Catalytic etherification of glycerol to produce biofuels over novel spherical silica supported Hyflon? catalysts

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• 作者：Francesco Frusteri ; Leone Frusteri ; Catia Cannilla ; Giuseppe Bonura
• 关键词：Spherical silica ; Hyflon catalysts ; Glycerol conversions ; Biofuels production ; Biodiesel
• 刊名：Bioresource Technology
• 出版年：2012
• 出版时间：August, 2012
• 年：2012
• 卷：118
• 期：Complete
• 页码：350-358
• 全文大小：450 K

文摘

Etherification of glycerol (GLY) with isobutylene (IB) to produce biofuels was investigated in liquid phase using spherical silica supported Hyflon? catalysts (SSHC). As reference catalyst, Amberlyst? 15 (A-15) acid ion-exchange resin was used. Experiments were carried out in batch mode at a reaction temperature ranging from 323 to 343 K. SSHC were found to be very effective systems in etherification of glycerol with IB, providing cumulative di- and tri-ethers yields higher than that obtained by using A-15 catalyst. Furthermore, such catalysts were stable and easily reusable; no leaching of active phase was observed. The formation of poly-substituted ethers, suitable additives for conventional fuels, was favored by operating at an isobutylene/glycerol molar ratio >3 and low reaction time (<6 h); however, the concentration of mono-ether reached values lower than 3 wt. % only when SSHC catalyst was used. Turnover frequency of glycerol (TOF_GLY) highlighted that SSHC systems were much more active than A-15 catalyst: the accessibility and nature of active sites and the surface properties of catalysts were indicated as the main factors affecting the catalytic behavior. A lower acid site density of SSHC than that of A-15 catalyst was decisive in preventing the occurrence of oligomerization reaction which leads to the formation of di-isobutylene (DIB), precursors of gummy products.