heating rate, and roasting for 2 hours at the temperature to obtain a sample ZrO 2 CaO/CoO, designated catalyst A-3.
Example 4
1.59mol of zirconyl nitrate, 0.039mol of calcium nitrate tetrahydrate and 0.003mol of nickel nitrate hexahydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Ca 2+ The concentration is 0.013mol L -1 、Ni 2+ At a concentration of 0.0011mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 78 ℃ water bath and vigorous stirring, and adjusting the pH to 9.8 to obtain a precipitate system; standing the precipitate system in a beaker for 2.7h; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed by drying at 74 ℃ for 2 hours, and further drying at 128 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 550deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 CaO/NiO, designated catalyst A-4.
Example 5
1.62mol of zirconyl nitrate, 0.018mol of calcium nitrate tetrahydrate and 0.009mol of copper nitrate trihydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.54mol L -1 、Ca 2+ The concentration is 0.006mol L -1 、Cu 2+ Concentration of0.003mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 75 ℃ water bath and vigorous stirring, and adjusting the pH to 10.0 to obtain a precipitate system; standing the sediment system in a beaker for 2.6 hours; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed by drying at 82 ℃ for 2 hours, and further drying at 124 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 500deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 CaO/CuO, designated as catalyst A-5.
Example 6
1.59mol of zirconyl nitrate, 0.048mol of calcium nitrate hexahydrate and 0.0024mol of zinc nitrate hexahydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Ca 2+ The concentration is 0.016mol L -1 、Zn 2+ The concentration is 0.0008mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 80 ℃ water bath and vigorous stirring, and adjusting the pH to 9.9 to obtain a precipitate system; standing the precipitate system in a beaker for 2.9h; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed by drying at 71 ℃ for 2 hours, and further drying at 129 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25 ℃ to 600 ℃ at a heating rate, and roasting for 2 hours at the temperature to obtain a sample ZrO 2 CaO/ZnO, designated as catalyst A-6.
Example 7
1.59mol of zirconyl nitrate, 0.063mol of magnesium nitrate and 0.027mol of copper nitrate trihydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Mg 2+ The concentration is 0.021mol L -1 、Cu 2+ The concentration is 0.009mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 78 ℃ water bath and vigorous stirring, and adjusting the pH to 10.1 to obtain a precipitate system; standing the sediment system in a beaker for 2.4 hours; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed byDrying at 65deg.C for 2 hr, and drying at 130deg.C for 2 hr; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 500deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 MgO/CuO, designated as catalyst A-7.
Example 8
1.62mol of zirconyl nitrate, 0.0006mol of barium nitrate and 0.246mol of copper nitrate trihydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.54mol L -1 、Ba 2+ At a concentration of 0.0002mol L -1 、Cu 2+ The concentration is 0.082mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 83 ℃ water bath and vigorous stirring, and adjusting the pH to 10.2 to obtain a precipitate system; standing the sediment system in a beaker for 2.6 hours; then, centrifugal separation was performed, and the obtained precipitate was washed with deionized water to ph=6.5, followed by drying at 75 ℃ for 2 hours and further drying at 125 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 800deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 BaO/CuO, designated catalyst A-8.
Example 9
1.59mol of zirconyl nitrate, 0.153mol of strontium nitrate and 0.0012mol of copper nitrate trihydrate are dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Sr 2+ The concentration is 0.051mol L -1 、Cu 2+ At a concentration of 0.0004mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 75 ℃ water bath and vigorous stirring, and adjusting the pH to 9.8 to obtain a precipitate system; standing the sediment system in a beaker for 2.4 hours; then, centrifugal separation is carried out, and the obtained precipitate is washed with deionized water to a pH=6.5, and then dried at 80 ℃ for 2 hours and at 120 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 550deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 SrO/CuO, designated catalyst A-9.
Comparative example 1
According to realityExample 5A catalyst was prepared by the method described in Table 1, except that zirconia powder was used as a main component source, and the calcination temperature at the time of preparation of the catalyst was 550℃to obtain a sample ZrO 2 (powder)/CaO/CuO to obtain a catalyst B-1.
Comparative example 2
A catalyst was prepared in the same manner as in example 5 except that zirconia powder was used as a main component source as shown in Table 1, and the calcination temperature at the time of preparing the catalyst was 900℃to obtain a sample ZrO 2 (powder)/CaO/CuO to obtain a catalyst B-2.
