The effect of hydrogen bonds on the reactivity of coniferous and deciduous dioxan lignins

Abstract

The slightly altered samples of dioxan lignin were extracted from coniferous (spruce and juniper) and deciduous wood (aspen) by the Pepper’s method. Lignins were characterized by data of elemental, functional composition, macromolecular and reactive (acid–base and redox) properties. IR spectra of lignins were recorded by the attenuated total refection method. The absorption band of lignins in the 3000–3700 cm⁻¹ region corresponds to the valence vibrations of hydroxyl groups involved in hydrogen bonds. This band was divided into separate Gaussian contours by deconvolution method. The characteristic parameters (energy, length, and relative content) were calculated on the basis of correlation dependencies for each type of H-bonds. The relationship between reactivity (acid–base and redox properties) and the involvement of hydroxyl groups of a natural polymer in H-bonds was shown. The highest reactivity of aspen lignins is caused by the presence of syringyl structures and lower H-bond energies involving reaction centers of macromolecules.

Graphic abstract

Keywords:

• IR spectroscopy
• deconvolution
• dioxan lignin
• hydroxyl group
• hydrogen bond

Acknowledgments

This research was funded from the project agreement No. 122011700252-1 «Physico-chemical bases of selective methods of isolation, characteristics and application of biologically active complexes of plant objects of high latitudes for solving problems of environmental control and health protection». The authors used the equipment of the «Critical Technologies of Russian Federation in the Field of Environmental Safety of Arctic» Centre of Collective Use of Scientific Equipment (Federal Center for Integrated Arctic Research, Russia). The authors are grateful to PhD A.A. Krasikova from FECIAR UrB RAS.

Disclosure statement

No potential conflict of interest was reported by the authors.