2-Chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane, a Reagent for the Accurate Determination of the Uncondensed and Condensed Phenolic Moieties in Lignins

Article abstract of DOI:10.1021/jf00054a023

The use of 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane as a phosphitylation reagent in quantitative 31P NMR analysis of the hydroxyl groups in lignins has been thoroughly examined, and an experimental protocol recommended for spectra acquisition has been developed.Quantitative analysis of six "standard lignins" gave results comparable to those obtained by other methods of analysis.Excellent resolution of the various phenolic hydroxyl environments including those present in condensed moieties was observed.Hovever, this was at the expense of resolution in the aliphatic hydroxyl region, where no distinction between primary, secondary, and the erythro and threo forms of the secondary hydroxyls of the β-O-4 bonds can be made. Keywords: Analysis; aromatic groups, hydroxyls; lignins; nuclear magnetic resonance (NMR); phenols; phosphorus; quantitative