WO2024078279A1 - 一种负载型钯催化剂、及其制备和应用 - Google Patents

一种负载型钯催化剂、及其制备和应用 Download PDF

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WO2024078279A1
WO2024078279A1 PCT/CN2023/119966 CN2023119966W WO2024078279A1 WO 2024078279 A1 WO2024078279 A1 WO 2024078279A1 CN 2023119966 W CN2023119966 W CN 2023119966W WO 2024078279 A1 WO2024078279 A1 WO 2024078279A1
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catalyst
palladium
carrier
range
combination
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PCT/CN2023/119966
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English (en)
French (fr)
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卫国宾
彭晖
铁锴
张立岩
穆玮
杨晨熹
易水生
卢红亮
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中国石油化工股份有限公司
中石化(北京)化工研究院有限公司
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Publication of WO2024078279A1 publication Critical patent/WO2024078279A1/zh

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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
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
    • 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
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/48—Silver or gold
    • B01J23/50—Silver
    • 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
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • 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
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/58—Platinum group metals 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/60—Platinum group metals with 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
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/62—Platinum group metals with gallium, indium, thallium, germanium, tin or lead
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/06—Halogens; Compounds thereof
    • B01J27/138—Halogens; Compounds thereof with alkaline earth metals, magnesium, beryllium, 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
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/20—Carbon compounds
    • B01J27/232—Carbonates
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/04—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing carboxylic acids or their salts
    • 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
    • B01J37/02—Impregnation, coating or precipitation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
    • C07C5/03—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of non-aromatic carbon-to-carbon double bonds
    • C07C5/05—Partial hydrogenation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
    • C07C5/08—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of carbon-to-carbon triple bonds
    • C07C5/09—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of carbon-to-carbon triple bonds to carbon-to-carbon double bonds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C11/00—Aliphatic unsaturated hydrocarbons
    • C07C11/02—Alkenes
    • C07C11/04—Ethylene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C11/00—Aliphatic unsaturated hydrocarbons
    • C07C11/02—Alkenes
    • C07C11/06—Propene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
    • C07C7/163—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation
    • C07C7/167—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation for removal of compounds containing a triple carbon-to-carbon bond

Definitions

  • the present application relates to the field of catalysts, and in particular to a supported palladium catalyst, and its preparation and application.
  • Palladium (Pd) catalysts have been widely used in the petrochemical industry, such as catalytic reforming, isomerization and dehydrogenation of alkanes and aromatics, selective hydrogenation in olefin production, and the production of organic chemical raw materials such as acetaldehyde, vinyl acetate, and methyl methacrylate.
  • palladium is an excellent catalyst or one of the important components of the catalyst in various organic chemical reactions such as hydrogenation, oxidative dehydrogenation, hydrocracking, coupling, hydroesterification, carbon-one chemistry, and automobile exhaust purification.
  • palladium noble metal catalysts Since pure noble metal catalysts have the disadvantages of high price, narrow active temperature range, easy deactivation in oxidation, etc., the application is severely limited. Therefore, the development of palladium noble metal catalysts is mainly based on supported catalysts, such as CN113067000A discloses a TiO2 with oxygen vacancies and loads Pd-Co nano alloy catalysts. By impregnation, metal ion vapor deposition, solvated metal atom impregnation, ion exchange and sol-gel method, palladium is dispersed in suitable carriers for use.
  • CN112517063A discloses a Pd-Au single substance state supported catalyst preparation method for preparing vinyl acetate by ethylene process, chloropalladic acid and chloroauric acid are impregnated on a silicon dioxide carrier, and then a surfactant and sodium silicate aqueous solution are added to precipitate palladium and gold compounds, and catalysts are prepared by hydrogen reduction to single substance state and potassium acetate solution impregnation, which effectively improves the activity and selectivity of the catalyst.
  • the pH value of the carrier surface directly affects the degree of "metal-carrier interaction" on the catalyst surface and the dispersion state of the active metal, which in turn determines the activity and selectivity of the catalyst.
  • the role of acidic or basic centers often enables many reactions to proceed smoothly, such as certain hydrogenations, hydrogen transfers, aldol condensation reactions, etc. Coking is often a troublesome problem in acidic catalytic hydrogenation reactions, while hydrogenation reactions on alkaline catalysts usually do not coke, but higher alkalinity can easily cause catalyst deactivation. Therefore, the art is in urgent need of developing a supported palladium catalyst with good catalytic effect.
  • the purpose of the present application is to provide a supported palladium catalyst, and its preparation and application.
  • the surface of the supported palladium catalyst is an overall weakly acidic environment and has a specific weakly basic center, so that the catalyst has better catalytic performance.
  • the present application provides a supported palladium catalyst, comprising a carrier, palladium supported on the carrier and a modifying component, wherein the carrier is selected from refractory metal oxides, silicon oxide, activated carbon, or a combination thereof, and the modifying component is selected from Bi, Sb, Pb, Sn, Zn, W, Mn, Si, Re, Group VIII elements other than palladium, alkali metal elements, alkaline earth metal elements, Group IIIA elements, Group IB elements, rare earth elements, halogen elements, or a combination thereof, wherein according to an in-situ infrared spectroscopy analysis of pyrrole adsorption carried out at 40°C, the catalyst shows an absorption peak in the range of 3251-3410cm -1 .
  • the ratio of the peak height of the absorption peak in the range of 3251-3410 cm -1 in the in-situ infrared spectrum of the catalyst measured when purged with nitrogen for 0 minute after 10 minutes of pyrrole adsorption to the peak height of the corresponding absorption peak in the range of 3251-3410 cm -1 in the in-situ infrared spectrum measured when purged with nitrogen for 15 minutes is greater than or equal to 5:1.
  • the alkalization treatment is achieved by spraying the alkaline solution, the spraying time is 2-8 minutes, and the spraying temperature is 35-70°C.
  • the supported palladium catalyst of the present application in the hydrogenation reaction of unsaturated hydrocarbons, wherein the unsaturated hydrocarbons are selected from alkynes, polyunsaturated hydrocarbons, or a combination thereof.
  • a method for hydrogenating unsaturated hydrocarbons comprising the step of contacting an unsaturated hydrocarbon feedstock containing alkynes and/or polyunsaturated hydrocarbons with the supported palladium catalyst of the present application in the presence of hydrogen for reaction.
  • the supported palladium catalyst of the present application shows an absorption peak in the range of 3251-3410 cm -1 in the pyrrole adsorption in situ infrared spectrum measured at 40°C, indicating that there are specific weak alkaline centers on the surface of the catalyst.
  • the surface of the supported palladium catalyst of the present application is weakly acidic as a whole, and at the same time
  • the catalyst has a specific weakly basic center, so that when used for hydrogenation of unsaturated hydrocarbons (especially selective hydrogenation of alkynes and polyunsaturated hydrocarbons), it has better catalytic activity and selectivity than existing catalysts.
  • the catalyst preparation method of the present application uses an alkaline solution to alkalize the intermediate of the loaded palladium and the modified component under specific conditions, providing a specific weak alkaline center for the obtained catalyst.
  • the catalyst shows an absorption peak in the range of 3251-3410 cm -1 in the pyrrole adsorption in-situ infrared spectrum measured at 40°C, thereby making it have better catalytic activity and selectivity when used for hydrogenation of unsaturated hydrocarbons (especially selective hydrogenation of alkynes and polyunsaturated hydrocarbons).
  • the preparation method is simple and easy to implement, and is convenient for industrial production.
  • Figures 1A to 1J show the pyrrole adsorption in-situ infrared spectra of catalysts A-J prepared in Examples and Comparative Examples;
  • FIG. 2 shows the in-situ infrared spectrum of pyrrole adsorption of Catalyst E as a function of time.
  • any specific numerical value disclosed herein is not limited to the exact value of the numerical value, but should be understood to also include values close to the exact value, such as all possible values within the range of ⁇ 5% of the exact value.
  • between the endpoint values of the range, between the endpoint value and the specific point value in the range, and between each Specific point values can be arbitrarily combined to obtain one or more new numerical ranges, and these new numerical ranges should also be deemed to be specifically disclosed herein.
  • polyunsaturated hydrocarbon refers to an aliphatic hydrocarbon compound having two or more (eg, 2-4) unsaturated bonds selected from carbon-carbon double bonds and carbon-carbon triple bonds, such as dienes having 3-5 carbon atoms.
  • the inventors of the present application have discovered through extensive research that, for supported palladium hydrogenation catalysts, the introduction of weak basic centers into an overall weakly acidic catalyst surface environment can significantly improve the performance of the catalyst, such as activity, selectivity and/or operating life, thereby completing the present invention.
  • the present application provides in the first aspect a supported palladium catalyst, comprising a carrier, palladium supported on the carrier, and a modifying component, wherein according to an in situ infrared spectrum analysis of pyrrole adsorption performed at 40°C, the catalyst shows an absorption peak in the range of 3251-3410cm -1 , preferably in the range of 3350-3400cm -1 .
  • the pyrrole adsorption in-situ infrared spectrum of the catalyst can be measured by the following method:
  • nitrogen purging can be maintained until the temperature drops to room temperature, with a nitrogen flow rate of 3-7 mL/min.
  • the granular catalyst sample is first ground into powder, filled in the in-situ sample pool and the surface is kept flat.
  • the purpose of steps a) to c) is to remove water and impurities adsorbed on the catalyst surface.
  • the in-situ infrared spectrum of the sample can also be recorded at different times as needed, for example, the in-situ infrared spectrum of the sample can be recorded at 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, and 10 minutes.
  • the NH bond stretching vibration absorption peak will appear in the range of 3150-3410cm -1 .
  • the position where the absorption peak appears characterizes the base strength of the basic center on the catalyst surface. The higher the wave number of the peak position (i.e., the closer to 3410cm -1 ), the weaker the base strength of the basic center (see "New Progress in the Study of Catalyst Alkalinity by Infrared Spectroscopy", Journal of Taiyuan University of Technology, Vol.24, pages 101-107, September 1993).
  • an NH bond stretching vibration absorption peak is shown in the range of 3251-3410cm -1 , for example, at 3260cm -1 , 3270cm -1 , 3300cm -1 , 3320cm- 1 , 3340cm -1 , 3360cm -1 , 3380cm-1, 3400cm -1 , 3410cm - 1 and any position within the range consisting of any two values therein, preferably in the range of 3350-3400cm - 1 , indicating the presence of extremely weak basic centers on the surface of the catalyst.
  • the inventors of the present application have found that when the surface of the supported palladium catalyst is weakly acidic as a whole, it is more conducive to the hydrogenation reaction of unsaturated hydrocarbons (especially the selective hydrogenation of alkynes and polyunsaturated hydrocarbons) than when the catalyst has a basic surface.
  • the catalyst surface further has the weakly basic center described in the present application (corresponding to When the pyrrole adsorption in-situ infrared spectrum shows an absorption peak in the range of 3251-3410 cm -1 )
  • the weakly basic center on the catalyst surface cooperates with the overall weakly acidic environment to more effectively inhibit the reaction of hydrogenating monoolefins to form alkanes, and reduce or eliminate the polymerization of alkynes and dienes on the catalyst surface, thereby further improving the catalytic performance of the catalyst, for example, the catalytic performance in the selective hydrogenation of alkynes and polyunsaturated hydrocarbons (such as materials containing propyne (MA) and propadiene (PD)), such as catalytic activity and selectivity.
  • MA propyne
  • PD propadiene
  • the intensity of the infrared absorption peak in the obtained spectrum will gradually weaken. If the peak height of the absorption peak in the range of 3150-3420 cm -1 in the spectrum when nitrogen is purged for 15 minutes changes significantly relative to the peak height of the corresponding absorption peak in the range of 3150-3420 cm -1 in the spectrum when purging for 0 minutes, it indicates that there are a significant number of basic centers on the catalyst surface that have adsorption capacity for pyrrole.
  • the peak height of the absorption peak displayed in the range of 3251-3410cm -1 in the in-situ infrared spectrum of the catalyst of the present application measured when purged with nitrogen for 0 minute after 10 minutes of pyrrole adsorption and the peak height of the corresponding absorption peak in the range of 3251-3410cm -1 in the in-situ infrared spectrum measured when purged with nitrogen for 15 minutes is greater than or equal to 5:1, preferably greater than or equal to 10:1, for example, 10:1 to 200:1.
  • the supported palladium catalyst may or may not show an absorption peak in the range of 3160-3250 cm -1 in the pyrrole adsorption in-situ infrared spectrum measured at 40° C.
  • the catalyst does not show an absorption peak in the range of 3200-3250 cm -1 , more preferably in the range of 3160-3250 cm -1 , indicating that there are no other stronger basic centers on the surface of the catalyst except for the extremely weak basic center.
  • the difference between the surface adsorbed pyridine concentration measured after desorption at 150°C and the surface adsorbed pyridine concentration measured after desorption at 300°C of the catalyst of the present application is in the range of 0.1-0.25 mmol/g, preferably in the range of 0.1-0.2 mmol/g, and the surface adsorbed pyridine concentration measured after desorption at 300°C is in the range of 0-0.1 mmol/g, preferably in the range of 0-0.08 mmol/g.
