Ultrasound as a Metrological Tool for Monitoring Transesterification Kinetics

Abstract

Ultrasound has been widely used as a technological alternative way to analyse noninvasively an assortment of materials. It includes liquids with dissimilar physical characteristics, including mono-and multi-phasic mixtures, suspension formation and dissolution, in-line processing, among other practical applications. Regardless the huge spread of uses, so far ultrasound has not been proved to be able to quantify transesterification kinetics with a metrological approach. The aim of this chapter is to demonstrate that a properly designed ultrasonic experiment can be developed to identify remarkable stages of a transesterification reaction to produce biodiesel. The method was compared both with gas chromatography and hydrogen nuclear magnetic resonance ( 1 H NMR). For an in-line application, ultrasound has been proved to work properly as a monitoring tool for chemical reaction kinetics.

Ultrasound Methods for Biodiesel Production and Analysis

“…From the both figures reprinted from [9], it is possible to notice that ultrasound follows the results obtained by the 1 H NMR technique but in an inline mode. Baesso et al [9] proved that for the four analyzed reactions, the ultrasound was capable to distinguish the end of Figure 13. Variation of (a) TAG concentration, (b) propagation velocity and (c) TAG conversion for the reactions with 520 rpm of rotation.…”

“…Baesso et al [9] disclose in their study that ultrasound can notice changes in the medium during transesterification reaction but can also monitor the kinetics behind the biodiesel production. That study analyzed four different reactions to produce biodiesel from commercial soybean oil.…”

“…Both CTAG and XTAG were monitored by 1 H NMR, as an offline method. Figures 12 and 13 show some results published in [9].…”

“…The behavior of those derived quantities as function of frequency is deeply related to density and viscosity. Many studies have been demonstrating the relationship between QUS and fuel [9,75,76,78]. Another approach to the use of ultrasound in the industry of fuel and biofuel is its use for production [1,8,54,63,64].…”

“…Not just as a way to accelerate the transesterification, the ultrasound is being studied as a tool to monitor the biodiesel reaction [9]. The use of low-power ultrasound to determine the end of the reaction in an inline method cannot just save time and energy, but also it can potentially avoid waste.…”