Selective Oxidation of Crude Glycerol to Dihydroxyacetone in a Biphasic Photoreactor

Abstract

In this paper, the first biphasic photoreactor was introduced and utilized for the conversion of glycerol to glyceraldehyde (GAD) and dihydroxyacetone (DHA) using water and ethyl acetate as dispersed (active) and continuous (inactive) phases, respectively. Increasing the ethyl acetate content in the reactor improved the DHA yield; however, the optimal DHA selectivity was obtained at an ethyl acetate to water ratio of 90:10 (vol/vol). Compared to a monophasic photoreactor containing only water and identical amounts of glycerol and photocatalyst, the biphasic reactor containing 90 vol % ethyl acetate increased the DHA yield by a factor of 2.9 (from 4.5% to 13%) and the concentration of DHA by approximately 14 times (from 0.08 mM to 1.1 mM) after 240 min. Additionally, photocatalytic conversion of crude glycerol extracted using a 90:10 (vol/vol) ethyl acetate-water mixture showed a similar DHA conversion and yield to that of pure glycerol.

Clarifying solvent effect during photocatalytic glycerol conversion on TiO2/GQD as selective photocatalyst

“…The biphasic reactor comprises numerous small micro-reactors (aqueous droplets) containing glycerol and a photocatalyst, where the photocatalytic glycerol oxidation occurs almost in those micro-reactors (droplet phase). On the other hand, ethyl acetate has negligible light absorbance, so a higher light intensity was affected in water droplets and more efficient light delivery to the photocatalyst than in the monophasic reactor 28 . This means biphasic media improves light penetration into the microreactor, increasing the photocatalytic glycerol oxidation reaction rate.…”

Editorial Catalysts: Special Issue on Recent Advances in TiO2 Photocatalysts

“…The heterogeneous photocatalytic process, as well as new TiO 2 -based materials applied in biomedical fields, energy storage, and energy conversion devices, can contribute to improving the quality of the natural environment [9][10][11]. High-efficiency TiO 2 -based photocatalysts are also successfully used in photocatalytic water splitting and photoconversion, providing a low-cost and environmentally friendly production method of clean fuels [12,13]. Separation of the photocatalyst particles after treatment is the main disadvantage of the suspended process.…”