Synthesis of hierarchical silicoaluminophosphate (SAPO) molecular sieves by post-synthetic modification and their catalytic application
Authors :- Rohit Prajapati, Divya Jadav, Madhu Pandey, Keisuke Nishimura, Satoshi Inagaki, Yoshihiro Kubota, Rajib Bandyopadhyay, Mahuya Bandyopadhyay
Publication :- European Journal of Inorganic Chemistry, (Wiley), 2022,
Silicoaluminophosphates SAPO-34 (CHA topology) and SAPO-5 (AFI topology) molecular sieves are selectively prepared by hydrothermal method using templates tetraethylammonium hydroxide and triethylamine, respectively and suitably modified. Hierarchical SAPO-34 & SAPO-5 catalysts were post-synthetically prepared by facile acid (HNO3 and HCl) and base (NaOH) etching. X-ray diffraction (XRD), Thermogravimetric analysis (TG), FT-IR and Scanning Electron Microscope (SEM) were employed to investigate structural changes of the molecular sieves. Hierarchical SAPO-34 & SAPO-5 were used for the ring opening reaction of propylene oxide with morpholine producing the corresponding β-amino alcohols, and catalytic activity of the acid-treated SAPO-34 & SAPO-5 was compared with that of alkali treated counterparts. The catalytic performance of the acid treated materials was found better than the base treated one. 91 % conversion was achieved using acid treated SAPO-34, whereas 74 % conversion was achieved using alkali treated SAPO-34.