Influence of Copper and Metallic Alloys on the Oxidation Reaction of Commercial Biodiesel in Mixture with Natural Antioxidant

• Autor(a) principal: Chendynski,Letícia T.
• Data de Publicação: 2019
• Outros Autores: Romagnoli,Érica S., Mantovani,Ana Carolina G., Kimura,Marissa, Marques,Leonardo C., Borsato,Dionisio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532019000100090
• topic: biodiesel; storage stability; oxidation; metallic alloys; natural antioxidant

The purpose of this research was to evaluate the influence of metallic alloys and copper in the degradation of biodiesel in mixture with blackberry extract. Biodiesel is formed by unsaturated esters highly susceptible to the oxidation reaction. The initial induction period (IP) of the control sample was 9.53 h and, after 208 days, the IP reduced to 5.74 h. However, with the addition of the antioxidant, the final IP was 6.27 h. The assays involving carbon steel, stainless steel, silver steel and copper showed final IP of 3.78, 4.43, 1.59 and 0.09 h, respectively. This behavior indicates that the reaction was catalyzed in the presence of metal. The addition of the blackberries extract favored the increase of the induction period and the decrease of the reaction rate constant values, aside from the carbon steel that presented a final IP of 1.22 h. The highest rate constant was 7.41 h obtained for biodiesel in contact with copper, as well as the highest IP. The acid number ranged from 0.34 to 0.60 mgKOH g-1. It was possible to observe in the oxidation reactions the presence of the linearity deviation proposed by Arrhenius.