Highly Efficient Iron-Based Catalyst for Light-Driven Selective Hydrogenation of Nitroarenes

Abstract

Light-driven hydrogenation of nitro compounds to functionalized amines is of great importance yet a challenge for practical applications, which calls for the development of high-performance, nonprecious photocatalysts and efficient catalytic systems. Herein, we report a high-efficiency Fe 3 O 4 @TiO 2 photocatalyst via a sol−gel and subsequent pyrolysis strategy, which exhibits desirable photothermal hydrogenation performance of nitro compounds to functionalized amines with the excellent selectivity of >90% exceeding those of the state-of-the-art heterogeneous photocatalysts. Our experimental results and theoretical calculations for the first time reveal that Fe 3 O 4 is the major active phase, and the strong metal−support interaction between Fe 3 O 4 and reducible TiO 2 further leads to performance improvement, taking advantage of the enhanced photothermal effect and the improved adsorption for the reactant and hydrazine hydrate. Notably, a variety of halonitrobenzenes and pharmaceutical intermediates can be completely converted to functionalized amines with high selectivities, even in gram-scale reactions. This work provides a new insight into the rational design of nonprecious photo/thermo-catalysts for other catalytic reactions.

A review on sustainable iron oxide nanoparticles: syntheses and applications in organic catalysis and environmental remediation

“…The selective hydrogenation of nitro compounds containing additional reducible groups such as alkene, carbonyl, and/or halide to produce functionalized amines poses a significant and challenging task in both contemporary chemical and pharmaceutical industry. 160–163 In this context, Ma et al 164 fabricated TiO 2 based iron oxide (Fe 3 O 4 @TiO 2 ) heterogeneous photocatalyst for the selective hydrogenation of nitroarenes into amine derivatives. The Fe 3 O 4 @TiO 2 photocatalyst was synthesized by the sol–gel approach followed by the pyrolysis process (Fig.…”

Recent Applications of Photothermal Conversion in Organic Synthesis

“…A recent report from the Zhao and Xiong groups detailed the use of a low-cost and high-performing Fe 3 O 4 –TiO 2 catalyst, which was able to successfully hydrogenate a diverse array of nitroarenes to afford the corresponding amine (Figure b) . Iron and titanium-based photothermal agents offer a more inexpensive and accessible catalyst, while addressing challenging reactivity.…”

Photo-thermal Catalytic Hydrogenation of Halogenated Nitrobenzenes over Ni/P25 Catalyst

“…On the other hand, the concept of photo-thermal catalysis has been proposed in recent years. − Photo-thermal catalysis integrates thermal catalysis and photocatalysis into a photo-thermal synergistic catalysis and exhibits a better catalytic performance than that of thermal catalysis and photocatalysis alone. Gao’s group found that Pd 3 Au 0.5 /SiC showed a 6 times greater turnover frequency under visible-light irradiation (1715 h –1 ) than in dark for the nitrobenzene hydrogenation under 0.1 MPa H 2 and 25 °C; they ascribed the outstanding catalytic performance to the synergistic effect of Pd and Au nanoparticles on the semiconductor SiC .…”