supported metal catalyst with synergistic sites, a preparation method therefor and an application thereof

Patent metadata

Field	Value
Publication number	US-2024082833-A1
Application number	US-202318452032-A
Country	US
Kind code	A1
Filing date	Aug 18, 2023
Priority date	Sep 13, 2022
Publication date	Mar 14, 2024
Grant date	—

Abstract

The present invention provides a supported metal catalyst with synergistic sites, a preparation method therefor and an application thereof. The preparation method of this catalyst is to utilize the unsaturated cubane-like structure, M cation with catalytic activity is introduced into the cluster core unit. By using the vertex vacancy as the capturing center, and adjusting the impregnation temperature to maximize the loading of the cluster precursor, as well as depending on the electrostatic adsorption of the support and the confinement of the cluster structural unit, the number of S vacancies and the distance between S vacancies and Miso sites are effectively controlled through liquid phase reduction and atmosphere treatment at room temperature to obtain supported X3MSx/Al2O3 catalyst with Miso-Vs synergistic sites. The method of the present invention achieves the joint enhancement of the activity, product selectivity, and stability of unsaturated carbon oxygen bond selective hydrogenation, carbon chlorine bond selective hydrogenation dechlorination, and carbon hydrogen bond dehydrogenation reactions. This catalyst is mainly used in various catalytic reaction processes in the fields of petrochemical, fine chemical, environmental chemical, and other fields. It has outstanding catalytic performance, excellent activity, selectivity, and good recyclability, and is easy to recover and reuse.

First claim

1 . A preparation method of a supported metal catalyst with synergistic sites, characterized in that the preparation method comprises the following steps:
A. Mix a soluble metal M salt solution uniformly with a solution of [X3S4(H2O)y]Clz cluster compound to obtain a [X3MS4(H2O)y+1]z+ solution; B. Disperse Al2O3 support uniformly into the solution obtained in step A, stir at the temperature of 25˜60° C. and the rotation speed of 200˜500 rpm for 2˜6 h until it becomes sticky, and dry it in a constant temperature drying oven at 40˜80° C. for 8˜24 h to obtain [X3MS4(H2O)y+1]z+/Al2O3 solid powder; C. Add 1.5 g solid powder obtained in step B into 5˜30 mL of deionized water, add excessive soluble reducing agent to reduce M2+/M3+ to metal M, wherein the molar ratio of the reducing agent to the M salt is 3:1˜7:1, stir for 18˜60 min to obtain black suspension, centrifugally wash it to neutrality, and dry it in a constant temperature drying oven at 60° C. for 8˜16 h to obtain X3MS4/Al2O3; D. Place the X3MS4/Al2O3 obtained in step C into an atmosphere furnace, and heat it to 300˜600° C. at a rate of 5˜20° C./min for 0.25˜6 h of treatment to obtain X3MSx/Al2O3 catalyst (0<x<4); The corresponding treatment atmosphere is one of air, 10 vol. % O2/N2, 5˜40 vol. % H2/N2 or 5˜40 vol. % CO/N2; The corresponding X3MSx/Al2O3 catalyst possesses Miso-Vs synergistic sites.

2 . A preparation method of a supported catalyst with synergistic sites according to claim 1 , characterized in that the corresponding [X3S4(H2O)y]Clz in step A is a trinuclear transition metal-sulfur cluster compound with an unsaturated cubane structure, wherein X is one of Mo, W, Re and Ir; y=9; when X is Re (+3), z=1; when X is one of W, Mo and Ir(+4), z=4.

3 . A preparation method of a supported catalyst with synergistic sites according to claim 1 , characterized in that the corresponding soluble metal M salt in step A is one of Na2PdCl4, Pd(NO3)2, Pd(C5H7O2)2, H2PtCl6, Pt(NO3)2, CoCl2, Ni(NO3)2·6H2O, NiCl2, RuCl3, Ga(NO3)3, Fe(NO3)3·9H2O, CuCl2·2H2O, Cu(NO3)2 and AgNO3.

4 . A preparation method of a supported catalyst with synergistic sites according to claim 1 , characterized in that the molar ratio of M to X3 in step A is 4˜25/1, and the concentration of the M salt is 0.0035˜0.0171 mol/L.

5 . A preparation method of a supported catalyst with synergistic sites according to claim 1 , characterized in that the theoretical loading of the soluble metal M salt in step B is 0.03˜5.00 wt. % of the catalyst, preferably 0.05˜2.50 wt. %; the corresponding Al2O3 support possesses rich pore structure while the crystalline phases is γ or δ, the specific surface area is 70˜190 m2/g, the pore volume is 0.3˜1.3 cm3/g, and the pore size is 15˜30 nm; the soluble reducing agent in step C is one of NaBH4, LiBH4, ascorbic acid or oxalic acid.

