Influence of Type of Organic Template on the Properties of Zeolites ZSM-23

Resumo

The influence of the type of organic template from the series: pyrrolidine, dimethylformamide, N-methylpyrrolidone on the physicochemical properties of zeolite of MTT structure (ZSM-23) was studied. The optimal composition of the reaction mixture and the synthesis conditions of ZSM-23 were determined for each template. The use of relatively inexpensive organic templates, dimethylformamide and N-methylpyrrolidone, makes it possible to obtain phase-pure zeolite of MTT topology with SiO₂/Al₂O₃ ratio from 60 to 100, the acid characteristics of which are similar to zeolites obtained with pyrrolidine expensive and not produced in Russia. The synthesis with use of dimethylformamide allows obtaining zeolite ZSM-23 with a yield of more than 95% calculated in term of silica spent and improved texture characteristics: the micropore volume 0.08–0.09 cm³ g⁻¹, the total pore volume 0.3–0.35 cm³ g⁻¹. An analysis of the features of the syntheses with different templates exhibited that dimethylformamide can be considered as the most suitable for use in producing MTT zeolite (ZSM-23).