Abstract
Each 17 gr. of Klason, hot methanol-soluble native, phenol and periodate lignin of ‘Sugi’ wood was heated with stirring in 500 cc. 2.4 N sodium hydroxide and 4 moles of cupric sulfate to a bilding unit (195) of lignin for 4 hours at 160°C., and insoluble material was removed by filtration. The solution was neutralized and extracted with ether.
The oxidation products in the ether extract was confirmed the following methods as shown Fig. 1 and 2. The results are given in Table 2.
From the experimental results, the probable reaction mechanism of periodic acid oxidation of proto lignin is as follows. Attack upon the aromatic nucleus and cutting of some carbon linkage of side chain in lignin occur during isolation of periodate lignin, and from the correlative difference of two oxidation, it is assumed that a substantial yield of of vanillin, indicating that amount of the vanillin-forming group in the periodate lignin molecule had been kept up, was isolated from the oxidation product.
