Teruyuki Seino

Homolytic scission of interunitary bonds in lignin induced by ultrasonic irradiation of MWL dissolved in dimethylsulfoxide.

Summary An electron spin resonance (ESR) method combined with a spin trapping technique was applied to trap and characterize unstable radicals which were generated by ultrasonic irradiation of the dimethylsulfoxide (DMSO) solution of a softwood, Yezo Spruce (Picea jezoensis carr.) lignin. It was found that an unstable secondary carbon radical, ~CH • in the solution was trapped as the stable nitroxide spin adduct when the DMSO solution was subjected to ultrasonic irradiation in the presence of a spin trapping reagent: 2,4,6-tri-tert-butylnitrosobenzene (BNB) at 50°C for 30 min. This means that the alkyl phenyl ether bonds, ~CH-O-phenyl, known as interunitary bonds in lignins were homolytically cleaved by the ultrasonic irradiation, although the phenoxy radical Ph-O •, called guaiacoxy radical, i.e. the counter radical of the secondary carbon radical, was not trapped by the BNB spin trap. This suggests that the trapping of the guaiacoxy radical, having a methoxy group in an ortho-position, by the BNB molecule, carrying two bulky butyl groups in the ortho-positions, is sterically hindered.

Rapid Assessment of Vessel Morphology by Pyrolysis-Gas Chromatography

Tree breeding has become more important as fixation sources of atmospheric CO2, since the global warming has been called a serious environmental problem. Therefore, the selection of elite trees possessing significant CO2 absorption ability together with excellent pulp properties is strongly needed to accelerate both atmospheric CO2 absorption and paper recycling rate since stronger papers can keep enough paper strength after repetitive recycling.

Feasibility Study of Tree Selection for High Pulp Yield, Brightness and Recyclable Chemithermomechanical Paper Production Using Eucalyptus globulus

Eucalyptus is one of the most widely utilized species for tree plantation, especially intended in the use for chemical pulp production [1]. E. globulus is a fast growing species in a moderate zone with an 8–10 year-rotation period [2]. The tree breeding programs are aiming to improve growth, pulp yield and strength in pulp and paper products because the elite tree selection contributes to reduce energy consumption, CO2 emission and pulp and paper cost.

Assessment of Vessel Anatomical Features in Eucalyptus camaldulensis by Pyrolysis-Gas Chromatography

Eucalyptus camaldulensis plays an important role as one of the major plantation species for pulpwood especially in sub-tropical regions. Tree selection for high pulp yield and strength in the management of pulpwood forests has attracted interest in the use of plantations with short term rotations to reduce the pulp cost and atmospheric CO2 [1]. The non-destructive method is preferable in the quality breeding program and the increment core method has an advantage to handle many samples since the core can be drilled out easily from the trunk without felling the tree down [2]. However, the estimation of whole-tree properties by this indirect selection method requires significantly high relationships between wood and pulp properties.

Characterization of Photo-Yellowing Trigger Compounds Repressing Paper Recyclability of Eucalyptus globulus by Pyrolysis-GC/MS

Aucalyptus is a widely utilized species in tree plantation, especially intended for pulp production [1]. E. globulus is one of the fast growing species in tempertae zone with a rotation period of 8–10 years [2]. We have reported that chemithermomechanical pulp (CTMP) paper prepared from several individuals of E. globulus showed high brightness (about 70% ISO) with more than 85% pulp yield [3]. To construct an effective carbon loop, higher paper recycling rate is preferable. The degree of photo-yellowing is crucial for recycling in CTMP paper because it determines requirement amount of bleaching agents. The photo-yellowing mechanism is proposed in which the photochemical reaction of lignin in pulp may lead to the formation of quinone species via intermediates of phenoxy radicals, which are produced through photoexcitation of the carbonyl groups involved in lignin (Scheme 1) [4].

Rapid Characterization of Total Fatty Acids in Wood by Reactive Thermal Desorption-Gas Chromatography with Tetrabutylammonium Hydroxide

Acacia species are widely used for raw materials of papers [1]. However, fatty acid components remaining in paper often cause the paper slide on a printer drum. For this reason, rapid characterization of total fatty acid components in wood is required for the selective tree breeding of Acacia species with less fatty acid content.