Formation rate of benzyl cation intermediate from p-Hydroxyphenyl, guaiacyl, or syringyl nucleus in acidolysis of lignin. (4th March 2017)

• Record Type: Journal Article
• Authors: Shioya, Toshinao; Akiyama, Takuya; Yokoyama, Tomoya; Matsumoto, Yuji
• Is Part Of: Journal of wood chemistry and technology. Volume 37:Number 2(2017)
• Page Start: 75
• Page End: 86
• Publication Date: 2017-03-04
• Subjects: Aromatic ring -- carbocation -- hardwood lignin -- softwood lignin; Wood -- Chemistry -- Periodicals; Wood; Wood -- Chemistry; Periodicals; 674.13
• DOI: 10.1080/02773813.2016.1235587
• Languages: English
• ISSNs: 0277-3813

Abstract

Abstract : The benzyl cation intermediate is believed to be primarily formed in the acid-catalyzed reaction of lignin, and the reaction route of the intermediate determines which reaction products are afforded and whether lignin undergoes depolymerization or condensation. This study aimed to examine the formation rate of the benzyl cation intermediate from phenolic (P) or non-phenolic (N) lignin model compounds with different types of aromatic nuclei, namely p -hydroxyphenyl (H), guaiacyl (G), or syringyl (S). The rate was in the order of H > G > S for both P- and N-type model compounds and of P > N for all H-, G-, and S- type model compounds. The orders were successfully explained by the electron-donating or electron-withdrawing properties of the hydroxy and methoxy groups at the para - and meta - of the benzyl position, which is the reaction center in the formation of the benzyl cation intermediate.