ORIGINAL PAPER A Novel, Low Temperature Synthesis Method of Dimethyl Ether Over Cu–Zn Catalyst Based on Self-Catalysis Effect of Methanol Prasert Reubroycharoen Æ Suwattana Teppood Æ Tharapong Vitidsant Æ Chaiyan Chaiya Æ Suchada Butnark Æ Noritatsu Tsubaki Published online: 4 June 2009 Ó Springer Science+Business Media, LLC 2009 Abstract A new DME synthesis route from syngas at a relatively low temperature (443 K) has been developed for the first time by the combination of a conventional DME synthesis catalyst (Cu/ZnO:HZSM-5 catalyst) with meth- anol as a catalytic solvent. The addition of methanol to the reaction system is the key to the success of DME synthesis at this temperature. Indeed, a CO conversion of 29 and 43% with a DME selectivity of 69 and 68% were achieved at 443 or 453 K, respectively, and 4 MPa, when methanol was used as a catalytic solvent. Importantly, no other by- products including methanol and hydrocarbons were observed in the DME product attained, suggesting no sig- nificant subsequent purification stages. Assuming no scale up problems, this process potentially provides a high purity of DME with less energy consumption, and so offers an opportunity for the economically viable future sustainable production of DME. Keywords Dimethyl ether  Methanol  Dehydration  HZSM-5  Low temperature 1 Introduction Dimethyl ether (DME) is produced in a large quantity from the non-renewable resources of natural gas and coal, but has the potential to be produced from renewable sources and, indeed, as a sustainable alternative fuel for 21st cen- tury. DME is currently known as a non-Freon aerosol propellant or as a precursor for dimethyl sulphate produc- tion. However, there is growing additional interest in its potential use as a fuel substitute for LPG and diesel fuel. This is because of the ease to be liquefied, high cetane number ( [ 55), low emissions of SOx, NOx and CO, and no particulate matter. Furthermore, existing combustion engines are easily modified to be compatible DME [1–3]. However, production via the two-step process of methanol synthesis from syngas followed by methanol dehydration over acid catalysts such as c-Al 2 O 3 and HZSM-5 [4], results in relatively low yields and production rates of DME. Moreover, the thermodynamic equilibrium for the conversion of syngas to methanol actually favors a high pressure and low temperature rather than the currently used relatively high temperatures [5]. Therefore, a single-step process, syngas to DME (STD), which has technical and economical advantages, has been suggested as a means to directly produce DME from syngas by using a hybrid catalyst [6–8]. The hybrid catalyst is a mixture of catalysts for methanol synthesis, composed of CuO, ZnO and Al 2 O 3 , and acid catalysts for the methanol dehydration stage. The P. Reubroycharoen (&)  S. Teppood  T. Vitidsant Department of Chemical Technology and Program of Petrochemistry & Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand e-mail: prasert.r@chula.ac.th C. Chaiya Division of Chemical Engineering, Faculty of Engineering, Rajamangala University of Technology Krungthep, Bangkok 10120, Thailand S. Butnark PTT Research and Technology Institute, PTT Public Company Limited, Ayutthaya 13170, Thailand N. Tsubaki Department of Applied Chemistry, School of Engineering, University of Toyama, Gofuku, Toyama 930-8555, Japan P. Reubroycharoen Center for Petroleum, Petrochemicals and Advanced Materials, Bangkok 10330, Thailand 123 Top Catal (2009) 52:1079–1084 DOI 10.1007/s11244-009-9252-y