Journal of Molecular Catalysis A: Chemical 238 (2005) 223–228 Esterification of 1 ◦ and 2 ◦ alcohol using an ecofriendly solid acid catalyst comprising 12-tungstosilicic acid and hydrous zirconia Nikunj Bhatt, Anjali Patel ∗ Chemistry Department, Faculty of Science, M.S. University of Baroda, Vadodara 390002, India Received 15 March 2005; received in revised form 19 May 2005; accepted 19 May 2005 Available online 5 July 2005 Abstract A series of ecofriendly solid acid catalyst was synthesized by supporting 12-tungstosilicicacid onto hydrous zirconia using impregnation method in order to contribute towards clean technology which is the most important need of the society. The support and resulting catalysts were characterized by various spectral, thermal, and physicochemical techniques. The techniques used were chemical stability, ion exchange capacity, DSC, FT-IR, electronic spectra, XRD, particle size distribution and surface area measurement (BET method). Further, the surface morphology was studied by scanning electron microscopy. The above studies indicate that the keggin structure does not get destructed after supporting. Their catalytic properties were evaluated for the esterification reaction. Esterification of 1 ◦ alcohols (n-butanol, iso-butanol) and 2 ◦ alcohols (2-butanol, cyclohexanol) was carried out by varying different parameters such as different amount of the catalysts, different mole ratio of acid to alcohol using the synthesized catalysts. It was found that using the present catalysts, very high activity in all esters synthesis can be obtained. © 2005 Published by Elsevier B.V. Keywords: Hydrous zirconia; 12-Tungstosilicicacid; Solid acid catalyst; Esterification; Clean technology 1. Introduction Among acid catalysed reactions, esterification is an important organic reaction and usually carried out by use of various conventional mineral acids such as H 2 SO 4 , HF, H 3 PO 4 , HCl, etc. The replacement of these conventional hazardous and polluting corrosive liquid acid catalysts by solid acid catalyst is one of the demands of the society. This could be possible by making use of environment friendly catalysts involving the use of solid acids. Reduction of environmentally unacceptable waste, reduction of pollution and use of catalyst as a user-friendly catalysts are the crucial factor for developing environmental friendly catalyst. Heteropolyacids (HPAs) are typical strong Bronsted acids and catalyze a wide variety of reactions in homogeneous phase offering strong option for efficient and cleaner ∗ Corresponding author. Tel.: +91 265 2795552; fax: +91 265 2795552. E-mail address: aupatel chem@yahoo.com (A. Patel). processing [1–5]. The major disadvantages of HPAs, as catalyst lies in their low thermal stability, low surface area (1–10 m 2 /g) and separation problem from reaction mixture. HPAs can be made ecofriendly insoluble solid acid with high thermal stability and high surface area by supporting them onto suitable supports. The support provides an opportunity to HPAs to be dispersed over a large surface area, which increases catalytic activity. Various supports like silica [1–6] titania [3,6], alumina [3] active carbon [6–11], MCM-41 [12–17], acidic ion exchange resins [18], clay [19–22] have been used for supporting HPAs. The literature survey shows that hydrous oxides have multiphase applications. Among metal oxides, especially hydrous zirconia has drawn great attention. One of the main reason that has drown great attention to the use of hydrated zirconia as a precursor of a catalyst carrier is the fact that its surface hydroxyl groups are able to undergo a chemical reaction or strong interaction with incorporated components. 1381-1169/$ – see front matter © 2005 Published by Elsevier B.V. doi:10.1016/j.molcata.2005.05.019