在甲苯选择性氧化反应条件下铁钼催化剂的物化性能  

PHYSICO-CHEMICAL PROPERTIES OF Fe-M0 OXIDE CATALYSTS UNDER CONDITION OF SELECTIVE OXIDATION OF TOLUENE

作　　者：张惠良[1] 沈俭一[1] 葛欣[1] 

机构地区：[1]南京大学化学系,南京210008

出　　处：《Chinese Journal of Catalysis》1993年第4期263-269,共7页催化学报（英文）

基　　金：中国科学院科学基金;南京大学现代分析中心测试基金;大连化学物理研究所催化基础研究实验室测试基金

摘　　要：采用原位穆斯堡尔谱、XRD、XPS、IR和UVDRS等对Fe/Mo=0.67的Fe_2(MoO_4)_3和Fe/Mo=0.29的Fe_2(MoO_4)_3-4MoO_3样品进行了研究。实验结果表明,在甲苯氧化反应条件下,样品中一部分Fe_2(MoO_4)_3相还原为β-FeMoO_4。在反应温度(450℃)下通空气氧化,生成的β-FeMoO_4又氧化为Fe_2(MoO_4)_3。在甲苯选择性氧化中,易还原为β-FeMoO_4的样品,其甲苯选择性氧化活性较高。样品中的Fe^(3+)起着稳定Mo^(6+)的作用而Fe^(3+)还原为Fe^(2+)。在氧的作用下,Fe^(2+)再氧化为Fe^(3+),并使表面上吸附的氧转化为晶格氧。Fe_2(MoO_4)_3中的Mo^(6+)吸附甲苯分子,反应时,钼酸铁的表面晶格氧和甲苯反应使之生成苯甲醛和水。Fe2(MoO4)3 (Fe/Mo =0.67)9 and Fe2(MoO4)3-4MoO3 (Fe/Mo = 0.29) were studied by in-situ Mossbauer spectroscopy,XRD,XPS,IR and UV-DRS.The results showed that under the condition of toluene oxidation,a part of Fe2(MoO4)3 in the samples was reduced to β-FeMoO4,and then reoxidized to Fe2(MoO4)3 while treated in air at 450℃.During the oxidation of toluene,the easier the samples to be reduced to β-FeMoO4,the higher the catalytic activity for selective oxidation of toluene is.Fe3+ ion in the samples played a role to hold the molybdenum in Mo8+ valence state and Fe3+ itself was reduced to Fe2+,and then the formed Fe2 + was reoxidized by oxygen to Fe3+,thus,the surface adsorbed oxygen could be transformed to lattice oxygen.The molybdenum of Fe2(MoO4)3 was in the form of Mo6+ ,and could adsorb the molecule of toluene,and during reaction the lattice oxygen on Fe2(MoO4)3 surface oxidized toluene to benzaldehyde and water.

关 键 词：甲苯 选择性氧化 铁钼催化剂 

分 类 号：O625.11[理学—有机化学]