Methanol as a Potential Hydrogen Source for Reduction Reactions Enabled by a Commercial Pt/C Catalyst

Abstract

Catalytic reduction reactions using methanol as a transfer hydrogenating agent is gaining significant attention because this simple alcohol is inexpensive and produced on a bulk scale. Herein, we report the catalytic utilization of methanol as a hydrogen source for the reduction of different functional organic compounds such as nitroarenes, olefins, and carbonyl compounds. The key to the success of this transformation is the use of a commercially available Pt/C catalyst, which enabled the transfer hydrogenation of a series of simple and functionalized nitroarenes-to-anilines, alkenes-to-alkanes, and aldehydes-to-alcohols using methanol as both the solvent and hydrogen donor. The practicability of this Pt-based protocol is showcased by demonstrating catalyst recycling and reusability as well as reaction upscaling. In addition, the Pt/C catalytic system was also adaptable for the N-methylation and N-alkylation of anilines via the borrowing hydrogen process. This work provides a simple and flexible approach to prepare a variety of value-added products from readily available methanol, Pt/C, and other starting materials.

Multi-Functionality of Methanol in Sustainable Catalysis: Beyond Methanol Economy

“…The research group of Natte reported the application of Pt/C as a reusable catalyst and methanol as a potential hydrogen donor for different reduction reactions such as nitroarenes-to-anilines, alkenes-to-alkanes, and aldehydes-to-alcohols (Scheme ). The Pt/C exhibited excellent stability and was easily recovered and reused for at least four times without any significant loss of reactivity …”

“…The Pt/C exhibited excellent stability and was easily recovered and reused for at least four times without any significant loss of reactivity. 171 1.2b. Copper.…”

Pt/C‐catalyzed Selective Hydrogenation of Nitroarenes to N‐arylhydroxylamines under Mild Conditions

“…The compounds were converted in high yields (i. e. 95 %, 97 % and 95 %) to the expected products (entries 4-6). Moreover, the reductively vulnerable functional group substituted nitroarenes such as À OCH 3 , À CHO, À COCH 3 , À COOH, À COOCH 3 were also showed excellent chemo-selectivity and delivered in 74-99 % yields (entries [7][8][9][10][11]. In short, we provided a mild and efficient catalytic reaction system for the selective hydrogenation of nitroarenes to the corresponding N-arylhydroxylamine.…”

“…In addition, the hydrogenation of nitroarenes is often run under drastic conditions, such as high reaction temperature and high pressure of H 2. [2e,3] Comparatively speaking, selective hydrogenation of nitroarenes to N-arylhydroxylamines by replacing traditional molecular hydrogen with hydrogen donors, such as silanes, [4] sodium borohydride, [5] formic acid, [6] methanol, [7] and hydrazine hydrate, [2a] offers a green, sustainable and atomic economic process. Among them, hydrazine hydrate is cheap, widely available and safe-to-handle.…”

Homogenous nickel-catalyzed chemoselective transfer hydrogenation of functionalized nitroarenes with ammonia–borane

“…Our group recently reported commercially available Pt/C and RuCl 3 · x H 2 O catalysts for the transfer hydrogenation reactions of nitroarenes using methanol. 12,13 Our interest in AB and nickel catalysis and the lack of reports concerning its application in the selective reduction of nitroarenes-to-aminoarenes motivated us to address this issue. Although homogeneous nickel-based catalysts are well recognized for borrowing hydrogen-type reactions and related chemistry, 14 they are largely unexplored for the transfer hydrogenation of nitroaromatics.…”