Selective Catalytic Oxidation of Benzyl Alcohol to Benzaldehyde by Nitrates

Abstract

In this paper, ferric nitrate was used to oxidize benzyl alcohol in a mild condition and demonstrated its better performance compared to HNO 3. In the reaction, the conversion rate and product selectivity could be both as high as 95% in N 2 atmosphere, while the benzaldehyde yield also reached 85% in air. Similar to Fe(NO 3) 3 •9H 2 O, the other metallic nitrates such as Al(NO 3) 3 •9H 2 O and Cu(NO 3) 2 •3H 2 O could also oxidize the benzyl alcohol with high activity. The applicability of Fe(NO 3) 3 •9H 2 O for other benzylic alcohol was also investigated, and the reaction condition was optimized at the same time. The results showed the Fe(NO 3) 3 •9H 2 O would be more conducive in oxidizing benzyl alcohol under the anaerobic condition. The experiments in N 2 or O 2 atmospheres were conducted separately to study the catalytic mechanism of Fe(NO 3) 3. The results showed the coexistence of Fe 3+ and NO − 3 will generate high activity, while either was with negligible oxidation property. The cyclic transformation of Fe 3+ and Fe 2+ provided the catalytic action to the benzyl alcohol oxidation. The role of NO − 3 was also an oxidant, by providing HNO 2 in anaerobic condition, while NO − 3 would be regenerated from NO in aerobic condition. O 2 did not oxidize the benzyl alcohol conversion directly, while it could still be beneficial to the procedure by eliminating the unwelcome NO and simultaneously reinforcing the circulation of Fe 2+ and Fe 3+ , which therefore forms a green cyclic oxidation. Hence, the benzyl alcohol oxidation was suggested in an air atmosphere for efficiency and the need of green synthesis.

Polar and nonpolar iron (II) complexes of isatin hydrazone derivatives as effective catalysts in oxidation reactions and their antimicrobial and anticancer activities

“…Finally, new additional bands were located at 551 and 711 nm with low energy for Fe (LDBu) 2 and Fe (LSO 3 Na) 2 , respectively, which corresponded to the electron transition between d orbitals (d → d transition), as reported for other Fe‐chelates elsewhere. [ 23,24 ] The high observed shift of the d → d transition band between Fe (LDBu) 2 and Fe (LSO 3 Na) 2 , despite the same molecular core, could be due to the difference in the polarity and the electron‐donating or electron‐withdrawing power of the substituted groups in the both coordinated ligands. HLDBu, with nonpolar nature, has high electron‐donating two tert ‐butyl groups, whereas HLSO 3 Na, with polar nature, has high electron‐withdrawing sodium sulfonate group.…”

“…d transition), as reported for other Fe-chelates elsewhere. [23,24] The high observed shift of the d ! d transition band between Fe (LDBu) 2 and Fe (LSO 3 Na) 2 , despite the same molecular core, could be due to the difference in the polarity and the electron-donating or electronwithdrawing power of the substituted groups in the both coordinated ligands.…”

“…[13,14] Such intermediates are recognized with highly active species for electron and/or oxygen atom transfer mechanism. [15] Consequently, many timely reported works for the oxidation of alcohols, for example, the catalytic action of Fe 2+/3+ -complexes of pyridylaminophenols, [16] carbohydrazides, [17] polydentate phosphines, [18] hydrazinylpyridine, [19] phenol-pyrazoles, [20] amino phenolates, [21] pyridylimines, [22] phthalocyanines, [23] and azo-arylhydrazones [24] were presented in the oxidation of primary and secondary alcohols and under various reaction conditions.…”

Successive oxidation–condensation reactions using a multifunctional gold-supported nanocomposite (Au/MgCe–HDO)

“…26 Generally, metals and alkalis co-catalyse alcohol oxidation under mild reaction conditions. 27 Kantam and co-workers 28 illustrated that the use of base was pertinent even in the presence of an alkali over Pd catalyst. On the contrary, R. Davis et al 29 has reported a much lower conversion for the gold catalysed alcohol to aldehyde oxidation without any alkali.…”

Biomass-Derived Nitrogen-Doped Porous Carbons Activated by Magnesium Chloride as Ultrahigh-Performance Supercapacitors

“…Carbon materials with different nanostructures have been extensively employed for environmental remediation, liquid phase catalysis, supercapacitors, and electrocatalysis . Among these various applications, carbon-based supercapacitors are highly promising because of their great capability, fast charge/discharge processes, long-period stability, and low-cost.…”