Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

Abstract

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. Due to its high reactivity and tendency to decompose at high temperatures, the study of lactic acid thermal behavior is essential for its separation processes and potential application. In the present study, differential scanning calorimetry (DSC) analyses showed endothermic peaks related to the process of evaporation. Data of thermogravimetry (TG/DTG) were correlated to Arrhenius and Kissinger equations to provide the evaporation kinetic parameters and used to determine the vaporization enthalpy. Activation energies were 51.08 and 48.37 kJ·mol−1 and frequency values were 859.97 and 968.81 s−1 obtained by Arrhenius and Kissinger equations, respectively. Thermogravimetry, coupled with mass spectroscopy (TG-MS), provided useful information about decomposition products when lactic acid was heated at 573 K for approximately 30 min.

Highly functional lactic acid ring‐opened soybean polyols applied to rigid polyurethane foams

“…The maximum DWL of this stage was centered at 167°C. From a previous study, we inferred that the initial stage was associated with the evaporation of water and methanol impurities. On the other hand, the subsequent stage was indeed the thermal degradation of LA and lactide.…”

“…A wide range of agents have been used for this purpose. Among those, the use of lactic acid (LA) as an ROA is one of the most promising routes because it is obtained by the fermentation of renewable raw materials, such as corn, potato, and other agricultural products . Another relevant reason is that an ROA based on LA can lead to polyols with higher functionalities, a key aspect for the synthesis of rPUFs.…”

The first amorphous and crystalline yttrium lactate: synthesis and structural features

“… 26 The oxidation of organic matter in the paper-like material was also indicated by a pronounced exothermic effect (maximum at 343 °C) in the DSC curve. Interestingly, the maximum rate of lactate moiety decomposition in air (∼370 °C) is observed at much higher temperatures than the maximum rate of pure lactic acid thermolysis in nitrogen flow (180–240 °C) reported by Komesu et al 69 The final decomposition stage (500–800 °C) of the paper-like material can be attributed to the decomposition of residual carbon-containing matter and the formation of yttrium oxide. The thermal analysis data seem to be similar to those obtained by Powell and Farrell 26 for hypothetical yttrium lactate trihydrate, Y(Lac) 3 ·3H 2 O, yet, in their report, they presented neither the results of chemical analysis of the compounds obtained, nor thermal analysis curves.…”

“…The weight loss ($9.6 wt%) in this temperature range corresponds well to the removal of 8.5 water molecules per Y 4 (OH) 5 ( 26 The oxidation of organic matter in the paper-like material was also indicated by a pronounced exothermic effect (maximum at 343 C) in the DSC curve. Interestingly, the maximum rate of lactate moiety decomposition in air ($370 C) is observed at much higher temperatures than the maximum rate of pure lactic acid thermolysis in nitrogen ow (180-240 C) reported by Komesu et al 69 The nal decomposition stage (500-800 C) of the paperlike material can be attributed to the decomposition of residual carbon-containing matter and the formation of yttrium oxide.…”

Recent Advances on Purification of Lactic Acid

“…[105] The temperature of the evaporator and condenser is the primary factor affecting the yield of LA. [106] Although high investment is involved in the early stage, some companies have been industrialized. Minzu Chemical Co. Ltd (Hubei, China) published a short-path molecular distillation process for LA purification.…”