In situ transesterification of the catolé coconut (Syagrus Cearensis) utilizing experimental design by Taguchi method

Abstract

This work proposes the optimization of biodiesel synthesis utilizing in situ transesterification, through experimental design by the Taguchi method. In this process, nine experiments were carried out and the influence of reaction parameters as catalyst mass, proportion of methanol in relation to oil content and temperature were statistically evaluated. The mass yield was analyzed as a response. The optimized condition was obtained through the reaction with 2 wt% of catalyst, ratio of methanol to oil 5:1 content and 60ºC. The experiment generated a yield of 66.17 wt%. In the experimental study, the evaluated parameters presented relevant p-value, with the catalyst rate being the factor that most impacted the synthesis yield. The synthesized biodiesel obtained from the confirmation experiment of the Taguchi modelling was characterized through the physical-chemical parameters. The material complies with international standards for biodiesel, highlighting the result of oxidative stability greater than 18 h, the combustion events in thermal analysis ranging from 224 to 258 ºC, and activation energy of 67.3 KJ.mol−1, justified by the profile of mostly saturated fatty acids demonstrated in the chromatography analysis. From nuclear magnetic resonance analysis, the synthesis proved to be effective to convert all the triglycerides extracted from the kernel into biodiesel, without the necessity of additional steps of oil extraction and purification. In this sense, an optimized reaction system allied to biodiesel with expressive quality makes catolé coconut a raw material with high commercial potential. The use of Taguchi design to obtain the best conditions for the reaction allowed for an easy interpretation of the results, providing good comprehension of the impacts of the reaction parameters in the synthesis.