赤外吸収スペクトルによる酸リグニンのアルカリ可溶化機構の検討

The β-lignin which was precipitated at pH. 3 from the soluble part of the technical sulfuric acid lignin dissolved by the sodium hydroxide of the concentration 6%, under 165-170℃, 2 hr, showed strong iufrared absorption band frequencies 1710 <cm>^<-1>, while the α-lignin insoluble at same treatment had not shown.
As a result of the comparison of specta of these and other lignin products, it may be given as a conclusion that one of the mechanisms of the resolution of the acid lignin by alkali is due to the formation of the carboxyl groups from the aldehyde or ketone groups of the side chain of the molecules of the acid lignin by the oxidation cleavage and that these structural changes are effected proportionally to the concentrations and quantities of alkali per the acid lignin.