A Simple Pseudo-Homogeneous Reversible Kinetic Model for the Esterification of Different Fatty Acids with Methanol in the Presence of Amberlyst-15

Abstract

Fatty acid esterification with alcohols is a crucial step in biodiesel synthesis. Biodiesel consists of long-chain alkyl esters that derive from the transesterification or hydro-esterification of the triglycerides that are contained in vegetable oils. In the first route, the esterification of the free fatty acids is an important pretreatment of the feed; in the second, it is the main reaction of the industrial process. Knowledge of appropriate kinetic models for the catalytic esterification of fatty acids with alcohols is critical in the design of biodiesel synthesis processes. In this work, the kinetic behavior of the reversible esterification of lauric, myristic, palmitic and stearic acid, which are the most common saturated fatty acids that are contained in triglyceride feedstocks for biodiesel, with methanol at different temperatures (70–150 °C) and molar ratios of the reactants (1:1–1:2–1:5) was investigated in a batch laboratory basket reactor both in the presence and absence of Amberlyst-15 as the catalyst. Results obtained with Amberlyst-15 were fitted through a ready-to-use pseudo-homogeneous reversible model suitable for process design. The kinetic model was compared with that obtained in a previous work with niobium oxide as the catalyst. With respect to the results that were obtained with niobium oxide, the influence of the chain length of the acid on the kinetic behavior was strongly reduced in the presence of Amberlyst-15. This phenomenon was ascribed to a different catalytic mechanism.

Facile synthesis of polyoxometalates tethered to post Fe-BTC frameworks for esterification of free fatty acids to biodiesel

“…52.3 kJ mol À1 , 78 kJ mol À1 , etc.). 45,46 Moreover, according to previous reported, 47,48 the esterication reaction is not diffusively controlled but kinetically controlled if the apparent activation energy is high enough (e.g., >20.0 kJ mol À1 ), and that the high apparent activation energy of esterication catalyzed by the PMA/Fe-BTC catalyst further demonstrates that diffusion is not important during our esterication processes. This nding suggests that the esterication reaction is chemically controlled and not by diffusion or mass transfer limitations.…”

Widely used catalysts in biodiesel production: a review

“…Thus, many research groups have studied the role of ion exchange resins as solid catalysts in FAME production. 299,300 Resin is the insoluble solid material that can retain and discharge ions simultaneously. 301 Resins are broadly categorized into cationic and anionic resin based on their functional groups and degree of cross-linkages.…”

Reutealis Trisperma Oil Esterification: Optimization and Kinetic Study

“…Table 8. Effect of fatty acid chain length on activation energy of esterification reaction [22]. The activation energy required for the model oil system was revealed to be 40.8 kJ/mol.…”

“…The model oil system contained only oleic acid (C18), while the R.trisperma oil was comprised of several fatty acids ranging from palmitic acid (C16) to docosanoic acid (C22). Additionally, the fatty acid chain length was found to have an impact on the activation energy of the FFA esterification reaction, a longer chain requiring higher activation energy (Table 8) [22]. Table 8.…”