Comparative example 3
1.59mol of zirconyl nitrate is weighed and dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 Is a solution of (a); then dropwise adding ammonia water solution (25 wt%) into the solution under the conditions of 70 ℃ water bath and vigorous stirring, regulating the pH of the solution to 10.0 to obtain a mixed system, and then standing the mixed system in a beaker for 2.5h; then, centrifugal separation is carried out, and the obtained precipitate is washed with deionized water to a pH=6.5, and then dried at 70 ℃ for 2 hours and at 130 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 500deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 Catalyst B-3 was recorded and the test results are shown in Table 1.
Comparative example 4
1.62mol of zirconyl nitrate and 0.036mol of calcium nitrate tetrahydrate are weighed and dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Ca 2+ The concentration is 0.012mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of water bath at 90 ℃ and vigorous stirring, and adjusting the pH to 9.9 to obtain a precipitate system; standing the sediment system in a beaker for 2.6 hours; then, centrifugal separation is carried out, and the obtained precipitate is washed with deionized water to a pH=6.5, and then dried at 65 ℃ for 2 hours and 140 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 450deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 CaO, noted as catalysisAgent B-4, test results are shown in Table 1.
Comparative example 5
1.60mol of zirconyl nitrate and 0.0009mol of chromium nitrate are weighed and dissolved in 3L of deionized water to prepare the zirconium element with the concentration of 0.53mol L -1 、Cr 3+ The concentration is 0.0003mol L -1 Is a mixed solution of (a) and (b); dropwise adding an ammonia water solution (25 wt%) into the mixed solution under the conditions of 80 ℃ water bath and vigorous stirring, and adjusting the pH to 9.8 to obtain a precipitate system; standing the sediment system in a beaker for 2.6 hours; then, centrifugal separation is performed, and the obtained precipitate is washed with deionized water to ph=6.5, and then dried at 75 ℃ for 2 hours, and further dried at 130 ℃ for 2 hours; finally, the product obtained by drying is placed in a muffle furnace for 3 ℃ min -1 Heating from 25deg.C to 500deg.C, and calcining at the temperature for 2 hr to obtain sample ZrO 2 /Cr 2 O 3 Catalyst B-5 was identified and the test results are shown in Table 1.
Comparative example 6
A catalyst was prepared in the same manner as in example 5 except that 0.00072mol of calcium nitrate tetrahydrate was weighed and dissolved in 3L of deionized water as shown in Table 1 to obtain a sample ZrO 2 CaO/CuO, designated as catalyst B-6.
Comparative example 7
A catalyst was prepared in the same manner as in example 5 except that 0.54mol of calcium nitrate tetrahydrate was weighed and dissolved in 3L of deionized water as shown in Table 1 to obtain a sample ZrO 2 CaO/CuO, designated as catalyst B-7.
Comparative example 8
A catalyst was prepared by the method of example 5, except that 0.0011mol of copper nitrate trihydrate was weighed and dissolved in 3L of deionized water, as shown in Table 1, to obtain a sample ZrO 2 CaO/CuO, designated as catalyst B-8.
Comparative example 9
A catalyst was prepared in the same manner as in example 5 except that 0.4mol of copper nitrate trihydrate was dissolved in 3L of deionized water as shown in Table 1 to obtain a sample ZrO 2 CaO/CuO, designated as catalyst B-9.
Comparative example 10
A catalyst was prepared in the same manner as in example 5 except that the catalyst was prepared at a calcination temperature of 250℃as shown in Table 1, to give a sample ZrO 2 CaO/CuO (250 ℃ C.) was designated as catalyst B-10.
Comparative example 11
A catalyst was prepared in the same manner as in example 5 except that the catalyst was prepared at a calcination temperature of 1000℃as shown in Table 1, to give a sample ZrO 2 CaO/CuO (1000 ℃ C.) was designated as catalyst B-11.
TABLE 1
Figure BDA0003326222750000151
Figure BDA0003326222750000161
Note that: 1-IIA means that relative to 100g of the main component ZrO 2 The weight of alkaline earth metal oxides;
2-transition means relative to 100g of the main component ZrO 2 The weight of the transition metal oxide;
3-1.7-2.6nm is the percentage of pore volume with the pore diameter in the range of 1.7-2.6nm to the total pore volume of the composite catalyst;
4- < 1.7nm pore volume with pore diameter smaller than 1.7nm is the percentage of the total pore volume of the composite catalyst.
Test example 1
This test example is used to illustrate the process for the preparation of 4-methyl-1-pentene by dehydration of methyl isobutyl carbinol (MIBC).
