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在第一报中已经证明,经过在空气中热处理的聚丙烯腈对甲酸分解反应有显著的催化活性,而且在反应过程中催化剂的选择性不断变化,脱氢活性逐渐增高,脱水活性逐渐降低,而其总活性则保持不变。进一步的研究证明,将经过一次反应的催化剂(500℃,空气中处理),在400℃通空气处理可以在一定程度上使其选择性复原,也就是使其脱水活性增高,而脱氢活性降低,对其总活性则基本上没有影响。经过这样处理的催化剂在反应过程中其选择性仍然不断变化。这种情况在两种不同的催化剂上(PAN-M-3和PAN-12-4)都得到了证实(图1,2)。
It has been proved in the first report that the polyacrylonitrile heat-treated in the air has significant catalytic activity for the decomposition of formic acid, and the selectivity of the catalyst is constantly changing during the reaction, the dehydrogenation activity is gradually increased and the dehydration activity is gradually decreased, While its total activity remains unchanged. Further studies have shown that the catalyst after a reaction (500 ℃, air treatment), at 400 ℃ air treatment can be selectively restored to some extent, which is to make its dehydration activity increased, while reducing the dehydrogenation activity , Its total activity is basically not affected. The selectivity of the catalyst after such treatment is still changing during the reaction. This was confirmed on two different catalysts (PAN-M-3 and PAN-12-4) (Fig. 1, 2).