Novel highly active FSM-16 supported molybdenum catalyst for hydrotreatmentw Shelu Garg, a Thallada Bhaskar, a Kapil Soni, a Gnanamani Muthu Kumaran, a Akinori Muto, b Yusaku Sakata b and Gudimella Murali Dhar* a Received (in Cambridge, UK) 10th June 2008, Accepted 28th July 2008 First published as an Advance Article on the web 15th September 2008 DOI: 10.1039/b809808e FSM-16 (Folded Sheet Silica) supported catalysts could accom- modate 12 wt% Mo (18% MoO 3 ) as a monolayer with higher dispersion than any other silica support; these catalysts showed outstanding HDS and HYD activities compared to c-Al 2 O 3 , amorphous silica, and other mesoporous silica supported catalysts. Hydrotreating is an important unit operation in petroleum refining. 1 Its importance is further emphasized by the stringent sulfur specifications of petroleum products needing ultra low sulfur fuels in the range 10–15 ppm. 2 On board fuel cells also require fuels with sulfur as low as 0.1 ppm. Calculations revealed that in order to produce such a low sulfur fuel, seven times more active catalysts are needed. Many approaches such as method of preparation of catalysts, variation of promoters or variation of supports are employed towards this end. Among these, variation of the support is an important one. 3–5 Many materials have been tested as supports for Mo with Co or Ni as promoters, some of which are SiO 2 , Al 2 O 3 , MgO, ZrO 2 , TiO 2 , carbon, mixed oxides such as TiO 2 –ZrO 2 , ZrO 2 – Al 2 O 3 , TiO 2 –Al 2 O 3 , ZrO 2 –SiO 2 , SiO 2 –Al 2 O 3 , TiO 2 –SiO 2 etc. Zeolites such as NaY, USY, b-zeolite have also been employed as supports. In recent years mesoporous materials 3,4,6,7 such as MCM-41, SBA-15, 8,9 and HMS 10 have been studied with great interest as supports for hydrotreating catalysts due to their high surface area, stability, and well defined pores with narrow size distribution. FSM-16 materials, which are analogous to MCM-41 (hexagonal, p6mm) materials, have gained much attention because of their high surface areas and pore volumes. To our knowledge there is no detailed report on FSM-16 supported molybdenum catalysts for hydrotreatment. Herein, we are reporting for the first time the outstanding activities of FSM-16 supported molybdenum catalysts promoted with cobalt and nickel for hydrotreating reactions. The FSM-16 material is prepared by a method similar to that used by Inagaki et al. 7 A typical synthesis procedure is as follows: 30 g of kanemite was dispersed in 300 ml of water and then stirred for 3 h at 300 K. Then the suspension was filtered out to obtain wet kanemite paste. All of the kanemite paste was dispersed in 480 ml of an aqueous solution of 2-hexadecyltrimethylammonium chloride (0.125 mol l 1 ) and then stirred at 343 K for 3 h. The suspension was kept stirring at 343 K for 3 h while keeping the pH value at 8–9. After cooling, the solid product was filtered out, washed with water, dried in air and calcined at 823 K to yield mesoporous silicate, FSM-16. A nitrogen adsorption/desorption isotherm of FSM-16 (BET SA: 885 m 2 g 1 ) and Mo/FSM-16 catalysts showed a typical reversible IUPAC type IV hysteresis loop with the average pore diameter ca. 3.0 nm. A series (2–16 wt%) of FSM-16 supported molybdenum catalysts, promoted with nickel or cobalt were prepared by an incipient wetness impreg- nation method, characterized by low temperature oxygen chemisorption (LTOC) 11 on catalysts sulfided at 673 K and catalytic activities were evaluated for hydrodesulfurization (HDS) of thiophene and hydrogenation (HYD) of cyclohexene. The reactions were carried out at 673 K on catalysts sulfided at the same temperature for 2 h in a flow of a CS 2 –H 2 mixture in a fixed bed reactor operating at atmospheric pressure. The first order rates were evaluated according to the equation x = r(W/F) where r is the rate in mol h 1 g 1 , x the fractional conversion, W the weight of catalysts in grams, and F the flow rate of the reactant in mol h 1 . The oxygen uptakes at 195 K, HDS, HYD activities are shown in Fig. 1. It can be seen that oxygen chemisorption increases with molybdenum loading and is maximum at 12 wt% Mo. This can be taken as completion of a MoS 2 monolayer on the FSM-16 surface. This observation is also Fig. 1 Effect of Mo loading on hydrodesulfurization reaction rate and oxygen chemisorption on FSM-16 supported catalysts. a Catalytic Conversion Process Division, Indian Institute of Petroleum, Dehradun 248005, India. E-mail: gmurli@iip.res.in; Fax: +91 135 2660202; Tel: +91 135 2660054 b Department of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan w Electronic supplementary information (ESI) available: EDAX analysis of FSM-16. See DOI: 10.1039/b809808e 5310 | Chem. Commun., 2008, 5310–5311 This journal is  c The Royal Society of Chemistry 2008 COMMUNICATION www.rsc.org/chemcomm | ChemComm Published on 15 September 2008. Downloaded by Temple University on 27/10/2014 15:07:21. View Article Online / Journal Homepage / Table of Contents for this issue