Bifunctional Solid Catalysts for the Selective Conversion of Fructose to 5-Hydroxymethylfurfural

Abstract

Solid catalysts based on SBA-15 silica were designed for the conversion of fructose to 5-hydroxymethylfurfural (HMF). The catalysts incorporate thioether groups that may promote the tautomerization of fructose to its furanose form, as well as sulfonic acid groups to catalyze its dehydration. The materials were characterized by elemental analysis, X-ray diffraction, N 2 adsorption/ desorption, and solid-state 13 C and 29 Si CP/MAS NMR spectroscopy. Functional groups incorporated into mesoporous silica by co-condensation are more robust under the reaction conditions (water at 180°C) than those grafted onto a non-porous silica. The bifunctional mesoporous catalyst achieved a selectivity for HMF of 74% at 66% fructose conversion.

Acid-Functionalized SBA-15-Type Periodic Mesoporous Organosilicas and Their Use in the Continuous Production of 5-Hydroxymethylfurfural

“…Previously, we showed that grafted acid sites in nonordered silicas are less stable than acid sites incorporated through co-condensation in ordered silicas. 35 The lower stability was ascribed to attachment of the propylsulfonic acid sites via fewer siloxane linkages. Interestingly, the 29 Si MAS NMR spectrum shows that the acid sites in the nonordered pSO 3 H-SC and E0 have similar siloxane attachments, yet the former is still much less stable.…”

Progress in the Development of Mesoporous Solid Acid and Base Catalysts for Converting Carbohydrates into Platform Chemicals

“…SBA-15 was fi rst synthesized in 1998 by Zhao [ 16 ] and has subsequently become very popular in both catalysis and materials research as it is readily functionalized by grafting acidic or basic functional groups to impart catalytic utility. The synthesis of 3-(Butylthio) propane-1-sulfonic acid (BTPSA)-functionalized SiO 2 catalysts, TAA-A380, and TAA-SBA-15, was reported by Scott et al [ 17 ] using post-grafting and co-condensation methods, respectively, as shown in Fig. 6.1 for TAA-SBA-15.…”

“…Proposed synthetic scheme for a bifunctional acid catalyst supported on silica (Reprinted from ref [ 17 ],. with kind permission from Springer Science+Business Media) The molecular structure of TESAS (3-((3-(trimethoxysilyl)-propyl)-thio)-propane-1-sulfonic acid) (Reprinted from ref [ 18 ],.…”

Sulfonic acid-functionalized mesoporous silica (SBA-Pr-SO3H) as solid acid catalyst in organic reactions

“…Selective dehydration of fructose 1 to HMF 6 was reported in the presence of silica-supported alkylsulfonic acids [97,98] and bifunctional silicas containing a propylsulfonic acid catalyst and a thioether group (Scheme 1) [99]. Using ionic liquid BmimCl as a solvent in this reaction was also investigated [100].…”