Synthesis of ZSM-5 Using a TBP Template and an Oligomeric Silicic Ester

The syntheses of pentasil zeolites were carried out using the system xNa2O·y(TBP)2O·Al2O3·zSiO2·1050H2O, keeping z = 50—600, y/z = 0.03 to 0.1, and x/z = 0.01 to 0.05 at 448 K. Pure ZSM-5 phase is found to form for any value of z in the range specified when y/z = 0.02 and x/z = 0.01. When these compositional ranges and ratios are altered either ZSM-11 or intergrowth of ZSM-5/11 or formation of ZSM-5 or ZSM-11 and quartz takes place. The decomposition of the templates, from the channels of ZSM-5 of different SiO2/Al2O3 ratio, showed differences in their patterns. After calcination of the samples phosphorus is retained in the zeolite channels in the form of a surface complex. Thermal analysis and FTIR studies support this observation. SEM pictures drive to the conclusion that a liquid–solid transformation mechanism operates in the crystallization of ZSM-5 under the conditions of the synthesis studied.