Interaction of ethanol with alumina, silica - Alumina and zeolites

Fourier-transform infrared spectroscopy (FT-IR) has been applied to study t he interaction of ethanol vapour with alumina (Degussa C), silica-alumina ( Grace Division Chemical Research), zeolite X (Union Carbide) and zeolite ZM S-5 (laboratory made). Different surface species have been identified after heating at 35, 200 and 300 degrees C. The interaction of ethanol with Al2O 3 at 200 degrees C results in formation of a carboxylate system, which at t emperature higher than 200 degrees C undergoes further decomposition with p roduction of conventional (aromatic) coke and a species resembling acetyl g roups. As a result of the interaction with amorphous silica-alumina, conven tional coke is produced already at 200 degrees C, while with NX zeolite a d eposit of a mixture of conventional coke and carboxylate coke is formed. At 300 degrees C, the carboxylic deposit substantially disappears. The intera ction of ethanol vapours with H-ZSM-5 zeolite at 200 and 300 degrees C lead s to formation of a conventional deposit of alkyl-substituted naphthalenes and /or plyphenylenes. As a result of ethanol dehydration water molecules w ere also detected.