Synthesis, characterization of Ga-TUD-1 catalyst and its activity towards styrene epoxidation reaction Sandip Mandal a , Apurba SinhaMahapatra b , Batchu Rakesh a , Rawesh Kumar a , Asit Panda b, ⁎, Biswajit Chowdhury a, ⁎ a Department of Applied Chemistry; Indian School of Mines, Dhanbad, India b DIMC, Central Salt and Marine Chemicals research Institute (CSIR) Bhavnagar, Gujarat, India abstract article info Article history: Received 10 November 2010 Received in revised form 16 December 2010 Accepted 5 January 2011 Available online 15 January 2011 Keywords: Styrene Epoxidation Mesoporous,TUD-1 Gallium Styrene epoxidation reaction has drawn attention from both academia and industry. After the synthesis of SBA-15 the research on mesoporous family has enriched by TUD-1 mesoporous material. Doped and undoped TUD-1, has been exploited for various oxidation reactions either as such or as a support for different active component. In this paper we report the characterization of recently developed Ga-TUD-1 catalyst with three different Ga/Si ratio (1/100, 2/100, 4/100) by BET SA, FTIR, UV–Vis, DRIFT, SEM, TEM, 29 Si NMR techniques. A steady activity of the catalyst towards styrene epoxidation without any loss of efficiency up to 48 h of reaction was found. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Modern catalytic sciences have played an important role in the development of heterogeneous catalysts for new chemical technolo- gies [1]. More than 20% of industrial organic chemicals are obtained by catalytic oxidation. Studies on epoxidation of C=C bond through the heterogeneous catalytic route have received a lot of attention, as epoxides are very useful to synthesize fine chemicals. Epoxidation of styrene is a major challenge for the chemical industries as styrene oxide produces many valuable products [2]. Despite of the fact that several studies have been done for epoxidation of styrene by heterogeneous catalytic path using different oxidant like hydrogen peroxide, TBHP or molecular O 2 , there is still a scrutiny of different catalysts which can effectively perform the epoxidation reaction, as in most of the cases benzaldehyde is produced in larger amounts. To develop a catalyst for styrene epoxide, not only the conversion and selectivity, but also the steady yield of the product for a prolonged period is needed. As per the literature, different types of mechanisms of styrene epoxidation was proposed. For the metallic nanoparticle catalyst e.g., gold and silver catalyst, formation of oxometallacycle was reported as an intermediate [3] that may decompose to yield styrene epoxide. Whereas for the titanosilicate catalysts, formation of peroxo species was observed by in-situ NMR studies [4]. In an interesting study, Zhan et al. showed that the acidic sites were responsible to generate hydroperoxo species which attacks the adsorbed styrene on La-MCM- 48 catalyst surface [5]. Research on the mesoporous silica family has been enriched by successful discovery of MCM-48, SBA-15 and very recently, TUD-1 catalyst [6–9]. Lot of work has been done to exploit the chemical property of TUD-1 material by doping different metal atoms like Mn, Co, Fe etc. In a close packed structure of silicates which consists of packages of negatively charged oxygen anions (O 2- ), the cations can be accommodated in the tetrahedral and octahedral coordination depending on the cation and oxygen anions radius ratio. Isomorphous substitution of Ga into the silicate matrix has always been a challenge to the catalytic chemistry of gallosilicate [10]. It has been shown along the last two decades that gallium containing catalysts are relevant materials for a series of technologically important processes such as light alkanes dehydrogenation and aromatization (Cyclar process), hydrocarbon isomerization, nitrogen oxides reduction by hydrocar- bons, and carbon dioxide hydrogenation to methanol. The doping of Ga into TiO 2 has been found very effective for oxidation of 4- methylanisole [11]. Very recently we have found that Ga-TUD-1 is very effective for synthesis of α-aminonitrile demonstrating solvent- less eco-friendly path [12]. In this work we assume that isomorphous substitution of gallium in TUD-1 will generate acidic sites, which may play a key role to generate hydroperoxo species in the catalyst surface. In this paper, we characterize a novel 3-D spongelike, mesoporous high surface area Catalysis Communications 12 (2011) 734–738 ⁎ Corresponding authors. Chowdhury is to be contacted at Department of Applied Chemistry, Indian School of Mines, Dhanbad-826004, India. Tel.: +91 326 2235663; fax: +91 326 2296563. E-mail addresses: abpanda@csmcri.org (A. Panda), chowdhury.b.ac@ismdhanbad.ac.in (B. Chowdhury). 1566-7367/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2011.01.004 Contents lists available at ScienceDirect Catalysis Communications journal homepage: www.elsevier.com/locate/catcom