Aromatic compounds, production from lignin

The modification of lignins with chlorophosphazenes allows the manufacture of products characterized by flame resistance and thermal stability. This can be attributed to the aromatic structure of the lignin-phosphazene polymer as well as to the presence of such flame inhibiting elements as phosphorous, nitrogen and sulfur. Other useful properties may also result from this combination. It has previously been reported (8-13) that the modification provides crosslinked products with suitably low chlorine content. This is a consequence of incomplete substitution of the phosphazenes cycles. Additional modification of the reaction products by chemical compounds with reactive hydroxyl or amine groups reduces the unreacted chlorine content and improves product properties (8-13). Some properties of the derivatives obtained are presented in Table I. 

Some of the pathways of animal and bacterial metabolism of aromatic amino acids also are used in plants. However, quantitatively more important are the reactions of the phenylpropanoid pathway,173-1743 which is initiated by phenylalanine ammonia-lyase (Eq. 14-45).175 As is shown at the top of Fig. 25-8, the initial product from phenylalanine is trails-cinnam-ate. After hydroxylation to 4-hydroxycinnamate (p-coumarate) and conversion to a coenzyme A ester,1753 the resulting p-coumaryl-CoA is converted into mono-, di-, and trihydroxy derivatives including anthocyanins (Box 21-E) and other flavonoid compounds.176 The dihydroxy and trihydroxy methylated products are the starting materials for formation of lignins and for a large series of other plant products, many of which impart characteristic fragrances. Some of these are illustrated in Fig. 25-8. 

Knowing that sulfonation of aromatic compounds is a reversible process, can you think of a way to remove the sulfonate groups from Kraft lignin The product would be an analogue of organosolv lignin. 

One side reaction which occurs with TMAH/ heat is the formation of ben-zenecarboxylic acid methyl esters from lignin [103] and from aromatic aldehydes [104,105]. Therefore our study summed all phenolic-containing products and their methylated derivatives (or phenolics ) observed in marine sediments (Figs. 6-8). Phenolic compounds are abundant in herbs, shrubs and trees. Phenolics can be released during degradation of lignin, from decomposition of leaves and are common plant metabolites. 

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