Ponomarev Alexander V, Ershov Boris G
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky prosp. 31, Moscow 119991, Russia.
Molecules. 2014 Oct 21;19(10):16877-908. doi: 10.3390/molecules191016877.
Thermal decomposition of cellulose can be upgraded by means of an electron-beam irradiation to produce valuable organic products via chain mechanisms. The samples being irradiated decompose effectively at temperatures below the threshold of pyrolysis inception. Cellulose decomposition resembles local "explosion" of the glucopyranose unit when fast elimination of carbon dioxide and water precede formation of residual carbonyl or carboxyl compounds. The dry distillation being performed during an irradiation gives a liquid condensate where furfural and its derivatives are dominant components. Excessively fast heating is adverse, as it results in a decrease of the yield of key organic products because pyrolysis predominates over the radiolytic-controlled decomposition of feedstock. Most likely, conversion of cellulose starts via radiolytic formation of macroradicals do not conform with each other, resulting in instability of the macroradical. As a consequence, glucosidic bond cleavage, elimination of light fragments (water, carbon oxides, formaldehyde, etc.) and formation of furfural take place.
纤维素的热分解可通过电子束辐照得到升级，从而通过链式反应机制生产有价值的有机产物。被辐照的样品在低于热解起始阈值的温度下有效分解。当快速消除二氧化碳和水先于残余羰基或羧基化合物形成时，纤维素分解类似于吡喃葡萄糖单元的局部“爆炸”。辐照过程中进行的干馏产生一种液体冷凝物，其中糠醛及其衍生物是主要成分。过快加热是不利的，因为这会导致关键有机产物产率下降，因为热解比原料的辐射控制分解占主导。很可能，纤维素的转化始于相互不一致的大自由基的辐射形成，导致大自由基不稳定。结果，糖苷键断裂、轻质碎片（水、碳氧化物、甲醛等）消除以及糠醛形成。
