The transformation of cyclohexanone was carried out on a series of bifunctional PdHFAU catalysts with Pd contents between 0.1 and 0.5 wt.% and framework Si/Al ratios equal to 5, 20, 40 and 100, under the following conditions: flow reactor, 473 K, pressures of cyclohexanone and hydrogen equal to 0.17 and 0.83 bar, respectively. With all the catalysts, cyclohexylcyclohexanone, the formation of which requires successive steps of aldolization, dehydration and hydrogenation, is directly formed. The effect of the balance between the hydrogenating and acid functions of the catalysts (taken as the ratio between their activity for toluene hydrogenation and their number of protonic acid sites, A_H/B) on their activity, stability and selectivity is the one expected from a bifunctional catalytic process. The activity per protonic site first increases with A_H/B, then remains constant above a certain value of A_H/B (0.4 h⁻¹), the limiting step of cyclohexylcyclohexanone formation being then cyclohexanone aldolization. The selectivity to cyclohexylcyclohexanone as well as the stability increase with A_H/B remaining constant for A_H/B>1 h⁻¹. While a high selectivity to cyclohexylcyclohexanone is obtained, the catalyst stability is relatively poor due to the retention inside the zeolite micropores of polar tricyclic C₁₈ compounds.

中文翻译：

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双功能钯八面沸石上环己基环己酮的合成：酸度和金属官能度之间的平衡影响

在以下条件下，在Pd含量在0.1和0.5 wt％之间且骨架Si / Al比等于5、20、40和100的一系列双功能PdHFAU催化剂上进行环己酮的转化：流动反应器473 K ，环己酮和氢气的压力分别等于0.17和0.83 bar。对于所有催化剂，直接形成环己基环己酮，其形成需要醛醇缩合，脱水和氢化的连续步骤。催化剂的加氢和酸功能之间平衡的影响（取作甲苯加氢活性与质子酸位点数A _H / B之比）的活性，稳定性和选择性是双功能催化工艺所期望的。每有质子现场首先增加活性甲_ħ /乙，然后保持高于一定值恒定甲_ħ /乙（0.4ħ ^-1），的cyclohexylcyclohexanone形成限制步骤是环己酮，然后缩醛反应。当A _H / B > 1 h ^-1时A _H / B保持恒定时，对环己基环己酮的选择性以及稳定性增加。尽管获得了对环己基环己酮的高选择性，但是由于极性三环C ₁₈化合物在沸石微孔内的保留，催化剂的稳定性相对较差。