Microwave mediated lipase-catalyzed synthesis of n-butyl palmitate and thermodynamic studies

Solvent-free esterifications mediated by immobilized lipases: a review from thermodynamic and kinetic perspectives

“…These parameters may be obtained successfully by mathematic modeling and computational simulation. These parameters help to check, in general terms, that: i) esterification reactions are spontaneous processes; ii) esterification reactions are frequently endothermic processes, with a positive variation of enthalpy; iii) the variation of entropy is positive, considering the formation of water and its partitioning in the reaction media (21,(26)(27)(28)(29)(30).…”

“…The free energy of the system (ΔG) tends to decrease with increasing temperatures in conventional esterification, which means that the reaction is thermodynamically favored (endothermic reaction, with positive enthalpy of reaction ΔH) (26,28,29,98,99). However, a recent publication by Khan & Rathod (2020) (30) found that although a positive variation of enthalpy is observed in enzymatic esterification (n-butyl palmitate synthesis) under conventional stirring, the opposite situation occurs under ultrasound stirring or microwave irradiation, considering the ability of these techniques for enhancing the effective collisions in reaction. Another interesting observation is that only marginal differences were observed in calculated values of ΔH, ΔG, and ΔS when the temperature varied from 40 to 70 °C under conventional stirring, ultrasound, or microwave irradiation (30).…”

“…However, a recent publication by Khan & Rathod (2020) (30) found that although a positive variation of enthalpy is observed in enzymatic esterification (n-butyl palmitate synthesis) under conventional stirring, the opposite situation occurs under ultrasound stirring or microwave irradiation, considering the ability of these techniques for enhancing the effective collisions in reaction. Another interesting observation is that only marginal differences were observed in calculated values of ΔH, ΔG, and ΔS when the temperature varied from 40 to 70 °C under conventional stirring, ultrasound, or microwave irradiation (30). Temperature also affects the reagents' solubility, which implies considerable changes in the availability of the reactants for the enzyme.…”

“…Studies that include additional evaluation of thermodynamic parameters (ΔH, ΔG, ΔS) or kinetic parameters (K m , V max , K i , etc.) are generally carried out after optimized condition of molar ratio, biocatalyst loading, and temperature or separately (30,45,90,98,100,101). Thus, relevant aspects of chemical equilibrium and enzyme kinetics directly associated with optimization of a reaction will be further discussed, considering the particularities of solvent-free systems.…”

Molecular Decoration of Ceramic Supports for Highly Effective Enzyme Immobilization—Material Approach

“…Lipase Candida antarctica type B from (CALB) is stable over a relatively broad pH range, especially in the alkaline pH range [8,9]. Lipase CALB has been used extensively in the resolution of racemic alcohols, amines, acids, and in the preparation of optically active compounds from meso substrates [10], as well as in polymer synthesis due to its high catalytic activity [11] sometimes supported by ionic liquids [9,12].…”