FTIR and UV/vis spectroscopic studies of reaction intermediates during direct propylene epoxidation using H2 and O2 over a Au-Ba/Ti-TUD catalyst

COLL 352

Jiqing Lu, jiqing-lu@aist.go.jp1, Juan J. Bravo-Suárez, juan-bravo@aist.go.jp1, Susumu Tsubota, susumu-tsubota@aist.go.jp1, and S. Ted Oyama, oyama@vt.edu2. (1) Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology, AIST Tsukuba West, 16-1 Onogawa, Tsukuba, 305-8569, Japan, (2) Department of Chemical Engineering, Virginia Tech, 140 Randolph Hall, Blacksburg, VA 24061
Gold supported barium-promoted mesoporous titanosilicate catalyst highly active and selective for direct propylene epoxidation using H2 and O2 has been studied by in situ UV/vis and FTIR spectroscopy. During in situ UV/vis measurements under a H2/O2 mixture a broad peak in the 30000 cm-1 region, assigned to a charge transfer interaction between the hydroperoxide (-OOH) ligand and Ti4+, was found and its intensity increased with reaction time. When introducing a mixture of C3H6/H2/O2 the same feature was observed but with a higher intensity, which could be related to adsorbed carbon species on the catalyst surface. FTIR bands arising at 2980, 2939 and 2884 cm-1 are assigned to the C-H stretching vibrations of bidentate propoxy species, which can result from PO decomposition. Bands at 1561 and 1423 cm-1 are due to the adsorption of formate and acetate species from the oxidation of the bidentate species.
 

Surface Chemistry Symposium in Honor of Gabor Somorjai
8:30 AM-11:50 AM, Tuesday, 12 September 2006 Sir Francis Drake -- Franciscan Room, Oral

Division of Colloid & Surface Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006