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The reaction products of an alkaline treatment of non-phenolic β-O-4-type lignin model compounds (C6–C2-type) consisting of p-hydroxyphenyl (H), guaiacyl (G), and/or syringyl (S) nuclei were identified and quantified. This was performed to examine how the type of H, G, or S nucleus affect the reaction product profiles. The major identified and quantified reaction products were phenol derivatives that were liberated from the aryl sides of the β-O-4 ether bonds of the lignin model compounds. Other products included derivatives of phenylethane-1,2-diol (glycol-type), benzaldehyde, and acetophenone, which originated from the alkyl sides of the β-O-4 ether bonds of the lignin model compounds. Although the type of aromatic nucleus of the aryl side of the β-O-4 ether bond of the lignin model compounds did not significantly affect the profile of the reaction products, the type of the alkyl side nucleus was influential. The glycol-type compound was the exclusive major reaction product when the S nucleus was on the alkyl side of the β-O-4 ether bond. On the other hand, when the H or G nucleus was present, a benzaldehyde derivative was the other major reaction product.

Several C6–C3 and C6–C2-type dimeric non-phenolic β-O-4 lignin model compounds, whose aromatic nuclei consisting of the carbon skeleton and β-O-4 linkage are named the A- and B-rings, respectively, were treated under alkaline pulping conditions to examine whether or not the substitution of methoxyl group on the B-ring or of guaiacyl for syringyl A-ring accelerates the β-O-4 cleavage as a further study of our previous reports. It was suggested that either first or second substitution of methoxyl group on the B-ring accelerates the β-O-4 cleavage in both C6–C3 and C6–C2 compounds although the former compounds are more sensitive to the substitution than the latter, suggesting that the lack of the γ-hydroxymethyl group makes model compound insensitive to the substitution. It was confirmed that the substitution of guaiacyl for syringyl A-ring accelerates the β-O-4 cleavage in both C6–C3 and C6–C2 compounds with the degrees similar to each other regardless of the type of the B-ring. It was clarified that the leaving ability of the leaving B-ring phenoxides in the β-O-4 cleavage does not correlate well with the pK a values of the conjugate acids of the phenoxides, which is not in accordance with the common property of a nucleophilic substitution reaction.

To examine why green liquor (GL) pretreatment of lignocellulosic materials effectively facilitates enzymatic saccharification under conditions milder than those of a common alkaline cooking process, dimeric β-O-4 type lignin model compounds with and without free phenolic hydroxyl group were reacted in several alkaline solutions including a model solution of GL, which mainly contains Na2CO3 and Na2S. The β-O-4 bond of the phenolic model compound was cleaved with a sufficient rate in the model solution of GL. The β-O-4 bond cleavage of the non-phenolic model compound was more frequent in the model solution of GL than in other alkaline solutions. These results suggest that β-O-4 bonds present in lignocellulosic materials are effectively cleaved in a GL pretreatment. It was also suggested that HS− and CO3 2− synergistically contribute to the β-O-4 bond cleavage of the non-phenolic model compound under GL pretreatment conditions.

The crystal growth rate of the α1, α2 and β forms of isotactic polypropylene (iPP) and their morphological changes were studied in a wide range of crystallization temperatures. The temperature dependence of the crystal growth rate of the α1 form showed a bell-shaped curve with the maximum growth rate (Gmax) at 70 °C. The crystal growth rate of the β form induced by calcium pimelate also showed a bell-shaped curve with Gmax at 79 °C. Two crossover points on the growth rate curve from the α1 form to the β form or vice versa were observed at 90 °C and 133 °C, respectively. Tear-drop shaped spherulites were observed at temperatures between the two crossover points. Electron diffraction patterns showed the high ordered structure of the α2 form for thin films crystallized at 140 °C. The α2 fraction became detectable in X-ray diffraction pattern for temperatures above 110 °C. The α2 fraction increased with crystallization temperature and saturated to 100% at about 140 °C. In the temperature region from 110 °C to 140 °C, several crystal growth rates were found at the same crystallization temperature. The growth rate variations could be associated with the co-crystallization of the α1 and α2 forms. Above 140 °C, the growth rate variations disappeared, since the fraction of the α2 reached to 100%. The extrapolated Gmax of the α2 showed at 72 °C.