Sulfonated Sporopollenin as an Efficient and Recyclable Heterogeneous Catalyst for Dehydration of d-Xylose and Xylan into Furfural

Abstract

The natural acidity of sporopollenin, the biopolymer coating the outer walls of pollen grains, was enhanced by the sulfonation of its surface. Modified sporopollenin displaying sulfonic acid groups has been prepared, characterized by elemental analysis, SEM, EDX, FTIR and XPS and tested as a heterogeneous catalyst in the dehydration of D-xylose and xylan to produce furfural. The optimal reaction conditions involve 10 wt % of sulfonated sporopollenin in the presence of 1.5 mmol of NaCl in a biphasic water-CPME system. When heated at 190 °C, the reaction affords furfural in a yield of 69% after 40 min under microwave irradiation. The time dependence of the dehydration and influence of temperature, pentose loading and positive effect of chloride ions on the reaction rate are reported. It was found that the catalytic system, recharged with the pentose and solvent, could be recycled ten times without loss of performance. The transformation of xylan into furfural at 190 °C for 50 min gave furfural in a yield of 37%.

Enhanced Conversion of Xylan into Furfural using Acidic Deep Eutectic Solvents with Dual Solvent and Catalyst Behavior

“…Better resultsw ere achievedf or the recovery of furfural from 2-MeTHF, although an additional step was required compared with the other strategy.F urthermore, this strategy allowedfaster extraction and stabilization of furfural by removing it from the acidic media, and therefore was chosen as the ideal methodology to be used in further assays. The purity of the recovered furfural was confirmed by 1 Ha nd 13 CNMR spectroscopy,a sw ell as HPLC spectroscopy at 268 nm ( Figures S2 and S3). Although distillation is often reported as a possible way to recover furfural, [42] actual methods forf urfural recovery are scarce.Nonetheless, the reported furfural recovery from the 2-MeTHF fraction was similartooptimized continuous processes.…”

“…The recovered DES-based solvent was used in at least three more cycles of xylan conversion to investigate the effect solvent recycling on the furfural production yield. Furthermore, the solvents stability was monitored through 1 Ha nd 13 CNMR spectroscopy.T he obtained furfural was compared with ar eference sample of furfural. The 1 HNMR and 13 CNMR spectra were recorded using aB ruker Avance3 00 at 300.13 MHz and 75.47 MHz, respectively,u sing deu- ChemSusChem 2020, 13,784 -790 www.chemsuschem.org terated water as solvent and trimethylsilyl propanoic acid (TMSP) as internal reference.…”

“…[10] Continuous research efforts have been undertaken over the years to develop cost-efficient and sustainable processes for the production of furfural. [12,13] In this arena,n ot only the productiono ff urfural needs to be optimized, but it is also necessary to avoid its degradation, which may occur by resinification, ar eactiono ff urfural with its precursors or condensation reactions between furfuralu nits. [11] Biphasic systemsa re commonly employed in continuous processest oi mprovef urfural yields by decreasing the occurrence of secondary reactions.…”

Recent Advances in Catalytic Hydrogenation of Furfural

“…In this regards, biomass conversion is a promising way to overcome the dependence of society on fossil hydrocarbons (oil, coal, and gas), especially in fuel production and energy areas [2]. Via bio-refinery, lignocellulose can be converted into relevant chemicals, such as furfural [3][4][5][6][7][8][9][10], 5-hydroxymethylfurfural (HMF) [11][12][13][14][15], and alkyl levulinates [16][17][18][19][20], among others. In particular, furfural has been recognized as a crucial bio-based platform molecule, and therefore, its valorization has been attracting researchers' attention in recent years.…”

Superparamagnetic nanoparticles as a recyclable catalyst: a new access to phenol esters via cross dehydrogenative coupling reactions

“…[12][13][14] As inspired by green chemistry principles, utilizing heterogeneous catalysts is favored owing to the possibility of separation and reusability. [15][16][17] "Nanocatalysis" has appeared as an speedily expanding area throughout the last few years, in which nanoparticles have been considered as alternative candidates, combining benets from both homogeneous and heterogeneous catalysts. [18][19][20] Nevertheless, because of their nanometerscaled sizes, the isolation from liquid phase and the reutilizing of the nanoparticles is undoubtedly challenging, and more efforts are needed to solve this issue.…”