Lactic acid kinetic models

As a model esterification reaction, the formation of ethyl lactate has been studied and its complete kinetic and thermodynamic analysis has been performed. The formation rate of ethyl lactate has been examined as a function of temperature and catalyst loading. In early experiments, it was determined that lactic acid itself catalyzes esterification, so that there is significant conversion even without ion exchange resin present. The Arrhenius plot for both resin-catalyzed and uncatalyzed reactions indicates that the uncatalyzed... 

Hoefnagel, M.H.N., Starrenburg, M.J.C., Martens, D.E., Hugenholtz, J., Kleerebezem, M., Van Swam, I.I., Bongers, R., Westerhoff, H.V. and Snoep, J.L. (2002) Metabolic engineering of lactic acid bacteria, the combined approach kinetic modelling, metabolic control and experimental analysis. Microbiology 148,1003-1013. 

Akerberg C, Hofvendahl K, Zacchi G, Hahn-Hagerdal B. (1998). Modeling the influence of pH, temperature, glucose and lactic acid concentration on the kinetics of lactic acid production by Lactococcus lactis ssp. lactis ATCC 19435 in whole-wheat flour. Appl Microbiol Biotechnol, 49, 682—690. 

Xiong XY, Tam KC, Gan LH (2005) Release kinetics of hydrophobic and hydrophilic model drugs from pluronic F127/poly(lactic acid) nanoparticles. J Control Release 103 73-82 Jalil R, Nixon JR (1990) Biodegradable poly(lactic acid) and poly(lactide-co-glycolide) microcapsules problems associated with preparative techniques and release piopoties. J Microencapsul 7 297-325... 

The kinetic behavior of esterification of lactic acid with isopropanol over Amberlyst 15 was investigated (Toor et al., 2011 Kirbaslar et al., 2001), at different temperatures from 323K to 353K The ER model was used to describe the reaction mechanism that takes place between adsorbed molecules of isopropanol and the molecules of lactic acid in bulk. The adsorption of ester is reported to be negligible. Hence the rate equation can be described as follows. 

Lee K, Lee DS. A kinetic model for lactic acid production in Kimchi, a Korean fermented vegetable dish.J Ferment Bioeng 1993 75 392-4. 

In the design of a modem lactic acid plant, mathematical models are indispensable. For example, the kinetic model of oligomerization of lactic acid and the right thermodynamic model for the gas/liquid equilibria are important in design for the concentration of lactic acid by evaporation as well as for prepolymerization in the lactide route. 

Kinetic models have been developed for hydrothermal oxidations and hydrolysis of lactic acid in near-critical water by molecular oxygen. On the basis of identified liquid and gaseous products, pathways for hydrothermal reactions involving lactic acid were proposed. AcOH and MeCHO were confirmed as the major intermediates for oxidation and hydrolysis reactions, respectively, and CO and CH4 were identified as the major gaseous by-products from these reactions. ... 

Yadav and Kulkami (2000) have studied the esterification of lactic acid with isopropanol in presence of various ion exchange resin catalysts (Indion-130, Amberlyst-36, Amberlyst-15, Amberlite-120, Dowex 50W, Filtrol-44, 20% DTPA/K-10 and 20% DTPA/Filtrol-44) A theoretical kinetic model was developed for evaluation of this slurry reaction. The effects of various parameters on the rate of reaction were evaluated. The reaction was found to be kinetically controlled and there were no intraparticle as well as interparticle mass transfer limitations on the rate of reactions. 

Lactic acid + iso-propanol Heterogeneous Kinetic and reactor modeling Yadav Kulkarni (2000)... 

Lactic acid + Methanol Dowex 50W, Amberlyst -15 and -36 Homogeneous, Heterogeneous kinetic model Sanz et al. (2002)... 

---