Palladium supported on a novel ordered mesoporous polypyrrole/carbon nanocomposite as a powerful heterogeneous catalyst for the aerobic oxidation of alcohols to carboxylic acids and ketones on water

Abstract

Aerobic oxidation of alcohols to carboxylic acids and ketones in water using palladium species supported on an ordered mesoporous polypyrrole/carbon nanocomposite.

Selective Aerobic Oxidation of Benzyl Alcohols with Palladium(0) Nanoparticles Suspension in Water

“…More recently bimetallic Au-Pd NPs supported on alumina showed higher activity than the monometallic NPs for the selective oxidation of various benzyl alcohol derivatives [12]. Pd(0) NPs deposited on mesoporous carbon nanocomposites correspond to a rare example of catalyst oxidizing benzyl alcohols to the corresponding carboxylic acids [13]. Beside these supported-metal catalysts, a recent approach based on metal suspensions in a solvent gives dispersed (colloidal) nanoparticles having catalytic behaviour often considered as "quasi-homogeneous" [14][15][16][17].…”

From Deep Eutectic Solvents to Nitrogen‐rich Ordered Mesoporous Carbons: A Powerful Host for the Immobilization of Palladium Nanoparticles in the Aerobic Oxidation of Alcohols

“…Our studies showed that in addition to benzyl alcohol, a wide range of both electron rich (such as OCH 3 , CH 3 , and i‐Pr) and electron deficient (such as Cl) derivatives of benzyl alcohol displayed outstanding catalytic performance under such a mild and low catalyst loading and afforded the corresponding carboxylic acids in excellent yields, although, in some rare cases, somewhat higher reaction temperatures and/or larger molar percentages of catalyst were required to obtain excellent results (Table 3, entries 2–8). It is important to note that, benzyl alcohol derivatives bearing sterically demanding substituents at ortho position such as 2‐methoxy, 2‐methyl‐ and 2‐chloro‐ groups are well‐known to react much slower in the oxidation reactions using metal nanoparticles under aerobic conditions than those containing meta and para substituents [8,20,95,96] . To our delight, the substituent positions did not significantly affect the selectivity overall yields of the corresponding carboxylic acids in the present catalyst system (Table 3, entries 9–11).…”

“…It is important to note that, benzyl alcohol derivatives bearing sterically demanding substituents at ortho position such as 2-methoxy, 2-methyl-and 2-chloro-groups are well-known to react much slower in the oxidation reactions using metal nanoparticles under aerobic conditions than those containing meta and para substituents. [8,20,95,96] To our delight, the substituent positions did not significantly affect the selectivity overall yields of the corresponding carboxylic acids in the present catalyst system (Table 3, entries 9-11). It is also worth noting that this catalyst system displayed a high activity for the oxidation of secondary aromatic alcohols such as 1phenylethanol and furnished the corresponding carbonyl products in quantitative yields and high selectivity (Table 3, entries 12).…”

Comparison of the Two Carbon Allotropes as Solid Support: Catalytic Efficiency of the Supported Metalloporphyrins for the Aerobic Oxidation of Alcohols

“…The selective oxidation of alcohols to the corresponding aldehydes or ketones has played an important role in organic synthesis, biochemistry, medicinal chemistry and in the life science especially at the industrial scale [1–3] . Recently, many efforts have been devoted to introduce efficient catalytic systems and develop new strategies for oxidation of alcohols in the presence of various metal complexes [4–7] . CYP450 and their biomimetic model compounds have attracted great attention due to their superior performance in the oxidation of a wide range of alcohols under mild conditions [8–11] .…”

“…[1][2][3] Recently, many efforts have been devoted to introduce efficient catalytic systems and develop new strategies for oxidation of alcohols in the presence of various metal complexes. [4][5][6][7] CYP450 and their biomimetic model compounds have attracted great attention due to their superior performance in the oxidation of a wide range of alcohols under mild conditions. [8][9][10][11] Catalyst decomposition and lack of catalyst recovery as the major intrinsic drawback of homogeneous catalytic systems led scientists to convert homogeneous into heterogenized catalysts via solid supports.…”