Simultaneous production of glyceric acid and hydrogen from the photooxidation of crude glycerol using TiSi2

The biodiesel industry is facing a problem with glycerol market saturation due to the large amounts of glycerol co-product that are produced during biodiesel processing. This is also having a negative impact on our environment. The crude glycerol obtained from biodiesel industry is at basic pH (∼12–14) because of soluble bases such as potassium hydroxide (KOH) or sodium hydroxide (NaOH). In this work, the use of solid photo catalyst, titanium disilicide (TiSi2) is investigated for glycerol oxidation in basic aqueous solution under mild conditions. The oxidation in a batch reactor at 65 °C and atmospheric pressure using in situ oxygen as oxidant showed 100% selectivity toward glyceric acid. Conversion efficiency of glycerol was observed around 64% over 6 h. Higher conversion (97.6%) was also observed over prolonged reaction conditions (∼12 h).

Waste glycerol and water are converted to two value added products under mild conditions with sun light. Figure optionsDownload as PowerPoint slideHighlights▸ For the first time, waste glycerol from the biodiesel process is converted to two value added products, glyceric acid and hydrogen. ▸ 98% conversion and 100% selectivity were achieved under mild reaction conditions. ▸ This process needs, solid TiSi2 catalyst, solar light and water.