ADSORPTION AND REACTION OF 2-PROPEN-1-OL IN H-ZSM-5

The adsorption of 2-propen-1-ol in H-ZSM-5 has been studied by temperature-programmed desorption (TPD), thermogravimetric analysis (TGA), and transmission infrared spectroscopy. Following adsorption at 295 K, an adsorption complex with a stoichiometry of 1 2-propen-1-ol molecule/Al site can be easily identified in TPD-TGA. This 1:1 complex reacts above 360 K to form water and an allylic intermediate that undergoes secondary reactions to form simple olefins and aromatics before leaving the zeolite. Infrared spectra of the intermediate at various temperatures indicate that the intermediate is highly reactive, and the spectra are consistent with the formation of an alkyl silyl ether species during reaction. However, the ease of forming dehydration products from the 1:1 adsorption complex with 2-propen-1-ol compared to that for other alcohols is well described by the relative gas-phase stability of the carbenium ions, implying that formation of the carbenium ion must be an important step in the reaction. © 1990 American Chemical Society.