TEA/MOR Mixed Template Synthesis of Nanostructured SAPO-34 Molecular Sieve with Various Ratios Used in Conversion of Methanol to Ethylene and Propylene

The nanostructured silicoaluminophosphate، SAPO-34، was reported to be the most promising catalyst. It is well-recognized that template plays important roles in the synthesis of molecular sieves. In this research، TEA and morpholine mixtures as organic templates were employed in synthesis of nanostructured SAPO-34 molecular sieve. To correlate the modification of the catalysts features with their performances in MTO reaction، characterizations by XRD، FESEM، PSD، BET، EDX and FTIR techniques were performed. Physiochemical properties of the catalyst were affected by the type of the used templates. The catalyst synthesized with 75% TEA and 25% morpholine showed rhombohedral shape of typical SAPO-34 and also hexagonal type crystal which is typical SAPO-5 morphology. XRD patterns afforded additional support for the obtained results from FESEM images showed diffraction peaks of both SAPO-5 and SAPO-34. Performance tests were carried out to investigate the influence of different temperatures on the catalyst activity in a range of 300-500ºC. The catalysts prepared with morpholine and TEA mixtures showed relatively the same product distribution with regard to light olefins selectivity in the MTO reaction