四种金属氯化物对纤维素快速热解的影响(Ⅱ) 机理分析

Catalytic effects of four metal chlorides on fast pyrolysis of cellulose (Ⅱ) Mechanism analysis

根据纯纤维素和LG快速热解的产物分布,确定纤维素热解过程中通过互相竞争的途径形成了LG以及其他脱水糖、呋喃类、小分子醛酮等产物。根据四种金属氯化物对热解产物的催化效果,初步探讨了纤维素解聚后脱水形成LGO、LAC、DGP、HMF和FF,以及吡喃环开裂形成HAA和acetol等产物的途径。进一步通过对主要产物的二次催化裂解的研究表明,LGO、LAC和DGP可通过纤维素负载FeCl3和ZnCl2后热解制备,但它们对催化剂较为敏感;HMF、HAA和acetol最适合通过负载KCl后热解制备;FF最适合通过负载ZnCl2后热解制备,且在ZnCl2作用下的适度二次裂解能够提高FF的产率和纯度。

Based on the products distribution from fast pyrolysis of cellulose and levoglucosan（LG）,it was determined that competing pyrolytic pathways were responsible for the formation of LG,other anhydrosugars,furans,light linear carbonyls and other products during the fast pyrolysis process.According to the catalytic effects of the four metal chlorides,the pyrolytic pathways for the formation of LGO,LAC,DGP,HMF and FF from depolymerization and dehydration of cellulose,as well as the formation of HAA and acetol from pyrolytic ring scission were discussed.Furthermore,experiments on secondary catalytic cracking of primary products were performed.The results indicated that LGO,LAC and DGP could be produced through the impregnation of FeCl3 or ZnCl2,but these anhydrosugars were sensitive to the catalysts.HMF,HAA and acetol could be produced through the impregnation of KCl.FF could be produced through the impregnation of ZnCl2,while moderate secondary cracking by ZnCl2 would promote the yield and purity of FF.