Synthesis of high-silica CHA type zeolite by interzeolite conversion of FAU type zeolite in the presence of seed crystals

Abstract

The influence of seed crystals on the interzeolite conversion of FAU type zeolite into CHA type zeolite was investigated in the presence of benzyltrimethylammonium hydroxide as a structure-directing agent under various hydrothermal synthesis conditions. Pure and highly 2 crystalline CHA type zeolites with a wide range of Si/Al ratios were obtained in a shorter crystallization time as compared with those obtained without seed crystals. Furthermore, we achieved the first successful synthesis of high-silica CHA type zeolite in the absence of Na + cations by increasing the seed content. The protonated CHA type zeolite with a Si/Al ratio of ca. 15 yielded the highest propylene yield of ca. 48 C-% in ethanol conversion into light olefins.

Effect of CO2 on the DeNOx Activity of a Small Pore Zeolite Copper Catalyst for NH3/SCR

“…[18] The CuSSZ13 catalyst with 3 wt % Cu loading (100 % ion-exchange level) was prepared by the wet ion-exchange method by using copper acetate solution at room temperature.…”

Preparation of chabazite membranes by secondary growth using zeolite-T-directed chabazite seeds

“…Ion exchange was carried out using 3 times of the calcined as-synthesized chabazite with 1 M CaCl 2 aqueous solution at 60°C for 2 h, and the solids were washed to remove the chloride anions. The 27 Al and 29 Si magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra of the powders were recorded at 104.2 MHz and 79.5 MHz, respectively, using a zirconia rotor of 4 mm diameter, on a Bruker Advance III 400 WB spectrometer. The rotor was spun with dry air at 4 kHz for 29 Si MAS NMR and at 15 kHz for 27 PV performance test for a water/ethanol (10/90 wt%) mixture was carried out at 75°C using a PV experimental apparatus described elsewhere [20].…”

Conversion of Y into SSZ-13 zeolites and ethylene-to-propylene reactions over the obtained SSZ-13 zeolites

“…SSZ-13 zeolites have been synthesized via various methods, including direct synthesis (from precursors of silica and alumina) and conversion of zeolite Y. For the synthesis of SSZ-13s, various templates, such as N,N,Ntrimethyl-1-adamantanamine iodide (TMAda-I) [5,7], TMAda-OH [8][9][10][11][12], choline chloride [13,14], copper-tetraethylenepentamine (Cu-TEPA) [15][16][17], tetraethylammonium hydroxide (TEA-OH) [18], benzyltrimethylammonium hydroxide [19], and N,N,Ndimethylethylcyclohexylammonium bromide [20] have been used despite several reports of its template-free [21][22][23][24] synthesis.…”