G. Menchi et al., CHANGES IN THE ACID STRUCTURE OF WOOD DUE TO AGING AND FOSSILIZATION PROCESSES, Wood Science and Technology, 31(5), 1997, pp. 391-397
Some fossil woods, differing in botanical species, age, degree of degr
adation and chemical composition, were analysed with respect to their
acid structure. A comparison was carried out with corresponding modern
species which, in the case of softwoods, contain carboxylic groups as
well as ester groups in almost equal amounts. Moreover the former are
subdivided into protonated (similar to 20%) and salified forms (simil
ar to 80%). The determination of the acid structures in woods was made
by means of cation exchange measurements. In all examined fossils the
initially protonated form is changed into the salified one because of
the leaching carried out by water containing soluble salts. Despite t
he loss of polyoses, an increase in the content of carboxylic groups w
as achieved due to hydrolysis of the ester groups. In more degraded sa
mples the amount of carboxylic groups was larger than in the other fos
sils even if the former possessed only traces of polyoses due to an at
tack on lignin assessed by acidity of the trifluoroacetic (TFA) deriva
tives. Proof of these changes and further information on fossils were
obtained by I.R. spectroscopy.