Ultraviolet-Raman studies of coke formation during hydrocarbon conversion over a zeolite catalyst

Small olefins are some of the initial products in methanol conversion reactions on zeolites. Using ethylene as a starting reagent can provide information about the reaction progression that can be related to methanol reactions. At 150°C several strong peaks can be identified at at 1481, 1550, and 1610 cm^-1. After further heating these peaks remain, though their intensity pattern changes. This indicates that each peak is the result of a different species. Identification is underway. Assignment of these bands has identified the 1481 cm^-1 band as a cyclopentadienyl species with an sp³ hybridized carbon, such as indene or fluorene. The sp³ carbon is not hydrogen substituted.