Esterification of wood with unsaturated carboxylic acids. III. : Dissolution of wood by the TFAA esterification method

Abstract

It was tried to dissolve wood directly in such organic solvents as acetone and chloroform by the TFAA esterification method. Only β-methylcrotonic acid among several aliphatic acids used gave its wood ester of the DS value (nearly 3) which would also enable the complete dissolution of cellulose carboxylic acid esters and, consequently, could dissolve wood up to approximately 30%, perhaps without degradation of its components under mild conditions. However, drastic esterifications accompanied by considerable degradation of wood components led to solubility of more than 60%. β-Methylcrotonylation of various wood species revealed some interrelation between lignin content and solubility, showing that the lignin component seemed to be an inhibitory factor in dissolving wood by the TFAA method

アセトンやクロロホルムなどの有機溶剤に溶解させるため, 反応条件を変え, TFAA法で木材のエステル化を行なった。木材のエステル化度と溶解性は有機酸の種類によって異なるが, 供試した脂肪酸の中では, β-メチルクロトン酸が最も優れ, この酸は木材をほぼ完全にエステル化すると共に, ほとんど木材構成成分の分解もなく, 木材を30%程度まで溶解した。成分の分解を生ずるような激しい条件下では, 溶解率はさらに大きくなり, 最高で66%に達した。次に, 各樹種のリグニン含有率と溶解率の間に, ほぼ逆比例関係が認められたことは, リグニン成分が, この方法での木材溶解を阻害することを示唆した。