  • the difference between the surface adsorbed pyridine concentration measured after desorption at 150°C and the surface adsorbed pyridine concentration measured after desorption at 300°C is greater than the difference between the surface adsorbed pyridine concentration measured after desorption at 150°C and the surface adsorbed pyridine concentration measured after desorption at 300°C.
  • the ratio of the surface adsorbed pyridine concentration is in the range of 60-100%, preferably in the range of 75-100%.
  • the surface adsorbed pyridine concentration of the catalyst measured after desorption at 150°C characterizes the total amount of acid on the catalyst surface (i.e., the total amount of weak acid, medium-strong acid and strong acid)
  • the surface adsorbed pyridine concentration of the catalyst measured after desorption at 300°C characterizes the total amount of medium-strong acid and strong acid on the catalyst surface
  • the difference between the two characterizes the weak acid content on the catalyst surface.
  • the ratio of the difference between the surface adsorbed pyridine concentration measured after desorption at 150°C and the surface adsorbed pyridine concentration measured after desorption at 300°C relative to the surface adsorbed pyridine concentration measured after desorption at 150°C characterizes the proportion of the weak acid amount on the catalyst surface to the total acid amount (also referred to as the weak acid proportion herein).
  • the acid centers on the catalyst surface include Acid (B acid for short) and Lewis acid (L acid for short).
  • the peak near the wavenumber 1540 cm -1 corresponds to B acid
  • the peak near the wavenumber 1440-1450 cm -1 corresponds to L acid.
  • the supported palladium catalyst uses palladium as the catalytically active component, and its content can be selected in a wide range.
  • the content of palladium in the catalyst is 0.01-20wt%, for example, it can be 0.01wt%, 0.02wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 20wt%, and any value within the range of any two values, preferably 0.01-5wt%, more preferably 0.02-1wt%.
  • palladium may exist on the catalyst surface in an oxidized state, a single substance state, other palladium compound forms, or a mixture of two or more thereof.
  • the carrier of the supported palladium catalyst can be a carrier conventionally used in the art, for example, the carrier can be selected from refractory metal oxides, silicon oxide, activated carbon, or a combination thereof, preferably selected from aluminum oxide, zirconium oxide, gallium oxide, silicon oxide, activated carbon, or a combination thereof.
  • the shape of the catalyst may include but is not limited to powder, granular, spherical, toothed spherical, Raschig ring, strip, cylindrical, sheet or clover, etc.
  • the specific surface area of the catalyst is 0.5-800m2 /g, more preferably 4-200m2 /g, and further preferably 15-110m2 /g.
  • the supported palladium catalyst further comprises a modifying component, which may be a modifying component conventionally used in the art, such as Bi, Sb, Pb, Sn, Zn, W, Mn, Si, Re, Group VIII elements other than palladium (such as Fe, Co, Ni, Ru, Rh, Os, Ir, Pt), alkali metal elements (such as Na, K), alkaline earth metal elements (such as Mg, Ca, Sr, Ba), Group IIIA elements (such as Ga, In, Tl), Group IB elements (such as Cu, Ag, Au), rare earth elements (such as La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y), halogen elements (such as F, Cl, Br, I), or a combination thereof, preferably selected from La, K, Ag, Zn, Ga, Cu, Au, Cs, Bi, Mg, Fe, Re, or a combination thereof.
  • a modifying component such as Bi
  • the modified component can be loaded on the carrier together with palladium as a co-active component, or can be used as a carrier modifier and uniformly distributed in the carrier.
  • the content of the modified component in the catalyst is 0.01-20wt%, for example, 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, and any value within the range of any two values, preferably 0.2-5wt%.
  • a method for preparing the supported palladium catalyst of the present application comprising the following steps:
  • the alkalization treatment is achieved by spraying the alkaline solution, the spraying time is 2-8 minutes, preferably 3-4 minutes, and the spraying temperature is 35-70°C, preferably 45-55°C.
  • the temperature fluctuation during the spraying process is controlled within 5° C., that is, the difference between the highest spraying temperature and the lowest spraying temperature during the spraying process is within the range of 0-5° C. More preferably, the spraying is constant temperature spraying.
  • the shape of the carrier may include but is not limited to powder, granular, spherical, toothed spherical, Raschig ring, strip, cylindrical, sheet or clover, etc.
  • the specific surface area of the carrier is 0.5-800m2 /g, more preferably 4-200m2 /g, and further preferably 15-110m2 /g.
  • the palladium and the modifying component can be loaded by using a solution containing a precursor of palladium and a solution containing a precursor of the modifying component, respectively, or by using
  • the specific method for carrying out the loading can be a conventional method in the art, such as spraying or impregnation, preferably spraying and equal volume impregnation, and the specific operation will not be described in detail.
  • the palladium precursor can be a soluble palladium compound conventionally known in the art, such as palladium chloride, palladium nitrate, palladium acetate, palladium sulfate, a palladium compound containing an organic group (such as palladium pivalate, octaethylporphyrin palladium, trimethylpalladium acetate, palladium trifluoroacetate, etc.), or a combination thereof, preferably selected from palladium chloride, palladium nitrate, palladium acetate, palladium sulfate, or a combination thereof.
  • an organic group such as palladium pivalate, octaethylporphyrin palladium, trimethylpalladium acetate, palladium trifluoroacetate, etc.
  • the pH value of the solution containing the palladium precursor used in step 1) is 2-5, preferably 3.8-4.5.
  • the content of the palladium precursor in the solution containing the palladium precursor can be selected in a wide range, for example, the content of the palladium precursor in the solution can be 1-200 g//L.
  • the amount of palladium is such that the content of palladium in the obtained catalyst is 0.01-20 wt %, more preferably 0.01-5 wt %, and further preferably 0.02-1 wt %, based on the weight of the carrier and in terms of metal element.
  • the amount of palladium is 0.01-20 parts by weight, more preferably 0.01-5 parts by weight, and further preferably 0.02-1 parts by weight relative to 100 parts by weight of the carrier.
  • the precursor of the modified component can be a soluble compound containing the modified component conventionally known in the art, such as a halide (such as chloride, bromide, iodide), nitrate, acetate, carbonate, sulfate, hydroxide, amide, a compound containing an organic group (such as citrate, oxalate, etc.) of the modified component, and a combination thereof.
  • a halide such as chloride, bromide, iodide
  • nitrate such as chloride, bromide, iodide
  • acetate such as carbonate, sulfate
  • hydroxide such as sodium bicarbonate
  • amide such as sodium bicarbonate
  • a compound containing an organic group such as citrate, oxalate, etc.
  • the content of the precursor of the modified component in the solution containing the precursor of the modified component can be selected in a wide range, such as the content of the precursor of the modified component in the solution can be 0.1-400g/L.
  • the amount of the modified component is such that the content of the modified component in the obtained catalyst is 0.01-20wt%, for example, 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 20wt%, and any value within the range of any two values, preferably 0.2-5wt%.
  • the amount of the modified component is 0.01-20 parts by weight, preferably 0.2-5 parts by weight.
  • the solvents in the solution containing the precursor of palladium and the solution containing the precursor of the modifying component can be independently selected from water, ether, ethanol, isobutanol and the like.
  • the drying temperature of step 1) is 50-220°C, preferably 80-150°C, and the time is 1-48h, preferably 2-24h; the calcination temperature is 300-1500°C, preferably 350-1250°C, and the time is 2-24h, preferably 6-24h, and the calcination atmosphere is selected from an inert gas, nitrogen, an oxygen-containing atmosphere, or a combination thereof, wherein the oxygen content in the calcination atmosphere is 0-40wt%.
  • the modifying component in step 1), can be loaded on the carrier together with palladium or separately.
  • palladium and the modifying component can be loaded on the carrier together, or the modifying component can be loaded on the carrier first, and then palladium and the optional additional modifying component can be loaded on the carrier.
  • step 1) palladium and a modifying component are loaded onto the support together.
  • the drying temperature in step 1) can be 60-180°C, for example, 60°C, 80°C, 120°C, 160°C, 180°C, and any value within the range formed by any two of the values, preferably 80-150°C.
  • the drying time can be independently 1-48h, for example, 1h, 5h, 10h, 20h, 30h, 40h, 48h, and any value within the range formed by any two of the values, preferably 2-24h.
  • the drying can be carried out in an inert atmosphere, a nitrogen atmosphere, an air atmosphere or a vacuum, preferably in an air atmosphere.
  • the drying can be carried out once or multiple times, and the drying conditions can be different each time.
  • the calcination temperature in step 1) can be 300-700°C, for example, 300°C, 400°C, 500°C, 600°C, 700°C, and any value in the range of any two values therein, preferably 350-600°C, for example, 350°C, 400°C, 500°C, 600°C, and any value in the range of any two values therein.
  • the calcination time can be 2-24h, for example, 2h, 4h, 8h, 12h, 16h, 20h, 24h, and any value in the range of any two values therein, preferably 6-15h.
  • the calcining atmosphere is selected from an inert gas, nitrogen, an oxygen-containing atmosphere, or a combination thereof, preferably selected from an atmosphere of nitrogen, air, or a mixture of an inert gas and oxygen.
  • the oxygen content in the calcining atmosphere is 0-40wt%, for example, 0wt%, 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, and any value within the range formed by any two of the values.
  • step 1) further comprises:
  • step 1b when the additional modifying component is used in step 1b), it may be the same as or different from the modifying component used in step 1a). Its specific selection is as described in the first aspect of the present application and will not be repeated here.
  • the drying temperature may be 50-220°C, for example, 50°C, 60°C, 80°C, 120°C, 160°C, 180°C, 200°C, 210°C, 220°C, and any value within the range of any two values, preferably 80-150°C.
  • the drying time may be 1-48h, for example, 1h, 5h, 10h, 20h, 30h, 40h, 48h, and any value within the range of any two values, preferably 2-12h.
  • the drying may be carried out in an inert atmosphere, a nitrogen atmosphere, an air atmosphere or a vacuum, preferably in an air atmosphere.
  • the drying may be carried out once or multiple times, and the drying conditions may be different each time.
  • the calcination temperature may be 700-1500°C, for example, 700°C, 800°C, 1000°C, 1200°C, 1400°C, 1500°C, and any value within the range of any two values therein; preferably 800-1250°C, for example, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1250°C, and any value within the range of any two values therein.
  • the calcination time may be 2-24h, for example, 2h, 4h, 8h, 12h, 16h, 20h, 24h, and any value within the range of any two values therein, preferably 6-15h.
  • the calcining atmosphere is selected from an inert gas, nitrogen, an oxygen-containing atmosphere, or a combination thereof, preferably selected from nitrogen, air, or an atmosphere of a mixture of an inert gas and oxygen.
  • the oxygen content in the calcining atmosphere is 0-40wt%, for example, 0wt%, 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, and any value within the range formed by any two of the values, and air atmosphere is particularly preferred.
  • the drying temperature may be 60-180°C, for example, 60°C, 80°C, 120°C, 160°C, 180°C, and any value within the range formed by any two of the values, preferably 80-150°C.
  • the drying time may be independently 1-48h, for example, 1h, 5h, 10h, 20h, 30h, 40h, 48h, and any value within the range formed by any two of the values, preferably 2-24h.
  • the drying may be carried out in an inert atmosphere, a nitrogen atmosphere, an air atmosphere or a vacuum, preferably in an air atmosphere.
  • the drying may be carried out once or multiple times, and the drying conditions may be different each time.
  • the calcination temperature may be 300-700°C, for example, 300°C, 400°C, 500°C, 600°C, 700°C, and any value within the range of any two values thereof, preferably 350-650°C, for example 350°C, 400°C, 500°C, 600°C, 650°C, and any value within the range formed by any two of them.
  • the calcination time can be 2-24h, for example, 2h, 4h, 8h, 12h, 16h, 20h, 24h, and any value within the range formed by any two of them, preferably 6-15h.
  • the calcination atmosphere is selected from an inert gas, nitrogen, an oxygen-containing atmosphere, or a combination thereof, preferably selected from nitrogen, air, or an atmosphere mixed with an inert gas and oxygen.
  • the oxygen content in the calcination atmosphere is 0-40wt%, for example, 0wt%, 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, and any value within the range formed by any two of them.
  • the alkaline compound contained in the alkaline solution used in step 2) is not strictly limited, as long as it can provide an alkaline solution with a desired pH value, for example, it can be an inorganic alkaline compound, an organic alkaline compound or a mixture thereof, preferably a weakly alkaline compound.
  • the organic alkaline compound is selected from organic amines (such as aliphatic amines, alcohol amines, amides, aromatic amines), pyridine compounds, or combinations thereof, more preferably selected from dimethylamine, triethylamine, trifluoroacetamide, pyridine, 4-dimethylaminopyridine, triethanolamine, or combinations thereof.
  • organic amines such as aliphatic amines, alcohol amines, amides, aromatic amines
  • pyridine compounds or combinations thereof, more preferably selected from dimethylamine, triethylamine, trifluoroacetamide, pyridine, 4-dimethylaminopyridine, triethanolamine, or combinations thereof.
