多孔WC-TiC催化剂的戊烷异构化活性

Catalytic activity of porous WC-TiC for pentane isomerization

以TiC和MoSi2为基体，WO3和仲钨酸铵为WC的前驱体，碳酸氢铵为造孔剂，采用固相合成技术，1560℃制备碳化钛基复合WC催化材料。分别通过X射线衍射仪、扫描电镜、压汞仪、气相色谱和气质谱表征催化材料的相组成、显微结构、孔径分布和对戊烷的催化性能。结果表明，碳化钛基复合WC材料的相组成为TiC、SiC、MoC、WC和（Ti，Si）C；当WO3为WC前驱体时，催化材料的孔径呈现单峰分布[（0．3～50μm）]，350℃其对戊烷的转化率为16．21％，异构化选择性为5．68％；当仲钨酸铵为WC前驱体时，催化材料的孔径呈现双峰分布[（100～800）nm和（1．5）μm]。WC颗粒在500nm以下，350℃戊烷转化率达到48．44％，异戊烷的选择性为12．91％。

Porous titanium carbide matrix catalysts were prepared by solid state reaction among TiC, MoSi2 and WO3 or 5（NH4）2O · 12WO3 · 5H2O at 1 560 ℃, using NH4HCO3 as the pore generating agent. The phase composition, microstructure, pore size distribution and the catalytic properties of the carbide catalysts were characterized by XRD, SEM, mercury intrusion porousimetry（ MIP）, gas chromatography（GC） and GC/MS. The results indicated that there existed TiC, SiC, MoC, WC and （Ti, Si） C phase in the porous carbide catalyst. Catalyst containing WO3, with larger pores [ （0.3 - 5.0） μm in radius ] and wide pore size distribution, attained pentane conversion of 16.21% and selectivity to isopentane of 5.68% at 350 %; When using ammonium paratungstate as the precursor for tungsten carbide, bimodal peaks [ （ 100 - 800） nm, （ 1 - 5 ） μm ] were observed, with relatively narrow pore size distribution and WC radius of less than 500 nm. The WC particles had excellent catalytic properties for pentane isomerization, with pentane conversion of 48.44% and selectivity to isopentane of 12.91% at 350 ℃.