Organosilane-assistant synthesis of hierarchical SAPO-34 aggregates with superior MTO performance

Hierarchical SAPO-34 aggregates were hydrothermally synthesized with the assistance of organosilane N-[3-(Trimethoxysilyl)propyl]ethylenediamine (TPED), during which the morpholine was used as the template. The resultant products were characterized by XRD, SEM, ICP-OES, NH3-TPD, N-2 adsorption-desorption and TGA, and a possible formation mechanism was proposed. As the amount of added TPED varies, the morphologies, compositions and acid properties of the resultant hierarchical SAPO-34 aggregates differ. The hierarchical SAPO-34 aggregates possessed higher external surface areas, lower Si content, weaker strength and lower concentration in the strong acid sites than the conventional SAPO-34. The investigation of formation process showed that the addition of the TPED had a pivotal role for the formation of hierarchical SAPO-34 aggregates. Compared to conventional SAPO-34, the hierarchical SAPO-34 aggregates exhibited a significant improvement in methanol to olefin reaction (MTO) reactions due to their hierarchical structure and mild acid properties.

Automated summary

The hierarchical SAPO-34 aggregates were synthesized with the assistance of organosilane TPED and using morpholine as the template. Different amounts of TPED led to varying morphologies, compositions, and acid properties of the resulting aggregates. The addition of TPED played a pivotal role in the formation of hierarchical SAPO-34 aggregates, which exhibited significant improvement in methanol to olefin reaction compared to conventional SAPO-34.