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|Title:||Lipase-catalyzed interfacial polymerization of ω-pentadecalactone in aqueous biphasic medium: A mechanistic study|
Lars O. Wiemann
Center for Agricultural Biotechnology (AG-BIO/PERDO-CHE
Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB
Laboratoire de Chimie Physique Macromoleculaire
Université de Lorraine
|Keywords:||Biochemistry, Genetics and Molecular Biology;Chemical Engineering|
|Citation:||Journal of Molecular Catalysis B: Enzymatic. Vol.88, (2013), 69-76|
|Abstract:||The synthetic activity of lipases in biphasic o/w systems was investigated with respect to their use in the synthesis of polyester chains via transesterification reactions. Lipase-catalyzed ring-opening polymerization (ROP) of pentadecalactone (ω-PDL) dispersed in water was used as a model reaction to understand the synthetic activity of lipases in biphasic o/w system. We conducted a systematic investigation of the influence of reaction conditions on the macromolecular characteristics of oligo(ω-PDL) encompassing chemical, thermophysical and colloidal properties of the reaction medium. A model was proposed assuming Michaelis-Menten interfacial kinetics followed by chain extension via lipase-catalyzed linear polycondensation. The solidification of oligo(ω-PDL) chains with a degree of polymerization of approximately three was identified as a major factor limiting the molecular weight of obtained oligomers to ∼870 g mol-1, despite the fast reaction rate and complete conversion of ω-PDL. The addition of toluene into the dispersed phase at a volumetric ratio of 0.3-0.5 of toluene to ω-PDL allowed us to circumvent this problem and increase the molecular weight of obtained oligomers up to 1460 g mol-1. The molecular weight of polymer product according to this model was thus inversely related to the weight ratio percentage of interfacial lipase PS to ω-PDL per droplet and correspondingly correlated with the activity of lipase. Taking into account all these parameters allowed increasing the molar mass of oligo(ω-PDL) from 870 g mol-1to 3507 g mol-1. © 2012 Elsevier B.V.|
|Appears in Collections:||Scopus 2011-2015|
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