The catalytic transformation of furfuryl alcohol and hexose into value-added chemicals have been investigated with a series of polymer-based catalysts including poly(styrenesulfonic acid) (PSS), graphite oxide-doped poly(styrenesulfonic acid) (PSS-GO), and graphite-doped poly(styrenesulfonic acid) (PSS-C). It is found that the selective conversion of furfuryl alcohol to methyl levulinate (MLE) was successfully performed with PSS as the catalyst, in which a 96.4% yield is attained in methanol solvent. Moreover, the efficient dehydration of d -fructose to produce 5-hydroxymethylfurfural (HMF) has also been achieved using PSS-GO as the catalyst, where a 76.5% yield of HMF was obtained in N -methylpyrrodinone solvent. The effects of reaction temperature, time and solvent were investigated. Furthermore, the used catalysts have been respectively characterized by XRD, TG, FTIR, SEM and TEM techniques to reveal the physical properties and structures of these polymeric catalytic materials.
A magnetically recyclable and efficient catalyst for biodiesel synthesis was fabricated by confining the Brønsted ionic liquid 1,4-butanediyl-3,3′-bis(3-sulfopropyl) imidazolium dihydrogensulfate in an amino-functionalized magnetic metal–organic-framework composite (Fe3O4@NH2-MIL-88B(Fe)) through a simple and efficient strategy via the amino groups. The catalyst was systematically characterized, proving ionic liquid was grafted in the amino-functionalized carrier, and the catalyst was spindle-shaped with superparamagnetism (7.2 emu/g). The prepared catalyst with high acidity (1.76 mmol H+ g–1) exhibited good catalytic activity in biodiesel synthesis from oleic acid and ethanol with a yield of 93.2%, optimized by Box-Behnken response surface methodology. The fine catalytic performance of the catalyst was mainly due to the combination of the characteristics of the ionic liquid and the structure of Fe3O4@NH2-MIL-88B(Fe). Moreover, the catalyst was recycled without significant loss of activity after being used for six runs and could be magnetically separated in magnetic force without obvious mass loss.
Zhenzhen Yang,Renliang Huang,Wei Qi,Liping Tong,Rongxin Su,Zhimin He
Reduced graphene oxide functionalized with magnetic Fe 3 O 4 nanoparticles and –PhSO 3 H groups (Fe 3 O 4 -RGO-SO 3 H) was reported for environmentally benign hydrolysis of cellulosic materials, which is an important process in integrated utilization of biomass resource. Except for –PhSO 3 H groups, –COOH and –OH groups derived from graphene oxide (GO) were also expected in the structure of Fe 3 O 4 -RGO-SO 3 H. Fe 3 O 4 -RGO-SO 3 H exhibited outstanding catalytic performance for the hydrolysis of cellulosic materials, due to its crumpling feature with clear layers and the coexistence of –COOH and –OH groups. The unique structure of Fe 3 O 4 -RGO-SO 3 H favors the accessibility of cellulose to the active sites of the material and facilitates the diffusion of the product molecules. –COOH groups on the surface of the material provide a large concentration of acidic functionality for hydrolyzing cellulose, while –OH groups readily adsorb cellulose through forming strong hydrogen bonds between –OH groups and the oxygen atoms in β-1,4 glycosidic bonds. Furthermore, Fe 3 O 4 -RGO-SO 3 H can also be easily separated from the reaction residue with an extra magnetic force and further used at least five times.