木聚糖CP-GC-MS法裂解行为研究

Study on Curie-point Pyrolysis of Xylan under CP-GC-MS Conditions

采用居里点裂解仪-气相色谱仪-质谱仪(CP-GC-MS)联用分析技术,以木聚糖作为半纤维素的模化物,研究了居裂解温度对木聚糖快速裂解产物组成及其含量的影响,并与纤维素居裂解行为进行了对比。结果表明,木聚糖居裂解过程可以分为两个区域:居裂解温度小于300℃时,木聚糖发生了剧烈的糖基断裂,生成了糠醛和糖类单体化合物,其中糠醛含量在280℃时达到了54.38%;居裂解温度大于300℃时,糠醛和糖类单体化合物等含量下降,小分子的醛酮类化合物种类和含量大幅度提高;纤维素与木聚糖居裂解行为存在明显差异,木聚糖居裂解温度明显低于纤维素;木聚糖裂解的主体产物是糠醛,而纤维素裂解的主体产物是葡聚糖。

The influence of temperature on the relative content of pyrolysis products obtained by Curie-point pyrolysis of xylan, which was considered as the model compound of hemicelluloses, was investigated by Curie-point pyrolysis-gas chromatography- mass spectroscopy （ CP-GC-MS）, and pyrolysis behavior of xylan was contrasted with cellulose. The results showed that the process of xylan Curie-point pyrolysis could be divided into two regions. At the temperature of less than 300℃, xylan by random glycosidic cleavage of xylan was cleaved to form furfural and monosaccharides, where furfural content reached 54.38 % in the pyrolysate. At the temperature of more than 300℃, the kind and content of chemicals of small molecular aldehyde and ketone were increased greatly with the enhancement of pyrolysis temperature. The difference of pyrolysis behaviors between xylan and cellulose was that pyrolysis temperature of xylan was lower than that of cellulose, and the main pyrolysis product from xylan was furfural, while that of cellulose was levoglucosan.