Review Article
Heterogeneous Tin Catalysts Applied to the Esterification and Transesterification Reactions
Table 6
Acidic properties of the
/SnO
2 catalysts synthesized at temperatures of 400, 550, and 750°C
a [
29].
| Calcination temperature (°C) | 400 | 550 | 750 | Pyridine loss (wt.%) | (°C) | content on SnO2 catalyst (wt.%) | NAS (meq g−1) | (mV) | NAS (meq g−1) | (mV) | NAS (meq g−1) | (mV) |
| 0 | 0.20 | −84 | 0.35 | +27 | 0.14 | −127 | 0.210 | 424.5 | 1 | 0.31 | −70 | 0.51 | +194 | 0.24 | −109 | 0.448 | 460.8 | 5 | 0.38 | −61 | 0.66 | +316 | 0.30 | −97 | 0.667 | 468.4 | 15 | 0.50 | −27 | 0.83 | +479 | 0.42 | −54 | 1.430 | 479.4 | 20 | 0.56 | +9 | 0.97 | +510 | 0.51 | −41 | 1.841 | 482.0 | 30 | 0.68 | +25 | 1.30 | +555 | 0.60 | −23 | 2.440 | 482.5 |
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NAS: acid sites number; : initial electrode potentional indicates the maximum acid strength of the sites; : pyridine loss temperature.
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