ANALYSIS OF LIGNIN BY PYROLYSIS-GAS CHROMATOGRAPHY .1. EFFECT OF INORGANIC SUBSTANCES ON GUAIACOL-DERIVATIVE YIELD FROM SOFTWOODS AND THEIR LIGNINS

To obtain lignin-derived pyrolysis products in larger yields, Curie-point pyrolysis was performed on the softwood species Japanese red pine (Pinus densiflora Sieb. et Zucc.), Japanese cedar (Cryptomeria japonica D. Don) and Japanese cypress (Chamaecyparis obtusa Endl.), and their dioxane lignins treated with various inorganic substances, over the temperature range 358-764°C. The resulting guaiacol derivatives (guaiacol, 4-methyl-, 4-ethyl- and 4-vinylguaiacols, eugenol, vanillin, cis- and trans-isoeugenol, and acetovanillone) were determined by gas chromatography. The softwood samples sandwiched between two sheets of heat-resistant filter paper made of borosilicate glass fibers yielded from 1.56 to 1.64 times more guaiacol derivatives than unsandwiched samples. Sandwiching the dioxane lignins between heat-resistant papers also increased the guaiacol-derivative yield, by 13 to 27%. The sandwich-2 method developed in this study is widely applicable as a sample preparation method for increasing the yield of lignin-derived products on Curie-point pyrolysis. © 1990.