Synthesis and evaluation of acid-base bi-functionalized SBA-15 catalyst for biomass energy conversation

In this work, a new strategy to construct the acid-base bi-functionalized SBA-15 catalysts Was reported. Bilayer zirconia conformal monolayers were first grafted and sulfated On SBA-15 to create 2SZ@SBA-15 catalyst with Bronsted/Lewis acid and base active sites. The obtained 2SZ@SBA-15 sample was further functionalized with acid (-SO3H), base (-NH2) and both acid-base (-SO3H and -NH2) functional groups (namely, 2SZ@SBA-15-SO3H, 2SZ@SBA-15-NH2 and 2SZ@SBA-15-SO3H-NH2, respectively). The catalytic activities of the SBA-15 supported catalysts were evaluated toward the cellulose conversion to 5-hydroxymethylfurfural (HMF) in an ILs-based system, which experiences a series of sequential processes involving a decomposition step to glucose, an isomerization reaction to fructose and the fructose triple dehydration step with three molecules of water to HMF. With the goal of understanding the role of catalysts in the sequential processes for cellulose to HMF conversion, the synthesized catalysts possessing different Bronsted/Lewis acidity and basicity were applied in the reactions using cellulose, glucose and fructose as starting materials. Results of catalytic experiments indicated the integration of required acid and base characters in one catalyst has advantageous property for cooperative catalysis of one-pot cellulose to HMF. Highest HMF yield of 42.2% and selectivity of 54.0% can be obtained from cellulose under the optimal conditions. This work represents a continuation of efforts for fabrication and application on multi-functional heterogeneous catalyst for excellent conversion of one-pot cellulose to HMF. (C) 2016 Elsevier B.V. All rights reserved.