1. G. Lopes, A. Ferreira, A.P. Gonçalves and J.B. Branco Instituto Tecnológico e Nuclear, Estrada Nacional 10, 2686-953 Sacavém, Portugal Unidade de Ciências Químicas e Radiofarmacêuticas Melting temperatures around 150 ºC; The addition and increase of cerium % increases the transition temperature XRD tests were performed before and after the catalytic tests. The melting of the salts under CO 2 leads to CeO 2 formation. XRD patterns for the molten salts New features are not seen before and after the catalytic reaction. Slight contraction of the CeO 2 lattice is observed. The study of the combined Flow Rate (L/h) and CH 4 / O 2 molar ratio was undertaken. The outlet gas composition was analyzed on-line by gas chromatography (GC) with a thermal conductivity detector (TCD). Catalyst activity was defined as the number of mol of methane converted per mol of catalyst and per hour (mol CH 4 /mol.h), m≈25 g. [1] a) B. Mishra et al., Journal of Physics and Chemistry of Solids, 2005, 66, 396; b) T.R. Griffiths et al., Journal of Alloys and Compounds, 2006, 418, 116; c) J.J. Peng, et al., Applied Catalysis A: General, 2000, 201, L55; d) Y.G. Wei, et al., Journal of Natural Gas Chemistry, 2007, 16, 6. This work was supported by FCT, under contract number PTDC/QUI/72290/2006 All experiments were carried out using a CuCl-KCl (59:41 wt.%) eutectic mixture (T=550 ºC) as solvent and cerium molten chloride prepared by the addition of appropriate amounts of CeCl3 (5, 10 and 15 wt.%). The molten salts were characterized by Differential Scanning Calorimetry (PAC-ATD ADI prototype, DSC recorded under argon-50 mL/min until 1000 o C at a 10 o C/ min heating rate), X-Ray Powder Diffraction (XRD, reflection geometry with a PANalitycal X’Pert Pro diffractometer using Cu, ka monochromatic radiation l=1.5406 Å), Infrared Spectroscopy (IR, recorded on a Bruker spectrometer with samples mounted as Nujol mulls) as well as Elemental Analysis (C,H,N, S and O, performed on a CE instrument EA1110 automatic analyzer). Effect of the Flow Rate at CH 4 /O 2 molar ratio = 2 Molar ratio CH 4 /O 2 = 2 – mixture of compounds Molar ratio CH 4 /O 2 = 8 – Selectivity ~ 80% of C x H y Higher molar ratios enhances the production of hydrocarbons Effect of the CH 4 /O 2 molar ratio at Flow Rate = 3 L/h The addition of cerium (wt%) influences the conversion oh CH 4 CuCl-KCl-CeCl3 (10%) unusual behaviour First time such results have been obtained The applications of molten salts have been well recognized for more than a century. In spite of the use of high temperature corrosive liquids, molten salts offer unique opportunities. Low temperature multi component molten salts, as well as room temperature ionic liquids have been developed for materials processing. Currently, molten salts are finding applications in fuel cell technology, in the field of separation processes of minor actinides from the rest of the fission products that are contained in the irradiated nuclear fuel, for the direct catalytic conversion of methane under mild conditions and the partial oxidation of methane to synthesis gas [1]. Here, we report the synthesis, characterization and behaviour of potassium-cerium (K-Ce) molten chlorides for the partial oxidation of methane. Phase diagram of the eutectic mixture DSC tests before catalytic tests Catalysts the selectivities at CH 4 /O 2 molar ratio = 2 and Flow Rate = 3 L/h Catalysts selectivities at CH 4 /O 2 molar ratio = 8 and Flow Rate = 3 L/h