Takashi Sasaya

Preparation of carbon fibers from Organosolv lignin obtained by aqueous acetic acid pulping

Lignin fibers as precursors for carbon fibers were prepared by melt spinning from organosolv lignin (AWL), which was obtained from birch wood by aqueous acetic acid pulping at atmospheric pressure and used without any chemical modification. The spinnability of AWL was attributable to polydispersity of the lignin and to partial acetylation of hydroxyl groups during the pulping. Production of satisfactory lignin fibers was achieved by simple thermal treatment of lignin, followed by continuous spinning at a rate of more than 400m/min. The thermostabilization of thin (less than 30μm in diameter) and thick threads was achieved by heating to 250°C at a rate of 0.5°C/min in air and under oxygen stream, respectively. Carbonization of thermostable fibers was achieved by heating to 1,000°C under nitrogen stream. The mechanical strength of the carbon fibers was found to be related to the diameter of fibers. Typical mechanical properties of carbon fibers from AWL were as follows : fiber diameter 14 ± 1.0 μm ; elongation, 0.98 ± 0.25% ; tensile strength, 355 ± 53 MPa ; modulus of elasticity, 39.1 ± 13.3 GPa. The carbon fibers derived from AWL can be classified as fibers of general performance grade.

Lignans of Larix leptolepis

Abstract Five lignans have been isolated from wood of Larix leptolepis . They are identified as 1-(4-hydroxy-3-methoxyphenyl)-2-4-[2-formyl-( E )-vinyl]-2-methoxyphenoxy-propane- 1,3-diol, 1-(4-hydroxy-3-methoxyphenyl)-2-2-methoxy-4-[1-( E )-propen-3-ol]-phenoxy- propane-1,3-diol, 1-(4-hydroxy-3-methoxyphenyl)-2-(4-formyl-2-methoxyphenoxy)-propane-1,3-diol, 1,2-bis-(4-hydroxy-3-methoxyphenyl)-propane-1,3-diol and a trilignol, leptolepisol C.

Lignans and Brauns' Lignins from Softwoods

Various new dimeric. trimeric, and tetrameric lignans were isolated from the extractives of Larix leptolepis and their structures were elucidated. These lignans have the same linkage patterns äs those of the degradation products from softwood protolignin, but they are different from the lignin degradation products in optical activity. Existence of oligomeric and polymeric lignans is probable in the same fraction. Distributions of Brauns* lignin (BL) and milled wood lignin (MWL) in the cross section of trunks of Picea jezoensis and Larix leptolepis were determined and ccmpared with each other. From these results, it is concluded that BL may be a polymer fraction of Lignans and not a true lignin.

Preparation of Moderate-Temperature Setting Adhesives from Softwood Kraft Lignin. Part 2. Effect of Some Factors on Strength Properties and Chracteristics of Lignin-Based Adhesives

The preparation of moderate-setting lignin adhesives was investigated. Softwood kraft lignin (NKL) was isolated from a commercial concentrated kraft pulping waste liquor. A mixture of NKL and phenol reacted with formaldehyde under alkaline conditions at 80 °C for 2 hours. To the resulting LP-resin solution were added small amounts of resorcinol and paraformaldehyde for the adhesives. Three-ply plywoods using the adhesives were prepared by pressing at 10 kg/cm and 100°C for 10-15 minutes, and their dry and wet tensile shear strenghts were tested. A satisfactory adhesives consisted of the following weight quantities: NKL 80, phenol 20, 37% formalin 75, methanol 20, NaOH 8, water 55, resorcinol 20 and paraformaldehyde 4. The analytical results of LP-resins showed that acetates of LP-resins were composed of ether insolubles (EI) and solubles (ES). The former was a reactive coplymer of NKL and phenol with Mn of 4,000-6,000.

Lignan biosynthesis inLarix leptolepis callus

Abstract Two lignans have been isolated from callus tissues of Larix leptolepis . They are identified as pinoresinol and 2,3-dihydro-2-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-5-(ω-hydroxypropyl)-7-methoxybenzofuran. The time-course of pinoresinol production was examined. A cell-free preparation of the callus tissues is shown to form pinoresinol from coniferyl alcohol. The enantiometric composition of pinoresinol from the callus tissues [(−)-isomer/(+)-isomer ratio: 0.74] was determined by HPLC analysis using a chiral column and compared with those of pinoresinols prepared by the cell-free preparation (1.13) and the (+)-isomer from the sapwood of L. leptolepis (0.04).

Structure elucidation of phenylpropanoid wood extractives

Publisher Summary Woody plants are capable of synthesizing a wide range of phenylpropane derivatives, including lignans, neolignans, coumarins, and flavonoids. The chapter presents a study in which the wood of A. sachalinensis was extracted with 95% EtOH. Repeated silica-gel column chromatographies of the diethyl ether solubles of the EtOH extract resulted in the isolation of fourteen lignans. Todolactol A, B, C, and D have not been reported as naturally occurring lignans, but similar types of lignans have been isolated from Carissa edulis , Piper clusii , P. cubeba , Dacrydium intermedium , Abies mariesii, and A. koreana . The family, Salicaceae, is very widely distributed in the temperate and subarctic zones of the northern hemisphere. Taxonomically, the family is usually divided into four genera, Populus , Salix , Toisusu , and Chosenia . The EtOH extracts of the wood of S. sachallnensis was fractionated with diethyl ether and the solubles subjected to silica-gel column and preparative thin-layer chromatographies to give (+)-syringaresinol and two lignan esters.