Group 6 metal oxide-carbon aerogels. Their synthesis, characterization and catalytic activity in the skeletal isomerization of 1-butene Original Research Article

Group 6 metal–organic aerogels were prepared by polymerization of a resorcinol–formaldehyde mixture which contained metallic salts of the elements of this group. The aerogels prepared were carbonized both at 773 and 1273 K to obtain the corresponding metal oxide–carbon aerogels. All these materials were characterized by different techniques including gas adsorption, mercury porosimetry, XRD, XPS and decomposition of isopropanol to determine their textural characteristics, state of the metallic phase and surface acidity, respectively.The metal oxide–carbon aerogels were tested in the isomerization reaction of 1-butene. The most active catalyst was the tungsten oxide–carbon aerogel pretreated at 773 K, which presented an isobutene yield of 40% at 448 K. This was due to its high surface acidity and more adequate porosity. Isobutene and trans-2-butene were the main reaction products obtained and no C3–C5 and C2–C6 by-products were observed.