31P NMR Spectroscopy in Wood Chemistry. I. Model Compounds |
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Authors: | Y Archipov D S Argyropoulos H I Bolker C Heitner |
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Affiliation: | 1. Pulp and Paper Research Institute of Canada , 570 St. John's Boulevard Pointe Claire, Quebec, Canada , H9R 3J9;2. Department of Chemistry , McGill University Montreal , Quebec, Canada , H3A 2A7;3. “S.M. Kirov” Forest Technical Academy , Leningrad, U.S.S.R. |
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Abstract: | The quantitative reaction in an NMR tube of 1,3,2-dioxaphospholanyl chloride (I) with compounds bearing active hydrogens was explored as a simple method for derivatizing the labile centres known to occur in lignins. Derivatives of phenols, alcohols and carboxylic acids with (I) gave 31P chemical shifts which appeared in different ranges of the NMR spectra. Any ortho substitution onto the aromatic ring of phenols significantly affected the magnitude of the 31P NMR chemical shifts, while para and/or meta substituents had a much smaller effect. A clear distinction between guaiacyl, syringyl and unsubstituted phenolic hydroxyls can thus be made in mixtures of model compounds. Primary alcohols were clearly distinguished from secondary and tertiary alcohols in their derivatives with (I), while different 31P NMR signals for derivatives of erythro and threo forms of lignin-like model compounds were identified. While alcohols, phenols and simple carboxylic acids on reaction with (I) gave derivatives that were substitution products, aldehydes reacted via a distinctly different addition mechanism; ketones did not react at all. |
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Keywords: | Acid leaching eucalyptus kraft pulping metals pulp properties |
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