Avaliação da glicerólise dos óleos de coco, macaúba, dendê e chia na presença do complexo organoestânico DBTDL

Abstract

Based on this work, we sought to study aspects related to the fatty acids present in coconut, macaúba, palm and chia oils when using them in glycerolysis reactions in the absence and presence of the atalyst dibutyltin dilaurate (DBTDL). Such reactions were carried out in a Parrtype reactor, also using echanical stirring, a thermocouple to check the reaction temperature and a valve through which aliquots were withdrawn after, respectively, 0.5, 1, 2, 3, 4 and 5 hours of reaction. The defined reaction temperature was 220 ºC and the proportions of oil, glycerol and catalyst, when used, were 1/6/0.01. From the collected aliquots, samples were prepared and the reaction products were analyzed by high performance liquid chromatography (HPLC). Through the analysis of the chromatograms and onsequent quantification of the products, it was observed that the glycerolysis reactions where DBTDL was used were the ones that resulted in a greater conversion of TAG into MAG and DAG, with an increase in the percentage of the respective products at each reaction time, proving the efficiency of the catalyst. It was noted that, for macaúba, palm and chia oils, which had higher acidity levels, glycerolysis and esterification occurred in parallel in the reaction medium. It was noticed that macaúba and chia oils, which have a higher percentage of C18 carbon chains and unsaturation, showed greater reactivity when using DBTDL and it was possible to determine the second order kinetic model as the most appropriate for the studies focused on glycerolysis reactions.