Dehydration of monoethanolamine over alkali-exchanged zeolites

The dehydration of monoethanolamine was carried out over a series of alkali-exchanged zeolites and aluminophosphate molecular sieves. The main product over all these samples is ethylenimine (EI). The Lewis basicity and Lewis acidity in these samples were characterized by the charges on framework oxygens and the charges on, extraframework cations divided by the square of the atomic radius, respectively, which were calculated from the Sanderson Electronegativity Equalization method (EEM). The relationship between these parameters and the EI yield suggests that the reaction is both Lewis basicity and Lewis acidity dependent. Moreover, the pore structure is also an important factor, which influences the EI formation. However, the deactivation is serious for some of these catalysts and the possible reasons for this deactivation are discussed.