50mL of the catalyst was weighed and placed in a fixed bed reactor, and was preheated at 310℃for 1 hour in a nitrogen atmosphere before the reaction, and methyl isobutyl methanol was metered by a metering pump for 0.3 hour -1 The liquid phase volume space velocity of (2) enters a reaction system, the dehydration reaction temperature is 320 ℃, the reaction pressure is 0.1MPa, and after the reaction is stable (namely, when the reaction is carried out for 200 hours), the reaction liquid is sampled and analyzed, and the analysis results are shown in Table 2.
The sampling analysis method is gas chromatography analysis, and calibration is carried out by preparing a correction factor of a standard sample;
the conversion and selectivity (methyl isobutyl carbinol is abbreviated as MIBC, 4-methyl-1-pentene is abbreviated as 4MP1, 4-methyl-2-pentene is abbreviated as 4MP2, methyl isobutyl ketone is abbreviated as MIBK) are calculated according to the molar content of each component in the reaction liquid.
MIBC conversion = 100% -n 1 /[(n 1 +n 2 +n 3 +n 4 )+2×n 5 ]×100％
4MP1 selectivity = n 2 /[(n 2 +n 3 +n 4 )+2×n 5 ]×100％
4MP2 selectivity = n 3 /[(n 2 +n 3 +n 4 )+2×n 5 ]×100％
Wherein n is 1 The molar content of MIBC in the reaction solution; n is n 2 The molar content of 4MP1 in the reaction liquid; n is n 3 The molar content of 4MP2 in the reaction liquid; n is n 4 The molar content of MIBK in the reaction liquid; n is n 5 The molar content of the oligomer in the reaction solution.
4MP1 duty cycle = 4MP 1/(4MP2+4MP1). Times.100%
The 4MP1 ratio is the ratio of 4MP1 selectivity to the sum of 4MP1 and 4MP2 selectivity, i.e. the ratio of alpha-olefin to the sum of alpha-olefin and beta-olefin, indicating that the reaction produces more alpha-olefin, i.e. the selectivity of alpha-olefin is high.
TABLE 2
Figure BDA0003326222750000171
As can be seen from the data in Table 2, in the reaction of preparing 4-methyl-1-pentene by dehydrating methyl isobutyl carbinol (MIBC), the conversion rate of the composite catalyst provided by the invention to methyl isobutyl carbinol is up to 95%, and the ratio of 4MP1 is up to 91%, which indicates that the composite catalyst provided by the invention has higher activity.
The conversion rate and the selectivity of the composite catalysts A-1 to A-9 are not obviously changed compared with those of the composite catalysts A-1 to A-9 at the time of catalytic reaction 1200h, the conversion rate reduction value of MIBC is not higher than 1.3%, the reduction value of the 4MP1 ratio is not higher than 1%, the conversion rate and the 4MP1 ratio of the composite catalysts B-1 to B-11 at the time of catalytic reaction 1200h are obviously reduced compared with those of the composite catalysts A-1 to A-9 at the time of catalytic reaction 200h, the conversion rate is reduced by 22-34%, and the 4MP1 ratio is reduced by 19% -38%; the carbon deposition of the composite catalysts A-1 to A-9 after the catalytic reaction for 1200 hours is lower than 2wt percent; the carbon deposition of the catalysts B-1 to B-11 reaches 3.9 to 8.6 weight percent, which shows that the catalyst prepared by the embodiment of the invention has longer service life.
Test example 2
This test example is used to illustrate the process for the preparation of 1-hexene by dehydration of 2-hexanol.
50mL of catalyst A-5 was placed in a fixed bed reactor, preheated at 310℃for 1h in a nitrogen atmosphere, and 0.3. Multidot.h of 2-hexanol was metered in -1 The liquid phase volume space velocity of (2) enters a reaction system, the dehydration reaction temperature is 310 ℃, the reaction pressure is 0.1MPa, after the reaction is stable, the reaction liquid is sampled and analyzed, and the analysis result is shown in table 3:
the sampling analysis method is gas chromatography analysis, and calibration is carried out by preparing a correction factor of a standard sample;
conversion and selectivity were calculated as the molar content of each component in the reaction solution.
2-hexanol conversion = 100% -m 1 /[(m 1 +m 2 +m 3 )+2×m 4 ]×100％
1-hexene selectivity = m 2 /[(m 2 +m 3 )+2×m 4 ]×100％
2-hexene selectivity = m 3 /[(m 2 +m 3 )+2×m 4 ]×100％
Wherein m is 1 The molar content of 2-hexanol in the reaction liquid; m is m 2 The molar content of 1-hexene in the reaction liquid; m is m 3 The molar content of 2-hexene in the reaction liquid; m is m 4 The molar content of the oligomer in the reaction solution.
