1 / 12

Wood Chemistry PSE 406/Chem E 470

Wood Chemistry PSE 406/Chem E 470. Lecture 9 Lignin Biosynthesis. Class Agenda Lignin I. Basic Lignin Biosynthesis Nomenclature Methoxyl Groups Phenoxy Radical Formation Radical Coupling. Random Lignin Information.

marthur
Download Presentation

Wood Chemistry PSE 406/Chem E 470

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Wood ChemistryPSE 406/Chem E 470 Lecture 9 Lignin Biosynthesis PSE 406 Lecture 9

  2. Class AgendaLignin I • Basic Lignin Biosynthesis • Nomenclature • Methoxyl Groups • Phenoxy Radical Formation • Radical Coupling PSE 406 Lecture 9

  3. Random Lignin Information • Anselme Payen 1838: Reacts wood with nitric acid and then sodium hydroxide. Undissolved material he names cellulose. • Schulze 1857: Names dissolved material lignin from the Latin lignum meaning wood. • Phenolic Polymer - The Glue that Holds the Fibers Together • Polydisperse (Large and Small Polymers) • 3 Dimensional Networks - Branched Polymer PSE 406 Lecture 9

  4. Lignin Biosynthesis I Notes PSE 406 Lecture 9

  5. Lignin Biosynthesis II Notes PSE 406 Lecture 9

  6. Lignin BiosynthesisNomenclature Side Chain Notes } Phenylpropane Unit C9 Common Names PSE 406 Lecture 9

  7. Lignin StructureMethoxyl Content Notes PSE 406 Lecture 9

  8. Lignin BiosynthesisNomenclature • Once incorporated into lignin, the ring structures of the precursors are given these names. PSE 406 Lecture 9

  9. Lignin BiosynthesisEnzymatic Formation of Phenoxy Radical • The initial step in the polymerization of lignin is an enzymatic directed one electron abstraction forming a phenoxy radical. Notes PSE 406 Lecture 9

  10. Lignin BiosynthesisResonance Forms of Phenoxy Radical • The phenoxy radical is only one of several resonance structures. • This figure shows a second resonance structure with the free radical on the 5 carbon of the ring. PSE 406 Lecture 9

  11. Lignin BiosynthesisResonance Forms of Phenoxy Radical Notes PSE 406 Lecture 9

  12. Lignin Coupling-O-4 Notes PSE 406 Lecture 9

More Related