The production of biodiesel from feed stock such as soybean and rapeseed oil, is generally accomplished by transesterifcation in the presence of either acids or bases, such as sulfuric acid or sodium hydroxide.

Under the guidance of Prof. Fang Zhen, Dr. Long Yunduo of XTBG proposed a new way to produce biodiesel and lactic acid from rapeseed oil by using sodium silicate as catalyst.

Their study highlighted that 99.6% biodiesel yield was achieved by using solid calcined sodium silicate. Solid calcined sodium silicate can be reused for six times with biodiesel yield higher than 92%. The catalyst after recycled six times was successfully used to hydrothermally produce lactic acid from glycerol with yield of 80.5%. Fresh sodium silicate was more active for lactic acid production with a maximum yield of 90.7%.

Their study has demonstrated that sodium silicate can be used as a catalyst for transesterificant of rapeseed oil and subsequently without modification for the production of lactic acid from the biodiesel by-product, glycerol.

The research has been published online in Bioresource Technology.

doi:10.1016/j.biortech.2011.04.007