Purification du Glycérol obtenu par réaction de Transestérification des Huiles Végétales par adsorption sur la Pouzzolane traitée.

Abstract

This study aimed at producing glycerol through the transesterification reaction of vegetable oils (palm, palm kernel, cotton) and purifying it by adsorption on the treated pozzolan. To achieve the first objective 500g of each oil reacted with ethanol in a molar ratio 8:1 in presence of sodium hydroxide used as catalyst of 1% of the oil mass. The resulting glycerol is crude due to its color and contains pigment oils such as beta –carotene, tocopherol and gossypol. Out puts superior to 100 prove that the solution contains an excess of ethanol since Soap, water and fatty acids did not produce any reaction. The method of separation such as decanting and permitted to separate respectively biodiesel and the excess of ethanol. Glycerol was characterised by oxidation acidified potassium permanganate followed by the addition of Fehling’s liquor. The Purification of the crude glycerol obtained was done in three stages including an acidification and neutralisation; an extraction of crude glycerol using ethanol and finally adsorption on pozzolan aiming at extracting pigments was conducted on the pozzolan reaching about 50 ̊C in the presence of hexane: measure of absorbances 0,153 (GPP); 0,883 (GPPt) 0,230 (GPC) revealed that glycerols obtained are not colorless. It is clear from this study, that out puts are not those expected. The decisive stage in the purification of glycerol through the transesterification reaction of vegetable oils resulted in acidification. The pozzolan treated has a weak discoloring power on glycerol.