Dissertações em Química (Mestrado) - PPGQ/ICEN
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/16399
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Item Acesso aberto (Open Access) Preparação e avaliação de catalisador heterogêneo ácido baseado em óxido de grafeno funcionalizado para síntese de biodiesel(Universidade Federal do Pará, 2021-09-24) SILVA, Paula Maria Melo da; CONCEIÇÃO, Leyvison Rafael Vieira da; http://lattes.cnpq.br/7467898936995220The present study aims at the synthesis of a heterogeneous acid catalyst derived from graphene oxide, applied in the transesterification reaction of soybean oil to obtain biodiesel. The graphene oxide catalytic support was synthesized from graphite oxidation and the catalyst was functionalized by impregnation of molybdenum trioxide (MoO3) as the active phase. The synthesis of the support and the catalyst was confirmed through the characterization techniques of Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TG/DTG), Scanning Electron Microscopy (SEM), Energy Dispersion X-Ray Spectroscopy (EDS) and XRay Diffraction (DRX). The catalytic tests optimization of the transesterification reactions had as parameters evaluated the temperature in the range of 120–160 °C, the time between 1–5 h, the catalyst concentration comprised in 10% (m/m) and molar ratio oil/ alcohol in the range of 25:1–45:1. The reaction studies evidenced as an optimum point the temperature of 140 °C, time of 5 h, catalyst concentration 6% (m/m) and molar ratio of 35:1, leading to the obtainment of a biodiesel with an ester content above 90%. The catalyst also maintained its catalytic activity even in the seventh reaction cycle. Therefore, the results obtained demonstrate that the graphene oxide catalyst supported by MoO3 is a new and promising heterogeneous acid catalyst with high catalytic efficiency in the transesterification reaction for the biodiesel synthesis.Item Acesso aberto (Open Access) Síntese de biodiesel utilizando catalisador bifuncional baseado em ferrita com óxido metálico suportado(Universidade Federal do Pará, 2021-07-23) GONÇALVES, Matheus Arrais; CONCEIÇÃO, Leyvison Rafael Vieira da; http://lattes.cnpq.br/7467898936995220In this study, a solid magnetic acid catalyst MoO3/SrFe2O4, composed of molybdenum oxide (MoO3) supported on strontium ferrite (SrFe2O4), was synthesized and applied in the transesterification of waste cooking oil (WCO). The catalyst was characterized by acid-base titration method in order to determine Surface acidity, Thermogravimetric analysis (TG/DTG), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersion X-ray spectroscopy (EDS) and Vibrating sample magnetometry (VSM) techniques. A central composite design of centered face 24 (FCCD) and a mathematical model was developed in order to describe the behavior of the ester content as a function of the independent variables temperature, alcohol:oil molar ratio, catalyst dosage and time reaction. The mathematical model (R2=0.9900) was validated and showed a relative error below 5% between the experimental and predicted values. Using linear regression methods and response surface methodology (RSM) the conditions of biodiesel synthesis reaction were optimized and 95.4% conversion into esters was obtained from the use of the reaction temperature of 164 °C, alcohol:oil molar ratio of 40:1, catalyst dosage of 10% and reaction time of 4 h . The catalyst showed high reusability, since it was possible to use it in 8 reaction cycles which it is an indication of its good prospectus for development and application as bifunctional catalyst.