Esterification of wood with unsaturated carboxylic acids. II : Reaction conditions of esterification and properties of the prepared esters of wood

Abstract

TFAA法による木材のエステル化の条件を検討した。カルボン酸とTFAAを稀釈剤中で等モル混合し, あらかじめ, 30分ほと熟成した後, 木材試料に対し大過剰添加すれば良いことが知られた。補助的な硫酸添加はエステル化を促進するが, その使用量には十分な注意を要する。エステル化の速度を両対数グラフに表わすと, 屈曲点を持つ直線関係が得られた。温度依存性から算出された見掛けの活性化エネルギーは, Hiller の値より多少小さかった。TFAA法で調製したエステル化木材はASEなどの物性が若干劣化した。

Several reaction conditions for the esterification of wood by the TFAA method were investigated. The results showed conclusively that wood could be esterified satisfactorily with an excess of an esterification mixture which contained nearly equimolar amounts of a carboxylic acid and TFAA in benzene as diluent and was preliminarily incubated for about 30 minutes. The additional sulfuric acid-catalyst gave a greater degree of esterification. The curves of the esterification rates, on a log scale, had refractive points which would show a change in the reaction mechanisms related to the crystalline structure of the wood. The apparent activation energies were also calculated from the slopes of the lines of the temperature-dependence of the reaction rates. This esterification method caused, however, an unfavourable reduction in the antishrink efficiency.