  • the inorganic alkaline compound is selected from ammonia water, a halide (such as KF, NaF, lithium chloride), a citrate (such as sodium citrate or potassium citrate), an oxalate (such as sodium oxalate, potassium oxalate), an acetate (such as sodium acetate, potassium acetate), a bicarbonate (such as sodium bicarbonate, potassium bicarbonate), a carbonate (such as sodium carbonate, potassium carbonate), or a combination thereof, preferably selected from KF, lithium chloride, potassium acetate, sodium bicarbonate, sodium citrate, or a combination thereof.
  • a halide such as KF, NaF, lithium chloride
  • a citrate such as sodium citrate or potassium citrate
  • an oxalate such as sodium oxalate, potassium oxalate
  • an acetate such as sodium acetate, potassium acetate
  • a bicarbonate such as sodium bicarbonate, potassium bicarbonate
  • the solvent in the alkaline solution can be any solvent that can dissolve the above alkaline compound, preferably selected from water, ethanol, acetone, tetrahydrofuran, or a combination thereof.
  • the concentration of the alkaline compound in the alkaline solution is 0.1-70wt%, for example, it can be 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, 70wt% and any value within the range formed by any two of the values.
  • the amount of the alkaline compound in step 2) is 0.1-25wt%, for example, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 4wt%, 6wt%, 8wt%, 10wt%, 15wt%, 20wt%, 25wt%, And any value within the range formed by any two of the values.
  • the amount of the basic compound is 0.1-25 parts by weight relative to 100 parts by weight of the carrier.
  • the drying temperature is 60-180°C, for example, 60°C, 80°C, 120°C, 160°C, 180°C, and any value within the range formed by any two of the values, preferably 70-140°C.
  • the drying time is 1-48h, for example, 1h, 5h, 10h, 20h, 30h, 40h, 48h, and any value within the range formed by any two of the values, preferably 6-20h.
  • the drying can be carried out in an inert atmosphere, a nitrogen atmosphere, an air atmosphere or a vacuum, preferably in an air atmosphere.
  • the drying can be carried out once or multiple times, and the drying conditions can be different each time.
  • the calcination temperature is 200-500°C, for example, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, and any value within the range of any two values therein, preferably 250-450°C, for example, 250°C, 300°C, 400°C, 450°C, and any value within the range of any two values therein.
  • the calcination time may be 2-24h, for example, 2h, 4h, 8h, 12h, 16h, 20h, 24h, and any value within the range of any two values therein, preferably 6-20h.
  • the calcining atmosphere is selected from an inert gas, nitrogen, an oxygen-containing atmosphere, or a combination thereof, preferably selected from nitrogen, air, or an atmosphere mixed with an inert gas and oxygen.
  • the oxygen content in the calcining atmosphere is 0-25wt%, for example, 0wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, and any value within the range formed by any two of the values.
  • the catalyst preparation method of the present application provides an overall weakly acidic surface environment and a specific weakly basic center for the catalyst by loading a modified component on the catalyst and combining a specific alkalization treatment step, so that the catalyst shows better catalytic activity and selectivity in the hydrogenation reaction of unsaturated hydrocarbons (especially the selective hydrogenation reaction of alkynes and polyunsaturated hydrocarbons, such as materials containing propyne and propadiene (MAPD)).
  • the preparation method is simple and easy to implement, and is convenient for industrial production.
  • the supported palladium catalyst of the present application in the hydrogenation reaction of unsaturated hydrocarbons, especially the selective hydrogenation reaction of alkynes and polyunsaturated hydrocarbons.
  • a method for hydrogenating unsaturated hydrocarbons comprising the steps of contacting an unsaturated hydrocarbon feedstock containing alkynes and/or polyunsaturated hydrocarbons with the supported palladium catalyst of the present application in the presence of hydrogen for reaction.
  • the catalyst of the present application is suitable for the hydrogenation reaction of various alkynes and polyunsaturated hydrocarbons, wherein the alkynes can be selected from C2-C5 alkynes, preferably selected from C2-C3 alkynes, and the polyunsaturated hydrocarbons can be selected from C3-C5 dienes, preferably selected from C3-C4 dienes.
  • Materials suitable for selective hydrogenation using the supported palladium catalyst of the present application include various materials containing dienes and/or alkynes commonly found in the chemical industry, such as materials containing dienes and/or alkynes in catalytic cracking or steam cracking processes, such as C2, C3 or C4 fractions, and in particular materials containing MAPD.
  • the method includes contacting a C3 fraction containing MAPD with a supported palladium catalyst of the present application in the presence of hydrogen at an inlet temperature of 20-60°C, a molar ratio of hydrogen to the sum of propyne (MA) and propadiene (PD) of 1.0-5.0:1, and a reaction pressure of 1.0-4.0 MPa, and selectively hydrogenating the MAPD in the fraction into propylene in the liquid phase.
  • a supported palladium catalyst of the present application in the presence of hydrogen at an inlet temperature of 20-60°C, a molar ratio of hydrogen to the sum of propyne (MA) and propadiene (PD) of 1.0-5.0:1, and a reaction pressure of 1.0-4.0 MPa
  • the method comprises contacting a cracked gas stream containing a C2 fraction, a C3 fraction, hydrogen, CO, methane, and a small amount of C4 fraction with the supported palladium catalyst of the present application in the presence of hydrogen under the conditions of an inlet temperature of 20-120° C. , a reaction pressure of 1.0-4.0 MPa, and a gas phase space velocity of 5000-30000 h -1, and reacting the acetylene and part of the MAPD in the cracked gas stream into ethylene and propylene.
  • the reagents used are all reagents conventionally used in the art, and the methods adopted are all conventional methods in the art.
  • the Al 2 O 3 carriers used in the following examples and comparative examples were purchased from Sinopec Catalyst (Beijing) Co., Ltd., with a specific surface area of 10-220 m 2 /g; the Al 2 O 3 -Ga 2 O 3 mixed carrier was from Sinopec (Beijing) Chemical Research Institute Co., Ltd., with a specific surface area of 10-200 m 2 /g; the activated carbon carrier was from Sinopec (Beijing) Chemical Research Institute Co., Ltd., prepared with organic polymer as the base material, with a specific surface area of 100-400 m 2 /g.
  • the specific composition of the obtained catalyst can be calculated based on the amounts of the carrier, Pd and the modified component, and the reagents used for alkalization treatment and adjusting the pH value of the solution are not included in the catalyst composition.
  • a 250 mL aqueous solution containing Pd(NO 3 ) 2 (0.3 g as Pd), AgNO 3 (0.5 g as Ag) and Zn(NO 3 ) 2 (1.1 g as Zn) was prepared, aqueous ammonia was introduced into the solution to make the pH value 4.1, an equal volume of 500 g of spherical carrier Al 2 O 3 (specific surface area of 112 m 2 /g) was immersed in the solution, the solution was dried at 105°C for 12 h, and calcined at 650°C for 15 h to obtain a Pd-Zn-Ag/Al 2 O 3 intermediate.
  • the amount of KF added was adjusted to prepare 250 mL of KF aqueous solution with a pH of 7.5.
  • the solution was sprayed on the Pd-Zn-Ag/ Al2O3 intermediate at a temperature of 45°C and a spraying time of 4 min.
  • the catalyst was dried at 160°C for 4 h and calcined at 300°C for 4 h to obtain catalyst A with a specific surface area of 101 m2 /g.
  • the amount of K(OAc) added was adjusted to prepare 400 mL of K(OAc) ethanol solution with a pH of 8.2.
  • the solution was sprayed on the Pd-Cs/ Al2O3 intermediate at a constant temperature of 60°C and a spraying time of 2 min.
  • the catalyst was dried at 80°C for 3 h and calcined at 400°C for 6 h to obtain catalyst C with a specific surface area of 15 m2 / g.
  • DMAP 4-dimethylaminopyridine
  • the solution was sprayed on the Pd-La-K/Al 2 O 3 intermediate at a temperature of 50°C and a spraying time of 3.5 min.
  • the catalyst was dried at 125°C for 10 h and calcined at 445°C for 16 h to obtain catalyst E with a specific surface area of 56 m 2/ g.
  • 500 g of spherical carrier Al 2 O 3 (specific surface area of 146 m 2 / g) was impregnated in the solution, dried at 125°C for 10 h, and calcined at 1050°C for 20 h to obtain an alkalized Al 2 O 3 intermediate.
  • catalyst F was obtained with a specific surface area of 78 m2 / g.
  • the amount of NaOH added was adjusted to prepare 220 mL of NaOH aqueous solution with a pH of 12.
  • the solution was sprayed on the Pd-La-K/Al 2 O 3 intermediate at room temperature for 5 min, dried at 105°C for 10 h, and calcined at 250°C for 4 h to obtain catalyst I with a specific surface area of 51 m 2/ g.
  • the amount of NaHCO 3 added was adjusted to prepare 290 mL of NaHCO 3 aqueous solution with a pH of 7.8.
  • the Pd-La-K/Al 2 O 3 intermediate was impregnated in the solution at room temperature and for 25 min, dried at 125 °C for 10 h, and calcined at 445 °C for 6 h to obtain catalyst J with a specific surface area of 45 m 2/ g.
  • This test example is used to illustrate the pyrrole in-situ adsorption infrared spectroscopy analysis of the catalysts obtained in the examples and comparative examples.
  • the catalysts prepared in the examples and comparative examples were tested for pyrrole adsorption using a pyrrole in-situ infrared analyzer (Thermonicolet 380). About 10 mg of the powder sample was pressed into a thin sheet, fixed in an infrared cell, first vacuum purified (350°C, 1 ⁇ 10 -3 Pa) for 2 h, cooled to 40°C, and the spectrum was scanned as background.
  • a pyrrole in-situ infrared analyzer Thermonicolet 380.
  • About 10 mg of the powder sample was pressed into a thin sheet, fixed in an infrared cell, first vacuum purified (350°C, 1 ⁇ 10 -3 Pa) for 2 h, cooled to 40°C, and the spectrum was scanned as background.
  • the determination method of the pyrrole adsorption in-situ infrared spectrum of the catalyst is as follows:
  • Figures 1A to 1J show the corresponding pyrrole adsorption in-situ infrared spectra of catalysts A-J prepared in Examples and Comparative Examples.
  • Figure 2 shows the in-situ infrared spectra of pyrrole adsorption of catalyst E over time.
  • 0min represents the infrared absorption spectrum before the end of nitrogen purge and the start of pyrrole adsorption
  • 4min, 6min, and 10min represent the infrared absorption spectra after 4min, 6min, and 10min of pyrrole adsorption, respectively
  • 25min represents the infrared absorption spectrum after 10min of pyrrole adsorption and nitrogen purge for 15min.
  • Table 1 shows that the pyrrole adsorption for 10 minutes is in the range of 3150-3420 cm -1 .
  • the pyrrole adsorption in-situ infrared spectra of catalysts AE and KL prepared by the method of the examples of the present application have absorption peaks in the wave number range of 3250-3410 cm -1 ; the peak position of the pyrrole adsorption in-situ infrared spectra of catalyst FH prepared in the comparative example is greater than 3410 cm -1 , while the peak positions of the pyrrole adsorption in-situ infrared spectra of catalysts I and J are both less than 3250 cm -1 .
  • This test example is used to illustrate the pyridine temperature program of the catalyst obtained in the examples and comparative examples. Adsorption-desorption in situ infrared spectroscopy analysis.
  • the catalysts prepared in the examples and comparative examples were subjected to a programmed temperature adsorption and desorption test using an in-situ infrared analyzer (Thermonicolet 380). About 10 mg of a powder sample was pressed into a sheet, fixed in an infrared cell, first vacuum purified (350°C, 1 ⁇ 10-3Pa) for 2 hours, cooled to 150°C, and the spectrum was scanned as background.
  • the method for determining the in-situ infrared spectrum of pyridine adsorption of the catalyst is as follows:
  • the temperature was programmed to the measuring temperature (the fixed point temperatures were 150°C and 300°C, respectively) for vacuum desorption (1 ⁇ 10 -3 Pa) for 0.5 h, and then cooled to room temperature, respectively, and the infrared spectrum in the wavenumber region of 1700-1400 cm -1 was recorded, wherein the programmed heating rate was 20°C/min.
  • the adsorbed pyridine concentration of the sample measured after desorption at 150°C represents the total amount of acids of different strengths (including L acid and B acid) on the sample surface
  • the adsorbed pyridine concentration of the sample after desorption at 300°C represents the total amount of strong acid and strong acid on the sample surface, where the absorption peak near 1540cm -1 corresponds to B acid and the absorption peak near 1450cm -1 corresponds to L acid.
  • the adsorbed pyridine concentration of the acid center on the catalyst surface at different temperatures is calculated according to the following adsorbed pyridine concentration formula:
  • C weak acid C 150°C -C 300°C
  • C represents the concentration of pyridine adsorbed on the acid center of the catalyst surface (mmol/g); 1.88 and 1.42 are the extinction coefficients of B acid and L acid, respectively; IA(B) and IA(L) are the integrated peak areas of the characteristic peaks of B acid and L acid, respectively; R represents the radius of the self-supporting molecular sieve tablet (cm); W represents the mass of the tablet (mg).
