“…Figure d shows the DRIFT spectra of the catalyst 150-S1 surface in a flow of a toluene and 1-decene mixture, recorded at different temperatures in comparison with the model spectra of 1-decene, toluene, and para -ethyl-toluene. The 1645 cm –1 band of antisymmetric stretching CC (ν as ) of 1-decene in the DRIFT spectrum splits into two broad bands at 1660–1630 cm –1 (ν as ) and 1550–1520 cm –1 (ν s ), which is characteristic of conjugated delocalized double bonds . The symmetric stretching vibrations (ν s ) of olefinic hydrocarbons, usually lying in the range of 1550–1530 cm –1 , do not appear.…”