THE SYNTHESIS OF FERRIERITE, ZSM-5, AND THETA-1 IN THE PRESENCE OF DIETHANOLAMINE - EXPERIMENTAL

The synthesis of zeolites from gels containing silica, alumina, potass ium and/or sodium hydroxide or chloride, diethanolamine, and water was studied. Zeolites Theta-1, ZSM-5, ferrierite, and mordenite, and the dense phase cristobalite, were produced by varying the SiO2/Al2O3 rati o, the alkalinity and the alkali metal cation. The effect of varying t he SiO2/Al2O3 ratio was found to be of great importance. The ranges of SiO2/Al2O3 ratios over which each zeolite is formed have been establi shed, and discrete upper and lower limits were found to exist in the c ases of ZSM-5, Theta-1, and ferrierite. The formation of these materia ls was followed under a variety of conditions using X-ray diffraction, thermal analysis, MAS n.m.r. and AAS. The kinetics of formation of th ese zeolites were investigated, as were the compositions and character istics of the solid phases collected during the syntheses. The locatio n and charge of the diethanolamine present within the solid materials were found to be significant. Diethanolamine is considered to have a p ore-filling role and also a charge-compensatory role when the amine gr oup is protonated, and hence its overall effectiveness as a stabilizer depends upon the type of zeolite structure and the aluminum content.