Ethyl Hexanoate Lab Report

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Introduction In recent years, there is an increasing demand of flavoured compounds in industry sectors, especially food and beverage, cosmetic and pharmaceutical industries 1–4. These compounds are generally short chain ethyl esters which are characterized by their strong fruity flavour and fragrance. Ethyl hexanoate is such a short chain acid ester which gives an apple-pineapple flavour 5,6. Most of the flavours are extracted from their natural source, but this process can take a long time and rigorous efforts eventually ending up with an inefficient yield. There are numerous ways for the synthesis of organic esters and most of which have been briefly studied by Yadav and Mehta 7. The simple and old route for preparing esters is by the reaction…show more content…
Antarctica (Novozyme 435) catalysed the synthesis of pineapple flavour; ethyl hexanoate by using central composite design and RSM analysis. The various parameters, affecting the synthesis, such as the substrate molar ratio, enzyme loading and the reaction temperature were studied. The system adopted was kept deprived of the solvent in the substrate. The optimization of the experimental conditions for an economic synthesis of ethyl hexanoate was done using the RSM, which statistically indicates the effects of the parameters on the synthesis using the central composite design to estimate the second degree polynomial model for…show more content…
Experiments have been conducted using optimum values of enzyme loading and ethanol to hexanoic acid molar ratio (as determined from the statistical experimental design) at these three reaction temperatures. Figure 6 shows the Arrhenius Plot of ln (k) versus reciprocal absolute temperature (1/T) from which activation energy can be determined. The thermodynamic parameters for enzymatic esterification were determined using the Eyring equation as follows 20 : ln⁡〖k/T= 〗 [(-ΔH)/R][1/T]+ln⁡[k_b/h ]+ΔS/R [5] ΔH=Ea-RT [6] ΔG= ΔH-TΔS [7] Where h = Planck’s constant (6.626×10-34 J.s), kb = Boltzmann constant (1.381×10-23 J/K), k = rate constant at temperature T, ΔH = Enthalpy of activation, ΔS = Entropy of activation, R = universal gas constant, and ΔG = Gibbs free energy. The values of activation energy and all thermodynamic parameters are given in Table.5. The values obtained from Arrhenius analysis can be substituted in the above set of equations to yield thermodynamic parameters, viz. ΔH, ΔS and ΔG in association with enzymatic esterification
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