  • Table 2 shows the adsorbed pyridine concentrations at the acid centers on the surfaces of various catalysts measured by in-situ infrared spectroscopy analysis of pyridine temperature-programmed adsorption-desorption.
  • the acid amount and acid amount distribution of the catalysts obtained in each embodiment and comparative example are different.
  • the weak acid amount of the catalysts A-E and K-L obtained in the examples of the present application is within the range of 0.1-0.25 mmol/g, and the medium-strong acid and strong acid amount are less than 0.1 mmol/g.
  • the catalysts H and J obtained in the comparative example have moderate weak acid amounts and no medium-strong and strong acids.
  • the medium-strong and strong acid amounts of catalysts F and G are high, while the acid amount of catalyst I is extremely low, indicating that there is almost no acid center.
  • the results of Table 2 show that the surfaces of the catalysts A-E and K-L of the present application are weakly acidic as a whole.
  • This example is used to illustrate the effect of the catalyst obtained in the examples and comparative examples on catalytic hydrogenation of carbon three.
  • the experiment was conducted in the range of 1.0-1.8 molar ratio of hydrogen to propyne and propadiene (MAPD) and 25-55°C reactor inlet temperature.
  • the outlet MAPD content was controlled to be less than 100 ppm.
  • the lowest H 2 /MAPD ratio and inlet temperature of each catalyst were selected, and the results are shown in Table 3.
  • the reaction pressure was controlled to be 1.8 MPa
  • the liquid phase space velocity was 62 h -1
  • the catalytic reaction was carried out
  • the selectivity of each catalyst reaction to propylene was calculated.
  • Table 3 the calculation method is:
  • the catalysts A-E obtained in the examples of the present application have higher selectivity for propylene while ensuring that the outlet MAPD is less than 100 ppm. This shows that the modification of adding extremely weak basic centers in the weak acid environment on the catalyst surface can better improve the catalytic performance of the catalyst, and the catalyst having the specific basic center of the present application has a better catalytic effect.
  • This example is used to illustrate the effect of using the catalysts obtained in the examples and comparative examples for hydrogenation of cracked gas streams.
  • the cracked gas stream hydrogenation process uses three sections of adiabatic fixed bed reactors in series for hydrogenation, with a catalyst loading of 200 ml in each section and a heat exchanger between each section to control the feed temperature.
  • the composition of the cracked gas stream at the reactor inlet is 13.5 mol% hydrogen, 755 ppm CO, 33 mol% ethylene, 0.6 mol% acetylene, 17 mol% propylene, 0.3 mol% MA, and PD
  • the space velocity of hydrogenation reaction is 15000h -1 , the pressure is 2.6MPa, the inlet temperature of the first reactor is 50-60°C, the inlet temperature of the second reactor is 50-60°C, and the inlet temperature of the third reactor is 55-65°C.
  • the catalysts prepared in the examples and comparative examples were used for the above hydrogenation reaction, and the acetylene content at the outlet of the final reactor was controlled to be less than 0.2 ppm.
  • the results of MAPD conversion (%), operation cycle (h), ethylene selectivity (%), propylene selectivity (%) and C4+ generation (mol%) are shown in Table 4.
  • the operation cycle refers to the time the system can operate when the total acetylene content at the outlet of the final reactor is controlled below 0.2 ppm.
  • the selectivity to ethylene is calculated as:
  • the calculation method for MAPD conversion rate is:
  • the selectivity to propylene is calculated as:
  • the amount of C4+ generated is the sum of the contents of C4 and above components in the component analysis at the outlet of the second-stage reactor.

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Abstract

提供了一种负载型钯催化剂、及其制备和应用，包括载体和负载在载体上的钯和改性组分，载体选自难熔金属氧化物、氧化硅、活性炭，或者它们的组合，改性组分选自Bi、Sb、Pb、Sn、Zn、W、Mn、Si、Re、不同于钯的第Ⅷ族元素、碱金属元素、碱土金属元素、第ⅢA族元素、第ⅠB族元素、稀土元素、卤族元素，或者它们的组合，其中根据40℃下进行的吡咯吸附原位红外光谱分析，催化剂在3251-3410cm -1范围内显示出吸收峰。负载型钯催化剂的表面整体呈弱酸性环境，并且具有特定的弱碱性中心，使得催化剂具有更好的催化性能。

Description

一种负载型钯催化剂、及其制备和应用 技术领域
本申请涉及催化剂领域，具体涉及一种负载型钯催化剂、及其制备和应用。
背景技术
钯(Pd)系催化剂在石化工业中已经得到广泛的应用，如催化重整、烷烃、芳烃的异构化反应、脱氢反应，烯烃生产中的选择加氢反应，乙醛、醋酸乙烯、甲基丙烯酸甲酯等有机化工原料的生产均离不开钯系催化剂。此外，在各类有机化学反应中如氢化、氧化脱氢、氢化裂解、偶联、氢酯基化、碳一化学以及汽车尾气净化等反应中，钯是优良的催化剂或是催化剂的重要组分之一。
由于纯的贵金属类催化剂存在价格昂贵、活性温度范围窄、有氧化存在容易失活等缺点，应用上受限严重，因此钯系贵金属类催化剂的开发主要以负载型催化剂为主，如CN113067000A公开一种含氧空位的TiO2上负载Pd-Co纳米合金催化剂。通过浸渍法、金属离子蒸汽沉积法、溶剂化金属原子浸渍法、离子交换法以及溶胶凝胶法，钯被分散在适宜的在载体上使用。针对不同的反应，采用适合的载体，如CN112517063A公开一种用于乙烯法制备醋酸乙烯的Pd-Au单质态负载催化剂制备方法，将氯钯酸、氯金酸浸渍于二氧化硅载体上，再加入表面活性剂和硅酸钠水溶液，使钯和金化合物沉淀，经过氢气还原为单质态和醋酸钾溶液浸渍制备催化剂，有效地提升了催化剂的活性和选择性。
载体表面酸碱度直接影响催化剂表面“金属—载体相互作用”的程度及活性金属的分散状态，随即决定催化剂的活性、选择性。酸性中心或碱性中心的作用往往使许多反应能顺利地进行，例如某些加氢、氢转移、醛醇缩合反应等。在酸性催化加氢反应中结焦常常是一个麻烦的问题，而碱性催化剂上的加氢反应通常不会结焦，但较高的碱性容易造成催化剂失活。因此，本领域亟待开发一种具有良好的催化效果负载型钯系催化剂。
发明内容
本申请的目的是提供一种负载型钯催化剂、及其制备和应用，所述负载型钯催化剂的表面整体呈弱酸性环境，并且具有特定的弱碱性中心，使得该催化剂具有更好的催化性能。
为了实现上述目的，一方面，本申请提供了一种负载型钯催化剂，包括载体和负载在载体上的钯和改性组分，所述载体选自难熔金属氧化物、氧化硅、活性炭，或者它们的组合，所述改性组分选自Bi、Sb、Pb、Sn、Zn、W、Mn、Si、Re、不同于钯的第Ⅷ族元素、碱金属元素、碱土金属元素、第ⅢA族元素、第ⅠB族元素、稀土元素、卤族元素，或者它们的组合，其中根据40℃下进行的吡咯吸附原位红外光谱分析，所述催化剂在3251-3410cm-1范围内显示出吸收峰。
优选地，根据40℃下进行的吡咯吸附原位红外光谱分析，所述催化剂在吡咯吸附10分钟后用氮气吹扫0分钟时测得的原位红外谱图中在3251-3410cm-1范围内显示出的吸收峰的峰高与用氮气吹扫15分钟时测得的原位红外谱图中3251-3410cm-1范围内的对应吸收峰的峰高之比大于或等于5：1。
另一方面，提供了制备本申请的负载型钯催化剂的方法，包括以下步骤：
1)将钯和改性组分负载到载体上，并干燥和焙烧，得到中间体；以及
2)用pH值为7.2-10的碱性溶液对所述中间体进行碱化处理，并干燥和任选地焙烧，得到所述催化剂，
其中所述碱化处理通过用所述碱性溶液进行喷涂来实现，喷涂时间为2-8min，喷涂温度为35-70℃。
