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Nalita (Trema orientalis) is one of the fastest growing trees in the tropical countries. The structural characteristics of lignin isolated at different ages of Nalita wood (Trema orientalis) by acidolytic dioxane method were examined by UV, FTIR, 1H‐NMR and 13C‐NMR spectroscopy, alkaline nitrobenzene oxidation, molecular weight determination, elemental and methoxyl analysis. The data were compared with aspen lignin. The structural analysis revealed that Nalita wood lignin is syringyl‐guaiacyl type. The methoxyl content in Nalita wood lignin was lower than aspen lignin. The C9 formulas for 30‐months‐old Nalita was C9H9.31O3.13(OCH3)1.27, whereas that of aspen was C9H8.94O3.15(OCH3)1.47. The weight average molecular weight of Nalita wood lignin was decreased from 36,500 to 25,500 with increasing tree age from 12 to 30 months, whereas weight average molecular weight of aspen was 20,000. Both alcoholic and phenolic hydroxyl group in Nalita wood lignin is lower than aspen lignin.

Treatment of guaiacylglycerol- and guaiacylpropanediol-β-(2-methoxyphenyl) ethers at 160 C in 50 % alcohol containing magnesium bisulfite was found to cleave the β-aryl ether linkages in these compounds to form isoeugenol and/or eugenol in up to 60 % yield as well as comparable yields of guaiacol. The linkage in a nonphenolic model was not cleaved to a discernible extent. Both an alcohol and bisulfite were essential for this reductive cleavage which proceeded efficiently in ethanol and isopropanol but not efficiently in methanol, t-butanol or dioxane. Magnesium was a better base than sodium for the reaction. Coniferyl alcohol was proposed to be an intermediate compound of this cleavage reaction which reasonably explains the formation of isoeugenol and eugenol from wood during the alcohol bisulfite pulping process.

Isopropanol bisulfite treatment of sugi (Cryptomeria japonica D. Don) MWL yielded a significant amount of lipophilic low-molecular-weight products as well as water-soluble high-molecular-weight lignin whereas with an aqueous bisulfite treatment a very small amount of lipophilic products was formed and about half of the MWL was changed to insoluble and probably condensed products. Seven monomeric and one dimeric lignin degradation products as well as two carbohydrate-derived products were found in the spent liquor from isopropanol bisulfite pulping of sugi wood of which eugenol and isoeugenol were the major products. After cooking for 50–100 minutes at 165°C, the combined yield of these two products reached a maximum of 4.5% based on lignin, which is ten times as high as the yield of a phenolic fraction previously obtained from aqueous bisulfite pulping of Pinus radiata. Formation of the other products such as stilbene and coniferaldehyde increased gradually after 100 minutes and the combined yiel...