Abstract
To possibly help in understanding the chemistry of the D process using E. urophylla×E. grandis LH 107 as the pulping material, residual lignin in kraft-oxygen pulp bleached by chlorine dioxide was extracted by the dioxane/water acidolysis method. The content of functional groups in the extracted lignin was determined by 13C and 31P NMR spectroscopy. A relatively significant difference could be seen in the chemical properties of residual lignin between oxygen delignified (O) and chlorine dioxide treated (OD) pulp. The results suggest a decreased function group content in the residual lignin of chlorine dioxide treated kraft-oxygen pulps. It is quite interesting that the depletion of phenolic hydroxyl and methoxyl group present in residual lignin is due to the quinone formation during the oxidation of chlorine dioxide, based on the data obtained in HSQC and 13C NMR spectra of non-cyclic and cyclic MATS, and the content in condensed and unsubstituted phenolics is reduced to the same degree, which is contrary to what we generally perceive.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
