Review Article

Heterogeneous Tin Catalysts Applied to the Esterification and Transesterification Reactions

Table 6

Acidic properties of the /SnO2 catalysts synthesized at temperatures of 400, 550, and 750°Ca [29].

Calcination temperature (°C)400550750Pyridine loss (wt.%) (°C)
content on SnO2 catalyst (wt.%)NAS (meq g−1) (mV)NAS (meq g−1) (mV)NAS (meq g−1) (mV)

00.20−840.35+270.14−1270.210424.5
10.31−700.51+1940.24−1090.448460.8
50.38−610.66+3160.30−970.667468.4
150.50−270.83+4790.42−541.430479.4
200.56+90.97+5100.51−411.841482.0
300.68+251.30+5550.60−232.440482.5

NAS: acid sites number; : initial electrode potentional indicates the maximum acid strength of the sites; : pyridine loss temperature.