Vapour phase hydrogenation of phenol over Pd/C catalysts: A relationship between dispersion,metal area and hydrogenation activity |
| |
| Affiliation: | 1. Catalysis Division, Indian Institute of Chemical Technology, Hyderabad 500 007, India;2. Catalysis Research Center, Hokkaido University, West 10, North 11, Kita-Ku, Sapporo 060-0811, Japan;1. Department of Organic Technology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 81237 Bratislava, Slovak Republic;2. Research Institute of Chemical Technology, VUCHT a.s., Nobelova 34, 83603 Bratislava, Slovak Republic;3. Department of Chemistry, Faculty of Metallurgy, The Technical University of Košice, Letná 9, 04200 Košice, Slovak Republic;1. School of Chemical Engineering, Federal University of Uberlândia, Uberlândia, 38400-098, Brazil;2. Division of Catalysis and Chemical Processes, National Institute of Technology, Rio de Janeiro, 20081-312, Brazil;3. Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, 99352, USA;1. Institute of Industrial Catalysis, College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, China;2. Advanced Materials and Catalysis Group, ZJU-NHU United R&D Center, Department of Chemistry, Zhejiang University, Hangzhou 310028, China;1. Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore;2. Department of Applied Chemistry, School of Advanced Engineering, Kogakuin University, 2665-1 Nakano-machi Hachioji-city, 192-0015 Tokyo, Japan;3. Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore |
| |
| Abstract: | A series of palladium supported on activated carbon catalysts, with Pd varying from 0.5 to 6.0 wt%, were prepared via wet impregnation method using PdCl2 · xH2O as a precursor salt. The dried samples were further reduced at 573 K in hydrogen and characterized by CO adsorption at room temperature in order to determine the dispersion, metal area and particle size. The catalysts were tested for vapour phase phenol hydrogenation in a fixed-bed all glass micro-reactor at a reaction temperature of 453 K under normal atmospheric pressure. The decrease in metal surface area as well as dispersion with corresponding increase in turn-over frequency (TOF) against palladium loadings suggest the unusual inverse relationship that exist between Pd dispersion and phenol hydrogenation activity over Pd/carbon catalysts. The stability of TOF at larger crystallite size indicates that phenol hydrogenation is less sensitive reaction especially beyond 3 wt% of Pd content. It is evident from the results that structural properties of the catalysts strongly influence the availability of Pd atoms on the surface for CO chemisorption and hence for phenol hydrogenation. A comparison between selectivity and product yield of the reaction against overall phenol conversion indicates that changes in reaction selectivity for cyclohexanone or cyclohexanol is independent of phenol conversion level and either of the product is not formed at the cost of another. The stability of the catalysts with reaction time suggests that coke formation on the surface of the catalyst is less significant and the formation of cyclohexanone remains almost total even at higher reaction temperatures. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
