Transesterificação de triacilglicerol de óleos de Milho e de soja: análise quimiométrica do processo e Propriedades físico-químicas essenciais do produto, Para uso como biodiesel

Abstract

This work dealt with the transesterification reaction as the chemical process to obtain biodiesel via either methyl or ethyl routes, using oils from corn or soybean grains. The thermal expansion coefficients were determined for both methyl and ethyl biodiesels, be from corn oil or soybean oil. Specific mathematical models were proposed to predict values of the thermal expansion for each of these biodíesels. It is remarkable the found difference between predictable values as obtained from the proposed mathematical model (algorithm) for the biodiesels, even if compared to the standard EN 14214 recommendation. The optimal set of reaction conditions for the transesterification process via ethylic route was more specifically investigate by using the following variables: temperature, speed, reaction time, type of catalyst, concentration of catalyst and molar ratio. The latter two were found to be operationally more important. The transesterification reaction with corn oil was found to be a robust process, in the sense that small variations on its condition do not significantly affect the whole yield: the tolerated range of values for the catalyst concentration is 1.56 ± 0.25% (m/m) whereas for the molar ratio (ethanol: oil) it is 10.9:1 ± 1. Conditions of maximum yield for this reaction are (i) type of catalyst: potassium hydroxide; (ii) catalyst concentration: 1.56 % (w/w); (iii) molar ratio (ethanol: oil): 10.9:1; (iv) temperature: 55 0C; (v) reaction time: 60 minutes and (vi) rotation: 100 rpm.