Mass spectra of lignin pyrolysis products

Fig. 4.7.10. a-f (pp 191-196). Electron impact (El) mass spectra of lignin pyrolysis products. Numbers refer to Table 4.7.1. Spectra recorded at 70 eV, source temp. 170°C... 

A catalog of degradation products from the analytical pyrolysis of lignin has been published recently (Faix et al. 1990a,b). The compilation comprises retention time data and the complete mass spectra of 82 compounds. 

Thus, the presence of the methoxyphenols in pyrolysis products indicates that lignin-like components have survived for approximately 3(X) million years. That the specific peak was indeed methoxyphenol was determined by retention time and by examination of the fragment ions at m/z 109 and 81. Similarly, the verification of the presence of methy thoxyphenol was made by retention time and by examination of fragment ions at nVz 123 and 95. Dir t comparison of mass spectra to library spectra of audientic methoxyphenols was not possible due to the trace quantities and the complexity of die pyrolysis mixture in the retention-time windows for elution of the methoxyphenols. 

The fragments seen in these spectra correspond well with compounds detected in the pyrolysis products of the two compounds, as well as with compounds seen in the pyrolysis products of several lignins (see Section 9.1). The compounds found in the pyrolysis products (generated at 600° C) of the two lignin models that are similar to the fragments seen in the mass spectra are shown in Table 3.6,1. 

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