Etherification of biodiesel-derived glycerol with ethanol for fuel formulation over sulfonic modified catalysts

• Published in: Bioresource technology Vol. 103; no. 1; pp. 142 - 151
• Main Authors: Melero, Juan A., Vicente, Gemma, Paniagua, Marta, Morales, Gabriel, Muñoz, Patricia
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-01-2012; Elsevier
• Subjects: Biofuel production; Biofuels - analysis; Biological and medical sciences; Biotechnology; Byproducts; Catalysis; Catalysts; Conversion; Energy; Ethanol; Ethanol - chemistry; Ethers; Ethers - chemistry; Ethyl alcohol; Fundamental and applied biological sciences. Psychology; Glycerol; Glycerol - chemistry; Glycerols; Industrial applications and implications. Economical aspects; Mesoporous silica; Models, Chemical; Oxygenated compounds; Recycling; Silicon Dioxide - chemistry; Sulfonic; Sulfonic Acids - chemistry; Temperature; Glycerol; Sulfonic; Mesoporous silica; Oxygenated compounds; Ethanol; Fuel; Oxygenation; Biodiesel; Etherification; Silica; Catalyst; Inorganic compound
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.09.105

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► We study the production of ethyl ethers of glycerol over acid catalysts. ► There is a great interaction among temperature, molar ratio and catalyst loading. ► Arenesulfonic silica is a good catalyst for etherification of glycerol with ethanol. ► Using low-grade water-containing glycerol shows similar results.
The present study is focused on the etherification of biodiesel-derived glycerol with anhydrous ethanol over arenesulfonic acid-functionalized mesostructured silicas to produce ethyl ethers of glycerol that can be used as gasoline or diesel fuel biocomponents. Within the studied range, the best conditions to maximize glycerol conversion and yield towards ethyl-glycerols are: T=200°C, ethanol/glycerol molar ratio=15/1, and catalyst loading=19wt%. Under these reaction conditions, 74% glycerol conversion and 42% yield to ethyl ethers have been achieved after 4h of reaction but with a significant presence of glycerol by-products. In contrast, lower reaction temperatures (T=160°C) and moderate catalyst loading (14wt%) in presence of a high ethanol concentration (ethanol/glycerol molar ratio=15/1) are necessary to avoid the formation of glycerol by-products and maximize ethyl-glycerols selectivity. Interestingly, a close catalytic performance to that achieved using high purity glycerol has been obtained with low-grade water-containing glycerol.