再一方面，提供了本申请的负载型钯催化剂在不饱和烃加氢反应中的应用，其中所述不饱和烃选自炔烃、多不饱和烃，或者它们的组合。
又一方面，提供了一种不饱和烃加氢方法，包括在氢气存在下，使包含炔烃和/或多不饱和烃的不饱和烃原料与本申请的负载型钯催化剂接触反应的步骤。
本申请的负载型钯催化剂在40℃下测得的吡咯吸附原位红外谱图中，在3251-3410cm-1范围内显示出吸收峰，表明该催化剂表面存在特定的弱碱性中心。本申请的负载型钯催化剂表面整体呈弱酸性，同时又 具有特定的弱碱性中心，使得该催化剂用于不饱和烃加氢(特别是炔烃和多不饱和烃的选择性加氢)时，相比现有催化剂具有更好的催化活性和选择性。
本申请的催化剂制备方法采用了碱性溶液在特定条件下对负载钯和改性组分的中间体进行碱化处理，为所得催化剂提供了特定的弱碱性中心，该催化剂在40℃下测得的吡咯吸附原位红外谱图中，在3251-3410cm-1范围内显示出吸收峰，进而使得其用于不饱和烃加氢(特别是炔烃和多不饱和烃的选择性加氢)时具有更好的催化活性和选择性。而且，该制备方法简单易行，便于工业化生产。
本申请的其他特征和优点将在随后的具体实施方式部分予以详细说明。
附图说明
附图是用来提供对本申请的进一步理解，并且构成说明书的一部分，与下面的具体实施方式一起用于解释本申请，但并不构成对本申请的限制。在附图中：
图1A至图1J示出了实施例和对比例中制备得到的催化剂A-J的吡咯吸附原位红外谱图；以及
图2示出了催化剂E的随时间变化的吡咯吸附原位红外谱图。
具体实施方式
以下结合附图对本申请的具体实施方式进行详细说明。应当理解的是，此处所描述的具体实施方式仅用于说明和解释本申请，并不用于限制本申请。
在这里专用的词“示例性”意为“用作例子、实施例或说明性”。这里作为“示例性”所说明的任何实施例不必解释为优于或好于其它实施例。尽管在附图中示出了实施例的各种方面，但是除非特别指出，不必按比例绘制附图。
在本文中所披露的任何具体数值(包括数值范围的端点)都不限于该数值的精确值，而应当理解为还涵盖了接近该精确值的值，例如在该精确值±5％范围内的所有可能的数值。并且，对于所披露的数值范围而言，在该范围的端点值之间、端点值与范围内的具体点值之间，以及各 具体点值之间可以任意组合而得到一个或多个新的数值范围，这些新的数值范围也应被视为在本文中具体公开。
除非另有说明，本文所用的术语具有与本领域技术人员通常所理解的相同的含义，如果术语在本文中有定义，且其定义与本领域的通常理解不同，则以本文的定义为准。
在本申请中，术语“多不饱和烃”指具有两个或更多个(例如2-4个)选自碳碳双键和碳碳三键的不饱和键的脂肪族烃类化合物，例如具有3-5个碳原子的二烯烃。
本申请中，除了明确说明的内容之外，未提到的任何事宜或事项均直接适用本领域已知的那些而无需进行任何改变。而且，本文描述的任何实施方式均可以与本文描述的一种或多种其他实施方式自由结合，由此形成的技术方案或技术思想均视为本申请原始公开或原始记载的一部分，而不应被视为是本文未曾披露或预期过的新内容，除非本领域技术人员认为该结合明显不合理。
在本文中提及的所有专利和非专利文献，包括但不限于教科书和期刊文章等，均通过引用方式全文并入本文。
本申请的发明人经过大量研究发现，对于负载型钯加氢催化剂，在整体呈弱酸性的催化剂表面环境中，引入弱势的碱性中心可显著改善催化剂的性能，例如活性、选择性和/或运行寿命，由此完成了本发明。
如上所述，本申请在第一方面提供了一种负载型钯催化剂，包括载体和负载在载体上的钯和改性组分，其中根据40℃下进行的吡咯吸附原位红外光谱分析，所述催化剂在3251-3410cm-1范围内、优选在3350-3400cm-1范围内显示出吸收峰。
根据本申请，在具体的实施方式中，所述催化剂的吡咯吸附原位红外谱图可以采用以下方法测得：
a)将粉末态的催化剂样品置于红外池中，经过真空处理后，升温至350℃，升温速率为20℃/min；
b)在真空状态中于350℃下保温2h，然后降温至40℃，降温速率为20℃/min；
c)保持温度为40℃，通入氮气吹扫30分钟，氮气流量为5mL/min；
d)保持温度为40℃，通入气态吡咯，吸附10分钟，气体流量为 5mL/min，并记录样品的原位红外谱图；
e)保持温度为40℃，改用氮气吹扫30分钟，氮气流量为5mL/min，并记录样品的原位红外谱图。
测定结束后，可以保持氮气吹扫直到温度降至室温，氮气流量为3-7mL/min。
在上述具体实施方式中，在进行测试之前，先将颗粒状的催化剂样品研磨为粉末状，填于原位样品池内并保持表面平整。步骤a)到c)的目的是去除催化剂表面吸附的水和杂质。在吡咯吸附步骤d)中，也可以根据需要在不同的时间记录样品的原位红外谱图，比如可以在1分钟、2分钟、3分钟、4分钟、5分钟、6分钟、7分钟、8分钟、9分钟、10分钟分别记录样品的原位红外谱图。
在固体催化剂的吡咯吸附原位红外谱图中，在3150-3410cm-1范围内会出现N-H键伸缩振动吸收峰，吸收峰出现的位置表征了该催化剂表面的碱性中心的碱强度，出峰位置的波数越高(即越接近3410cm-1)表明该碱性中心的碱强度越弱(参见“用红外光谱方法研究催化剂碱性的新进展”，太原工业大学学报，Vol.24，第101-107页，1993年9月)。如果在3150-3410cm-1范围内出现多个N-H键伸缩振动吸收峰，表明该催化剂表面的碱性中心呈现多元化。不同固体催化剂的吡咯吸附原位红外谱图的出峰位置有较大的区别，当出现多个吸收峰时，其中两个或以上的峰会发生重叠，在某些情况下其中一个峰会成为另一个峰的肩峰。为了计算出各个吸收峰的出峰位置，可使用常用的数据处理软件对3150-3410cm-1区间的吸收曲线进行分峰拟合。
根据本申请的负载型钯催化剂在40℃下测得的吡咯吸附原位红外谱图中，在3251-3410cm-1范围内，例如在3260cm-1、3270cm-1、3300cm-1、3320cm-1、3340cm-1、3360cm-1、3380cm-1、3400cm-1、3410cm- 1以及其中任意两个值构成的范围内的任意位置，优选在3350-3400cm- 1范围内显示出N-H键伸缩振动吸收峰，表明所述催化剂的表面存在极弱的碱性中心。
不局限于具体理论，本申请的发明人发现，当负载型钯催化剂的表面整体呈弱酸性时，用于不饱和烃加氢(特别是炔烃和多不饱和烃的选择性加氢)，相比于表面呈碱性的催化剂更有利于加氢反应的进行。进一步地，当该催化剂表面进一步具有本申请所述的弱碱性中心(对应在 吡咯吸附原位红外谱图的3251-3410cm-1范围内显示出吸收峰)时，所述催化剂表面的弱碱性中心与整体的弱酸性环境协同配合，能够更有效地抑制单烯烃加氢生成烷烃的反应，并减少或消除炔烃和二烯烃在催化剂表面的聚合，从而进一步改善该催化剂的催化性能，例如在炔烃和多不饱和烃(如包含丙炔(MA)和丙二烯(PD)的物料)的选择性加氢中的催化性能，如催化活性和选择性。
在上述吡咯吸附原位红外光谱分析过程中，在步骤e)中使用氮气进行吹扫后，所得谱图中的红外吸收峰的强度会逐渐减弱。氮气吹扫15分钟时谱图中3150-3420cm-1范围内的吸收峰的峰高相对于吹扫0分钟时谱图中3150-3420cm-1范围内对应吸收峰的峰高如果发生明显变化，则表明催化剂表面存在显著量的对于吡咯具有吸附能力的碱性中心。
在优选的实施方式中，根据40℃下进行的吡咯吸附原位红外光谱分析，本申请的催化剂在吡咯吸附10分钟后用氮气吹扫0分钟时测得的原位红外谱图中在3251-3410cm-1范围内显示出的吸收峰的峰高与用氮气吹扫15分钟时测得的原位红外谱图中3251-3410cm-1范围内的对应吸收峰的峰高之比大于或等于5：1，优选大于或等于10：1，例如为10:1至200:1。
根据本申请，所述负载型钯催化剂在40℃下测得的吡咯吸附原位红外谱图中，在3160-3250cm-1范围内可以显示或不显示吸收峰。优选地，所述催化剂在3200-3250cm-1范围内、更优选在3160-3250cm-1范围内不显示吸收峰，表明该催化剂的表面除了所述极弱的碱性中心之外不存在其他更强的碱性中心。
在优选的实施方式中，根据吡啶程序升温吸附脱附原位红外光谱分析，本申请的催化剂在150℃脱附后测得的表面吸附吡啶浓度与300℃脱附后测得的表面吸附吡啶浓度的差值在0.1-0.25mmol/g的范围内，优选在0.1-0.2mmol/g范围内，并且在300℃脱附后测得的表面吸附吡啶浓度在0-0.1mmol/g的范围内，优选在0-0.08mmol/g的范围内。
在优选的实施方式中，根据吡啶程序升温吸附脱附原位红外光谱分析，本申请的催化剂在150℃脱附后测得的表面吸附吡啶浓度与300℃脱附后测得的表面吸附吡啶浓度的差值相对于150℃脱附后测得 的表面吸附吡啶浓度的比例在60-100％范围内，优选在75-100％范围内。
根据本申请，在所述催化剂的吡啶程序升温吸附脱附原位红外光谱分析中，在150℃脱附后测得的所述催化剂的表面吸附吡啶浓度表征了所述催化剂表面的总酸量(即弱酸、中强酸和强酸的总量)，在300℃脱附后测得的所述催化剂的表面吸附吡啶浓度表征了所述催化剂表面的中强酸和强酸的总量，而两者的差值则表征了所述催化剂表面的弱酸含量。相应地，所述催化剂在150℃脱附后测得的表面吸附吡啶浓度与300℃脱附后测得的表面吸附吡啶浓度的差值相对于150℃脱附后测得的表面吸附吡啶浓度的比例表征了所述催化剂表面的弱酸量相对总酸量的占比(本文中也称为弱酸占比)。所述催化剂表面的酸中心包括酸(简称B酸)和Lewis酸(简称L酸)，在该催化剂的吡啶程序升温吸附脱附原位红外谱图中，波数1540cm-1附近的谱峰对应于B酸，而波数1440-1450cm-1附近的谱峰对应于L酸。
根据本申请，所述负载型钯催化剂以钯为催化活性组分，其含量可以在较宽范围内选择。优选地，以载体的重量为基准并以金属元素计，所述催化剂中钯的含量为0.01-20wt％，例如，可以为0.01wt％、0.02wt％、0.05wt％、0.1wt％、0.5wt％、1wt％、5wt％、10wt％、20wt％、以及其中任意两个值构成的范围内的任意值，优选为0.01-5wt％，更优选0.02-1wt％。
根据本申请，钯在所述催化剂表面的存在形态可以为氧化态、单质态、其它钯化合物形态，或它们中两种以上的混合态。
根据本申请，所述负载型钯催化剂的载体可以为本领域常规使用的载体，比如，所述载体可以选自难熔金属氧化物、氧化硅、活性炭，或者它们的组合，优选选自氧化铝、氧化锆、氧化镓、氧化硅、活性炭，或者它们的组合。
根据本申请，对所述催化剂的形状没有严格的要求，例如可以包括但不限于粉末状、粒状、球状、齿球状、拉西环、条状、圆柱状、片状或三叶草等。优选地，所述催化剂的比表面积为0.5-800m2/g，更优选为4-200m2/g，进一步优选为15-110m2/g。
根据本申请，所述负载型钯催化剂还包含改性组分，所述改性组分可以为本领域常规采用的改性组分，比如可以选自Bi、Sb、Pb、Sn、 Zn、W、Mn、Si、Re、不同于钯的第Ⅷ族元素(比如为Fe、Co、Ni、Ru、Rh、Os、Ir、Pt)、碱金属元素(比如Na、K)、碱土金属元素(比如Mg、Ca、Sr、Ba)、第ⅢA族元素(比如为Ga、In、Tl)、第ⅠB族元素(比如为Cu、Ag、Au)、稀土元素(比如为La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Yb、Lu、Y)、卤族元素(比如F、Cl、Br、I)，或者它们的组合，优选选自La、K、Ag、Zn、Ga、Cu、Au、Cs、Bi、Mg、Fe、Re，或者它们的组合。
根据本申请，所述改性组分可作为助活性组分与钯共负载于载体上，也可用作载体改性剂均匀分布于载体之中。在优选的实施方式中，以载体的重量为基准并以金属元素计，所述催化剂中所述改性组分的含量为0.01-20wt％，例如可以为0.01wt％、0.05wt％、0.1wt％、0.5wt％、1wt％、5wt％、10wt％、15wt％、20wt％，以及其中任意两个值构成的范围内的任意值，优选0.2-5wt％。
在第二方面，提供了制备本申请的负载型钯催化剂的方法，包括以下步骤：
1)将钯和改性组分负载到载体上，并干燥和焙烧，得到中间体；以及
2)用pH值为7.2-10，优选为7.5-9的碱性溶液对所述中间体进行碱化处理，并干燥和任选地焙烧，得到所述催化剂，
其中所述碱化处理通过用所述碱性溶液进行喷涂来实现，喷涂时间为2-8min，优选3-4min，喷涂温度为35-70℃，优选45-55℃。
在优选的实施方式中，所述喷涂过程中的温度波动控制在5℃以内，即喷涂过程中的最高喷涂温度与最低喷涂温度的差值在0-5℃范围内。更优选地，所述喷涂为恒温喷涂。
在本申请的第二方面中，所述改性组分和载体的具体选择如本申请的第一方面中所述，在此不再赘述。
在本申请的方法中，对所述载体的形状没有严格的要求，例如可以包括但不限于粉末状、粒状、球状、齿球状、拉西环、条状、圆柱状、片状或三叶草等。优选地，所述载体的比表面积为0.5-800m2/g，更优选为4-200m2/g，进一步优选为15-110m2/g。
在某些具体实施方式中，所述钯和改性组分的负载可以分别采用包含钯的前体的溶液和包含改性组分的前体的溶液来进行，或者采用 包含钯前体和改性组分前体的混合溶液来进行。进行所述负载的具体方法可以为本领域常规采用的方法，比如喷涂法或浸渍法，优选喷涂法和等体积浸渍法，具体操作不再赘述。
