A method for glycerin purification by sequential extraction of raw
glycerin from waste cooking oil biodiesel production, using petroleum
ether and toluene, was presented. The extraction was complemented
with discoloration of the refined glycerin by adsorption on activated
coal. The consecutive extractions with petroleum ether and toluene,
and subsequent discoloring by adsorption on activated carbon at the
ratio of 5% produced 99.2% pure glycerin in 67.0% total recovery, with
89.8% of glycerin recovery. The purifying scheme presented has as
main advantages, in comparisonwith vacuumdistillation of rawglycerin,
lower risk of material decomposition and less dangerous operations,
as it happens at lower temperatures.