Properties of faujasite zeolites containing methyl-substituted ammonium cations

This paper describes the properties of new X zeolite catalysts, whose anions are compensated by different methylammonium cations. The properties of these catalysts, with varying degrees of exchange, are compared with those of Y zeolites containing the same cations. For steric reasons, cation exchange was restricted to the faujasite supercavity, and the degree of ion exchange decreased with the radius of the organic cation. The basicity of the catalysts was analyzed using X-ray photoelectron spectroscopy (XPS) and the Knoevenagel condensation reaction, with good correlation obtained between the results of the two methods. The best catalytic activity was observed for the faujasite with the highest aluminum content (X zeolite), exchanged using the monomethylammonium cation. The better performance of this catalyst was attributed to its basicity, as well as the available micropore volume.