Photodegradation of Acidolysis Lignin from BCMP

Molecules

Mohammad Azadfallah¹   Seyed Ahmad Mirshokraei² 

[1] Wood and Paper Science and Technology Department, University of Tehran, Karaj, Iran;Department of Chemistry, Payam-e-Nour University, Tehran, Iran; E-mail:

关键词: Lignin;    Photodegradation;    BCMP;    ¹H-NMR;   

DOI  :  10.3390/molecules13123129

来源: mdpi

【 摘 要 】

A mild acidic dioxane extraction method was employed to isolate lignin from hardwood bleached chemimechanical pulp (BCMP). The isolated lignin was then purified and undergone elemental analysis. To study the photodegradation behavior, the lignin samples were impregnated onto the Whatman filter papers and irradiated with UV light for various periods. The photolyzed lignin was then recovered and analyzed by ¹H-NMR spectroscopy. Phenylpropane-based formula (C₉) of CMP pulp lignin and the photolyzed samples were then established with elemental analysis and ¹H-NMR spectroscopy data. The results indicated that the benzaldehyde and benzoic acid type compounds were the main photodegradation products of BCMP lignin. The lignin photodegradation probably involved the degradation of phenylcoumaran units. Irradiation also increased the phenolic hydroxyl group content and decreased that of methoxyl groups, due to demethoxylation. The degrees of aromatic ring condensation were increased upon continuing the irradiation time, which imples the formation of condensed structures in photolyzed lignin.

【 授权许可】

CC BY   
© 2008 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.