266813 Dehydration of Fructose to 5-Hydroxymethylfurfural Using Solid Acid Catalysts Modified with Polyvinylpyrroldine

Wednesday, October 31, 2012: 12:50 PM
315 (Convention Center )
Jean Marcel R. Gallo1, Ricardo Alamillo1, Anthony J. Crisci2, Susannah L. Scott2 and James A. Dumesic1, (1)Chemical & Biological Engineering, University of Wisconsin-Madison, Madison, WI, (2)Departments of Chemical Engineering and Chemistry, University of California, Santa Barbara, Santa Barbara, CA

The use of carbohydrates, a key component of biomass, presents one route towards the production of renewable fuel and chemicals such as 5-hydroxymethylfurfural (HMF), levulinic acid, gamma-valerolactone, furfuryl alcohol, ethylene glycol, and polyols. HMF, a high value added chemical derived from biomass, can be produced from the acid-catalyzed dehydration of fructose. Research on HMF production has primarily focused on homogenous systems using mineral acids or ionic liquids reaching yields above 80%. However, such systems are limited by costs associated with corrosion, separation, and/or water sensitivity. Solid acid catalysts can provide an efficient route for the production of biomass derived HMF. One of the most significant challenges in the fructose dehydration chemistry is the development of solid acid catalysts that can reach yields comparable to those of the classical homogeneous systems. We report a new solid acid catalyst based on using the amphiphilic polymer polyvinylpyrroldine (PVP) as a surface modifier for the selective production of HMF. PVP was impregnated onto commercial silica spheres modified with propylsulfonic acid groups (SS). PVP is soluble in polar solvents and has shown to play an important role in increasing the selectivity to HMF for fructose dehydration in biphasic liquid phase systems. PVP was crosslinked onto the SS catalyst surface to minimize polymer leaching. The catalyst preparation was optimized by varying the concentration and type of crosslinking agent and both the overall PVP weight loading and PVP molar weight distribution. Under optimal conditions, 8 wt% of insoluble PVP was impregnated onto SS. This catalyst, named SS/PVP, was studied in the dehydration of fructose to HMF, and it achieved 63%selectivity to HMF, which is 30% higher than unmodified SS at similar conversions. If homogeneous PVP is added to a reaction using SS as catalyst, the selectivity of the reaction is still lower than that observed for SS/PVP, indicating that the interaction between the acid sites and PVP on the silica surface in the SS/PVP catalyst has an important role in its enhanced performance. Replacing PVP with a different polymer, such as polyvinylalcohol, did not result in a significant increase in the selectivity to HMF, indicating that the functionality of PVP accounts for the increased selectivity to HMF. Catalysts were also prepared by impregnating PVP onto mesoporous silicas modified with propylsulfonic acid groups. SBA-15 impregnated with PVP reaches selectivities for HMF that are higher than 80%, which is comparable to the selectivities observed in homogeneous systems using mineral acids or ionic liquids. This class of materials presents a new route for the production of chemicals from carbohydrates with high selectivities.  

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