Int. J. Mol. Sci. 2001, 2(5), 230-245; doi:10.3390/i2050230
Article

The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents

Carlo Lamberti 1,2,3,* email, Carmelo Prestipino 1,3 , Luciana Capello 1,2 , Silvia Bordiga 1,3 , Adriano Zecchina 1,3 , Giuseppe Spoto 1,3 , Sofia Diaz Moreno 4 , Andrea Marsella 5 , Barbara Cremaschi 5 , Marco Garilli 5 , Sandro Vidotto 5  and Giuseppe Leofanti 5
1 Department of Inorganic, Physical and Material Chemistry, University of Turin, Via P. Giuria 7 10125 Torino Italy 2 INFM UdR di Torino Università, Italy 3 INSTM Research unit of Turin University, Italy 4 ESRF, BP 220, F-38043 Grenoble Cedex, France 5 EVC Italia, Technological Centre, Via della Chimica 5, 30175 Porto Marghera (Venezia), Italy
* Author to whom correspondence should be addressed.
Received: 2 October 2001 / Accepted: 7 November 2001 / Published: 13 November 2001
(This article belongs to the Special Issue Elementary Steps in Heterogeneous Catalysis: Theory and Experiment (Papers from Euroconference on Molecular Mechanism of Heterogeneous Catalysis Held in San Feliu de Guixols, Spain, in June 2001))
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Abstract: Alumina supported CuCl2, the basic catalyst for ethylene oxychlorination, has been investigated by UV-Vis spectroscopy, EPR, EXAFS and XANES in a wide range (0.25-9.0 wt%) of Cu concentration. We have evidenced that, at low Cu content, the formation of a surface aluminate species takes place. The formation of this surface copper aluminate stops at 0.95 wt% Cu / 100 m2; at higher Cu concentrations excess copper chloride precipitates directly from solution during the drying step forming an highly dispersed CuCl2.H2O, phase, overlapping progressively the surface aluminate. Depletion tests and IR spectroscopy of adsorbed NO have demonstrated that the latter is the only active phase. A complete catalytic cycle has then been performed on CuCl2/Al2O3 catalyst. EPR, XANES and EXAFS, have been used to demonstrate that the ethylene oxychlorination reaction: C2H4 + 2HCl + ½ O2 --> C2H4Cl2 + H2O follows a three steps mechanism: (i) reduction of CuCl2 to CuCl (2CuCl2 + C2H4 --> C2H4Cl2 + 2CuCl), (ii) oxidation of CuCl to give an oxychloride (2CuCl + ½ O2 --> Cu2OCl2) and (iii) closure of the catalytic circle by rechlorination with HCl, restoring the original CuCl2 (Cu2OCl2 + 2HCl --> 2CuCl2 + H2O). Finally, we have shown that time resolved, in situ, spectroscopy is a very promising technique to investigate the interplay between catalyst activity and oxidation state of copper.
Keywords: Al2O3 supported CuCl2; ethylene oxychlorination; EPR; XANES; EXAFS

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MDPI and ACS Style

Lamberti, C.; Prestipino, C.; Capello, L.; Bordiga, S.; Zecchina, A.; Spoto, G.; Moreno, S.D.; Marsella, A.; Cremaschi, B.; Garilli, M.; Vidotto, S.; Leofanti, G. The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents. Int. J. Mol. Sci. 2001, 2, 230-245.

AMA Style

Lamberti C, Prestipino C, Capello L, Bordiga S, Zecchina A, Spoto G, Moreno SD, Marsella A, Cremaschi B, Garilli M, Vidotto S, Leofanti G. The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents. International Journal of Molecular Sciences. 2001; 2(5):230-245.

Chicago/Turabian Style

Lamberti, Carlo; Prestipino, Carmelo; Capello, Luciana; Bordiga, Silvia; Zecchina, Adriano; Spoto, Giuseppe; Moreno, Sofia D.; Marsella, Andrea; Cremaschi, Barbara; Garilli, Marco; Vidotto, Sandro; Leofanti, Giuseppe. 2001. "The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents." Int. J. Mol. Sci. 2, no. 5: 230-245.

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