Catalytic Aldol Condensation of 5-Hydroxymethylfurfural and its Synthesis from Concentrated Feed of Carbohydrates

1-(5-(Hydroxymethyl)furan-2-yl)-5-methylhex-1-en-3-one was prepared from cellulose or glucose by a sequence of depolymerization/dehydration/aldol condensation reactions. The synthesis of HMF was first performed starting from a highly concentrated feed of glucose and cellulose (31 wt.%) using choline chloride in MIBK/water biphasic media via the formation of a glucoside intermediate. Next, the aldol condensation of HMF with MIBK was investigated over alkaline metal oxides. Among the catalysts used, commercial BaO was highly efficient with a yield of aldol product above 90 %. Under air, BaO instantaneously transformed into Ba(OH)(2), H2O and BaO2 which are regarded as active phases for the reaction. The catalyst basicity and solvent were key parameters to govern the selectivity of the reaction by limiting secondary reactions.

Automated summary

1-(5-(Hydroxymethyl)furan-2-yl)-5-methylhex-1-en-3-one was synthesized from cellulose or glucose through a series of depolymerization/dehydration/aldol condensation reactions. The synthesis of HMF started from a highly concentrated feed of glucose and cellulose (31 wt.%) using choline chloride in MIBK/water biphasic media, followed by aldol condensation with MIBK over alkaline metal oxides. Among the catalysts used, commercial BaO exhibited the highest efficiency with an aldol product yield above 90%. BaO readily transformed into Ba(OH)(2), H2O, and BaO2 in air, which were considered as the active phases for the reaction. The catalyst basicity and solvent played crucial roles in determining the reaction selectivity by limiting secondary reactions.