Role of surface properties of the vanadyl pyrophosphate in the formation of maleic and phthalic anhydrides by n-pentane oxidation

被引:21
作者
Cavani, F
Colombo, A
Giuntoli, F
Gobbi, E
Trifiro, F
Vazquez, P
机构
[1] Dipto. Chim. Industriale Materiali, 40136 Bologna
[2] CINDECA 47 n. 257, La Plata
关键词
surface properties; vanadyl pyrophosphate; maleic anhydride; phthalic anhydride; n-pentane oxidation;
D O I
10.1016/S0920-5861(96)00085-5
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
The mechanism of synthesis of maleic and phthalic anhydrides by the gas phase oxidation of n-pentane over VPO-based catalysts was studied. The oxidation of the paraffin was carried out under conditions which may lead to the isolation of possible reaction intermediates: very low residence time and high n-pentane/oxygen ratio. Under these conditions a number of by-products were identified, which were attributed to the oxidation of intermediate pentene and pentadiene, as well as other products with more than 5 C atoms, among which were alkylaromatics. Alkylaromatics also were found to be formed in the anaerobic transformation of pentadiene. A mechanism is proposed, which takes into account the oxidehydrogenation of the paraffin to pentene and pentadiene, followed by two parallel pathways: (i) dimerization, dehydrocyclization and aromatization of the diolefin, followed by oxidation of the alkylaromatic to phthalic anhydride, and (ii) multi-step oxidation of pentadiene to maleic anhydride.
引用
收藏
页码:125 / 132
页数:8
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