根据本申请，所述钯的前体可以为本领域常规已知的可溶性钯化合物，比如可以选自氯化钯、硝酸钯、醋酸钯、硫酸钯、含有机基团的钯化合物(比如新戊酸钯、八乙基卟啉钯、三甲基乙酸钯、三氟乙酸钯等)，或者它们的组合，优选选自氯化钯、硝酸钯、醋酸钯、硫酸钯，或者它们的组合。
在优选的实施方式中，步骤1)中所用的包含钯前体的溶液的pH值为2-5，优选为3.8-4.5。
根据本申请，所述包含钯的前体的溶液中钯前体的含量可以在较宽范围内选择，比如所述溶液中钯前体的含量可以为1-200g//L。优选地，以载体的重量为基准并以金属元素计，钯的用量使得所得催化剂中钯的含量为0.01-20wt％，更优选0.01-5wt％，进一步优选0.02-1wt％。换言之，以金属元素计，相对于100重量份的载体，钯的用量为0.01-20重量份，更优选0.01-5重量份，进一步优选0.02-1重量份。
根据本申请，所述改性组分的前体可以为本领域常规已知的包含所述改性组分的可溶性化合物，比如可以选自所述改性组分的卤化物(比如氯化物、溴化物、碘化物)、硝酸盐、醋酸盐、碳酸盐、硫酸盐、氢氧化物、氨化物、含有机基团的化合物(比如为柠檬酸盐、草酸盐等)，和它们的组合。本领域技术人员可以根据所选的具体改性组分确定对应的前体化合物，在此不再一一列举。
根据本申请，所述包含改性组分的前体的溶液中改性组分的前体的含量可以在较宽范围内选择，比如所述溶液中改性组分的前体的含量可以为0.1-400g/L。优选地，以载体的重量为基准并以金属元素计，所述改性组分的用量使得所得催化剂中所述改性组分的含量为0.01-20wt％，例如可以为0.01wt％、0.05wt％、0.1wt％、0.5wt％、1wt％、5wt％、10wt％、20wt％，以及其中任意两个值构成的范围内的任意值，优选0.2-5wt％。换言之，以金属元素计，相对于100重量份的载体，所述改性组分的用量为0.01-20重量份，优选0.2-5重量份。
根据本申请，所述包含钯的前体的溶液和包含改性组分的前体的溶液中的溶剂可以各自独立地选自水、乙醚、乙醇和异丁醇等。
在优选的实施方式中，步骤1)的干燥温度为50-220℃、优选80-150℃，时间为1-48h，优选2-24h；焙烧温度为300-1500℃、优选350-1250℃，时间为2-24h，优选6-24h，焙烧气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，其中焙烧气氛中的氧气含量为0-40wt％。
根据本申请，在步骤1)中，所述改性组分可以与钯一同或者分开负载在所述载体上。例如，可以将钯和改性组分一起负载到载体上，或者先将改性组分负载到载体上，再将钯和任选的附加改性组分负载到所述载体上。
在某些优选的实施方式中，在所述步骤1)中，将钯和改性组分一起负载到所述载体上。
在此类优选实施方式中，步骤1)中所述干燥的温度可以为60-180℃，例如为60℃、80℃、120℃、160℃、180℃，以及其中任意两个值构成的范围内的任意值，优选为80-150℃。干燥时间可各自独立地为1-48h，例如为1h、5h、10h、20h、30h、40h、48h，以及其中任意两个值构成的范围内的任意值，优选为2-24h。所述干燥可在惰性气氛、氮气气氛、空气气氛或者真空下进行，优选在空气气氛下进行。所述干燥可以进行一次或多次，每次干燥的条件可以不同。
在此类优选实施方式中，步骤1)中所述焙烧的温度可以为300-700℃，例如为300℃、400℃、500℃、600℃、700℃，以及其中任意两个值构成的范围内的任意值，优选为350-600℃，例如为350℃、400℃、500℃、600℃，以及其中任意两个值构成的范围内的任意值。焙烧时间可为2-24h，例如可以为2h、4h、8h、12h、16h、20h、24h，以及其中任意两个值构成的范围内的任意值，优选为6-15h。所述焙烧的气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，优选选自氮气、空气或者惰性气体与氧气混合的气氛，进一步优选地，焙烧气氛中的氧气含量为0-40wt％，例如为0wt％、5wt％、10wt％、20wt％、30wt％、40wt％，以及其中任意两个值构成的范围内的任意值。
在另一些优选的实施方式中，所述步骤1)进一步包括：
1a)将改性组分负载到载体上，并干燥和焙烧，得到改性载体；以及
1b)将钯和任选的附加改性组分负载到载体上，并干燥和焙烧，得到所述中间体。
在该优选实施方式中，当步骤1b)中采用所述附加改性组分时，其可以与步骤1a)中所用的改性组分相同或不同，其具体选择如本申请第一方面中所述，在此不再赘述。
在进一步优选的实施方式中，在步骤1a)中，所述干燥的温度可以为50-220℃，例如为50℃、60℃、80℃、120℃、160℃、180℃、200℃、210℃、220℃，以及其中任意两个值构成的范围内的任意值，优选80-150℃。干燥时间可以为1-48h，例如为1h、5h、10h、20h、30h、40h、48h，以及其中任意两个值构成的范围内的任意值，优选2-12h。所述干燥可在惰性气氛、氮气气氛、空气气氛或者真空下进行，优选在空气气氛下进行。所述干燥可以进行一次或多次，每次干燥的条件可以不同。
在进一步优选的实施方式中，步骤1a)中，所述焙烧的温度可以为700-1500℃，例如为700℃、800℃、1000℃、1200℃、1400℃、1500℃，以及其中任意两个值构成的范围内的任意值；优选为800-1250℃，例如可以为800℃、900℃、1000℃、1100℃、1200℃、1250℃，以及其中任意两个值构成的范围内的任意值。焙烧时间可为2-24h，例如可以为2h、4h、8h、12h、16h、20h、24h，以及其中任意两个值构成的范围内的任意值，优选为6-15h。所述焙烧的气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，优选选自氮气、空气或者惰性气体与氧气混合的气氛，进一步优选地，焙烧气氛中的氧气含量为0-40wt％，例如为0wt％、5wt％、10wt％、20wt％、30wt％、40wt％，以及其中任意两个值构成的范围内的任意值，特别优选为空气气氛。
在进一步优选的实施方式中，在步骤1b)，所述干燥的温度可以为60-180℃，例如为60℃、80℃、120℃、160℃、180℃，以及其中任意两个值构成的范围内的任意值，优选为80-150℃。干燥时间可各自独立地为1-48h，例如为1h、5h、10h、20h、30h、40h、48h，以及其中任意两个值构成的范围内的任意值，优选为2-24h。所述干燥可在惰性气氛、氮气气氛、空气气氛或者真空下进行，优选在空气气氛下进行。所述干燥可以进行一次或多次，每次干燥的条件可以不同。
在进一步优选的实施方式中，在步骤1b)中，所述焙烧的温度可以为300-700℃，例如为300℃、400℃、500℃、600℃、700℃，以及其中任意两个值构成的范围内的任意值，优选为350-650℃，例如为 350℃、400℃、500℃、600℃、650℃，以及其中任意两个值构成的范围内的任意值。焙烧时间可为2-24h，例如可以为2h、4h、8h、12h、16h、20h、24h，以及其中任意两个值构成的范围内的任意值，优选为6-15h。所述焙烧的气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，优选选自氮气、空气或者惰性气体与氧气混合的气氛，进一步优选地，焙烧气氛中的氧气含量为0-40wt％，例如为0wt％、5wt％、10wt％、20wt％、30wt％、40wt％，以及其中任意两个值构成的范围内的任意值。
根据本申请，步骤2)中所用的碱性溶液中所含的碱性化合物没有严格的限制，只要能够提供具有所需pH值的碱性溶液即可，例如可以为无机碱性化合物、有机碱性化合物或者它们的混合物，优选为弱碱性化合物。
在优选的实施方式中，所述有机碱性化合物选自有机胺(比如为脂肪胺、醇胺、酰胺、芳香胺)、吡啶类化合物，或者它们的组合，更优选选自二甲胺、三乙胺、三氟乙酰胺、吡啶、4-二甲氨基吡啶、三乙醇胺，或者它们的组合。
在优选的实施方式中，所述无机碱性化合物选自氨水、卤化物(比如KF、NaF、氯化锂)、柠檬酸盐(比如柠檬酸钠或柠檬酸钾)、草酸盐(比如草酸钠、草酸钾)、醋酸盐(比如醋酸钠、醋酸钾)、碳酸氢盐(比如碳酸氢钠、碳酸氢钾)、碳酸盐(比如碳酸钠、碳酸钾)，或者它们的组合，优选选自KF、氯化锂、醋酸钾、碳酸氢钠、柠檬酸钠，或者它们的组合。
根据本申请，所述碱性溶液中的溶剂可以为任意能够溶解上述碱性化合物的溶剂，优选选自水、乙醇、丙酮、四氢呋喃，或者它们的组合。
在优选的实施方式中，所述碱性溶液中的碱性化合物的浓度为0.1-70wt％，例如可以为0.1wt％、0.5wt％、1wt％、5wt％、10wt％、20wt％、30wt％、40wt％、70wt％以及其中任意两个值构成的范围内的任意值。
在某些优选的实施方式中，以载体的重量为基准，步骤2)中所述碱性化合物的用量为0.1-25wt％，例如可以为0.1wt％、0.5wt％、1wt％、2wt％、4wt％、6wt％、8wt％、10wt％、15wt％、20wt％、25wt％， 以及其中任意两个值构成的范围内的任意值。换言之，相对于100重量份的载体，所述碱性化合物的用量为0.1-25重量份。
在优选的实施方式中，在步骤2)中，所述干燥的温度为60-180℃，例如为60℃、80℃、120℃、160℃、180℃，以及其中任意两个值构成的范围内的任意值，优选为70-140℃。干燥时间为1-48h，例如为1h、5h、10h、20h、30h、40h、48h，以及其中任意两个值构成的范围内的任意值，优选为6-20h。所述干燥可在惰性气氛、氮气气氛、空气气氛或者真空下进行，优选在空气气氛下进行。所述干燥可以进行一次或多次，每次干燥的条件可以不同。
在优选的实施方式中，在步骤2)中，所述焙烧的温度为200-500℃，例如为200℃、250℃、300℃、350℃、400℃、450℃、500℃，以及其中任意两个值构成的范围内的任意值，优选为250-450℃，例如为250℃、300℃、400℃、450℃，以及其中任意两个值构成的范围内的任意值。焙烧时间可为2-24h，例如可以为2h、4h、8h、12h、16h、20h、24h，以及其中任意两个值构成的范围内的任意值，优选为6-20h。所述焙烧的气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，优选选自氮气、空气或者惰性气体与氧气混合的气氛，进一步优选地，所述焙烧气氛中的氧气含量为0-25wt％，例如为0wt％、5wt％、10wt％、15wt％、20wt％、25wt％，以及其中任意两个值构成的范围内的任意值。
本申请的催化剂制备方法通过在催化剂上负载改性组分，结合特定的碱化处理步骤为催化剂提供了整体弱酸性的表面环境和特定的弱碱性中心，使其在不饱和烃加氢反应(特别是炔烃和多不饱和烃，例如包含丙炔和丙二烯(MAPD)的物料，的选择性加氢反应)中显示出更好的催化活性和选择性。而且，该制备方法简单易行，便于工业化生产。
在第三方面，提供了本申请的负载型钯催化剂在不饱和烃加氢反应，特别是炔烃和多不饱和烃的选择性加氢反应中的应用。
在第四方面，提供了一种不饱和烃加氢方法，包括在氢气存在下，使包含炔烃和/或多不饱和烃的不饱和烃原料与本申请的负载型钯催化剂接触反应的步骤。
本申请的催化剂适用于各种炔烃和多不饱和烃的加氢反应，其中所述炔烃可以选自C2-C5炔烃、优选选自C2-C3炔烃，所述多不饱和烃可以选自C3-C5的二烯烃、优选选自C3-C4的二烯烃。
适用于采用本申请的负载型钯催化剂进行选择性加氢的物料包括各种化工领域常见的含二烯烃和/或炔烃的物料，比如可以为催化裂化或蒸汽裂解工艺中含二烯烃和/或炔烃的物料，如为碳二、碳三或碳四馏分等，特别是含MAPD的物料。
本领域技术人员可以根据具体的反应类型选择合适的操作条件实现反应。例如，在某些具体实施方式中，所述方法包括在入口温度20-60℃，氢气与丙炔(MA)和丙二烯(PD)之和的摩尔比为1.0-5.0:1和反应压力为1.0-4.0Mpa的条件下，使包含MAPD的碳三馏分在氢气存在下与本申请的负载型钯催化剂接触反应，将该馏分中的MAPD液相选择性加氢为丙烯。
在另一些具体实施方式中，所述方法包括在入口温度为20-120℃，反应压力为1.0-4.0MPa，气相空速为5000-30000h-1的条件下，使含有碳二馏分、碳三馏分、氢气、CO、甲烷，以及少量碳四馏分的裂解气物流在氢气存在下与本申请的负载型钯催化剂接触反应，将该裂解气物流中的乙炔和部分MAPD选择性加氢为乙烯和丙烯。
实施例
下面结合实施例对本申请作进一步说明，但本申请的范围并不局限于这些实施例。
如无特殊说明，以下实施例和对比例中，使用的试剂均为本领域常规使用的试剂，采用的方法均为本领域常规的方法。
以下实施例和对比例中使用的Al2O3载体均购自中石化催化剂(北京)有限公司，比表面积为10-220m2/g；Al2O3-Ga2O3混合载体来自中石化(北京)化工研究院有限公司，比表面积为10-200m2/g；活性炭载体来自中石化(北京)化工研究院有限公司，是以有机高分子为基材制备而成，比表面积为100-400m2/g。
