AuPd/TiO₂ catalysts, synthesized using controlled surface reactions, are active for the gas-phase amination of 1-hexanol using ammonia. The bimetallic active sites for these catalysts have been characterized using CO chemisorption and XAS techniques, and the absence of monometallic Pd species in the AuPd catalysts was confirmed using UV-vis and STEM-EDS analysis. The bimetallic catalysts exhibit synergy between Au and Pd, as the rate of hexanol conversion increases from 8.7 μmol ks⁻¹ (μmol total Pd)⁻¹ over Pd/TiO₂ to up to 42 μmol ks⁻¹ (μmol total Pd)⁻¹ over AuPd/TiO₂ with a Pd/Au atomic ratio of 0.06. The rate of hexanol conversion is also enhanced with respect to Au content, with a 5-fold increase in the total Au-normalized rate from Au/TiO₂ to AuPd_0.67/TiO₂. As Pd is added to Au/TiO₂ in increasing quantities, the production rate of primary species (i.e., hexylamine and hexanenitrile) is preferentially increased. The rate of dihexylamine production increases to a lesser extent, while trihexylamine formation remains relatively constant across Pd loadings. Moreover, trihexylamine, which cannot be formed via the condensation of dihexylamine and hexanol, is shown to be produced via the secondary aldimine, N-hexylidene hexylamine. The AuPd bimetallic catalysts also exhibit reduced hydrogenolysis activity compared to monometallic Pd/TiO₂.

中文翻译：

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1-己醇在双金属AuPd / TiO ₂催化剂上的胺化

使用受控的表面反应合成的AuPd / TiO ₂催化剂对于氨法1-己醇的气相胺化具有活性。这些催化剂的双金属活性位点已使用CO化学吸附和XAS技术进行了表征，并且使用UV-vis和STEM-EDS分析证实了AuPd催化剂中不存在单金属Pd物种。双金属催化剂表现出的Au和Pd之间的协同作用，如己醇的转化率提高8.7微摩尔KS率^-1（微摩尔总的^Pd）-1在Pd /二氧化钛₂至高达42微摩尔KS ^-1（微摩尔总的^Pd）-1在AuPd / TiO _2上Pd / Au原子比为0.06。相对于Au含量，己醇转化率也得到了提高，从Au / TiO ₂到AuPd _0.67 / TiO ₂的总Au归一化率提高了5倍。随着Pd越来越多地添加到Au / TiO ₂中，主要物质（即己胺和己腈）的生产率得到优先提高。二己胺产生的速率增加的程度较小，而三己胺的形成在Pd负载中保持相对恒定。此外，三己基胺，这不能形成通过二己基胺和己醇的缩合，被示出为产生经由副醛亚胺，Ñ-亚己基己胺。与单金属Pd / TiO ₂相比，AuPd双金属催化剂还表现出降低的氢解活性。