Avaliação do desempenho da argila vermiculita como suporte e catalisador na reação de transesterificação dos óleos de soja de algodão.

Abstract

The use as biodiesel fuel has shown promising potential in the world. The transesterification or esterification of fats or oils is carried out in the presence of acidic catalysts , basic or enzymatic . A large number of heterogeneous catalysts have been studied , such as zeolites , metal oxides , enzymes , ion exchange resins , clays , always aiming at an optimization of the catalytic process . The physico-chemical behavior of clay materials presents a promising catalytic activity . It is important to mention that in a few cases the clays are active in their natural form , requiring almost always treatments to enhance their catalytic properties . Therefore, this study aims to test the natural clay vermiculite and treated chemically as catalysts for the transesterification of soybean oil and cotton in order to obtain biodiesel . The catalysts were subjected to the impregnation process with MoO3 , pillaring and acid activation . After preparation of the catalysts , they were characterized using the following techniques : X-ray Diffraction ( XRD ) , Energy Dispersive X-ray ( EDX ) and Scanning Electron Microscopy ( SEM) and Spectroscopy in the Region of Fourier Transform Infrared ( FTIR ) . In the first stage of the study was to evaluate the efficiency of the catalysts in the transesterification of soybean oil and cotton , using a batch reactor with autogenous pressure ( S1 ), according to a molar ratio oil / alcohol 1/12 with 5 % catalyst under a temperature of 200 º C for 4 hours , then the catalyst ( natural vermiculite soaked) NIV that performed better in the conversion to ester was tested in a sequence of experiments obeying certain conditions in an experimental design . Biodiesel obtained by S1 was characterized using the techniques of determination of kinematic viscosity and ester content by gas chromatography. The planning results showed that the temperature is the variable most influential in the conversion of triglycerides to ethyl esters . This improved catalyst performance VNI can be explained by the presence of molybdenum oxide on the surface of the clay and by activation of the acid sites likely occurred during the heat treatment that it has undergone . After testing planning to study the effect of stirring, and reuse of the catalyst , showing that the unrest has great influence on the reaction and the catalyst NIV can be used in more than one consecutive reaction cycle .