以下实施例和对比例中，所得催化剂的具体组成可以根据载体、Pd和改性组分的用量计算得到，用于碱化处理和调节溶液pH值的试剂不计入催化剂组成。
以下实施例和对比例中，如无明确表示，所用焙烧气氛为空气气氛。
实施例1
制备250mL含Pd(NO3)2(以Pd计为0.3g)、AgNO3(以Ag计为0.5g)和Zn(NO3)2(以Zn计为1.1g)的水溶液，向该溶液中通入氨水使pH为4.1，将500g球型载体Al2O3(比表面积为112m2/g)等体积浸渍于该溶液中，在105℃干燥12h，在650℃焙烧15h，得到Pd-Zn-Ag/Al2O3中间体。
调整KF的加入量，制备pH为7.5的KF水溶液250mL，在温度45℃、喷涂时间4min的条件下，将该溶液恒温喷涂于Pd-Zn-Ag/Al2O3中间体上，在160℃干燥4h，在300℃焙烧4h，得到催化剂A，比表面积为101m2/g。
实施例2
制备含3.1gCu的醋酸铜乙醇溶液400mL，将500g齿球型载体Al2O3(比表面积为201m2/g)浸渍于该溶液中，在75℃干燥40h，在1100℃焙烧20h，得到Cu改性的载体Al2O3。
制备280mL含0.5gPd的Pd(Cl)2水溶液，向溶液中加入(NH4)2CO3使pH为5.0，将Cu改性的载体Al2O3浸渍于该溶液中，在105℃干燥6h，在700℃焙烧4h，得到Pd-Cu/Al2O3中间体。
调整四甲基乙二胺加入量，制备pH为8.6的四甲基乙二胺的水溶液。取该溶液300mL，在温度40℃、喷涂时间6min的条件下，将该溶液恒温喷涂于Pd-Cu/Al2O3中间体上，再采用分步干燥，在75℃干燥2h，140℃干燥8小时，得到催化剂B，比表面积为47m2/g。
实施例3
制备400mL含Pd(OAc)2(以Pd计为1.2g)和Cs(OAc)(以Cs计为5.0g)的乙酸溶液，向该溶液中加入Na2CO3使pH为3.0，将500g三叶草型载体Al2O3(比表面积为18m2/g)浸渍于该溶液中，在80℃干燥48h，在450℃焙烧8h，得到Pd-Cs/Al2O3中间体。
调整K(OAc)加入量，制备pH为8.2的K(OAc)乙醇溶液400mL，在温度60℃、喷涂时间2min的条件下，将该溶液恒温喷涂于Pd-Cs/Al2O3中间体上，在80℃干燥3h，在400℃焙烧6h，得到催化剂C，比表面积为15m2/g。
实施例4
制备含0.5gAu的HAuCl4异丁醇溶液265mL，将500g柱状载体Al2O3(比表面积为53m2/g)浸渍于该溶液中，在110℃干燥2h，在1270℃焙烧6h得到Au改性的载体Al2O3。
制备含Pd(NO3)2(以Pd计为4.8g)和Ga(NO3)3(以Ga计为0.8g)的水溶液300mL，向该溶液中加入Na2CO3使pH为4.5，将该溶液喷涂于Au改性的载体Al2O3上，在140℃干燥12h，在470℃焙烧14h，得到Pd-Ga-Au/Al2O3中间体。
调整4-二甲氨基吡啶(DMAP)加入量，制备pH为9.5的DMAP丙酮溶液。取该溶液300mL，在温度55℃、喷涂时间3min的条件下，将该溶液恒温喷涂于Pd-Ga-Au/Al2O3中间体上，再采用分步干燥，在80℃干燥2h，在180℃干燥12h，得到催化剂D，比表面积为27m2/g。
实施例5
制备含La(NO3)3(以La计为0.5g)和KNO3(以K计为1.0g)的水溶液610mL，将500g球型载体Al2O3(比表面积为146m2/g)浸渍于该溶液中，在80℃干燥12h，在1120℃焙烧8h得到La和K改性的载体Al2O3。
制备180mL含2.5gPd的PdSO4水溶液，向该溶液中逐步加入NaHCO3，使溶液pH为4.2，将该溶液喷涂于La和K改性的载体Al2O3上，在140℃干燥12h，在620℃焙烧10h，得到Pd-La-K/Al2O3中间体。
调整NaHCO3加入量，制备pH为7.8的NaHCO3水溶液180mL。在温度50℃、喷涂时间3.5min的条件下，将该溶液恒温喷涂于Pd-La-K/Al2O3中间体上，在125℃干燥10h，在445℃焙烧16h，得到催化剂E，比表面积为56m2/g。
对比例1
调整NaHCO3加入量，制备pH为7.8的NaHCO3水溶液450mL，在温度50℃、浸渍时间6min的条件下，将500g球形载体Al2O3(比表面积为146m2/g)浸渍于该溶液中，在125℃干燥10h，在1050℃焙烧20h，得到碱化处理过的Al2O3中间体。
制备含2.5gPd的PdSO4水溶液180mL，将该溶液喷涂于500g被碱化处理过的Na/Al2O3中间体上，在140℃干燥12h，在620℃焙烧 10h，得到催化剂F，比表面积为78m2/g。
对比例2
制备含2.5gPd的PdSO4水溶液220mL，将该溶液喷涂于500g球型载体Al2O3(比表面积为146m2/g)上，在140℃干燥6h，在620℃焙烧10h，得到催化剂G，比表面积为139m2/g。
对比例3
制备含La(NO3)3(以La计为0.5g)和KNO3(以K计为1.0g)的水溶液610mL，将500g球型载体Al2O3(比表面积为146m2/g)浸渍于该溶液中，在80℃干燥12h，在1120℃焙烧8h得到La和K改性的载体Al2O3。
制备180mL含2.5gPd的PdSO4水溶液，向该溶液中逐步加入NaHCO3，使溶液pH为4.2，将该溶液喷涂于La和K改性的载体Al2O3上，在140℃干燥6h，在620℃焙烧10h，得到催化剂H，比表面积为62m2/g。
对比例4
制备含La(NO3)3(以La计为0.5g)和KNO3(以K计为1.0g)的水溶液610mL，将500g球型载体Al2O3(比表面积为146m2/g)浸渍于该溶液中，在80℃干燥12h，在1120℃焙烧8h得到La和K改性的载体Al2O3。
制备180mL含2.5gPd的PdSO4水溶液，向该溶液中逐步加入NaHCO3，使溶液pH为4.2，将该溶液喷涂于La和K改性的载体Al2O3上，在140℃干燥12h，在620℃焙烧10h，得到Pd-La-K/Al2O3中间体。
调整NaOH加入量，制备pH为12的NaOH水溶液220mL。在室温、喷涂时间5min的条件下，将该溶液恒温喷涂于Pd-La-K/Al2O3中间体上，在105℃干燥10h，在250℃焙烧4h，得到催化剂I，比表面积为51m2/g。
对比例5
制备含La(NO3)3(以La计为0.5g)和KNO3(以K计为1.0g)的 水溶液610mL，将500g球型载体Al2O3(比表面积为146m2/g)等体积浸渍于该溶液中，在80℃干燥12h，在1120℃焙烧8h得到La和K改性的载体Al2O3。
制备180mL含2.5gPd的PdSO4水溶液，向该溶液中逐步加入NaHCO3，使溶液pH为4.2，将该溶液喷涂于La和K改性的载体Al2O3上，在140℃干燥12h，在620℃焙烧10h，得到Pd-La-K/Al2O3中间体。
调整NaHCO3加入量，制备pH为7.8的NaHCO3水溶液290mL。在室温、浸渍时间25min的条件下，将Pd-La-K/Al2O3中间体浸渍于该溶液中，在125℃干燥10h，在445℃焙烧6h，得到催化剂J，比表面积为45m2/g。
实施例6
制备含Bi(NO3)3(以Bi计为0.2g)和MgNO3(以Mg计为2g)的水溶液420mL，将500g球型Al2O3-Ga2O3混合载体(载体中Ga2O3含量为20％，比表面积为84m2/g)浸渍于该溶液中，在80℃干燥12h，在800℃焙烧8h得到Bi和Mg改性的Al2O3-Ga2O3混合载体。
制备320mL含0.5gPd的Pd(Cl)2水溶液，向该溶液中逐步加入KHCO3，使溶液pH为4.8，将该溶液喷涂于Bi和Mg改性的Al2O3-Ga2O3混合载体上，在120℃干燥12h，在520℃焙烧6h，得到Pd-Bi-Mg/Al2O3-Ga2O3混合载体的中间体。
调整氯化锂加入量，制备pH为8.0的水溶液。取该溶液310mL，在温度50℃、喷涂时间5min的条件下，将该溶液恒温喷涂于Pd-Bi-Mg/Al2O3-Ga2O3混合载体的中间体上，在120℃干燥8h，在360℃氮气气氛焙烧6h，得到催化剂K，比表面积为75m2/g。
实施例7
制备440mL含Pd(NO3)2(以Pd计为4g)、Fe(NO3)3(以Fe计为1g)和高铼酸(以Re计为0.5g)的水溶液，向该溶液中逐步加入(NH4)2CO3，使溶液pH为3.5，将该溶液喷涂于500g柱状载体活性炭(比表面积为296m2/g)上，在105℃干燥8h，在360℃氮气气氛焙烧18h，得到Pd-Fe-Re/活性炭载体的中间体。
调整三乙醇胺加入量，制备pH为10的水溶液。取该溶液420ml， 在温度45℃、喷涂时间3min的条件下，将该溶液恒温喷涂于Pd-Fe-Re/活性炭载体的中间体上，在105℃干燥4h，在270℃氮气气氛焙烧5h，得到催化剂L，比表面积为289m2/g。
测试例1
本测试例用于说明实施例和对比例中所得催化剂的吡咯原位吸附红外光谱分析。
使用吡咯原位红外分析仪(Thermonicolet380)，对实施例和对比例制备得到的催化剂进行吡咯吸附测试。取10mg左右的粉末样品压成薄片，固定在红外池中，先经真空净化(350℃，1×10-3Pa)2h后，冷却至40℃，扫描谱图作本底。
所述催化剂的吡咯吸附原位红外谱图的测定方法如下：
a)将粉末态的催化剂样品置于红外池中，经过真空处理后，升温至350℃，升温速率为20℃/min；
b)在真空状态中于350℃下保温2小时，然后降温至40℃，降温速率为20℃/min；
c)保持温度为40℃，通入氮气吹扫30分钟，氮气流量为5mL/min；
d)保持温度为40℃，通入气态吡咯，吸附10分钟，气体流量为5mL/min，并在通入气态吡咯的2分钟、4分钟、6分钟、8分钟、10分钟分别记录样品在1000-4000cm-1波数区域的原位红外谱图；
e)保持温度为40℃，改用氮气吹扫30分钟，氮气流量为5mL/min；以及
f)保持氮气吹扫直到温度降至室温，氮气流量为5mL/min。
图1A至1J示出了实施例和对比例中制备得到的催化剂A-J相应的吡咯吸附原位红外谱图。
图2示出了催化剂E的随时间变化的吡咯吸附原位红外谱图。谱图中0min代表氮气吹扫结束且吡咯吸附开始之前的红外吸收谱图；4min、6min、10min分别代表吡咯吸附4min、6min、10min时的红外吸收谱图；25min代表吡咯吸附10min后再次氮气吹扫15min的红外吸收谱图。
表1中示出了在吡咯吸附10分钟时在3150-3420cm-1范围内，实 施例和对比例所得催化剂的吡咯红外吸收峰的出峰位置，以及峰高比H10min/H25min，其中，H10min为吡咯吸附10min时(即吸附10分钟后用氮气吹扫0分钟时)在3150-3420cm-1范围内的最高峰的峰高值，H25min为吡咯吸附10min后再用氮气吹扫15min时在3150-3420cm-1范围内的对应谱峰的峰高值。
表1实施例和对比例中所得催化剂的吡咯吸附原位红外光谱分析结果
*在3150-3410cm-1范围之外的红外吸收峰对应的并非碱性中心。
从表1可知，采用本申请实施例的方法制备的催化剂A-E和K-L的吡咯吸附原位红外谱图在波数3250-3410cm-1范围内均具有吸收峰；对比例制备的催化剂F-H的吡咯吸附原位红外谱图的出峰位置大于3410cm-1，而催化剂I和J的吡咯吸附原位红外谱图的出峰位置均小于3250cm-1。吡咯吸附结束(即吡咯吸附10分钟后)改用氮气吹扫之后，催化剂表面吸附的吡咯会迅速脱附，各个催化剂的峰高比H10min/H25min均在10以上。表1的结果表明，本申请的催化剂A-E和K-L具有不同于对比催化剂F-J的特殊的碱性中心。
测试例2
本测试例用于说明实施例和对比例中所得催化剂的吡啶程序升温 吸附脱附原位红外光谱分析。
使用原位红外分析仪(Thermonicolet380)，对实施例和对比例制备得到的催化剂进行程序升温吸附脱附测试。取10mg左右的粉末样品压成薄片，固定在红外池中，先经真空净化(350℃，1×10-3Pa)2h后，冷却150℃，扫描谱图作本底。所述催化剂的吡啶吸附原位红外谱图的测定方法如下：
a)将粉末态的催化剂样品置于红外池中，经过真空处理后，升温至350℃，升温速率为20℃/min；
b)在真空状态中于350℃下保温2h，然后降温至室温，降温速率为20℃/min；
c)保持室温，通入氮气吹扫30分钟，氮气流量为5mL/min；
d)保持室温，通入吡啶，吸附10分钟，气体流量为5mL/min；以及
e)程序升温到测定温度(定点温度分别为150℃，300℃)进行真空脱附(1×10-3Pa)0.5h，然后分别冷却至室温，记录1700-1400cm-1波数区域的红外光谱，其中程序升温速率为20℃/min。
150℃脱附后所测样品的吸附吡啶浓度(C150℃)代表了样品表面不同强度酸(包括L酸和B酸)的总量，而300℃脱附后样品的吸附吡啶浓度(C300℃)代表了样品表面中强酸和强酸的总量，其中1540cm-1附近的吸收峰对应B酸，1450cm-1附近的吸收峰对应L酸。根据以下的吸附吡啶浓度公式计算出不同温度下的催化剂表面酸中心的吸附吡啶浓度：

