Thermally induced polymerizations of a series of 1,3‐benzoxazines with a variety of substituents on the nitrogen atom were investigated in detail, particularly in the following three aspects of the polymerization: (1) N‐alkyl‐1,3‐benzoxazines are much more reactive than N‐phenyl‐1,3‐benzoxazine. (2) The polymerization rate depended on the bulkiness of the N‐substituent. The bulkier the substituent was, the slower the polymerization was. (3) The polymerizations accompanied weight loss due to the elimination of the corresponding imine (R‐N = CH2), and its extent became larger when R was more bulky. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2777–2782, 2010

Acetylacetonato (acac) complexes of transition metals in the 4th period were examined as catalysts for the ring‐opening polymerization of benzoxazine. This examination revealed that acac complexes of manganese, iron, and cobalt exhibited the highest activity, which was comparable or slightly higher than that exhibited by p‐toluenesulfonic acid. By replacing acac ligand by hexafluoroacetylacetonato (F6‐acac) ligand, the activity of manganese and iron complexes was remarkably enhanced. These metal F6‐acac complexes were tolerant to moisture to allow their use under air without special caution. Another advantage was their negligible effect to promote unfavorable weight loss during the polymerization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 479–484, 2010

In recent years, environmental problems such as production of industrial waste are getting worse in Japan. In particular, food processing residues are typically disposed of by spending a large amount of money. This paper studied the treatment of two by-products from vinegar production (rice bran and sake lees) using subcritical water and analyzing the extracted solution for functional ingredients. The results from sake lees showed that an operating temperature of 180 °C and a reaction time of 30 min solubilized 85% of the nitrogen-containing component (mainly protein) from the raw material into water-soluble peptides. When rice bran was used as the raw material the solubilization rate of the nitrogen-containing components was greatly decreased at a reaction temperature of 190 °C or higher. It was shown that calcium in the raw material caused the formation of water-insoluble complexes with amino acids and ammonia such as CaCN 2. Subcritical water treatment was shown to be a useful technique to recover useful water-soluble components from residual solid biomass.

Angelica furcijuga (A. furcijuga), as a material for traditional Chinese medicine, has been widely used in Asian countries, such as China, Korea, and Japan, for several centuries owing to its therapeutic effects. In this study, A. furcijuga leaves were used as starting materials to extract functional substances using supercritical carbon dioxide (SC-CO2) at pressure and temperature ranges of 20–40 MPa and 40–80 °C, respectively. The extraction process was performed in a semibatch-type system with extraction times of 15–120 min. The high-performance liquid chromatography analysis indicated that kaempferol, ferulic acid, ligustilide, and butylidenephthalide as selected functional substances were successfully extracted under these operating conditions. An operating pressure of 30 MPa with an extraction time of 60 min seems to be an appropriate pressure to extract functional components from A. furcijuga leaves. The Hansen solubility parameter values and statistical analysis showed that SC-CO2 with 10% ethanol addition is a feasible tool to isolate these selected functional substances from the A. furcijuga matrix.