Thermogravimetric analysis and kinetic study of lactic acid

Actually, there is a growing interest in the biotechnological production of lactic acid by fermentation aiming to substitute fossil fuel routes. The development of an efficient method for its separation and purification from fermentation broth is very important to assure the economic viability of production. Because lactic acid is a molecule with high reactivity and tendency to decompose at high temperatures, the study of lactic acid thermal characterization is relevant for their separation process and potential application. In the present study, the use of thermoanalytical techniques, such as thermogravimetry (TG/DTG) and thermogravimetry coupled with mass spectroscopy (TG-MS), provided useful information about the lactic acid thermal behavior. TG/DTG curve profiles showed information on lactic acid stability and data were correlated to Arrhenius and Kissinger equations to provide evaporation kinetic parameters. TG-MS curve profiles showed many decomposition products when lactic acid was heated at high temperature. The results deliver a better understanding of the lactic acid thermal behavior and therefore allow the development of adequate separation process.