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CN-121988319-A - Catalyst for cyclohexanol dehydrogenation and preparation method thereof

CN121988319ACN 121988319 ACN121988319 ACN 121988319ACN-121988319-A

Abstract

The invention relates to the field of catalysts, and provides a catalyst for cyclohexanol dehydrogenation and a preparation method thereof, which aim to solve the problem that the selectivity of the conventional platinum-series catalyst is lower when the catalyst is used for cyclohexanol gas-phase low-temperature dehydrogenation. When the catalyst provided by the invention is used for cyclohexanol dehydrogenation, the selectivity of the catalyst can be up to 99.3% while maintaining high activity (the conversion rate is more than 50%) even if the reaction temperature is 230 ℃ and the cyclohexanol airspeed is 2.0h ‑1 , which is far higher than that of the existing platinum-series catalyst.

Inventors

  • ZHOU WEI
  • PENG GONGMING
  • CUI TONGYU
  • WANG JIANHUI
  • ZHANG MENGXU
  • LI CONGCONG
  • WANG HONGQIN
  • GUAN QINGWEI

Assignees

  • 贵研工业催化剂（云南）有限公司

Dates

Publication Date
20260508
Application Date
20260126

Claims (10)

  1. 1. The catalyst for cyclohexanol dehydrogenation is characterized by comprising a main catalytic component, a promoting component and a carrier, wherein the main catalytic component comprises platinum, the promoting component comprises iron, tin or cerium, and the carrier comprises alumina.
  2. 2. The catalyst of claim 1, further comprising an additional component comprising at least one of Na or K.
  3. 3. The catalyst of claim 1 or 2, wherein the platinum is present in an amount of 0.1wt% to 2.0wt%, the co-catalytic component is present in an amount of 0.1wt% to 0.5wt%, and the additional component is present in an amount of 0.1wt% to 4.0wt%.
  4. 4. A catalyst according to claim 3, characterized in that the selectivity of the catalyst is 85.7-99.1%.
  5. 5. A process for preparing a catalyst according to any one of claims 1 to 4, comprising the steps of: S100, after mixing and impregnating the main catalytic component, the water-soluble compound of the auxiliary catalytic component and the carrier, sequentially passing through a first drying process and a roasting process to obtain a first initial product; S200, washing the first initial product through a water-soluble compound with an additional component after a chlorine removal procedure to obtain a second initial product; And S300, sequentially passing the second initial product through a second drying process and a reduction process to obtain the catalyst.
  6. 6. The method according to claim 5, wherein the drying temperatures of the first and second drying steps are 80 to 100 ℃ and the drying times are 2 to 4 hours.
  7. 7. The method according to claim 5, wherein the temperature of the firing step is 350 to 550 ℃ and the firing time is 2 to 4 hours.
  8. 8. The method according to claim 5, wherein the temperature of the reduction step is 180-250 ℃, the reduction time is 2 hours, and the reducing atmosphere is hydrogen.
  9. 9. The method of claim 5, wherein the water-soluble compound of the additional component comprises one or more of NaOH, na 2 CO 3 、NaHCO 3 、KOH、K 2 CO 3 , and KHCO 3 .
  10. 10. The method according to any one of claims 4 to 9, wherein the chlorine removal process comprises adding deionized water to the primary product, boiling for 0.5 to 1 hour, and vacuum filtering to obtain the first primary product after chlorine removal.

