Seed-assisted grinding synthesis of SAPO-34 catalyst and its prolonged catalytic lifetime in the conversion of methanol to olefins

Investigation of synthesis time and type of seed along with reduction of template consumption in the preparation of SAPO-34 catalyst and its performance in the MTO reaction

“…T ¼ 400 C -GHSV ¼ 4200 h À1 Sun et al 34 TEAOH ¼ 0.94 & TEA ¼ 1.56 396 83% (C 2 -C 3 ) T ¼ 425 C Conv > 99% WHSV ¼ 2 h À1 Lyu et al 24 TEAOH ¼ 1 330 83.6% (C 2 -C 4 ) T ¼ 400 C Conv > 95% WHSV ¼ 0.5 h À1 Lu et al 23 MOR…”

“…The resultant samples with a reduction of crystal size to 200-500 nm and lower acidity, as well as larger external surface areas, showed better performance in the MTO reaction compared to the conventional sample. In another research, Lu and coworkers 23 synthesized pure SAPO-34 using activated seed crystals with a low concentration of template (MOR/Al 2 O 3 ¼ 1). The results showed that the addition of seed crystals not only decrease the crystal size to 500-800 nm but also led to an appropriate acidity.…”

Down the Microporous Rabbit Hole of Silicoaluminophosphates: Recent Developments on Synthesis, Characterization, and Catalytic Applications

“…118 Here there is no need for a separate evaporation step, as no additional water is added, creating a paste that is ground for 10-15 minutes into a solid, which is transferred to an autoclave for crystallisation. 83 This was shown to make particularly crystalline SAPO-34 species, which was easily followed as a function of crystallization time. Likely the more regular particles are due to the grinding, ensuring a homogeneous mixture of reagents.…”

“…Therefore, inspiration has been taken from zeolite synthesis into SDA-free methods with some success. In many cases the necessity of the SDA can be reduced (though rarely completely removed) by using seed crystals. ,− Adding small quantities of the desired framework into the synthesis gel provides ready-made nucleation sites for the framework; this speeds up the crystallization kinetics for that species, as a blueprint has already been supplied.…”

“…Collaborative efforts from China provided an alternative solvent-free method for SAPO (and AlPO) synthesis based on grinding . Here, there is no need for a separate evaporation step, as no additional water is added, creating a paste that is ground for 10–15 min into a solid, which is transferred to an autoclave for crystallization . This was shown to make particularly crystalline SAPO-34 species, which was easily followed as a function of crystallization time.…”