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CN-122006742-A - Noble metal catalyst, preparation method and application thereof, and method for dehydrogenating cycloparaffin compound

CN122006742ACN 122006742 ACN122006742 ACN 122006742ACN-122006742-A

Abstract

The invention relates to the field of dehydrogenation, and discloses a noble metal catalyst, a preparation method and application thereof, and a method for dehydrogenating a cycloparaffin compound. The noble metal catalyst comprises a carrier, platinum and transition metal M which are loaded on the carrier, wherein the transition metal M exists in the form of a metal complex MO x , and x is 0.5-1.4. The noble metal catalyst provided by the invention is applied to the dehydrogenation reaction of cycloparaffin compounds, and has good stability.

Inventors

  • TIAN HAO
  • TONG FENGYA
  • WANG HAO
  • ZHANG TAO
  • SONG LEI
  • MIAO CHANGXI

Assignees

  • 中国石油化工股份有限公司
  • 中石化（上海）石油化工研究院有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (13)

  1. 1. A noble metal catalyst is characterized by comprising a carrier, platinum and transition metal M, wherein the platinum and the transition metal M are loaded on the carrier, the transition metal M exists in the form of a metal compound MO x , and x is 0.5-1.4.
  2. 2. The catalyst according to claim 1, wherein the transition metal M is at least one of a group VIII metal element and a group VIIB metal element, preferably at least one selected from Fe, co, ni and Mn; Preferably, x is 1-1.4.
  3. 3. The catalyst of claim 1 or 2, wherein the platinum is present in the form of elemental platinum; preferably, platinum does not form intermetallic compounds with the transition metal M.
  4. 4. A catalyst according to any one of claims 1 to 3, wherein the catalyst has a lower electron cloud density of platinum as characterized by carbon monoxide infrared adsorption than a platinum catalyst without the introduction of transition metal M; And/or, the peak position of the catalyst is 2056-2065cm -1 after the infrared absorption of carbon monoxide.
  5. 5. The catalyst according to any one of claims 1 to 4, wherein the platinum is present in an amount of 0.1 to 0.9%, preferably 0.2 to 0.6% by weight and the transition metal M is present in an amount of 0.05 to 0.2%, preferably 0.05 to 0.1% by weight, based on the total weight of the catalyst.
  6. 6. A method for preparing a noble metal catalyst, comprising the steps of: (1) Carrying out first contact on a carrier and a solution containing a transition metal M precursor, and then carrying out first drying and first roasting to obtain the precursor; (2) Carrying out second contact, second drying and second roasting on the precursor and a solution containing a platinum precursor, and then reducing a roasting product; wherein the reduction is carried out in a hydrogen-containing atmosphere having a water content of 30 to 300 ppm.
  7. 7. The method according to claim 6, wherein the transition metal M is at least one of a group VIII metal element and a group VIIB metal element, preferably at least one selected from Fe, co, ni and Mn; Preferably, the carrier, the solution containing the transition metal M precursor and the solution containing the platinum precursor are used in amounts such that the weight percentage of the platinum in the prepared catalyst is 0.1-0.9%, preferably 0.2-0.6%, and the weight percentage of the transition metal M is 0.05-0.2%, preferably 0.05-0.1%, based on the total weight of the catalyst; Preferably, the platinum precursor is selected from at least one of chloroplatinic acid, tetraminoplatinum nitrate and dichlorotetraminoplatinum; Preferably, the transition metal M precursor is selected from at least one of water-soluble hydrochloride, nitrate, sulfate, citrate and acetate, preferably at least one of hydrochloride, nitrate and sulfate.
  8. 8. The method according to claim 6 or 7, wherein the concentration of transition metal M ions in the solution containing the transition metal M precursor is 1 to 15 mmol-L -1 ; Preferably, the temperature of the first contact is from 30 to 50 ℃; and/or the pH value of the solution containing the carrier and the transition metal M precursor is 2-5; preferably, the temperature of the first firing is 600-850 ℃; preferably, the first calcination is performed under an atmosphere having an oxygen concentration of 20 to 30% by volume.
  9. 9. The method of any of claims 6-8, wherein the concentration of the platinum precursor in the solution containing the platinum precursor is 5-30mg/mL; preferably, the temperature of the second contact is 40-50 ℃; preferably, the temperature of the second firing is 400-580 ℃; and/or the oxygen concentration of the second roasting atmosphere is lower than the oxygen concentration of the first roasting atmosphere; preferably, the second calcination is performed under an atmosphere having an oxygen concentration of 10 to 20% by volume.
  10. 10. The process according to any one of claims 6 to 9, wherein in step (2), the reduction is carried out under a hydrogen-containing atmosphere having a water content of 50 to 250 ppm; preferably, the reducing conditions include a reduction temperature of 300-450 ℃.
  11. 11. A noble metal catalyst obtainable by the process of any one of claims 6 to 10.
  12. 12. Use of the noble metal catalyst of any one of claims 1 to 5 or the noble metal catalyst of claim 11 in the dehydrogenation of a cycloalkane, preferably a cycloalkane of C 6 -C 10 .
  13. 13. A process for dehydrogenating a cycloalkane compound, wherein the process comprises subjecting a cycloalkane compound to a dehydrogenation reaction in the presence of the noble metal catalyst according to any one of claims 1 to 5 or the noble metal catalyst according to claim 11; Preferably, the reaction conditions include a reaction temperature of 450-500 ℃; and/or, the mass space velocity of the cycloalkane compound is 1-6h -1 .

