Acid stability evaluation of CHA-type zeolites synthesized by interzeolite conversion of FAU-type zeolite and their membrane application for dehydration of acetic acid aqueous solution

High Potential of Interzeolite Conversion Method for Zeolite Synthesis

“…Figure 9 shows the relationship between the Si/Al ratios prior to and subsequent to the acetic acid treatment 43) . No differences were observed between these Si/Al ratios for CHA type zeolites synthesized by the interzeolite conversion method.…”

“…To clarify the effect of structure defects on the acid stability, the chemical states of the silicon in the CHA type zeolites synthesized by interzeolite conversion and in SSZ-13 were investigated by 29 Si MAS NMR with and without 1 H _29 Si cross polarization (CP). Figure 10 shows the 29 Si MAS NMR spectra of CHA type zeolite and SSZ-13 43) . Three peaks were observed centered at (0Al), respectively.…”

Selective Production of Light Olefins over MSE-type Zeolite Catalyst

“…-1 after 70 min), probably due to its potentially moderate acidity similar to ZSM-5 and a lower density of acid sites in the threedimensional micropore system. Mordenite (45) and dealuminated beta (41) showed gradual increases in the initial activity with increase in the reaction temperature as shown in Fig. 4, but these two catalysts were typically deactivated during 70 min of reaction 11) , despite similar acid site contents to dealuminated MCM-68(51).…”

“…Hydrothermal conversion of a low density zeolite into a high-density zeolite is possible; for example, they transformed zeolite Y (FAU) transformed into SSZ-13 (CHA) 27) 33) . More recently, rapid crystallization of various zeolites was achieved from an FAU-type zeolite in the presence of a specific OSDA 34) 47) , including the successful transformation of the FAU phase into B E A 34) 36) , R U T 37), 38) , C H A 39) 41) , L E V 42) 44) , MTN 34), 45) , and OFF phases 46) . Synthesis of CHA-type zeolite from LEV-type zeolite was also reported 47) .…”

“…3. Figure 4 shows the conversions and product distributions after cracking reactions for 5 min at 450, 500, 550 and 600 catalyzed by MCM-68(12), MCM-68(51), ZSM-5(45), mordenite (45), and beta (41) (the values in parentheses are Si/Al ratios). The product distributions for hexane cracking over various zeolite catalysts as well as the effect of reaction temperature on hexane conversion after 5 min of time-on-stream are given.…”