Studying of optical breakdown of dioxane lignin as a result of structural changes in the functional groupscarbonyl, ether C-O and phenolic hydroxylwith the use of Raman and FT-IR Spectroscopy

In this study the resulting changes as a result of exposure to UV radiation on dioxane Lignin is a purification was studied by Raman and FT-IR spectroscopy . ased on the results was determined, three carbonyl functional group C = O, ether C-O and the free phenolic O-H, are the three main indexes in light of changes to come at 24, 96 and 240 h . With increasing exposure time the rate of absorption frequency of carbonyl groups and C-O vibrations in phenols is declining . The reason for this can be arranged attributed to the conjugated the carbonyl group with C = C double bonds and failure ether bonds the dioxane lignin . Also with increasing exposure time is increase the number and thus the rate of absorption Percent in the conjugated and non-conjugated carbonyl groups and free phenolic hydroxyl is reduced the number and intensity of C-O adsorbed ether . In fact,are the C-O ether, mostly in the linked structures α-O-4 , β-O-4 , 4-O-5 , Discrete and conversion to the free phenolic O-H and subsequent with increasing light oxidation, are converted to the conjugated and non-conjugated carbonyl groups.In the meantime increased the intensity of absorption of Carbonyl groups and the phenolic hydroxyl with a decrease in the absorption intensity of ether C-O is extreme in the first 24 hours of exposure. Therefore, the formation kinetics of chromophoric gruops depends on the exposure time and the maximum variation of color and chromophoric gruops formation takes place at the beginning of irradiation time.

کلیدواژه ها:

dioxane Lignin ، carbonyl functional group ، ether C-O ، phenolic hydroxyl ، Reaction kinetics ، Raman and FT-IR Spectroscopy