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Title: Rhodium-catalyzed hydrogenation of carbon dioxide to formic acid

Abstract

The complex [Rh(NBD)(PMe{sub 2}Ph){sub 3}]BF{sub 4} (2; NBD = norbornadiene) has been found to serve as a precatalyst for the hydrogenation of carbon dioxide to formic acid at moderate temperatures in THF solution, with turnover numbers of 10-60/day. Water accelerates formic acid production, whereas PMe{sub 2}Ph is an inhibitor. Kinetic studies show that the rate of formic acid appearance in first order each in [2], pH{sub 2}, and p{sub CO2} in the range 50-300 psi (following prehydrogenation). In situ high-pressure IR and NMR experiments reveal that the addition of H{sub 2} to [Rh(NBD)(PMe{sub 2}Ph){sub 3}]BF{sub 4} (2) produces rhodium dihydride complexes [H{sub 2}Rh(PMe{sub 2}Ph){sub 3}(S)]BF{sub 4}(4, 5; S = H{sub 2}O, THF) and [H{sub 2}Rh(PMe{sub 2}Ph){sub 4}]BF{sub 4} (3). IR and NMR studies of the reaction of 3-5 with CO{sub 2} indicate that 3 is unreactive toward CO{sub 2} but that 4 and 5 insert CO{sub 2} to give species 6 and 7, formulated as formato complexes [HRh(S)(PMe{sub 2}Ph){sub 2}({eta}{sup 2}-OCHO)]BF{sub 4}, respectively; complexes 6 and 7 are also detected under catalytic conditions by IR spectroscopy. Aquo dihydride complex 4 has been found to insert CO{sub 2} more rapidly than the THF complex 5. [H{sub 2}Rh(PMe{sub 2}Ph){sub 3}(S)]BF{sub 4} (4,more » 5) also catalyze the decomposition of formic acid to CO{sub 2} and H{sub 2}. Combined kinetic and spectroscopic results suggest that reductive elimination of formic acid from the intermediate formato complexes is the rate-limiting step in the catalytic cycle. 30 refs., 11 figs., 1 tab.« less

Authors:
;  [1]
  1. Univ. of Oklahoma, Norman, OK (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
284988
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 114; Journal Issue: 13; Other Information: PBD: 17 Jun 1992
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 10 SYNTHETIC FUELS; 01 COAL, LIGNITE, AND PEAT; RHODIUM; CATALYTIC EFFECTS; CARBON DIOXIDE; HYDROGENATION; ABSORPTION SPECTROSCOPY; NUCLEAR MAGNETIC RESONANCE; FORMIC ACID

Citation Formats

Tsai, Jing-Cherng, and Nicholas, K M. Rhodium-catalyzed hydrogenation of carbon dioxide to formic acid. United States: N. p., 1992. Web. doi:10.1021/ja00039a024.
Tsai, Jing-Cherng, & Nicholas, K M. Rhodium-catalyzed hydrogenation of carbon dioxide to formic acid. United States. https://doi.org/10.1021/ja00039a024
Tsai, Jing-Cherng, and Nicholas, K M. 1992. "Rhodium-catalyzed hydrogenation of carbon dioxide to formic acid". United States. https://doi.org/10.1021/ja00039a024.
@article{osti_284988,
title = {Rhodium-catalyzed hydrogenation of carbon dioxide to formic acid},
author = {Tsai, Jing-Cherng and Nicholas, K M},
abstractNote = {The complex [Rh(NBD)(PMe{sub 2}Ph){sub 3}]BF{sub 4} (2; NBD = norbornadiene) has been found to serve as a precatalyst for the hydrogenation of carbon dioxide to formic acid at moderate temperatures in THF solution, with turnover numbers of 10-60/day. Water accelerates formic acid production, whereas PMe{sub 2}Ph is an inhibitor. Kinetic studies show that the rate of formic acid appearance in first order each in [2], pH{sub 2}, and p{sub CO2} in the range 50-300 psi (following prehydrogenation). In situ high-pressure IR and NMR experiments reveal that the addition of H{sub 2} to [Rh(NBD)(PMe{sub 2}Ph){sub 3}]BF{sub 4} (2) produces rhodium dihydride complexes [H{sub 2}Rh(PMe{sub 2}Ph){sub 3}(S)]BF{sub 4}(4, 5; S = H{sub 2}O, THF) and [H{sub 2}Rh(PMe{sub 2}Ph){sub 4}]BF{sub 4} (3). IR and NMR studies of the reaction of 3-5 with CO{sub 2} indicate that 3 is unreactive toward CO{sub 2} but that 4 and 5 insert CO{sub 2} to give species 6 and 7, formulated as formato complexes [HRh(S)(PMe{sub 2}Ph){sub 2}({eta}{sup 2}-OCHO)]BF{sub 4}, respectively; complexes 6 and 7 are also detected under catalytic conditions by IR spectroscopy. Aquo dihydride complex 4 has been found to insert CO{sub 2} more rapidly than the THF complex 5. [H{sub 2}Rh(PMe{sub 2}Ph){sub 3}(S)]BF{sub 4} (4, 5) also catalyze the decomposition of formic acid to CO{sub 2} and H{sub 2}. Combined kinetic and spectroscopic results suggest that reductive elimination of formic acid from the intermediate formato complexes is the rate-limiting step in the catalytic cycle. 30 refs., 11 figs., 1 tab.},
doi = {10.1021/ja00039a024},
url = {https://www.osti.gov/biblio/284988}, journal = {Journal of the American Chemical Society},
number = 13,
volume = 114,
place = {United States},
year = {Wed Jun 17 00:00:00 EDT 1992},
month = {Wed Jun 17 00:00:00 EDT 1992}
}