通过不溶的三乙胺盐的形成,用纤维素的邻苯二甲酸 半 酯可以观察到此现象.This was observed with phthalic half - ester of cellulose due to formation of an insoluble triethylamine salt....

“不溶的”的英语可以翻译为：indissoluble，infusible，undissolved，insoluble ...