摘要
麦草和纤维素、木质素等原料分别在乙二醇反应介质中,以浓硫酸/苯酚为催化剂进行液化反应。分析了液化产物组成,探讨了液化过程中各成分的液化情况。实验表明:麦草中木质素组分在酸性条件下酚化降解,生成一系列单体、二聚体和多聚体,纤维素则最终降解生成乙二醇缩 2 羰基戊酸乙酯。元素分析显示,麦草、碱木质素液化残渣主要成分为灰分,且灰分中主要成分为SiO2。残渣中碳的含量比原料有显著增加,显示原料在反应条件下发生了炭化。测定了产物的相对分子质量分布,发现随着反应的进行,降解和缩合同时发生,从而导致相对分子质量分布变宽。
Liquefactions of wheat straw,soda lignin and cellulose were conducted respectively in ethylene glycol in the presence of sulfuric acid and phenol as catalyst.Suitable wheat straw/phenol ratio and proper sulfuric acid concentration were 7∶3 and 3% (by mass) respectively.The minimum residue content was 4.6% obtained at 160 ℃ and 70 min.Mw and the Mn of the liquefaction products obtained at 60 min were 3 050 and 1 270 respectively.Relative molecular mass distribution became broader as the reaction was prolonged,indicating condensation occurred simultaneously with degradation of lignin.Addition of phenol suppressed the recondensation of lignin fragment formed during liquefaction procedure. Liquefaction products of cellulose and soda lignin were characterized by IR,13C NMR and ESIMS respectively.It was found that lignin was phenolated in acidic medium and degraded to monomers,dimers and oligomers.Cellulose was finally converted into 1,3dioxolane ethyl valerate.Major component of liquefaction residue was ash,especially SiO2.
出处
《林产化学与工业》
EI
CAS
CSCD
2003年第1期78-82,共5页
Chemistry and Industry of Forest Products
基金
广东省自然科学基金资助项目(994572)
华南理工大学制浆造纸工程国家重点实验室资助项目
关键词
麦草
液化
碱木质素
纤维素
wheat-straw
liquefaction
soda lignin
cellulose