用醇还原VOPO4·2H2O制备的VOHPO4·0.5H2O的择优取向性能

 研究了用醇还原VOPO4·2H2O制备的VOHPO4·0．5H2O的晶面择优rn取向现象及其在正丁烷和空气混合气体中活化后，产物（VO）2P2O7的rn晶面择优暴露对正丁烷氧化制顺酐性能的影响．以伯醇还原VOPO4·2Hrn2O制备的VOHPO4·0．5H2O晶体，晶面择优取向于（220）面，晶型为玫rn瑰状或扭曲的片状聚集体；活化后的产物仅含（VO）2P2O7相，其（02rn0）晶面择优暴露．以仲醇还原VOPO4·2H2O制备的VOHPO4·0．5H2O晶rn体，晶面择优取向于（001）面，晶型为平板片状体；活化后的产物由rn（VO）2P2O7，VOPO4和无定形相组成，其中（VO）2P2O7相含量低，其rn（020）晶面暴露少．由苄醇、环己醇和3－甲基－3庚醇还原VOPO4·2rnH2O制备的VOHPO4·0．5H2O的XRD谱与用仲醇制备的相似．用一般方法rn（V2O5／异丁醇／H3PO4）制备的VOHPO4·0．5H2O晶体不具有晶面择优rn取向性质，活化后得到的（VO）2P2O7的结晶度较低．由正辛醇还原VOrnPO4·2H2O制备的VOHPO4·0．5H2O经活化后，对正丁烷氧化制顺酐的催rn化性能优于用仲辛醇和一般方法制备的VOHPO4·0．5H2O．

Preferential Orientation of VOHPO4.0.5H2O Prepared by Reducing VOPO4.2H2O with Alcohol

VOHPO4.0.5H2O was prepared by reducing VOPO4.2H2O with various alcoho ls and then calcinated in n-butane/air to produce the final catalysts. The preferential orientation of VOHPO4.0.5H2O and the influence of the prefere ntial exposition of the plane of the final catalysts on catalytic oxidation of n-butane to maleic anhydride (MA) were investigated. VOHPO4.0.5H2O wi th rose-like or twist agglomerated type structure prepared by reducing VOPO4 .2H2O with primary alcohol orientates preferentially the (220) plane, the fin al catalyst contains only (VO)2P2O7 phase, the (020) plane is preferential exposition. VOHPO4.0.5H2O with platelet type structure prepared by reduci ng VOPO4.2H2O with secondary alcohol orientates preferentially the (001) pl ane, the final catalyst is composed of (VO)2P2O7, VOPO4 and amorphous ph ase, and the exposition of the (020) plane of (VO)2P2O7 is less. The XRD p atterns of VOHPO4.0.5H2O prepared from cyclohexanol, benzyl alcohol and 3 -methyl-3-enanthol are similar to that prepared from secondary alcohol. VOHPO 4.0.5H2O derived from V2O5/isobutanol/H3PO4 (ordinary method) has no the preferential orientation of the plane. The results show that the catalyti c properties of the final catalyst prepared from 1-octyl alcohol for the oxidat ion of n-butane to MA are superior to that of the catalyst derived from 2- octyl alcohol and ordinary method.