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Oxidative coupling of various aromatic phenols and anilines in water using a laccase from Trametes villosa and insights into the ‘PEG effect’
Author(s) -
Steevensz Aaron,
AlAnsari Mohammad Mousa,
Taylor Keith E.,
Bewtra Jatinder K.,
Biswas Nihar
Publication year - 2012
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2734
Subject(s) - peg ratio , chemistry , laccase , polyethylene glycol , oxidative coupling of methane , molar mass , aniline , peg 400 , organic chemistry , nuclear chemistry , phenol , polymer chemistry , catalysis , polymer , enzyme , finance , economics
BACKGROUND: Studies with peroxidases (EC 1.11.1.7) have demonstrated extended lifetimes for conversion of phenolics into insoluble polymers in the presence of polyethylene glycol (PEG). Yet the mechanism of this ‘PEG effect’ has eluded investigators. The effectiveness of a laccase (EC 1.10.3.2) with PEGs of various average molar masses on the conversion of phenol, o ‐, m ‐, p ‐cresols, aniline, o ‐, m ‐, and p ‐toluidines was investigated. This structure‐activity comparison, with and without the additive, could provide further insight into the ‘PEG effect’. RESULTS: The ‘PEG effect’ was observed only with the cresols and only with PEGs of average molar mass ≥ 1450. Other additives capable of H‐bonding, such as polyvinylpyrrolidone, had similar results. When a ‘PEG effect’ was observed there was a linear relationship between the amount of additive used and the amount incorporated into the precipitate, suggesting a strong interaction between products and PEG, which was confirmed by nuclear magnetic resonance spectroscopy. Optimum pH was not affected by the quantity or molar mass of the PEG added. CONCLUSION: PEG only enhances the laccase‐catalyzed oxidative coupling of certain substrates implying a product‐additive relationship that may be related to the functionality and substituent positioning of the substrate. Copyright © 2011 Society of Chemical Industry