Synthesis of Micro-Mesoporous ZSM-23 Zeolite

Two procedures were suggested for preparing a micro-mesoporous zeolite of MTT topology (ZSM-23 type) with the molar ratio SiO 2 /Al 2 O 3 = 100 in the presence of dimethylformamide as a template. The first procedure involves hydrothermal crystallization under the conditions ensuring the formation of nanosized crystals. The second procedure is postsynthetic treatment of the zeolite with a NaOH solution to increase the mesopore volume. Samples of ZSM-23 zeolites with the crystal size of 100–200 nm with improved textural characteristics (micropore volume up to 0.1 cm 3 g –1 , mesopore volume up to 0.70 cm 3 g –1 ) were obtained in >85% yield based on the silica used. The acid characteristics of the synthesized samples are similar to those of the zeolites prepared using pyrrolidine, which is expensive and is not produced in Russia.