Abstract
Separations of Hinoki cypress (Chamaecyparis obtusa)-lignophenol (p-cresol type, HCLC), which are phenolic lignin-based polymers derived directly from lignocellulosics through the phase-separation system, by molecular weight using diethylether (EtOEt), cyclopentylmethylether (CPME), tert-Buthylmethyether (TBME) and EtOEt / CPME (1 / 1, v / v) in ordinary purification processes were carried out. After purification, each lignophenol showed different purification yields: HCLC-E, HCLC-C, HCLC-T and HCLC-B showed 63.7 %, 50.3 %, 71.0% and 62.8 %, respectively. These HCLC samples showed different average molecular weights estimated by GPC. To begin with number average molecular weight (Mn) were 7 870, 9 960, 11 850 and 8 920, respectively. Next, weight average molecular weight (Mw) were 17 960, 22 510, 24 770 and 20 370, respectively. These HCLC samples showed almost same chemical properties such as appearance, solubility for solvents. Moreover same structural features were confirmed by FT-IR and 1H-NMR. Since these HCLC samples also showed almost same thermal properties, there are just a little difference for 5 ℃ on TMA. In conclusion, Molecular weight separation can contribute to not only new advanced chemical modifications for lignophenols, but to investigate new structural features of both lignophenols and whole native lignins in ligunocellulosics.
