With the increasing selective energy demand, fossil fuels are becoming scarce and environmentally incorrect, a viable alternative to this problem being the production of biodiesel. However, the esterification and transesterification reactions used are slow, expensive and ecologically incorrect because they produce polluting waste. Thus, it is necessary to develop techniques, reagents and equipment that make them fast, cheap and environmentally friendly. This work evaluated the performance of the thermal heating, microwave and ultrasonic methods in the esterification efficiency of oleic and stearic fatty acids via homogeneous acid catalysis. The efficiency of the reaction was certificated with the variables: time, yield and conversion and the biodiesel characterization were done with TG / DTG, FTIR and NMR. Conversions were determined by TG and 1H NMR and the yield by gravimetry. The results showed conversion with all methods with differences in the analyzed variables. The yields decrease in the microwave order (52%) conduction (33%) ultrasound (30%) for reactions with oleic acid and are practically the same (22, 22 and 20), independently of the stearic acid. Among the methods used, the most efficient is the microwave, because it has a higher yield in the case of oleic acid and reducing the reaction time.
FATTY ACID ESTERIFICATION: EFFECTS OF UNSATURATION AND SYNTHESIS WITH THERMAL HEATING VIA ULTRASON AND MICROWAVES
