Fast catalytic conversion of recalcitrant cellulose into alkyl levulinates and levulinic acid in the presence of soluble and recoverable sulfonated hyperbranched poly(arylene oxindole)s

Abstract

Sulfonated hyperbranched polymers were recently reported to efficiently mimic cellulase activity, producing large quantities of glucose from cellulose.

Highly Active Catalytic Ruthenium/TiO2 Nanomaterials for Continuous Production of γ‐Valerolactone

“…[6][7][8][9][10] Due to the complexity and recalcitrance of abundant lignocellulosicb iomass, the direct transformation of these feedstocks into valuable products (fuels, chemicals, and materials) has emerged as ab ottleneck, [11,12] whereas the valorization of carbohydrates derived from lignocellulosic biomass through differents trategies has been widely reported. [13][14][15][16][17][18][19][20][21][22] Levulinic acid (LA) is one of the most promising primary building blocks and platform moleculesf rom biomass refinery,w hich is select-ed as one of the top 12 sugar-derived building blocks [23] and the top 10 chemical opportunities from biorefinery carbohydrates [24] by the US Department of Energy( DOE). Therefore, there is great potential to valorize LA and its ester deviriates, alkyl levulinates, into more valuable products,s uch as g-valerolatone (GVL).…”

“…[25][26][27][28][29] Notably,h ydrogenation of alkyl levulinates to form GVL is preferable because alkyl levulinates have higher levelso fp roduction from lignocellulose anda re easier to separate compared with LA. [22,30] Heterogeneous catalysts have been reported to play ak ey role in the hydrogenation process, most of which are carbon, zeolite, and metal oxide supports decorated by transition metals (Au, Co, Cu, Ir,N i, Pd, Pt, Re, Rh, Ru). [28][29][30][31][32][33][34][35][36][37][38][39] In particular, ruthenium catalysts are one of the most widely reported catalysts fort he hydrogenation of LA and alkyl levulinates because of their outstanding catalytic performance and efficiency as the most active catalysts for the hydrogenationo f aliphatic carbonyl compounds.…”

Alcoholysis: A Promising Technology for Conversion of Lignocellulose and Platform Chemicals

“…Despite such great advantages, alcoholysis has some unsolved shortcomings. The formation of dialkyl ether is unavoidable in self‐etherification reactions, although it does not affect the alcoholysis efficiency . Additionally, the use of excess alcohol solvent increases the cost of separation of products and reduces the environmental viability.…”

“…More recently, Sels and co‐workers developed an attractive strategy for the preparation of the polymeric acid catalyst chlorinated sulfonated hyperbranched poly(arylene oxindole) (5‐Cl‐SHPAO), which behaves as a functional cellulose bio‐mimic for the synthesis of AL from one‐pot conversion of cellulose with ethanol . 5‐Cl‐SHPAO showed exceedingly high catalytic performance, yielding 60 % AL at 160 °C (Table , entry 26).…”

“…[61] More recently,S els and co-workersd eveloped an attractive strategy for the preparation of the polymeric acid catalyst chlorinated sulfonated hyperbranched poly(arylene oxindole) (5-Cl-SHPAO), which behaves as af unctional cellulose biomimic for the synthesis of AL from one-pot conversion of cellulose with ethanol. [62] 5-Cl-SHPAO showede xceedingly high catalytic performance, yielding 60 %A La t1 60 8C ( Table 2, entry 26). The outstanding performance of 5-Cl-SHPAO is strongly linked with the low apparent activatione nergy of 54 kJ mol À1 ,w hich is much lower than 123 kJ mol À1 over H 2 SO 4 , as well as 162 kJ mol À1 in aw ater mediumd espitet he use of ball-milled cellulose.…”