Determination of Biodiesel Oxidation Stability of Biodiesel B100 With Optical Spectroscopies of Electronic Absorption UV-Visible Correlation With Rancimat Method DIN EN 14112

摘要

Biodiesel is a biodegradable fuel that consists of alkyl esters, obtained from renewable sources, vegetal oil and animal fats reacting with a short-chain of aliphatic alcohols (typically methanol or ethanol) in the presence of a catalyst (reaction known as transesterification). An important property to use the biodiesel as fuel in diesel engines is its oxidation stability because biodiesel can contain unsaturated fatty acids, which are susceptible to oxidation, being able to change into polymerized compounds, which can cause engine problems such as blocked fuel filters. Numerous analytical methods have been applied to determine oxidation stability, European Union and Brazil use the same method DIN EN 14112 - known as Rancimat method that consists in the sample heating to 110°C where the products formed by the decomposition are blown inside by a flow of air in to measurement cell with distilled water. The time of induction is determined by the measure of the conductivity being minimum limit to be approved according to the Brazilian and European Union standard is 6 hours. As alternative to this method it was developed a correlation study of the obtained by the method DIN EN 14112 - Rancimat with the method using UV-Vis in the wavelength of 550 nm getting R2 = 0,9767 indicate that the model fits better the data, shorter answer response time, only one minute and small amount of sample and the possibility of its reuse.