Synthesis and Characterization of Sulfonated Carbon-Based Graphene Oxide Monolith by Solvothermal Carbonization for Esterification and Unsymmetrical Ether Formation

Abstract

Herein, we report solvothermal carbonization of biomass, such as glucose, in the presence of a small amount of graphene oxide (GO) as a structure-directing agent that yields a carbon-based graphene oxide monolith (CGO monolith). The CGO monolith was functionalized with chlorosulfonic acid under mild reaction conditions to achieve sulfated carbon-based graphene oxide (SO3H@CGO monolith). It was used for the esterification of levulinic acid with benzyl alcohol and the etherification of benzyl alcohol with butanol as model reactions. The activity of the catalyst was compared with different solid acid catalysts, such as GO, CGO monolith, nanocrystalline sulfated titania (NCST), SO3H@HTC (sulfated hydrothermal carbon), amberlyst-15, and SO3H@GO for esterification of levulinic acid with benzyl alcohol. The SO3H@CGO monolith showed excellent conversion (97%) toward benzyl levulinate at 110 °C with low catalyst loading (0.008 g/cm3) and mole ratio. The catalyst was well characterized by SEM, EDXA, TEM, XRD, FTIR, BET surface area, CHNS, and TGA analysis. The role of various parameters, such as speed of agitation, molar ratio, catalyst loading, and temperature, on the reaction rate using SO3H@CGO monolith as catalyst was studied to establish the mechanism of the reaction, and the catalyst was reused up to five times, including the fresh one. The overall process is novel and green.

Sulfonated reduced graphene oxide catalyzed cyclization of hydrazides and carbon dioxide to 1,3,4-oxadiazoles under sonication

“…The synthesis of rGO 34, 35 (Hummers method NaNO 3 and KMnO4 in concentrated H 2 SO 4 ) and GOPhSO 3 H 36–39 usually involves the oxidation of graphite oxide. The harsh conditions used in these synthesis procedures introduce a diversity of oxygen-containing functionalities such as alcohols, epoxides, and carboxylates onto GO 34, 40 and then conversion into GOPhSO 3 H (pH 4.8 at 0.1 mgmL −1 ) 37, 41 material (Fig.…”

Esterification of Palm Fatty Acid Distillate Using a Sulfonated Mesoporous CuO‐ZnO Mixed Metal Oxide Catalyst

“…The vibration bands at 1702 and 1575 cm −1 were assigned to the presence of carboxyl groups (COOH) on the surface of the catalyst. The presence of sulfonic acid groups (SO 3 H) on the active sites became obvious due to appearance of strong vibrations at 1042 and 1209 cm −1 which is in accordance with reported data .…”

Pickering emulsions assisted synthesis of fatty acetal over phenyl sulfonic groups grafted on activated charcoal

“…The choice of carbonaceous materials can be activated charcoal [6][7][8], ordered mesoporous carbon [9,10], carbon black [11], carbon nanofibers [12] and graphene oxide [13]. It is also possible to generate carbon-based materials from lignocellulosic biomass either by hydrothermal carbonization technic (HTC) [14][15][16][17][18][19] or solvothermal carbonization technic [20]. The functionalization of carbonaceous materials to solid acids is usually carried out by acid treatment with concentrated H2SO4 or fuming SO3 [6,[14][15][16][17]20], and by chemical reduction of aryl diazonium salts [7][8][9][10][11][12].…”