Description

Noble metal catalyst, preparation method and application thereof, and method for dehydrogenating cycloparaffin compound Technical Field The invention relates to the field of dehydrogenation, in particular to a noble metal catalyst, a preparation method and application thereof, and a method for dehydrogenating a cycloparaffin compound. Background The organic liquid hydrogen storage is a novel hydrogen storage technology for storing hydrogen in organic molecules through chemical reaction, so that long-distance safe transportation of the hydrogen is realized. In view of the great advantage of organic liquid hydrogen storage in large-scale safe transportation of hydrogen, the scientific research team in germany, japan and china has developed intensive research and industrial application exploration for the technology. In a plurality of organic liquid hydrogen storage systems, the comprehensive reaction energy consumption, the reaction process flow optimization, the raw material cost and other factors are combined, and methylcyclohexane/toluene is the organic liquid hydrogen storage system with the most industrial application prospect. The organic liquid dehydrogenation catalyst with high stability is a precondition for large-scale application of an organic liquid hydrogen storage system. Research shows that the dehydrogenation process of methylcyclohexane is accompanied by side reactions such as toluene disproportionation, toluene hydrogenolysis, intermediate product isomerism and the like. At present, scientific researchers generally consider that the stability of a methylcyclohexane dehydrogenation catalyst is mainly related to the deep reaction of toluene (such as coupling toluene to form biphenyl), so that a metal element doping strategy is often adopted in designing the catalyst to inhibit the deep reaction of toluene as a product so as to improve the stability of the catalyst, but the stability improvement degree of the catalyst is limited. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a noble metal catalyst, a preparation method and application thereof, and a method for dehydrogenating a cycloalkane compound. At present, scientific researchers generally consider that the stability of a methylcyclohexane dehydrogenation catalyst is mainly related to the deep reaction of toluene (such as toluene coupling to form biphenyl), so that a metal element doping strategy is often adopted to improve the electron cloud density of Pt in designing the catalyst, reduce the adsorption of Pt on toluene, and inhibit the deep reaction of toluene product so as to improve the stability of the catalyst. However, the inventor finds that under the high-temperature running condition (450-500 ℃) in the research process, toluene can be rapidly removed from the Pt catalytic surface, so that the content of diphenyl and acene organic matters in the product is very low, but the content of the isomerism product-cyclopentane compounds is higher. The deep dehydrogenation product of cyclopentane compounds can have a great influence on the stability of the catalyst. The inventors of the present invention found that controlling the isomerization reaction under the high temperature reaction of the Pt-based dehydrogenation catalyst is of great importance for improving the high temperature stability of the catalyst. In order to achieve the above object, the present invention provides a noble metal catalyst, wherein the catalyst comprises a carrier, and platinum and a transition metal M supported on the carrier, the transition metal M being present in the form of a metal complex MO x, x being 0.5 to 1.4. Preferably, x is 1-1.4. The second aspect of the present invention provides a method for preparing a noble metal catalyst, wherein the method comprises the steps of: (1) Carrying out first contact on a carrier and a solution containing a transition metal M precursor, and then carrying out first drying and first roasting to obtain the precursor; (2) Carrying out second contact, second drying and second roasting on the precursor and a solution containing a platinum precursor, and then reducing a roasting product; wherein the reduction is carried out in a hydrogen-containing atmosphere having a water content of 30 to 300 ppm. Preferably, the first calcination is performed under an atmosphere having an oxygen concentration of 20 to 30% by volume. Preferably, the second calcination is performed under an atmosphere having an oxygen concentration of 10 to 20% by volume. A third aspect of the present invention provides a noble metal catalyst obtainable by the process according to the second aspect described above. A fourth aspect of the present invention provides the use of the noble metal catalyst according to the first aspect described above or the noble metal catalyst according to the third aspect described above in the dehydrogenation of cycloalkanes. In a fifth aspect, the present invention provid