1-hexene ratio = 1-hexene/(2-hexene + 1-hexene) ×100%
The ratio of 1-hexene to the sum of 1-hexene and 2-hexene, i.e. the ratio of alpha-olefin to the sum of alpha-olefin and beta-olefin, shows that the reaction product has more alpha-olefin, i.e. the selectivity of alpha-olefin is high.
TABLE 3 Table 3
Figure BDA0003326222750000181
Figure BDA0003326222750000191
As can be seen from Table 3, in the reaction of preparing 1-hexene by catalyzing 2-hexanol to dehydrate, the conversion rate of 2-hexanol is up to 92.52%, the 1-hexene content is up to 90.3%, after the catalytic reaction is carried out for 1200 hours, the conversion rate of 2-hexanol and the 1-hexene content are not obviously changed compared with 200 hours, the reduction value of the conversion rate is not higher than 0.1%, and the reduction value of the 1-hexene content is not higher than 0.1%, which indicates that the catalyst obtained by the embodiment of the invention has long service life.
Test example 3
This test example is used to illustrate the process of the present invention for the preparation of 1-butene by dehydration of 2-butanol.
50mL of catalyst A-5 was placed in a fixed bed reactor, preheated at 310℃for 1h in a nitrogen atmosphere, and metering the 2-butanol for 0.3h -1 The liquid phase volume space velocity of (2) enters a reaction system, the dehydration reaction temperature is 310 ℃, the reaction pressure is 0.1MPa, and after the reaction is stable, the reaction liquid is sampled, analyzed and analyzed, and the results are shown in Table 4:
the sampling analysis method is gas chromatography analysis, and calibration is carried out by preparing a correction factor of a standard sample;
conversion and selectivity were calculated as the molar content of each component in the reaction solution.
2-butanol conversion = 100% -w 1 /[(w 1 +w 2 +w 3 )+2×w 4 ]×100％
1-butene selectivity = w 2 /[(w 2 +w 3 )+2×w 4 ]×100％
2-butene selectivity = w 3 /[(w 2 +w 3 )+2×w 4 ]×100％
Wherein w is 1 The molar content of 2-butanol in the reaction solution; w (w) 2 The molar content of 1-butene in the reaction liquid; w (w) 3 The molar content of 2-butene in the reaction liquid; w (w) 4 The molar content of the oligomer in the reaction solution.
1-butene ratio = 1-butene/(2-butene + 1-butene) ×100%
The ratio of 1-butene to the sum of 1-butene and 2-butene, i.e., the ratio of alpha-olefin to the sum of alpha-olefin and beta-olefin, indicates that the reaction produces a product with more alpha-olefin, i.e., a product with high alpha-olefin selectivity.
TABLE 4 Table 4
Figure BDA0003326222750000201
As can be seen from Table 3, in the reaction of preparing 1-butene by catalyzing 2-butanol to dehydrate, the conversion rate of 2-hexanol is up to 91.08%, the 1-butene ratio is up to 88.6%, after the catalytic reaction is carried out for 1200 hours, the conversion rate of 2-hexanol and the 1-butene ratio are not obviously changed compared with 200 hours, the reduction value of the conversion rate is not higher than 0.1%, and the reduction value of the 1-butene ratio is not higher than 0.1%, which indicates that the catalyst obtained by the embodiment of the invention has long service life.
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 composite catalyst comprising ZrO as a main component 2 Alkaline earth metal oxides and transition metal oxides; wherein, in the composite catalyst, the pore volume with the pore diameter within the range of 1.7-2.6nm accounts for the total pore volume of the composite catalyst60% or more;
relative to 100 parts by weight of ZrO as main component 2 0.05-8 parts by weight of alkaline earth metal oxide and 0.08-10 parts by weight of transition metal oxide;
wherein the transition metal oxide is selected from one of VIB, VIII, IB, IIB group metal oxides.
2. The composite catalyst according to claim 1, wherein the alkaline earth metal oxide is selected from at least one of magnesium oxide, calcium oxide, strontium oxide, and barium oxide; preferably magnesium oxide and/or calcium oxide;
preferably, the transition metal oxide is selected from one of chromium oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, and zinc oxide; preferably nickel oxide or copper oxide.
3. The composite catalyst according to claim 1 or 2, wherein the amount of the primary component ZrO is 100 parts by weight 2 0.1-5 parts by weight of alkaline earth metal oxide;
preferably, relative to 100 parts by weight of the main component ZrO 2 0.1 to 4.5 parts by weight of the transition metal oxide;
preferably, the weight ratio of alkaline earth metal oxide to transition metal oxide is from 0.1 to 62.5:1, preferably from 0.75 to 14:1.
