多级孔ZSM-5分子筛催化剂上5-羟甲基糠醛自醚化反应

Self-etherification of 5-hydroxymethylfurfural catalyzed by ZSM-5 with hierarchical porous structure

利用碱处理结合柠檬酸处理技术对商业微孔ZSM-5分子筛改性,制备了多级孔ZSM-5分子筛催化剂(ZSM-5-AT-CA)。利用XRD、N_(2)吸脱附、NH_(3)-TPD、Py-IR、^(27)Al MAS NMR等表征技术研究了ZSM-5-AT-CA催化剂的形貌结构和物理化学性质,以5-羟甲基糠醛(HMF)自醚化制双-(5-甲酰基糠基)醚(OBMF)为模型反应进一步考察其催化性能。结果表明,ZSM-5-AT-CA催化剂具有多级孔结构(微孔、介孔)、适宜酸位点浓度和强度,有利于HMF自醚化反应。多级孔ZSM-5-AT-CA催化剂在反应温度90℃时HMF转化率达到91.2%,OBMF产率为73.6%。催化剂具有良好的循环稳定性。

The ZSM-5 catalyst with hierarchical porous structure(ZSM-5-AT-CA)was prepared via modification of commercial microporous ZSM-5 zeolites through the alkali and citric acid treatment.The morphological and physicochemical features of the ZSM-5-AT-CA were analyzed by the techniques of XRD,N_(2)adsorption-desorption isotherms,NH_(3)-TPD,Py-IR and^(27)Al MAS NMR.Self-etherification of 5-hydroxymethylfurfural(HMF)to 5,5′(oxy-bis(methylene))bis-2-furfural(OBMF)was selected as model reaction to study the catalytic performance of the as-prepared catalyst.The results indicated that ZSM-5-AT-CA catalyst possessed the ordered hierarchical porous structure(micropore and mesopore),suitable concentration and strength of acidic sites,which was favorable for the self-etherification of HMF.When the self-etherification of HMF was catalyzed by ZSM-5-AT-CA at 90℃,the conversion efficiency of HMF was up to 91.2%while the yield of OBMF was 73.6%,indicating the ZSM-5-AT-CA catalyst had excellent recyclability.