Isomorphous substitution in zeolite frameworks. 1. Acidity of surface hydroxyls in [B]-, [Fe]-, [Ga]-, and [Al]-ZSM-5

Aromatization of propane over MFI-gallosilicates

“…1 ) will be due to the lower acid strength of the gallosilicates, as measured earlier by ammonia temperature-programmed desorption (TPD) experiments and infrared analysis [25 ]. In addition, the deposition of some coke on the gallosilicate during subsequent measurements at different temperatures can give rise to some activity' loss.…”

Studies of Fe(III) incorporated into AlPO4-20 by X- and W-band EPR spectroscopies

“…The composition of the synthesis gel of all Fe-containing AlPO 4 4 , Baker) dissolved in ³80% of the total water amount. Then, a 25% solution of tetramethyl ammonium hydroxide (TMAOH, Aldrich) was added.…”

“…The white product was centrifuged and dried at 100°C. 57 FAPO was prepared similarly, except for using a 1% 57 Post-synthesis incorporation of Fe(III) was done as follows: 70 ml of a 2% solution of Fe NO 3 3 Ð9H 2 O was mixed with 2 g of AlPO 4 20 synthesized without Fe. The mixture was heated in a Teflon-lined autoclave for 4 h at 150°C.…”

Precise Control in Characteristics of Nano-particulate MFI-Type Ferrisilicate and Their Catalysis in the Conversion of Dimethyl Ether into Light Olefins

“…NH 3 (5% in He, 60 mL·min -1 ) was adsorbed on the samples at 100 C for 30 min after treating with He (500 C, 1 h, 60 mL·min -1 ). After the saturation of NH 3 adsorption, the sample was exposed to water vapors (100 C, 4 kPa, 30 min) twice to remove the weakly held NH 3 species, such as hydrogen-bonded NH 3 . The sample cell was heated from 100 C to 700 C at a rate of 10 C·min -1 , and the desorbed NH 3 was measured by the amount of fragment of m/z = 16 in the quadrupole mass spectra.…”