1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 z Catalysis Sulphated Zirconia Supported on Cordierite Honeycomb Monolith for Effective Synthesis of Solketal from Acetalisation of Glycerol with Acetone Vanagoor T. Vasantha, [a, b, d] Naragalu J. Venkatesha, [c] Sathgatta Z. Mohamed Shamshuddin,* [a] Joyce Queeny D’Souza, [e] and Bongu G. Vijayasimha Reddy [b] Liquid phase acetalisation of glycerol with acetone to synthe- size a value added glycerol acetal (solketal) has been studied over solid oxides such as ZrO 2, ZrO 2 -Al 2 O 3 and SO 4 2À /ZrO 2 coated on cordierite honeycomb monoliths. Such honeycomb monoliths were characterized by XRD, TPD-NH 3, BET, SEM and FTIR techniques. Characterization results indicate that the incorporation of calculated amounts of Al 2 O 3 or SO 4 2À on ZrO 2 strongly influences the surface acidity of ZrO 2 , increases the catalytically active tetragonal phase of ZrO 2 and improves surface area and pore volume. Modified ZrO 2 catalysts coated on honeycombs show better conversion and selectivity towards solketal when compared to pure ZrO 2 . Moreover cordierite honeycomb monoliths coated with catalytic materials were found to be efficient, easily reactivable and reusable for at least 6 reaction cycles. 1. Introduction Cordierites (2Al 2 O 3 .2MgO.5SiO 2 ) have very low thermal expan- sion co-efficient and honeycomb monolith structures play a vital role in heterogeneous catalysis. Honeycomb monoliths generally are in circular shape with interconnected cells or channels and easy to construct. The honeycomb monoliths are catalytically inactive material with very low acidity and higher surface area. The active sites can be improved by supporting thin layers of various acidic metal oxides and their modified forms, which are very useful for industrially important catalytic organic transformations. [1] The supported honeycomb monolith catalysts were origi- nally developed for gas phase reactions such as, automotive emission control systems as catalytic converters in diesel and gasoline engines, ozone abatement in aircrafts and selective reduction of NO x . [2–9] Advantages of catalyst coated on honeycomb monolith (HC) over powder form of catalyst are: safe operation and very thin layer of the catalysts loading on monolith is highly effective and gives high surface active sites, easy separation and complete recovery from the reaction mixture, tolerate a wide range of temperatures, safe to store and long life time and environmentally safe disposal. Moreover, the application of cordierite honeycomb monolith coated with active catalysts can be an interesting initiative step in the field of organic fine chemical synthesis. [10] Zirconia and its modified forms have played an important role as catalysts in pharmaceutical, petrochemical and organic fine chemical industries. The surface and catalytic properties of pure zirconia can be modified by incorporating anions (SO 4 2À ) or cations (Al 3 + , Mo 6 + ). It reported that zirconia modified with such ions drastically increase the acidic properties of pure zirconia there by increasing their applications in a wide range of acid catalyzed reactions such as esterification, transesterifica- tion, isomerization, etc. [11–13,32] The acetalisation of glycerol with carbonyl compounds has been reported to produce oxygenated compounds, currently used as fuel oxygenates. [14–17] 1–5 vol% solketals blended with regular gasoline improves the octane number up to 2.5 points and also decreases the gum formation. [24,25] The solketal and its derivatives were prepared using various carbonyl compounds such as acetone, benzaldehyde, acetaldehyde, acetophenone, cyclohexanone, etc., using homogeneous protonic acids such as HCl, H 2 SO 4 and H 3 PO 4 . [18] The affinity has been to replace highly corrosive, hazardous and polluting liquid acids by other environment friendly heterogeneous-solid acid catalysts like clays, zeolites, etc. . [19–23] The aim of this work is to prepare catalytic materials such as cordierite honeycomb coated with solid acids like ZrO 2 and its modified forms such as ZrO 2 -Al 2 O 3 and SO 4 2À /ZrO 2 , determi- nation of their physico-chemical properties and synthesis of solketal from acetalisation of glycerol with acetone. Synthesis [a] V. T. Vasantha, Prof. S. Z. M. Shamshuddin Chemistry Research Laboratory, HMS Institute of Technology, NH4, Kya- thasandra, Tumakuru, Karnataka, India Phone: + 91 9844718742 E-mail: mohamed.shamshuddin@gmail.com [b] V.T. Vasantha, Dr. B. G. V. Reddy Vemana Institute of Technology, Koramangala, Bengaluru, Karnataka, India [c] Dr. N. J. Venkatesha Assistant Professor, Chemistry Research Centre, Bangalore Institute of Technology, K. R. Road, V.V Pura, Bengaluru, Karnataka, India [d] V. T. Vasantha Visveswaraya Technological University - Research Resource Center, Bela- gavi, Karnataka, India [e] Dr. J. Q. D’Souza Department of Chemistry, St. Josephs’ College, Langford Road, Bengaluru, Karnataka, India Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201702186 Full Papers DOI: 10.1002/slct.201702186 602 ChemistrySelect 2018, 3, 602 – 608  2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim