abstract
Cholinium alkanoates, a class of benign ionic liquids, were demonstrated to efficiently extract suberin domains from cork. A detailed characterisation of the extracted material has yet to be attained. In the present study the significance of the alkylic chain length of the anion and the ionic liquid's basicity was investigated. The results obtained emphasise cholinium hexanoate's selection; it proved to be a straightforward process, also ensuring the recyclability and reusability of the ionic liquid. The extracted suberinic material has been thoroughly characterised for the first time by ATR-FTIR, NMR, GC-MS and thermal analyses. Data showed that it is mainly composed of oligomeric or polymeric aliphatic esterified structures, resulting from suberin partial cleavage. More than 40 wt% of the extracted suberinic material was found to be cross-linked. Even though, the composing monomeric units were similar to those usually identified in suberin samples obtained by the conventional extraction processes. These data pave the way for advanced studies of suberin monomers/oligomers as building-blocks for the development of novel biopolymers and biomaterials.
keywords
NUCLEAR-MAGNETIC-RESONANCE; SOLID-STATE C-13-NMR; QUERCUS-SUBER; CELL-WALLS; L. CORK; METHANOLYSIS; DISSOLUTION; SPECTROSCOPY; DEGRADATION; VARIABILITY
subject category
Chemistry
authors
Ferreira, R; Garcia, H; Sousa, AF; Petkovic, M; Lamosa, P; Freire, CSR; Silvestre, AJD; Rebelo, LPN; Pereira, CS
our authors
Andreia Fernandes de Sousa
Assistant Researcher
Armando Jorge Domingues Silvestre
Full professor
Carmen Sofia da Rocha Freire Barros
Coordinating Researcheracknowledgements
R.F. is grateful to Fundacao para a Ciencia e a Tecnologia (FCT), Portugal, for the fellowship SFRH/BD/48286/2008, A. F. S. is also grateful to FCT for the fellowship SFRH/BPD/73383/2010 and H. G. is indebted to Fundacao Calouste Gulbenkian, Portugal, for the fellowship 21-95587-B. The work was partially supported by a grant from Iceland, Liechtenstein and Norway through the EEA financial mechanism (Project PT015), and FCT through the grants PEst-OE/EQB/LA0004/2011, Pest-C/CTM/LA0011/2011 and PTDC/QUI-QUI/120982/2010. The authors wish to thank I. Nogueira from Instituto Superior Tecnico, Portugal, for the acquisition of SEM. The National NMR Network (REDE/1517/RMN/2005) was supported by POCI 2010 and FCT, Portugal.