Effect of external mass transfer on activation energy of butyl oleate ester synthesis using a whole cell biocatalyst

• Published in: Journal of chemical and petroleum engineering (Online) Vol. 50; no. 1; pp. 9 - 13
• Main Authors: Shabnam Shahhoseyni, Bahram Nassernejad, Farzaneh Vahabzadeh
• Format: Journal Article
• Language: English
• Published: University of Tehran 01.06.2016
• Subjects: activation energy; arrhenius equation; butyl oleate; ester synthesis; loofa sponge
• ISSN: 2423-673X; 2423-6721
• DOI: 10.22059/jchpe.2016.57840

In the present research, synthesis of butyl oleate ester from oleic acid and butanol using loofa-immobilized Rhizopus oryzae as a whole cell biocatalyst (LIC) was studied in which hexane was used as the hydrophobic solvent. Decrease of mass transfer limitations as result of the interface formation between the two immiscible substrates, positively affected on the reaction progress (87% as the ester product yielded within 10 h). By applying Arrhenius equation, the activation energy of the ester synthesis was determined as Ea=18.2 kJ/mol within temperature range of 15-45°C. It was notable to test appearance of the nonlinearity in Arrhenius plot which was indicative of presence of two sections. The reaction limited region was 15-35°C; Ea=27 kJ/mol and diffusion limited region was >35°C; Ea=6.8 kJ/mol. Eventually, in this research, influence of external mass transfer on activation energy with reference to the catalytic role of the LIC in the ester synthesis was discussed.