therm0chimica acta ELSEVIER Thermochimica Acta 276 (1996) 209 220 Copper-zinc oxide catalyst. Part II. Preparation, IR characterization and thermal properties of novel bimetallic precursors Jura) 12ernfik a, Jozef Chomi~ a, Charles Kappenstein b,., Rachid Brahmi b, Daniel Duprez b a Department of Inorganic Chemistry, P.J. Safdrik University, Moyzesova 11,041 54 Ko~;ice, Slovakia b URA-CNRS 350, Equipe de Chimie Min&ale, University of Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers, France Received 23 March 1995;accepted 11 September 1995 Abstract Four new bimetallic model precursors of copper-zinc oxide catalysts for rnethanolization were prepared: Zn(NH3)2Cu(CN)3 (ZCA), [Zn(en)3]6[Cus(CNhv]'nH20 (n = 8.4) (ZCE3), Zn(en)Cu(CN)3 (ZCE1) and [Znl xCux(en)] [Cu(CN) 3] (ZCCE1). The new compounds were characterized by elemental analysis, IR spectroscopy, and thermal analysis under dynamic conditions. Thermal stability increases in the order ZCE3 (65) < ZCA (120) < ZCE1 or ZCCE1 (155°C). Thermal decomposition in air proceeds via the following steps: dehydration (if water molecules are present), deamination, redox decomposition of the cyano groups with formation of metallic copper and ZnO, and finally re-oxidation of copper to CuO. In the case ofen-containing compounds an unexplained phase transition was observed at 800°C. Keywords. Bimetallic precursors of catalysts; Copper zinc oxide catalysts; Methanol synthesis; IR; TG DTA; Thermal analysis 1. Introduction Copper zinc oxide are well known catalysts for the synthesis of methanol from syngas (CO + H e mixture) [1], but they can also be used for other catalystic reactions such as the synthesis of higher alcohols with cobalt-promoted samples [2], the water gas shift reaction [3] or the hydrogenation of alkenes [4]. Most publications deal with * Corresponding author. Fax: 33 49 45 40 20. 0040-6031/96/$15.00 '(C:1996 Elsevier Science B.V. All rights reserved SSDI 0040-6031(95)O2736-X