Catalytic activity of titanium silicates synthesized in the presence of alkali metal and alkaline earth ions

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1995.1010· OSTI ID:75795

Khouw, C B; Davis, M E ^[1]

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1. California Institute of Technology, Pasadena, CA (United States)

Titanium containing aluminum-free ZSM-5 (TS-1) synthesized in the presence and absence of alkali metal and alkaline earth ions are investigated as catalysts for the selective oxidation of alkanes and alkenes using aqueous H{sub 2}O{sub 2} as oxidant at temperatures below 100{degrees}C. Sodium-exchanged TS-1 is not active for alkane oxidations. Similarly, no catalytic activity is observed for TS-1 synthesized in the presence of high concentrations of alkali metal ions (Si/Na < 20). For both cases, the catalytic activity can be restored by washing the solid with acid solution prior to catalytic evaluation. Similar results are obtained for TS-1 synthesized in the presence of other alkali metal ions, e.g., Li, K. However, the presence of alkaline earth ions, e.g., Mg, in the synthesis gel does not have a significant effect on the catalytic activity of TS-1. Based on the catalytic data and the physicochemical properties of the samples, a plausible explanation for the above results is described. The acid treatment may be useful in overcoming the problems of synthesizing TS-1 from reagents that contain alkali metal ions, e.g., TPAOH solutions. More importantly, this treatment opens the possibility of synthesizing other titanium-containing silicate structures that require the presence of alkali metal ions in the synthesis gel for their formation. 32 refs., 12 figs., 8 tabs.

• OSTI ID: 75795
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 151; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
40 CHEMISTRY
ALKALI METALS
ALKALINE EARTH METALS
ALKANES
ALKENES
CATALYTIC EFFECTS
CHEMICAL PREPARATION
OXIDATION
TITANIUM SILICATES