Quantitative Determination of Noncondensed and Condensed Phenyl Nuclei in Hardwood Protolignins

5 Quantitative Determination of Noncondensed and Condensed Phenyl Nuclei in Hardwood Protolignins 

NEPS110 has to be multiplied by a factor, f , to obtain the quantitative yield of NEPS. Because of the similarity between guaiacyl and syringyl nuclei in their respones to the NE reaction (Funaoka and Abe 1982e), f can be conveniently obtained from the ratio of quantitative NEPg yield obtained at 180°C to NEPg yield at U0°C (NEPg °)  

From the known quantity of noncondensed syringyl nuclei (NEPS), the quantity of total guaiacyl nuclei is calculated according to Eq. (8). The quantity of condensed guaiacyl nuclei is then obtained from Eq. (9). 

When the sample under investigation is an isolated protolignin, e.g., milled wood lignin, the syringyl nuclei content can be directly calculated from the analytical composition expressed on a C9(OCH3)x basis. 

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