Description

Catalyst for cyclohexanol dehydrogenation and preparation method thereof Technical Field The invention relates to the field of catalysts, in particular to a catalyst for cyclohexanol dehydrogenation and a preparation method thereof. Background Cyclohexanone is a traditional Chinese medicine organic chemical raw material, and is a main intermediate for producing caprolactam and adipic acid. The main stream production process of cyclohexanone takes cyclohexanol as raw material and is obtained through catalytic conversion. The preparation of cyclohexanone from cyclohexanol is mainly classified into an oxidation method and a dehydrogenation method, wherein the oxidation method is to prepare cyclohexanone from cyclohexanol and air at 250-300 ℃ through a catalyst. The dehydrogenation method is to prepare cyclohexanone by the catalyst through anaerobic dehydrogenation, and has the advantages of relatively fewer byproducts, simple operation, high yield, safety and wider application in the industrial production of cyclohexanone. Early catalysts for cyclohexanol dehydrogenation have mostly employed high temperature dehydrogenation Zn-based catalysts, such as ZnO-CaCO 3 catalyst systems, with high reaction temperatures (350-400 ℃) and high conversion but poor selectivity and short life, which are basically replaced. In recent years, cu-based catalysts are mainly used in industrial production, and are classified into Cu-Zn-Al-based catalysts and Cu-Si-based catalysts, wherein the operation temperature of the catalysts is 220-260 ℃, the selectivity is more than or equal to 99%, but the conversion rate is lower (45% -52%). In order to increase the conversion of cyclohexanol and thus increase the productivity, a small number of patents have reported that adding small amounts of noble metals on the basis of Cu-based catalysts can increase the conversion of cyclohexanol. US5227530 discloses a catalyst with Cu, al, cr, B four components as the main body, with the addition of small amounts of Pd. SU891145 discloses a catalyst in which phosphate precipitates are formed by adding an alkaline sodium hypophosphite solution to an aqueous mixed chloride solution containing Cu, co and Pd. The catalyst disclosed by SU978909 contains Cu and Zn as main components, with a small amount of Ru added as an auxiliary. CN02807661.3 discloses a copper oxide based catalyst for the dehydrogenation of cyclohexanol, which contains a very small amount of one noble metal promoter from palladium, platinum and ruthenium, which can be used to produce cyclohexanone at reduced reaction temperatures compared to conventional catalysts, and although the addition of noble metals can increase the conversion of cyclohexanol, the conversion of cyclohexanone to phenol is promoted, resulting in a reduced selectivity. On the other hand, there are also few reports on the use of Pt as a catalyst for cyclohexanol dehydrogenation. For example, richardson et al (JournalofCatalysis, 1976,42, 275-281) report the use of 0.5wt% Pt/C catalyst without any doping agent for the high temperature (315 ℃) dehydrogenation of liquid phase cyclohexanol. Wherein, the conversion rate of cyclohexanol is 70%, and the selectivity is only 80%. Kanta et al (CATALLETTERS, 1997,45, 93-96) report the use of alumina supported Pt-Co bimetallic catalysts in gas phase cyclohexanol dehydrogenation reactions. The reaction temperature was 250 ℃, and when 5wt% Pt-5wt% co/Al 2O3 was used as catalyst, the conversion to cyclohexanol was 62.4% and the selectivity was 92%, although the conversion was higher, the Pt loading was too high and the selectivity was lower. Therefore, the development of a high-activity selective Pt catalyst for the gas-phase low-temperature dehydrogenation of cyclohexanol has great industrial prospect. Disclosure of Invention In view of the shortcomings of the prior art, the invention provides a platinum-based supported catalyst for gas-phase low-temperature dehydrogenation of cyclohexanol. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a platinum-based supported catalyst for gas-phase dehydrogenation of cyclohexanol comprises a main catalytic component, a promoting component, an additional component and a carrier, wherein the main catalytic component comprises platinum, the promoting component comprises iron, tin or cerium, the additional component is Na or K, and the carrier comprises alumina. The mass content of platinum in the silver-based supported catalyst for cyclohexanol gas phase dehydrogenation is 0.1-2.0wt%, the mass content of auxiliary iron, tin or cerium is 0.1-0.5wt%, and the mass content of Na or K is 0.1% -4.0 wt%. Preferably, the platinum content is 0.1wt% to 2.0wt%, the promoting component content is 0.1wt% to 0.5wt%, and the additional component content is 0.1wt% to 4.0wt%. Preferably, the selectivity of the catalyst is 85.7% -99.1%. A method for preparing the catalyst, comprising the steps of: S100, after m