液体石蜡体系中含铜物种的化学变化

Chemical Change of Copper Species in Liquid Paraffin

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。

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 Cu2＋ 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.