Coupling and Reactions of 5-Hydroxyconiferyl Alcohol in Lignin Formation

Research output: Contribution to journalArticlepeer-review

13 Scopus Citations

Abstract

The catechol alcohols, caffeyl and 5-hydroxyconiferyl alcohol, may be incorporated into lignin either naturally or through genetic manipulation. Due to the presence of o-OH groups, these compounds form benzodioxanes, a departure from the interunit connections found in lignins derived from the cinnamyl alcohols. In nature, lignins composed of caffeyl and 5-hydroxyconiferyl alcohol are linear homopolymers and, as such, may have properties that make them amenable for use in value-added products, such as lignin-based carbon fibers. In the current work, results from density functional theory calculations for the reactions of 5-hydroxyconiferyl alcohol, taking stereochemistry into account, are reported. Dehydrogenation and quinone methide formation are found to be thermodynamically favored for 5-hydroxyconiferyl alcohol, over coniferyl alcohol. The comparative energetics of the rearomatization reactions suggest that the formation of the benzodioxane linkage is under kinetic control. Ring-opening reactions of the benzodioxane groups show that the bond dissociation enthalpy of the α-O cleavage reaction is lower than that of the β-O reaction. The catechol lignins represent a novel form of the polymer that may offer new opportunities for bioproducts and genetic targets.

Original languageAmerican English
Pages (from-to)4742-4750
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Volume64
Issue number23
DOIs
StatePublished - 15 Jun 2016

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

NREL Publication Number

  • NREL/JA-5100-66685

Keywords

  • 5-hydroxyconiferyl alcohol
  • benzodioxane
  • coniferyl alcohol
  • lignin
  • stereochemistry

Fingerprint

Dive into the research topics of 'Coupling and Reactions of 5-Hydroxyconiferyl Alcohol in Lignin Formation'. Together they form a unique fingerprint.

Cite this