摘要
用浸渍法制备组成通式为(V_2O_5)_(20)(P_2O_5)_2(SiO_2)_(100)(0<x<60)的12种催化剂,并评价了活性和选择性,测定了各催化剂中钒的平均氧化数、四价钒含量及钒的价态分布。考察此系列催化剂上苯的气相催化氧化反应可知,催化剂活性与V^(5+)及V^(4+)之和有关,而顺酐选择性则与V^(4+)相关。
The catalysts with the compositions (V2O5)2o(P2O5)x(SiO2)100(0<x<60) were prepared by impregnation method. The catalytic properties of benzene oxidation on these samples were measured in a micro-reactor. The average oxidation numbers of V and the content of V4+ were determined by potassium permaganate titration and ESR, respectively. Thus the contents of V4+ and V3+ were calculated and the results were related to the catalytic property. It is found that the conversion of benzene and the selectivity to MA in the reaction were related closely to the total content of V5+ + V4+ and the content of V4+, respectively. By comparing the variation of the average oxidation numbers before and after reaction , we have come to the conclusion that the first attack to the aromatic ring is made by the lattice oxygen (double-boned).
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1990年第6期628-632,共5页
Chemical Journal of Chinese Universities
关键词
苯
氧化
钒磷催化剂
氧化数
价态
V-P-O/SiO2 Catalysts, ESR, Average oxidation number, Valance distribution, Benzen oxidafion
