TUN, IMF and -SVR Zeolites; Synthesis, Properties and Acidity

Abstract

The effect of synthesis conditions on the preparation and properties of three novel zeolites TUN, IMF, and -SVR was investigated and compared with MFI. X-ray powder diffraction, infrared spectroscopy, chemical analysis, sorption measurements, and scanning electron microscopy were employed to characterize the textural and chemical properties of these zeolites. FTIR spectroscopy in combination with pyridine as probe molecule was used to describe the type, concentration and acid strength of these zeolites. Zeolite -SVR was synthesized with Si/Al ratios higher than 100 in contrast with TUN and IMF having Si/ Al ratios about 20-30, respectively. TUN, MFI and IMF zeolites exhibit similar concentrations of Brønsted and Lewis acid sites and also similar acid strength of Brønsted sites. In contrast, the presence of one vacancy/unit cell in the case of -SVR zeolite substantially changes its acidic properties. Generally, zeolites TUN and IMF exhibit similar acidic properties in terms of acid strength and Brønsted to Lewis acid site ratio like MFI and due to their slightly larger pores higher activities in catalytic reactions are expected.

The proximity of aluminium atoms influences the reaction pathway of ethanol transformation over zeolite ZSM-5

“…3a). The isotherms of ZSM-5 (s) and ZSM-5 (p) were representative for purely microporous structures (Table 1) 28 . The value of the specific area (419-440 m 2 g −1 ) and micropore volume (0.17-0.18 cm 3 g -1 ) were also typical of 10-ring zeolites 12,26 (Table 1).…”

A New Family of Two‐Dimensional Zeolites Prepared from the Intermediate Layered Precursor IPC‐3P Obtained during the Synthesis of TUN Zeolite

“…The organic SDA cation 1,4-bis(Nmethylpyrrolidinium)butane (1,4-MPB) was prepared, purified, and characterized according to the literature. [37] The final molar gel composition was: 4.5A C H T U N G T R E N N U N G (1,4-MPB):11 Na 2 O:0.5 Al 2 O 3 :30 SiO 2 :1200 H 2 O. The mixture was stirred at room temperature for 1 day.…”

“…Synthesis of IPC‐3P : The synthesis of IPC‐3P was based on the procedure described in reference 21. The organic SDA cation 1,4‐bis( N ‐methylpyrrolidinium)butane (1,4‐MPB) was prepared, purified, and characterized according to the literature 37. The final molar gel composition was: 4.5(1,4‐MPB):11 Na 2 O:0.5 Al 2 O 3 :30 SiO 2 :1200 H 2 O.…”

Effect of H2SiF6 modification of IM-5 on catalytic performance in benzene alkylation with ethylene

“… 16 With similar acidic properties ( e.g. similar acid strength and Brønsted to Lewis acid site ratio), 17 a better thermal and hydrothermal stability 18,19 as well as higher adsorption capacity of alkyl aromatic hydrocarbon 20 compared to ZSM-5, IM-5 is expected to replace ZSM-5 in many petrochemical processes. The catalytic performance of IM-5 zeolite has been investigated in alkane hydro-isomerization, 21 methylation of toluene, 22,23 disproportionation of toluene 24 and alkylation of benzene with ethanol 25 as well as alkylation with methanol.…”