Calculation of IR-spectra of structural fragments of lignins
St. Petersburg State University of industrial technologies and design, 198095 St. Petersburg, Russia
* Corresponding author: firstname.lastname@example.org
Published online: 13 December 2016
To study structure of softwood lignins the experimental and theoretical IR-spectra in middle IR-diapason were analyzed. To interpret these data the quantum chemical calculations of IR-spectra of general dimmer fragments of softwood lignins by method of density functional theory (DFT/B3LYP) with 6-31G(d,p) as basis set were carried out. These calculations showed that frequencies of normal vibrations of fragment with β-alkyl-aryl linkage are close to the experimental values of the IR absorption bands of lignin, and infrared spectrum of this structure is similar to the experimental spectrum of lignin. The calculations with accounting for the solvent showed a strong increase in the intensity of the majority of the bands and the solvent effect on the frequencies of vibrations.
© The Authors, published by EDP Sciences, 2017
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