An Escape from Noble Metals for Generating Urethanes via Reductive Carbonylation of Nitroarenes over FeSe2/γ-Al2O3 †

Abstract

The reaction of FeCl3, SeO2, and Pyridine (Py) in the presence of methanol (MeOH) under CO pressure generates a black precipitate, which has been confirmed as ferric di-selenide, FeSe2 through different structure characterization methods. Furthermore, impregnation of 5 wt% of FeSe2 onto γ-Al2O3 exhibits better catalytic performance than FeSe2 due to the highly dispersed and smaller particle sizes ca. 200–300 nm. The reductive carbonylation of nitrobenzene (NB) was investigated over FeSe2/γ-Al2O3 as a heterogeneous catalyst, delivering an excellent yield and high selectivity of methyl-N-phenyl carbamate (MPC). Moreover, a set of reactions was performed with variation in the reaction time, temperature, and pressure to investigate the effects of these factors. In particular, FeSe2/γ-Al2O3 is highly stable and can be recycled for up to five cycles without significant loss in catalytic performance. A mechanistic study was also conducted on this low-cost catalyst system, especially proposing a crucial role of FeSe2 (μ-CO) active species.

How To Get Isocyanate?

“…This reaction primarily utilizes homogeneous transition metal catalysts such as Pt, Rh, Ru, and Pd. − However, recycling of these catalysts proves challenging. To address the separation issue, heterogeneous catalysts, including Fe–Cu metal selenides supported by cerium and γ-Al 2 O 3 , as well as Rh, Ru, and Pd complexes, , have been suggested, and various forms of such catalysts have been developed.…”

Reductive Carbonylation of Nitroarenes Using a Heterogenized Phen-Pd Catalyst

“…Despite the high catalytic activity of homogeneous catalysts, their recovery and recycling are a major concern for industrial applications. For effective separation of the homogeneous catalysts, various heterogeneous catalysts for the reductive carbonylation of nitroarenes have been developed by employing selenium, metal selenides of Fe and Cu supported on ceria and γ-Al 2 O 3 , and supported Rh, Ru, and Pd complexes. − Unfortunately, the reactivity of these heterogeneous catalytic systems is lower relative to that of homogeneous Pd-based catalysts. For instance, Cenini et al attempted the use of Pd/Al 2 O 3 and Rh/Al 2 O 3 as heterogeneous catalytic systems for the reductive carbonylation of nitrobenzene (NB) .…”

“…Recently, Tran et al reported a CuSe 2 /CeO 2 as a novel heterogeneous catalyst for the reductive carbonylation of NB . This catalytic system showed >99% conversion with 96.4% MPC yield using an NB/CuSe 2 molar ratio of 44 under 8.3 MPa of CO at 160 °C in 4 h. In 2020, the same group reported a FeSe 2 system supported by γ-Al 2 O 3 as a heterogeneous catalyst revealing an improved TON of 85 . Although the recyclability was studied, a limited MPC was generated.…”