Comparative Synthesis and Physicochemical Properties of Nanostructured SAPO-34 Molecular Sieve Using TEA and Morpholine Templates

Olefins are the basic building blocks for the most of petrochemical industries. Remarkable array of light olefins applications creates a sense of excitement among researchers to explore recently accepted processes like methanol to olefins (MTO), thus opening new opportunities for methanol utilization. The silicoaluminophosphate, SAPO-34, was reported to be the most promising catalyst. It is well-recognized that template plays important roles in the synthesis and physicochemical properties of molecular sieves. In this research, TEA and morpholine 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 and FTIR techniques were performed. Physiochemical properties of the catalyst were affected by the type of the used templates. The catalyst synthesized with TEA 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 in which the catalyst templated with TEA 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 catalyst prepared with morpholine exhibited superior activity with regard to light olefins selectivity in the MTO reaction

Keywords:

MTO , SAPO-34 , TEA , Morpholine , Methanol , Olefins