Synthesis, characterization and catalytic activity of SAPO-34 obtained with piperidine as templating agent

Highly selective SAPO 34 membrane on surface modified clay–alumina tubular support for H2/CO2 separation

“…2 describes the Fourier transform infrared (FTIR) spectra of the SAPO 34 zeolite powders collected at different time starting from 0 (initial gel) to 120 h, during seed synthesis by hydrothermal technique. The various zeolitic vibration frequencies were assigned in accordance to the reported literature [37]. The characteristic band at 480, 534 and 568 cm À1 was attributed to the vibration of SiO 4 , (Si, Al) O 4 and PO 4 respectively.…”

Improving the selectivity to C4 products in the aldol condensation of acetaldehyde in ethanol over faujasite zeolites

“…Aldol condensation is a well-known reaction for C-C bond formation that can be catalyzed by either acid or basic catalysts [19][20][21][22][23][24][25][26][27]. Specifically, the aldol condensation of acetaldehyde has been investigated in several previous studies as an important intermediate reaction in the ethanol to BD process.…”

A study of the acidity of SAPO-34 by solid-state NMR spectroscopy

“…NH 3 -TPD (temperature-programmed desorption) studies show that there are two desorption peaks. The peak at lower temperature is due to the weak acid sites originating from surface POH, SiOH or AlOH groups, and the peak at higher temperature is due to the moderately strong acid sites in the form of bridging hydroxyl groups [9][10][11]. The acid strength is independent on the content of Si atoms, the SAPO-34 particle size and the metal incorporation [12,13], and the number of the strong acid sites did not change significantly with the silicon content of the synthesis gels [14].…”