Generating and optimizing the catalytic activity in UiO-66 for aerobic oxidation of alkenes by post-synthetic exchange Ti atoms combined with ligand substitution

[EN] The catalytic activity for the aerobic epoxidation of cyclooctene of UiO-66 has been introduced by post synthetic ion exchange of Zr4+ by Ti4+ at the nodes and the performance optimized by nitro substitution in the terephthalate ligand. In this way a TON value of 16,600 (1660 considering Zr + Ti content) was achieved, comparing favorably with the highest catalytic activity reported in homogeneous for the same reaction (10,000 for gamma-SiW10{(Fe3+(OH2)}(O-38(6-)). Kinetic studies have shown that the most likely reactive oxygen species involved in the oxidation is superoxide, with hydroxyl radicals also contributing to the reaction. UiO-66(Zr-5.4 Ti-0.6)-NO2 is stable under catalytic conditions, being used six times without any change in the conversion temporal profile and in the X-ray diffractogram. The scope of UiO-66(Zr-5.4 Ti-0.6)-NO2 promoted aerobic oxidation of alkenes was expanded by including smaller rings cycloalkenes, as well as acyclic and aryl conjugated alkenes. (C) 2018 Elsevier Inc. All rights reserved.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2014-53292-R and CTQ2015-69563-CO2-14) is gratefully acknowledged. Generalidad Valenciana is also thanked for funding (Prometeo 2017/018). SN thanks financial support by the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016).Santiago-Portillo, A.; Navalón Oltra, S.; Alvaro Rodríguez, MM.; García Gómez, H. (2018). Generating and optimizing the catalytic activity in UiO-66 for aerobic oxidation of alkenes by post-synthetic exchange Ti atoms combined with ligand substitution. Journal of Catalysis. 365:450-463. https://doi.org/10.1016/j.jcat.2018.07.03245046336