甲烷无氧脱氢芳构化W/MCM-22基催化剂积炭的表征研究

利用TEM和XRD对积炭的甲烷无氧脱氢芳构化W／MCM-22基催化剂及其参比样进行观测，结果显示。催化剂上的积炭主要是无定形碳，间或有为数甚少的碳纳米管或碳纤维，无可观量石墨状碳存在的XRD证据．利用氢氟酸溶液处理积炭的W／MCM-22基催化剂试样，溶解除去沸石分子筛基催化剂组分，后用溶剂CH2Cl2进行萃取分离．可得不溶性和可溶性两类碳沉积物，前占主体量，后占总积炭量不足10％；利用FTIR、MS和^1H NMR等谱学方法对积炭进行表征，结果表明，可溶性碳沉积物主要是一些分子量在523～745范围的饱和脂肪烃高聚物，不溶性碳沉积物主要为稠环芳烃大分子．

Characterization of Carbon Deposits on W/MCM-22-based Catalysts for Dehydro-aromatization of CH4 in Absence of O2

With XRD and TEM methods,the texture and structure of carbon deposits on the W/MCM-22-based catalysts for reaction of dehydro-aromatization of CH_4 in absence of O_2 (DHAM) were observed,and the results showed that those carbon deposits on the catalysts undergoing 6 h of DHAM reaction were mainly amorphous carbon,occasionally involving a small quantity of carbon nanotubes and nanofibers,and that there was no confident XRD evidence for existence of graphitized carbon.With hydrofluoric acid to immerse the used catalyst to resolve the W/MCM-22-based catalyst components,followed by extraction by CH_2Cl_2,the two types of carbon deposits,soluble and insoluble in CH_2Cl_2 solvent,were separately obtained.Using FTIR,MS,and (~1H) NMR spectroscopies,characterization of those carbon deposits were done.The results indicated that the CH_2Cl_2-soluble carbon deposits were mainly a series of polymer of saturated aliphatic hydrocarbons with molecular weight in range of 523~745,and the CH_2Cl_2-insoluble carbon deposits were mainly macromolecular compounds of condensed aromatics.