Estudo cinético das reações de esterificação de ácidos graxos catalisadas por ácidos de Lewis e de Brønsted para produção de biodiesel

• Autor(a) principal: Cardoso, Abiney Lemos
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2054
• topic: Biodiesel; Compostos de estanho; Catálise homogênea; Esterificação; Biodiesel; Tin compounds; Catalysis; Esterification; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA INORGANICA

The biodiesel obtaining, it is still today done through reactions of vegetable oil transesterification with chain alcohol it tans. However, it can also be produced via esterification of free fatty acids (FFA) presents in industrial and domestic rejects, or animal fats. Usually, NaOH is the catalyst used for transesterification reactions and H2SO4 for esterification reactions. However, the use those catalysts cause great environmental impacts. In addition, when the oils contain a high amount of FFA, sidereactions like saponification occurs. This undesirable process, which is favoured in alkaline medium, reduces the yield and it hinders the separation of phases. Thus, are necessary great investments in research for obtaining of new catalysts, which being more be efficient that the common acid catalysts, results in processes that are environmentally less aggressive. Following this tendency, this work presents the tin chloride di-hydrate (SnCl2.2H2O) as an alternative to the common acid catalysts in esterification reactions for biodiesel production. Several studies were performed where SnCl2.2H2O activity catalytic was compared with catalysts acids of Brønsted (H2SO4, PTSA, H3PW12O40.10H2O). It was also studied the influence of the catalyst and FFA concentration, and of the size of the chain of the alcohols. They were other appraised catalysts the tin based on tin oxides (SnO and SnO2) and organotincompounds, such as (Sn(C6H5)4, SnCl(C6H5)3, SnCl2(C6H5)2). A detailed kinetic study was accomplished and the energy of activation of the reactions catalyzed by SnCl2.2H2O, besides the order in relation to FFA and Sn(II) concentration were determinates.