초음파 전처리에 따른 리그닌 아세틸화 반응 효율 향상 평가 = Evaluation of Enhanced Lignin Acetylation Efficiency via Ultrasonication Treatment

다국어 초록 (Multilingual Abstract)

Lignin acetylation is a time-consuming process, and long reaction times often lead to the cleavage of ester bond of lignin, resulting in a decrease in the degree of substitution (DS). To improve the efficiency of the lignin acetylation process, an eco-friendly ultrasonication pre-treatment was applied. The degree of substitution of acetyl groups was measured using IR spectroscopy to evaluate and compare the reaction efficiency. The optimal ultrasonication treatment time for controlling lignin particle size was determined to be 60 min, with an average particle size of 13.9 µm. In the case of acetylation of ultrasonicated lignin, the DS of aromatic and aliphatic acetyl groups increased by 17.8% and 36.1%, respectively, compared to untreated lignin, reaching values of 2.05 and 4.6. Notably, there was no reduction in DS due to reverse reactions, even with extended reaction times. Therefore, ultrasonication treatment can be applied as an environment friendly process to reduce particle size and increase specific surface area without catalysts and chemical treatment, thereby enhancing the efficiency of derivative reactions.