Tetramethylammonium hydroxide (TMAH) thermochemolysis of lignin: Improvement of the distribution profile of products derived from β-aryl ether subunits
✍ Scribed by Ken-Ichi Kuroda; Akiko Nakagawa-izumi
- Publisher
- Elsevier Science
- Year
- 2006
- Tongue
- English
- Weight
- 267 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0165-2370
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✦ Synopsis
Tetramethylammonium hydroxide (TMAH) thermochemolysis of softwood lignin provides Z/E-1-(3,4-dimethoxyphenyl)-2-methoxyethene (5) and erythro/threo-1-(3,4-dimethoxyphenyl)-1,2,3-trimethoxypropane (9), as products derived from b-aryl ether subunits. To increase the contribution of 9, Japanese cedar (Cryptomeria japonica) wood meals were derivatized by: (1) diazomethane-methylation, (2) acetylation and (3) a combination of the methylation and acetylation. The non-derivatized (control) and derivatized wood meals were moistened with a 25% TMAH aqueous solution, dried at 80 8C for 15 min and followed by TMAH thermochemolysis at 315 8C for 4 s. Although all samples produced 5 and 9, their yields and the 9/5 ratios differed. The diazomethane-methylated cedar provided the largest values for the 5 + 9 yield, the 9 yield and the 9/5 ratio. The 5 + 9 yield from the diazomethane-methylated cedar was 1.17 that from the control and the 9 yield of the methylated cedar was 1.82 that of the control. The 9/5 ratios were 1.80 and 0.71 for the diazomethane-methylated cedar and the control, respectively. Acetylated cedars provided a lower 5 + 9 yield and a lower 9/5 ratio than the control.