Síntese de hidrotalcitas com amido de milho acidificado por ozônio como precursores de catalisadores para produção de biodiesel etílico.
Carregando...
Arquivos
Data
2018-05-23
Autores
Santos, Cibele Favoreto
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
RESUMO Pesquisa destinada a melhorar e gerar rotas de produção de biocombustíveis como fonte alternativa a combustíveis derivados do petróleo está se tornando mais frequente. Nesta área, desenvolver novas técnicas que facilitem, ou ajudem a otimizar processos como a transesterificação de óleos vegetais ganham espaço no meio científico. Óxidos provenientes de materiais semelhantes a hidrotalcitas pertencentes à família de argilas aniônicas foram estudados recentemente como um substituinte para catalisadores básicos na síntese de biodiesel. Para testar estes catalisadores, a síntese de materiais de hidrotalcita como (HDLs) com fórmula molecular MgxXAly (CO3)(OH)16.4H2O em diferentes proporções x / y foi realizada com substituição total de Na2CO3 por amido de milho e amido de milho acidificado pelo ozono. A síntese dos HDLs foi realizada pelo método de coprecipitação e os materiais secados pela técnica de pulverização e para gerar os óxidos estes precursores foram calcinados a 450 e 600 °C . A caracterização do HDLs foi realizada por difração de raios-X (XRD), espectroscopia vibracional (ATR-FTIR) e decomposição térmica (TGA) e dos óxidos por XRD, BET, adsorção de CO2 (basicidade) e n-butilamina (acidez) e microscopia eletrônica de varredura (MEV). As reações de transesterificação foram processadas por 12 horas a 120 ° C na proporção molar de óleo de soja /etanol (1/20) com 20% (m / m) de catalisador em relação à massa, e os produtos foram quantificados por GC-FID. Com a introdução de amido de milho ou amido de milho acidificado no sólido, características físico-químicas típicas de HDLs foram alteradas com base nos dados obtidos das caracterizações. Foi observado o aumento nas áreas superficiais dos óxidos (800m2 g-1) e nas propriedades de acidez e basicidade. Nos testes iniciais o precursor sem a presença de amido (3:1 Mg:Al) alcançou 36,1% de conversão. Embora o melhor resultado de conversão tenha sido alcançado a partir do sólido sem amido de milho, existe uma correlação interessante entre as atividades catalíticas e as propriedades físico-químicas dos sólidos com os materiais modificados e seus respectivos homólogos. Estudos suplementares buscando melhorar o rendimento destes óxidos foram realizados resultando com resultados próximos a 50% de rendimento de biodiesel.
Research to improve biofuel production routes as an alternative source of petroleumderived fuels has been matter of recent efforts. In this area, developing new techniques that facilitate or help optimize processes such as transesterification of vegetable oils have been gaining attention. Oxides from hydrotalcite-like materials belonging to the anionic clays family were recently studied as substitute for basic catalysts in the synthesis of biodiesel. In order to test these catalysts, the synthesis of hydrotalcite materials (HDLs) with molecular formula MgxXAly(CO3)(OH)16.4H2O in different x/y ratios was carried out with total substitution of Na2CO3 by corn starch and corn starch acidified by ozone. The synthesis of the HDLs was performed by the coprecipitation method and the materials dried by the spray technique and the oxides generated by calcination at 450 and 600 °C. The characterization of HDLs was performed by XRD, vibration spectroscopy (ATR-FTIR) and thermal decomposition (TGA) and the oxides by XRD, BET, CO2 adsorption (basicity) and nbutylamine (acidity), and scanning electron microscopy (SEM). The transesterification reactions were carried out for 12 hours at 120 °C in 1/20 molar ratio of soybean / ethanol with 20% (w/w) of catalyst and the products were quantified by GC-FID. With the introduction of corn starch or acidified maize starch into the solid, typical physico-chemical characteristics of HDLs were successfully modified based on the characterization data. It was observed the increase in the surface areas of the oxides (800 m2 g -1 ) and in the acidity and basicity properties. In catalytic assays the precursor without the presence of starch (3:1 Mg:Al) reached 36.1% conversion. Although the best conversion result has been achieved from the solid without cornstarch, there is an interesting correlation between the catalytic activities and the physico-chemical properties of the solids with the modified materials and their respective counterparts. Further studies to improve the yield of these oxides were performed resulting in results close to 50% biodiesel yield.
Research to improve biofuel production routes as an alternative source of petroleumderived fuels has been matter of recent efforts. In this area, developing new techniques that facilitate or help optimize processes such as transesterification of vegetable oils have been gaining attention. Oxides from hydrotalcite-like materials belonging to the anionic clays family were recently studied as substitute for basic catalysts in the synthesis of biodiesel. In order to test these catalysts, the synthesis of hydrotalcite materials (HDLs) with molecular formula MgxXAly(CO3)(OH)16.4H2O in different x/y ratios was carried out with total substitution of Na2CO3 by corn starch and corn starch acidified by ozone. The synthesis of the HDLs was performed by the coprecipitation method and the materials dried by the spray technique and the oxides generated by calcination at 450 and 600 °C. The characterization of HDLs was performed by XRD, vibration spectroscopy (ATR-FTIR) and thermal decomposition (TGA) and the oxides by XRD, BET, CO2 adsorption (basicity) and nbutylamine (acidity), and scanning electron microscopy (SEM). The transesterification reactions were carried out for 12 hours at 120 °C in 1/20 molar ratio of soybean / ethanol with 20% (w/w) of catalyst and the products were quantified by GC-FID. With the introduction of corn starch or acidified maize starch into the solid, typical physico-chemical characteristics of HDLs were successfully modified based on the characterization data. It was observed the increase in the surface areas of the oxides (800 m2 g -1 ) and in the acidity and basicity properties. In catalytic assays the precursor without the presence of starch (3:1 Mg:Al) reached 36.1% conversion. Although the best conversion result has been achieved from the solid without cornstarch, there is an interesting correlation between the catalytic activities and the physico-chemical properties of the solids with the modified materials and their respective counterparts. Further studies to improve the yield of these oxides were performed resulting in results close to 50% biodiesel yield.
Descrição
Palavras-chave
Biodiesel etílico, hidrotalcita, hidróxido duplos lamelares, amido de milho, catálise heterogênea., Ethyl biodiesel, Bioenergy, Hydrotalcite, Layered double hydroxides, Corn starch, Heterogeneous catalysis