4. The composite catalyst according to any one of claims 1 to 3, wherein the carbon dioxide adsorption amount of the composite catalyst is 0.17 to 0.3 mmol-g -1 ；
Preferably, the amount of the medium strong basic center of the composite catalyst is 0.09-0.24 mmol.g -1 。
5. The composite catalyst according to any one of claims 1 to 4, wherein the composite catalyst has a specific surface area of 50 to 130m 2 ·g -1 ；
Preferably, in the composite catalyst, the pore volume with the pore diameter in the range of 1.7-2.6nm accounts for 65-90% of the total pore volume of the composite catalyst, and the pore volume with the pore diameter smaller than 1.7nm accounts for 0-6% of the total pore volume of the composite catalyst.
6. A method of preparing a composite catalyst, the method comprising: zirconium source, alkaline earth metal salt and transition metal salt are mixed according to the mole ratio of 1:0.0003-0.2: mixing 0.0001-0.02 in solvent to obtain mixed solution; adding a precipitant into the mixed solution for coprecipitation reaction, and then aging; roasting the aged product;
wherein the transition metal salt is selected from one of a group VIB metal salt, a group VIII metal salt, a group IB metal salt and a group IIB metal salt.
7. The method of claim 6, wherein the zirconium source is selected from at least one of zirconium oxychloride, zirconium nitrate, zirconyl nitrate, and zirconyl sulfate;
the precipitant is at least one selected from ammonia water, urea, sodium carbonate and sodium hydroxide.
8. The method according to claim 6 or 7, wherein the alkaline earth metal salt is present in the form of a solution of an alkaline earth metal salt selected from at least one of an alkaline earth metal nitrate, an alkaline earth metal formate, an alkaline earth metal oxalate and an alkaline earth metal lactate;
preferably, the alkaline earth metal salt is selected from at least one of magnesium nitrate, calcium nitrate, strontium nitrate and barium nitrate, preferably magnesium nitrate and/or calcium nitrate;
preferably, the transition metal salt is selected from at least one of transition metal nitrate, transition metal formate, transition metal oxalate and transition metal lactate;
preferably, the transition metal salt is selected from one of chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate and zinc nitrate, preferably nickel nitrate and/or copper nitrate.
9. The method of any of claims 6-8, wherein the aging conditions include: the temperature is 60-90 ℃ and the time is 0.5-9h;
preferably, the roasting conditions include: at 1-5deg.C for min -1 The temperature rising rate of (2) is raised from room temperature to 400-800 ℃, and roasting is carried out for 1-18h at 400-800 ℃.
10. A composite catalyst prepared by the method of any one of claims 6-9.
11. A process for producing olefins by dehydration of alcohols, the process comprising: contacting an alcohol with the catalyst of any one of claims 1-5 and 10 in the presence or absence of a carrier gas to effect dehydration;
preferably, the conditions of the dehydration reaction include: the temperature is 250-380 ℃, preferably 260-340 ℃; the pressure is 0.08-0.3MPa; the volume space velocity of the liquid phase is 0.05 to 0.8h -1 Preferably 0.15-0.55h -1 ；
Preferably, when the carrier gas is present, the flow rate of the carrier gas is 15-45mL min -1 Preferably 20-40mL min -1 。
12. The method of claim 11, wherein the alcohol is selected from C 3 -C 18 An alcohol of (a);
preferably, the alcohol is selected from the group consisting of 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 2-propanol, 2-butanol, 2-pentanol, 2-hexanol, 2-heptanol, 2-octanol, 2-nonanol, 2-decanol, 2-undecanol, 2-dodecanol, 2-tridecanol, 2-tetradecanol, 2-hexadecanol, 2-heptadecanol, 2-octadecanol, methyl isobutyl methanol, diacetyl alcohol, phenethyl alcohol, 1-phenyl-2-propanol, 4-phenyl-2-butanol, 5-phenyl-2-pentanol, phenylpropanol, 4-phenyl butanol, 2-methyl-2-pentanol, 2-methyl-2-hexanol, 2-methyl-2-heptanol, 2-methyl-2-hexanol, 2-methyl-heptanol, 2-methyl-2-hexanol, and at least one of 2-methyl-2-hexanol.
CN202111262363.9A 2021-10-28 2021-10-28 Composite catalyst, preparation method thereof and method for preparing olefin by alcohol dehydration Pending CN116037099A (en)

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