Porous Anodic Aluminum Oxide as an Efficient Support for Ruthenium-Catalyzed Aerobic Oxidation of Alcohols and Amines

Abstract

The oxidation reactions of alcohols and amines to their respective aldehydes/ketones and nitriles are important reactions in the laboratory and industry. A highly robust and activated ruthenium-supported anodic aluminum oxide (Ru@AAO) has been synthesized through the sonochemical method. The sonochemical technique allowed a short synthesis time and uniform distribution of Ru on the AAO surface as confirmed by the scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and BET surface-area analysis. The synthesized catalyst was employed for the oxidation of alcohols and amines in the presence of atmospheric air at a relatively lower temperature. The synthesized catalyst showed excellent conversions of both alcohols and amines with high selectivities toward their respective aldehydes/ketones and nitriles. The function of the AAO support in Ru@AAO catalytic activity has also been elaborated in the present investigation.

The toolbox of porous anodic aluminum oxide–based nanocomposites: from preparation to application

“…Additionally, Hussain et al had prepared embedded ruthenium (Ru) in an AAO by reduction of ruthenium precursor via a sonochemical method, and the obtained Ru@AAO was able to catalyze the oxidation reaction of 1-naphthalenemethanol with higher catalytic activity owing to the porous structure and surface area of AAO [114].…”

Improved catalytic performance by changing surface and textural properties of Ru supported bifunctional periodic mesoporous organosilicas in aerobic oxidation of alcohols

“…[1][2][3] To avoid the shortcomings of traditional-to-recent applied methods for this key transformation, including the use of toxic organic solvents and stoichiometric amounts of hazardous oxidants and reagents, which resulted in production of a large volume of wastes, as well as the problems associated with the use of homogeneous catalysts, a lot of attention has been given to perform this reaction in the presence of heterogeneous catalysts and green oxidants, especially molecular oxygen. [4][5][6][7][8] During the past decade, numerous metal-based heterogeneous catalysts, such as palladium, 9-19 ruthenium, [20][21][22][23][24][25][26][27][28] cobalt, [29][30][31][32][33][34][35][36][37] platinum, [38][39][40][41][42][43][44][45] gold, 46-57 copper, [58][59][60][61][62][63][64][65][66]…”

“…During the past decade, numerous metal-based heterogeneous catalysts, such as palladium, 9–19 ruthenium, 20–28 cobalt, 29–37 platinum, 38–45 gold, 46–57 copper, 58–69 vanadium, 70–72 and nickel, 73,74 have successfully been employed in the aerobic oxidation of alcohols to their corresponding carbonyl compounds. Among them, ruthenium-based catalysts, in either homogeneous or heterogeneous form, are the most reliable catalytic systems reported in this research area because of possessing wide range of oxidation states and displaying a high degree of selectivity and efficiency in the oxidation of a variety of structurally diverse alcohols.…”

Supported copper on a diamide–diacid-bridged PMO: an efficient hybrid catalyst for the cascade oxidation of benzyl alcohols/Knoevenagel condensation

“…[53][54][55][56][57][58][59][60] Nowadays, the sequential oxidation of alcohols and the subsequent Knoevenagel condensation reaction of the obtained aldehyde compounds has received much attention in terms of green and sustainable standpoints of view compared to the classical multi-step reactions. 16,[61][62][63][64][65][66] Traditionally, stoichiometric amounts of oxidants such as chromium reagents, 67 Dess-Martin periodinane, 68,69 or permanganates 70 are used for oxidation of alcohols. These oxidants have adverse environmental impacts due to their toxicity and large amounts of waste.…”