6 . A supported catalyst with synergistic sites according to claim 1 , characterized in that the preparation method of a [X3 S4(H2O)y]Clz cluster solution comprises the following steps: Dissolve thiometalate in deionized water to prepare a solution with a concentration of 50˜120 mmol/L, alternately drop excessive reducing agent and acid solution, and fully stir at room temperature to obtain a suspension, crystallize it at 60˜100° C. for 10˜20 h, add acid solution dropwise to keep pH value of the suspension in the range of 1˜3 during the crystallization process, and make it naturally cool down to room temperature after the color of the suspension turns dark green to obtain a [X3S4(H2O)y]Clz cluster solution.

7 . A supported catalyst with synergistic sites prepared by the method according to claim 1 , characterized in that the catalyst is expressed as MX3Sx/Al2O3, wherein x represents sulfur-containing number in the range of 0<x<4; MX3Sx is an active component, with M as an active metal being one of Pd, Pt, Co, Ni, Ru, Ga, Fe, Cu and Ag; X represents a transition metal being one of Mo, W, Re and Ir; Al2O3 is a support; and the corresponding loading of M is 0.03˜5.00 wt. %; The structure of the catalyst is characterized in that the MX3Sx (0<x<4) active component is stably dispersed on the Al2O3 support, in which Miso presents a geometric site isolation, and forms a Miso-Vs synergistic sites with the adjacent S vacancies.

8 . An application of a supported catalyst with synergistic sites prepared by the method according to claim 7 to catalyze the selective hydrogenation of unsaturated carbon-oxygen bonds, characterized in that the corresponding catalyst and 2-ethylanthraquinone working solution are weighed and loaded into a reactor, hydrogen is introduced into the reactor until the pressure reaches 0.3 MPa, the stirring is turned on at a rotation speed of 1000 rpm until the reactor is heated to 50° C., wherein the amount of the catalyst is 0.02˜0.10 g, the reaction temperature is 40˜80° C., the rotation speed is 700˜1000 rpm, the 2-ethylanthraquinone working solution is 100˜150 g/L, and the test pressure is 1˜4 bar. The liquid phase valve is opened every 30 minutes to take 1 mL working solution and mix it with 20 mL deionized water in a 250 mL separatory funnel and oxidize it with pure oxygen. When the upper organic phase turns from brownish black to bright yellow, stop introducing oxygen, and extract with deionized water for three times. The lower water phase obtained is titrated with 0.02 mol/L potassium permanganate solution under acidic conditions. Finally, the concentration of hydrogen peroxide is calculated.

9 . An application of a supported catalyst with synergistic sites prepared by the method according to claim 7 to catalyze alkanes to produce olefins, characterized in that the catalyst is weighed and fully mixed with quartz sand possessing a particle size of 40˜70 meshes, and then loaded into a quartz tube reactor with a diameter of 8 mm, the feed gas composed of 2.0% propane/4% hydrogen/94% nitrogen equilibrium gas is introduced, wherein the molar ratio of hydrogen to alkane is 1/1˜2/1. The catalytic performance is tested under the reaction temperature of 550˜580° C., pressure of 1˜4 bar and space velocity of 3000˜6000 h˜1. The composition and content of reactants and products are analyzed by gas chromatography with recording every 10 minutes.

10 . An application of a supported catalyst with synergistic sites prepared by the method according to claim 7 to catalyze the selective hydrodechlorination of chlorine-containing organic compounds, characterized in that the catalyst is weighed and fully mixed with quartz sand possessing a particle size of 40˜70 meshes, and then loaded into a quartz tube reactor with a diameter of 7 mm, the feed gas composed of 0.14% dichloroethane/0.8% hydrogen/99.06% nitrogen equilibrium gas is introduced. A catalytic reaction is conducted under the certain conditions, wherein the amount of the catalyst is 0.02˜0.50 g, the reaction temperature is 170˜500° C., the ratio of hydrogen to chlorine is 1/1˜10/1, and the space velocity is 2000˜12000 h˜1. The composition and content of reactants and products are analyzed by gas chromatography with recording every 10 minutes.

Assignees

• Univ Beijing Chem Tech

Inventors

• Liu Yanan
• Li Dianqing
• Yu He
• Li Ning

Classifications

• B01J37/16

  Reducing · CPC title

• B01J37/04

  Mixing {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/06

  Washing {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/0236

  Drying, e.g. preparing a suspension, adding a soluble salt and drying · CPC title