纤维素低氧环境下热解特性和糖类生成机制

Pyrolysis characteristics and mechanism of carbohydrate formation of cellulose in low oxygen environment

在最小化二次反应的金属网反应器下对微晶纤维素进行低氧热解实验。采用带有脉冲安培检测的高性能阴离子交换色谱法(HPAEC-PAD)的Dionex ICS-6000离子色谱(IC)对热解后的产物水溶性中间态活性纤维素(WSIAC)和水溶性初生焦油(WSPT)的组成和分布进行分析。重点关注纤维素热解过程中几种脱水糖和糖聚物的生成转化规律。实验发现氧气通过促进中间态纤维素的生成来提前纤维素的分解。氧化气氛下,聚合度越高的脱水糖稳定性越差。氧气的存在一方面促进纤维二聚糖和纤维三聚糖生成,另一方面,它们的破碎或其他分解反应也在一定程度下受到氧气影响。

Low oxygen pyrolysis of microcrystalline cellulose was carried out in a metal mesh reactor(WMR)with minimal secondary reaction.The composition and distribution of water-soluble intermediate active cellulose(WSIAC)and water-soluble primary tar(WSPT)were analyzed by Dionex ICS-6000 ion chromatography(IC)using high-performance anion exchange chromatography(HPAEC-PAD)with pulsed amperometric detection.The formation and transformation of several dehydrated sugars and glycopolymers during cellulose pyrolysis was emphasized.It was found that oxygen predates the decomposition of cellulose by promoting the formation of intermediate cellulose.In oxidizing atmosphere,the higher degree of polymerization,the worse the stability of dehydrated sugar.The presence of oxygen promotes the production of cellobiose and cellotrian.On the other hand,their fragmentation or other decomposition reactions are also affected by oxygen to a certain extent.