Aniline methylation over AEL type molecular sieves

ALPO-11, SAPO-11 and MAPSO-11 were prepared hydrothermally. These microporous solid catalysts could be used for the synthesis of industrially important N-alkylated products during aniline methylation. The activity of these catalysts was compared with aluminosilicates of high silica having Mm structure. A number of stronger acid sites enhance successive alkylation. Activity and selectivity of N,N-dialkylated product for SAPO-11 is higher at all temperatures as compared to that of ALPO-11. By introduction of Mg in SAPO-11, during hydrothermal synthesis, a decrease in total acid strength and an increase in basic strength, as compared to SAPO-11, is observed. This acidity-basicity function is correlated with the activity of the catalyst and product pattern of the methylation of aniline. C-alkylated products via direct alkylation of aniline with methanol are not enhanced during the alkylation reaction, catalysed by ALPO-11 and its derivatives, whereas the reaction catalysed by aluminosilicates and high silica aluminosilicates with MFI structure, some amount of C-alkylated products (toluidines) are formed.