Ni/HZSM-5催化剂的孔道调控及其对C-O键的催化裂解

Rore Regulation of Ni/HZSM-5 Catalyst and Its Catalytic Cracking for C-O Bond

C-O桥键是褐煤有机质中重要的含氧官能团之一,通过切断C-O桥键可以实现褐煤的温和解聚,得到含有芳环和杂环的小分子化合物。本文通过碱刻蚀的手段制备了高分散Ni基多级孔HZSM-5催化剂,并对催化剂进行氮气脱吸附、扫描电镜和X-射线衍射仪等表征。HZSM-5在0.01 mol/L和0.1 mol/L的NaOH溶液处理下能够提高分子筛的比表面积和孔径,并且能保持分子筛的晶型结构。采用苯基苄基醚作为探针分子探究了催化剂的催化活性以及产物选择性,结果表明在反应温度为300℃时,Ni/Z0.01催化苯基苄基醚裂解的转化率接近100%,对甲苯和苯酚的选择性分别为34.9%和33.7%。因此,Ni/Z的孔道结构调控对C-O键的裂解及产物的选择性有重要作用。

C-O bridge bond is one of the important oxygen-containing functional groups in organic matter of lignite.Small molecular compounds containing aromatic ring and heterocyclic ring can be obtained by cleaving C-O bond.In this paper,highly dispersed Ni-based multi-stage pore catalyst was prepared by alkali etching of HZSM-5,and the catalyst was characterized by nitrogen deadsorption,SEM and XRD.The specific surface area and pore size of HZSM-5 were increased under the treatment of 0.01 mol/L and 0.1 mol/L NaOH solution,which could also maintain the crystalline structure of HZSM-5.The catalytic activity and product selectivity were investigated by using phenyl benzyl ether as the probe compound.The results showed that the conversion of phenyl benzyl ether from the catalytic cracking by Ni/Z0.01 at 300℃was 100%,and the selectivity of toluene and phenol were 34.9%and 33.7%,respectively.Therefore,the pore structure regulation of Ni/Z plays an important role in cleaving C-O bond and enhancing product selectivity.