Catalytic etherification of glycerol to produce biofuels over novel spherical silica supported Hyflon® catalysts.
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.
CNR-ITAE, Nicola Giordano, Via S. Lucia 5, 98126 Messina, Italy. francesco.frusteri@itae.cnr.it
Francesco
F
Frusteri
Leone
L
Frusteri
Catia
C
Cannilla
Giuseppe
G
Bonura
D000475:Alkenes / Q000737:chemistry; D056804:Biofuels / Q000032:analysis*; D002384:Catalysis; D055598:Chemical Phenomena; D004987:Ethers / Q000737:chemistry*; D005742:Gasoline / Q000032:analysis; D005990:Glycerol / Q000737:chemistry*; D016062:Porosity; D059027:Recycling; D012015:Reference Standards; D012822:Silicon Dioxide / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013696:Temperature; D013997:Time Factors
D000475:Alkenes; D056804:Biofuels; D004987:Ethers; D005742:Gasoline; D012822:Silicon Dioxide; D005990:Glycerol; C008176:isobutylene