液体石蜡体系中含铜物种的化学变化

针对完全液相法制备的Cu-Zn-Al催化剂在还原前就有低价态Cu存在的问题，考察了几种不同类型的含铜物质在液体石蜡中热处理时，热处理气氛、催化剂各组分间的相互作用以及铜源种类对热处理产物的影响。 结果表明，液体石蜡在受热情况下能将Cu2+还原，并且遵循先生成Cu+，再生成单质Cu的逐级还原；Cu2+被还原的程度与铜盐的种类和热处理温度有关。 CuO在240 ℃时可以被液体石蜡还原为Cu2O，在300 ℃时被还原为单质Cu；在相同温度下，硝酸铜比乙酸铜更容易被液体石蜡还原。 完全液相法制备的Cu基催化剂在还原前就有低价态Cu存在的根本原因是液体石蜡的存在。

Chemical Change of Copper Species in Liquid Paraffin

To reveal the chemical species of copper, typically the low-valence speices, in Cu-Zn-Al catalyst prepared by complete liquid-phase method before reduction, the effects of heat-treatment atmosphere, interactions among all components and copper precursor on heat treatment have been systematically studied during the heat treatment of several different kind of copper precursor in liquid paraffin. The results showed that Cu2+ could be reduced by liquid paraffin under heating condition. The Cu+ is formed before the formation of Cu. The reductive degree of Cu2+ was related with the category of copper salts and heat-treatment temperature. CuO can be reduced to Cu2O by liquid paraffin at 240 ℃, and then to Cu at 300 ℃. The copper nitrate could be easily reduced by liquid paraffin than copper acetate at the same temperature. The reason of the low-valent copper appearing in Cu-base catalyst prepared by complete liquid-phase method before reduction could be attributed to the presence of liquid paraffin.