Acidolysis monomers

Lundquist and Kirk (1971) treated spruce lignin with the acidolysis reagent at reflux temperature for 4, 8, and 24 h Ketol la (Fig 6 11) predominates in the 4-h acidolysis mixture (yield, 4 6% of the lignin) and prolonged treatment does not result in any appreciable increase in the yield of acidolysis monomers The yields of the primary ketols la and 2a (Fig 6 11) from birch lignin (a typical... 

A variety of work-up procedures have been described in the literature. Lundquist and Kirk (1971) applied gel permeation chromatography to separate the acidolysis monomers from polymeric materials in the initial step. This is, however, not a requirement when the acidolysis monomers are analyzed by gas chromatography as their trimethylsilyl derivatives. 

In an attempt to circumvent the analytical problems discussed above, a method for the analysis of acidolysis monomers has been developed which involves reduction of carbonyl and carboxyl groups with borane dimethyl sulfide... 

Several derivatives obtained by reduction/acetylation of acidolysis monomers have been analyzed by high performance liquid chromatography (HPLC) (Kristersson and Lundquist unpubl. work 1983). The relative elution volumes for these compounds are listed in Table 6.1.1. Nonacetylated reduction products of acidolysis monomers have also been examined by HPLC (Kristersson and Lundquist unpubl. work 1983). From the results shown in Table 6.1.2, it is evident that good separation was achieved but, unfortunately, compounds 6a (threo form), 6b and 6c have very similar elution volumes. 

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