杨木与芦苇乙醇-水抽提液中的组分变化规律

Changes in the components of ethanol-water extraction solution from aspen and reed

通过乙醇-水法抽提杨木和芦苇,考察了抽提后的浆料得率和木素脱除率;采用超高效液相色谱检测了抽提液中的低分子脂肪酸、糠醛和5-羟甲基糠醛。结果表明,杨木成浆所需保温温度明显高于芦苇;抽提液中均含有甲酸、乙酸和乙酰丙酸;杨木的抽提液中含有大量乙酸、少量甲酸和少量乙酰丙酸,芦苇抽提液中含有大量甲酸、少量乙酸和少量乙酰丙酸。两者甲酸的差异导致杨木水解液酸性弱于芦苇,需要更高保温温度才能成浆;相同保温时间的芦苇抽提液中糠醛和5-羟甲基糠醛的含量都大于杨木。根据芦苇5-羟甲基糠醛、乙酰丙酸和甲酸变化结果可以推断出,芦苇乙醇-水抽提时甲酸的生成有除了纤维素的其他来源。

Aspen and reed were extracted by ethanol-water solution method and yield of pulp and removal efficiency of lignin were calculated,respectively.The contents of fatty acids with low molecular weight,furfural and 5-hydroxymethyl furfural in the extraction solution were analyzed by ultra performance liquid chromatography(UPLC).The results showed that pulp from aspen needed higher holding temperature than that from reed.The extraction solutions from aspen and reed contained large amounts of formic acid,acetic acid and levulinic acid.The extraction solution from poplar contained a large amount of acetic acid,a small amount of formic acid and acetopropionic acid,while that from reed contained a large amount of formic acid,a small amount of acetic acid and acetopropionic acid.The acidity of the aspen hydrolysate was weaker than that of reed due to the difference of formic acid in these two types of hydrolysates,which made the pulp from aspen required a higher holding temperature.Under the same holding time,the contents of furfural and 5-hydroxymethyl furfural in the extraction solution from reed of were larger than those from aspen.According to the results of 5-hydroxymethyl furfural,acetylpropionic acid and formic acid in the extraction solutions from reed,it was concluded that the formation of formic acid might not only be from cellulose in the ethanol-water extraction solution from reed.