Design of a highly active silver-exchanged phosphotungstic acid catalyst for glycerol esterification with acetic acid
2013
Zhu, Shanhui | Gao, Xiaoqing | Dong, Fang | Zhu, Yulei | Zheng, Hongyan | Li, Yongwang
A series of highly active, selective, and stable silver-exchanged phosphotungstic acid (AgPW) catalysts were prepared, characterized, and evaluated for bio-derived glycerol esterification with acetic acid to produce valuable biofuel additives. The structures, morphologies, acidities, and water tolerance of these samples were determined by FTIR, Raman, XRD, SEM-EDX, FT-IR of pyridine adsorption, and H₂O-TPD. Several typical acidic catalysts were also performed for comparison. Among them, partially silver-exchanged phosphotungstic acid (Ag₁PW) presented exceptionally high activity, with 96.8% conversion within just 15min of reaction time and remarkable stability, due to the unique Keggin structure, high acidity as well as outstanding water-tolerance property. A plausible reaction mechanism was also proposed. In addition, this Ag₁PW catalyst exhibited universal significance for esterification, holding great potential for a wide range of other acid-catalyzed reactions.
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