This paper reports on the catalytic oxidative cleavage of trans-1,2-cyclohexanediol with air, catalysed by supported Au NPs, as one of the steps of a new adipic acid synthesis process. Catalysts proved to be active, with a moderate cyclohexanediol conversion and selectivity to adipic acid close to 70%. The reaction network included several steps in sequence, amongst which the key one is the oxidation of the diol into 2-hydroxycylohexanone, which is then oxidised by air – even in the absence of a catalyst – to adipic acid and lesser amounts of lighter acids, i.e. glutaric and succinic acids. The oxidation of the second hydroxyl moiety in the diol would lead to the formation of 1,2-cyclohexanedione. The latter, however, is rapidly transformed into several by-products, especially glutaric acid, under the basic conditions which are necessary for allowing the reaction to occur at an acceptable rate. With Au-based catalysts, this undesired reaction occurs much more slowly than with the previously investigated Ru hydroxide catalysts. The nature of the support, either TiO₂ or MgO, also affected catalytic performance; the best performance was shown by the Au/MgO catalyst which, however, suffered from a remarkable deactivation, found to be due to both the increase in NPs size and the formation of carbonaceous residua on the catalyst surface.

本文报道了反式的催化氧化裂解负载的Au NPs催化的带有空气的-1,2-环己二醇是新的己二酸合成工艺的步骤之一。事实证明，该催化剂具有活性，环己二醇转化率适中，对己二酸的选择性接近70％。反应网络按顺序包括几个步骤，其中关键之一是将二醇氧化成2-羟基环己酮，然后即使没有催化剂也被空气氧化成己二酸和少量的轻质酸，即戊二酸和琥珀酸。二醇中第二个羟基部分的氧化将导致1,2-环己二酮的形成。然而，在使反应以可接受的速率发生所必需的碱性条件下，后者迅速转变成几种副产物，尤其是戊二酸。使用金基催化剂，这种不希望的反应发生的速度比以前研究过的氢氧化钌催化剂要慢得多。TiO 2载体的性质₂或MgO，也会影响催化性能；Au / MgO催化剂表现出最好的性能，然而，Au / MgO催化剂却发生了显着的失活，这是由于NPs尺寸的增加和催化剂表面碳残留物的形成所致。