Isolation, characterization and evaluation of photochemical potential of rice husk-based furfural via continuous flow reactor

• Furfural was isolated from rice husk via acid catalyzed methods.
• Performance of these methods were compared.
• For the first time, simple quartz flow capillary microreactor was designed for photochemical reaction using sunlight.
• Sunlight is demonstrated as a clean energy source in transforming furfural into 5-hydroxy-2-(5H)-furanone.

Rice husk is an abundant agricultural waste containing about 120 g pentosan per kilogram of dry husk; a precursor for furfural production. Furfural, among the furan-based compounds, shows interesting properties as a building-block or industrial solvent in the production of higher-valued co-product chemicals. In our study, we isolated furfural from rice husk using known acid-catalyzed methods (microwave, reflux and autoclave) and compared their performance in terms of percentage furfural yield. Relatively higher furfural yield ≤68% was obtained using microwave-assisted method. We developed a simple and innovative quartz flow capillary microreactor to investigate the photochemical potential of sunlight as a clean energy source in transforming furfural into 5-hydroxy-2-(5H)-furanone; a versatile synthon in organic synthesis. Excellent furanone yield (84%, RSD = 0.78–4.67) was obtained after 6 h of sunlight irradiation in presence of Rose Bengal photosensitizer.

Schematic illustration of continuous flow micro reactor design.Figure optionsDownload as PowerPoint slide