C弱酸＝C150℃-C300℃
C表示吸附在催化剂表面酸中心的吡啶浓度(mmol/g)；1.88和1.42分别是B酸和L酸的消光系数；IA(B)和IA(L)分别是B酸特征峰和L酸特征峰的积分峰面积；R表示自支撑分子筛压片的半径(cm)；W表示压片的质量(mg)。
表2示出了吡啶程序升温吸附脱附原位红外光谱分析测得的各催化剂表面酸中心的吸附吡啶浓度。
表2实施例和对比例中所得催化剂的吡啶程序升温吸附脱附原位红外光谱分析结果

*符号“/”表示未测出。
从表2可知，各实施例和对比例所得的催化剂的酸量和酸量分布不同，以酸中心吸附的吡啶浓度表示，本申请实施例所得的催化剂A-E和K-L的弱酸量在0.1-0.25mmol/g范围内，中强酸和强酸量小于0.1mmol/g，对比例所得的催化剂H和J具有适中的弱酸量且无中强和强酸，催化剂F和G的中强和强酸量偏高，而催化剂I的酸量极低，表明几乎无酸中心。表2的结果表明，本申请的催化剂A-E和K-L的表面整体呈弱酸性。
应用实施例1
本实施例用于说明实施例和对比例中所得催化剂催化碳三加氢的效果。
在乙烯装置中碳三加氢侧线，将500mL催化剂装入绝热固定床反应器中，使用氮气置换后，将液相碳三馏分原料通入反应器中催化加氢。其中，反应原料的组成(摩尔分数)为：丙烷6.106％、丙烯89.864％、丙二烯1.994％、丙炔2.035％。
在氢气与丙炔和丙二烯(MAPD)的摩尔比为1.0-1.8，反应器入口温度25-55℃的范围内进行实验，控制出口MAPD含量小于100ppm，筛 选出每种催化剂最低的H2/MAPD比例和入口温度，结果见表3。在表3所示的条件下，控制反应压力为1.8MPa，液相空速为62h-1，进行催化反应，并计算各催化剂反应对丙烯的选择性，结果见表3，其计算方法为：
表3实施例和对比例中所得催化剂的碳三加氢测试条件和结果
*催化剂I和J无法实现出口MAPD小于100ppm。
从表3可以看出，MAPD加氢生成丙烯的反应中，与对比例的催化剂相比，本申请实施例所得催化剂A-E在保证出口MAPD小于100ppm的情况下，丙烯的选择性更高。这表明在催化剂表面弱酸环境中加入极弱碱性中心的修饰，可更好地改善催化剂的催化性能，而且具有本申请的特定碱性中心的催化剂具有更好的催化效果。
应用实施例2
本实施例用于说明实施例和对比例中所得催化剂用于裂解气物流加氢的效果。
裂解气物流加氢工艺采用三段绝热固定床反应器串联加氢，每段催化剂装填量为200ml，每段间有换热器控制进料温度。反应器入口的裂解气物流的组成中氢气为13.5mol％，CO为755ppm，乙烯含量33mol％，乙炔含量为0.6mol％，丙烯为17mol％，MA为0.3mol％，PD 为0.3mol％，余量为乙烷和丙烷。加氢反应的空速为15000h-1、压力为2.6MPa，；一段反应器入口温度50-60℃，二段反应器入口温度50-60℃，三段反应器入口温度55-65℃。
将实施例和对比例制备的催化剂用于上述加氢反应，控制末段反应器出口乙炔含量小于0.2ppm，MAPD转化率(％)、运行周期(h)、乙烯选择性(％)、丙烯选择性(％)和C4+生成量(mol％)，结果如表4所示。
其中，运行周期是指将末段反应器出口乙炔的总含量控制在0.2ppm以下时，系统能够运行的时间。
对乙烯选择性的计算方法为：
对MAPD转化率的计算方法为：
对丙烯选择性的计算方法为：
C4+生成量为二段反应器出口组分分析中C4及以上组分的含量总和。
表4实施例和对比例中所得催化剂用于原油制裂解气物流加氢的测试结果
从表4给出的裂解气物流选择加氢反应结果可以看出，为保证出口乙炔小于0.2ppm，各个催化剂的运行周期、MAPD转化率、乙烯和丙烯选择性以及C4+生成量各不相同。实施例制备的催化剂与对比例催化剂相比，其运行时间更长，乙烯和丙烯的选择性更佳，MAPD转化率更高、C4+生成量更低。这表明采用本申请的催化剂进行裂解气物流中炔烃和二烯烃的选择性加氢，可在较高的空速的条件下有效地脱除乙炔，并获得更高的乙烯选择性、丙烯选择性和MAPD转化率，实现长周期稳定运行。
以上详细描述了本申请的优选实施方式，但是，本申请并不限于上述实施方式中的具体细节，在本申请的技术构思范围内，可以对本申请的技术方案进行多种简单变型，这些简单变型均属于本申请的保护范围。
另外需要说明的是，在上述具体实施方式中所描述的各个具体技术特征，在不矛盾的情况下，可以通过任何合适的方式进行组合，为了避免不必要的重复，本申请对各种可能的组合方式不再另行说明。
此外，本申请的各种不同的实施方式之间也可以进行任意组合，只要其不违背本申请的思想，其同样应当视为本申请所发明的内容。

Claims (19)

  1. 一种负载型钯催化剂，包括载体和负载在载体上的钯和改性组分，所述载体选自难熔金属氧化物、氧化硅、活性炭，或者它们的组合，所述改性组分选自Bi、Sb、Pb、Sn、Zn、W、Mn、Si、Re、不同于钯的第Ⅷ族元素、碱金属元素、碱土金属元素、第ⅢA族元素、第ⅠB族元素、稀土元素、卤族元素，或者它们的组合，其中根据40℃下进行的吡咯吸附原位红外光谱分析，所述催化剂在3251-3410cm-1范围内、优选在3350-3400cm-1范围内显示出吸收峰。
  2. 根据权利要求1所述的催化剂，其中根据40℃下进行的吡咯吸附原位红外光谱分析，所述催化剂在吡咯吸附10分钟后用氮气吹扫0分钟时测得的原位红外谱图中在3251-3410cm-1范围内显示出的吸收峰的峰高与用氮气吹扫15分钟时测得的原位红外谱图中3251-3410cm- 1范围内的对应吸收峰的峰高之比大于或等于5：1，优选大于或等于10：1，例如为10:1至200:1。
  3. 根据在先权利要求中任一项所述的催化剂，其中根据40℃下进行的吡咯吸附原位红外光谱分析，所述催化剂在3200-3250cm-1范围内不显示吸收峰、例如在3160-3250cm-1范围内不显示吸收峰。
  4. 根据在先权利要求中任一项所述的催化剂，其中根据吡啶程序升温吸附脱附原位红外光谱分析，所述催化剂在150℃脱附后测得的表面吸附吡啶浓度与300℃脱附后测得的表面吸附吡啶浓度的差值在0.1-0.25mmol/g，优选在0.1-0.2mmol/g范围内，在300℃脱附后测得的表面吸附吡啶浓度在0-0.1mmol/g的范围内，优选在0-0.08mmol/g的范围内。
  5. 根据在先权利要求中任一项所述的催化剂，其中根据吡啶程序升温吸附脱附原位红外光谱分析，所述催化剂在150℃脱附后测得的表面吸附吡啶浓度与300℃脱附后测得的表面吸附吡啶浓度的差值相对于150℃脱附后测得的表面吸附吡啶浓度的比例在60-100％范围内，优选在75-100％范围内。
  6. 根据在先权利要求中任一项所述的催化剂，其中以载体的重量为基准并以金属元素计，所述催化剂中钯的含量为0.01-20wt％，优选0.01-5wt％，更优选0.02-1wt％。
  7. 根据在先权利要求中任一项所述的催化剂，其中所述催化剂的比表面积为0.5-800m2/g，优选4-200m2/g，更优选15-110m2/g。
  8. 根据在先权利要求中任一项所述的催化剂，其中所述载体选自氧化铝、氧化锆、氧化镓、氧化硅、活性炭，或者它们的组合；所述改性组分选自La、K、Ag、Zn、Ga、Cu、Au、Cs、Bi、Mg、Fe、Re，或者它们的组合。
  9. 根据权利要求8所述的催化剂，其中以载体的重量为基准并以金属元素计，所述催化剂中所述改性组分的含量为0.01-20wt％，优选0.2-5wt％。
  10. 制备在先权利要求中任一项所述的负载型钯催化剂的方法，包括以下步骤：
    1)将钯和改性组分负载到载体上，并干燥和焙烧，得到中间体；以及
    2)用pH值为7.2-10，优选为7.5-9的碱性溶液对所述中间体进行碱化处理，并干燥和任选地焙烧，得到所述催化剂，
    其中所述碱化处理通过用所述碱性溶液进行喷涂来实现，喷涂时间为2-8min，优选3-4min，喷涂温度为35-70℃，优选45-55℃，优选地，所述喷涂过程中的温度波动控制在5℃以内，更优选所述喷涂为恒温喷涂。
  11. 根据权利要求10所述的方法，其中：
    步骤1)的干燥温度为50-220℃、优选80-150℃，时间为1-48h，优选2-24h；焙烧温度为300-1500℃、优选350-1250℃，时间为2-24h，优选6-24h，焙烧气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，其中焙烧气氛中的氧气含量为0-40wt％；和/或
    步骤2)的干燥温度为60-180℃、优选70-140℃，时间为1-48h，优选6-20h；焙烧温度为200-500℃、优选250-450℃，时间为2-24h，优选6-20h，焙烧气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，其中焙烧气氛中的氧气含量为0-25wt％。
  12. 根据权利要求10或11所述的方法，其中所述步骤1)包括将钯和改性组分一起负载到所述载体上，并干燥和焙烧，得到所述中间体，其中步骤1)的干燥温度为60-180℃、优选80-150℃，时间为1-48h，优选2-24h；焙烧温度为300-700℃，优选350-600℃，时间为2-24h， 优选6-15h，焙烧气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，其中焙烧气氛中的氧气含量为0-40wt％。
  13. 根据权利要求10或11所述的方法，其中所述步骤1)进一步包括：
    1a)将改性组分负载到载体上，并干燥和焙烧，得到改性载体；以及
    1b)将钯和任选的附加改性组分负载到载体上，并干燥和焙烧，得到所述中间体，
    优选地：
    步骤1a)的干燥温度为50-220℃、优选80-150℃，时间为1-48h，优选2-12h；焙烧温度为700-1500℃，优选800-1250℃，时间为2-24h，优选6-15h，焙烧气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，其中焙烧气氛中的氧气含量为0-40wt％；和/或
    步骤1b)的干燥温度为60-180℃、优选80-150℃，时间为1-48h，优选2-24h；焙烧温度为300-700℃，优选350-650℃，时间为2-24h，优选6-15h，焙烧气氛选自惰性气体、氮气、含氧气氛，或者它们的组合，其中焙烧气氛中的氧气含量为0-40wt％。
  14. 根据权利要求10-13中任一项所述的方法，其中在步骤1)中，使用包含钯的前体的溶液和包含改性组分的前体的溶液来进行所述负载，负载方式选自喷涂和浸渍，优选选自喷涂和等体积浸渍；
    优选地：
    步骤1)中所用的包含钯前体的溶液的pH值为2-5，优选为3.8-4.5；
    步骤1)中，以载体的重量为基准并以金属元素计，钯的用量使得所述催化剂中钯的含量为0.01-20wt％，优选0.01-5wt％，更优选0.02-1wt％；
    步骤1)中，以载体的重量为基准并以金属元素计，所述改性组分的用量使得所述催化剂中所述改性组分的含量为0.01-20wt％，优选0.2-5wt％；和/或
    步骤2)中，以载体的重量为基准，所述碱性溶液中包含的碱性化合物的用量为0.1-25wt％。
  15. 根据权利要求14所述的方法，其中：
    所述钯的前体为可溶性钯化合物，优选选自氯化钯、硝酸钯、醋酸钯、硫酸钯、新戊酸钯、八乙基卟啉钯、三甲基乙酸钯、三氟乙酸钯，或者它们的组合，更优选选自氯化钯、硝酸钯、醋酸钯、硫酸钯，或者它们的组合；和/或
    所述改性组分的前体为包含所述改性组分的可溶性化合物，优选选自所述改性组分的卤化物、硝酸盐、醋酸盐、碳酸盐、硫酸盐、氢氧化物、氨化物、含有机基团的化合物，或者它们的组合。
  16. 根据权利要求10-15中任一项所述的方法，其中：
    所述碱性溶液中包含的碱性化合物为有机碱性化合物、无机碱性化合物或者它们的混合物，其中所述有机碱性化合物选自有机胺、吡啶类化合物，或者它们的组合，优选选自二甲胺、三乙胺、三氟乙酰胺、吡啶、4-二甲氨基吡啶、三乙醇胺，或者它们的组合；以及，所述无机碱性化合物选自氨水、卤化物、柠檬酸盐、草酸盐、醋酸盐、碳酸氢盐、碳酸盐，或者它们的组合，优选选自KF、氯化锂、醋酸钾、碳酸氢钠、柠檬酸钠，或者它们的组合；和/或
    所述碱性溶液中的溶剂选自水、乙醇、丙酮、四氢呋喃，或者它们的组合；
    优选地，所述碱性溶液中碱性化合物的浓度为0.1-70wt％。
  17. 权利要求1-9中任一项所述的负载型钯催化剂在不饱和烃加氢反应中的应用，其中所述不饱和烃选自炔烃、多不饱和烃，或者它们的组合。
  18. 一种不饱和烃加氢方法，包括在氢气存在下，使包含炔烃和/或多不饱和烃的不饱和烃原料与权利要求1-9中任一项所述的负载型钯催化剂接触反应的步骤。
  19. 根据权利要求17所述的应用或者根据权利要求18所述的方法，其中所述炔烃选自C2-C5炔烃、优选选自C2-C4炔烃，所述多不饱和烃选自C3-C5的二烯烃、优选选自C3-C4的二烯烃。
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