1. Contribution from the Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnéstrasse 5, D-04103 Leipzig, Germany, Cepsa Research Center, Picos de Europa, 7 Poligono Industrial San Fernando de Henares II, 28850 San Fernando de Henares, Spain, Department of Hydrocarbon Process Chemistry, SINTEF Materials and Chemistry, P.O. Box 124 Blindern Forskningsveien 1, N-0314 Oslo, Norway, Grace GmbH & Co. KG, In Der Hollerhecke 1, D-67545 Worms, Germany, and Institute of Chemical Technology,...