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 (similar to 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 degrees 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 (similar to 12 h). (C) 2012 Published by Elsevier B.V.