活性炭担载的钾钼合成醇催化剂

STUDY ON ACTIVECARBONSUPPORTED Mo - K CATALYSTS FORALCOHOLSYNTHESIS

采用ＸＲＤ，ＬＲＳ技术研究了活性炭担载的不同Ｍｏ 含量Ｍｏ－ Ｋ催化剂结构，并关联其ＣＯ加氢合成低碳混合醇性能。结果表明，氧化态Ｍｏ－ Ｋ／Ｃ催化剂体系中，在低钼载量情况下，由于部分Ｋ离子渗透进活性炭的微孔，使得钾钼作用不充分，钼主要以ＭｏＯ２ 形式存在。保持钾钼比不变，随着钼载量的增加，钾钼作用逐渐增强，当ＭｏＯ３ 载量为７２ｗ ％ 时，Ｍｏ 主要以Ｋ２Ｍｏ２Ｏ７ 形式存在。经硫化还原处理后，发生了氧硫交换，钼主要以ＭｏＳ２ 物种形式存在，其粒度随着Ｍｏ 含量的增加而明显增大。高钼载量的样品（ 如ＭｏＯ３（７２ ％） － Ｋ／Ｃ） ，活性炭和Ａｌ２Ｏ３ 担载的硫钼物相基本相同。在硫化态催化剂中，增加Ｍｏ 的载量不仅能提高ＣＯ加氢合成醇的收率和选择性，而且有利于改善产物的分布。

The structure of oxidic and sulfided Mo catalysts supported on active carbon was studied by means of X-ray diffraction and Raman spectroscopy ,andthe activity for al coholsynthesis was also accounted- In oxidic state ,the Mo phase onthesample with low Mo loadingis mainly presentas MoO2 ,due to possiblereason thatpart of potassium anions per meateinto micropore of active carbon- As the increasing of Mo loading ,the interaction be tween potassium and molybdenum isenhanced- Atthe MoO3loading of72w % ,Mo mainlyex istsintheform of K2Mo2O7species- Aftersulfidation ,the O- Ssubstitution takes place ,the Mo phaseis highly dispersed asisolated or polymerized monolayer species atlow Mo loading and astinythree- dimensionalparticles at higherloading- XRDand LRSresults demonstrate that MoS2isthe major phase presentafter sulfidation- The higher catalytic activity for Mo - K/Ccompared to Mo - K/Al2O3 is explained by the difference in the structure of sulfide phase and in theinteraction between these phases and the respective supports-