Abstract
The adsorption properties of framework Sn sites in a siliceous zeolite beta were examined by comparing the adsorption of acetonitrile, diethyl ether, and 2-methyl-2-propanol on a Sn-Beta zeolite, a purely siliceous Beta zeolite, and a siliceous Beta zeolite with impregnated SnO2, using temperature-programmed desorption (TPD) and thermogravimetric analysis (TGA). Adsorption stoichiometries close to one molecule per framework Sn site were observed for each of the probe molecules. Although the 1:1 complexes with acetonitrile and diethyl ether decompose reversibly upon mild heating in vacuo, the 1:1 complex formed by 2-methyl-2-propanol underwent dehydration to butene and water over a very narrow temperature range centered at 410 K. FTIR spectra of acetonitrile-d3 at a coverage of one molecule per site exhibit a υ(C-N) stretching frequency at 2312 cm-1 that is not observed with nonframework Sn, providing a convenient method for characterizing the presence of framework Sn sites. Water interacts strongly enough with the Sn sites to prevent adsorption of acetonitrile.
| Original language | English |
|---|---|
| Pages (from-to) | 573-580 |
| Number of pages | 8 |
| Journal | ACS Catalysis |
| Volume | 3 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Apr 5 2013 |
| Externally published | Yes |
Keywords
- Lewis acid base complexes
- Lewis catalysis
- Sn-Beta
- temperature programmed desorption
- tin zeolites
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)