Avaliação e desenvolvimento de métodos de caracterização e controle de qualidade de biodieseis metílicos e etílicos por cromatografia gasosa capilar a altas temperaturas

• Ano de defesa: 2008
• Autor(a) principal: REZENDE, Daniela Rodrigues de
• Orientador(a): ANTONIOSI FILHO, Nelson Roberto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Química
• Departamento: Educação em Química
• País: BR
• Palavras-chave em Português: biodiesel; cromatografia gasosa; controle de qualidade
• Palavras-chave em Inglês: biodiesel; gas chromatography; quality control
• Área do conhecimento CNPq: CNPQ::OUTROS
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/1027

In this work, a chromatographic method for simultaneous determination of free and total glycerol, mono-, di- and triacylglycerides contents in biodiesel it was evaluated. It s an alternative method for the reference ASTM D-6584 and EN 14105 standard methods with the advantages of being more practical, economical and faster. Moreover the method is applicable to methylic and ethylic biodiesel and biodiesel with long chain triacylglycerides. For this, High Temperature Capillary Gas Chromatography (HT-CGC) on short (15 m) and non-polar column (DB-5HT) and flame ionization detection were used. The accuracy of EN 14103 standard method in the determination of ester content in biodiesel also it was evaluated. Furthermore, a rapid chromatographic method for accompanying the conversion of fats and oils in biodiesel in function of alterations in the reactive conditions of the production system it is presented. For this, the same column and detector were used. The monitoring can be done in just 13 minutes of analysis and it was realized through of the relative proportion between methyl or ethyl esters and triacylglycerides total areas. In addition, the influence of silylation in the analysis of acylglycerides by gas chromatography was also investigated. Mono and diacylglycerides reference standards, silylated and non-silylated, were analyzed by HT-CGC. In non-silylated standards intramolecular reactions occurring inside the chromatographic column it was observed. It was verified that the intensity of these reactions depends on the type and unsaturation degree of the acylglycerides, of the carbon chain length, injection mode, injector temperature and column conditions. Therefore, silylation protects the hydroxyl groups for this kind of reaction and it is a necessary step in gas chromatographic analysis of mono- and diacylglycerides.