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Kalinovskii, I. O.; Gel'bshtein, A.I.; Погорелов, В. В.

doi:10.1023/a:1013922523320

Cited by 12 publications

(14 citation statements)

References 4 publications

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“…Factors Inhibiting the Activity of Rh(III). Experimental studies of the oxidative carbonylation of toluene by Rh(III) dissolved in a mixture of TFAH and TFAA has shown that the presence of H 2 O, an excessively high CO partial pressure, and high Rh concentrations can lead to a loss of catalyst activity. ,, Each of these factors was examined in the course of the present study.…”

Section: Resultsmentioning

confidence: 98%

Theoretical Analysis of the Mechanism for the Oxidative Carbonylation of Toluene to p-Toluic Acid by Rhodium Complexes

Zheng

Bell

2008

J. Phys. Chem. C

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Density functional theory has been used to investigate the mechanism and kinetics of the liquid-phase, oxidative carbonylation of toluene to p-toluic acid (C 7 H 8 + CO + 1 / 2 O 2 f p-C 7 H 6 COOH + H 2 O) catalyzed by Rh(III) cations. In toluene solution containing trifluoroacetic acid and dissolved CO, Rh(III) is coordinated to three trifluoroacetate (TFA) anions and two CO molecules as Rh(CO) 2 (TFA) 3 . The oxidative carbonylation of toluene is initiated by the addition of toluene across one of the Rh-O bonds of Rh(CO) 2 (TFA) 3 to form (C 7 H 7 )Rh-(CO) 2 (TFAH)(TFA) 2 . The latter species undergoes isomerization and CO migration to produce (C 7 H 7 CO)-Rh(CO)(TFAH)(TFA) 2 , which then coordinates another molecule of CO. The mixed anhydride of toluic and tirfluoroacetic acid, C 7 H 7 C(O)O(O)CCF 3 and Rh(CO) 3 (TFA), are produced by reductive elimination from (C 7 H 7 CO)Rh(CO) 2 (TFAH)(TFA) 2 . Para-toluic acid is then formed by hydrolysis of C 7 H 7 C(O)O(O)CCF 3 . The proposed reaction mechanism explains many of the observations reported in our previous experimental work (Zakzeski, J. J.; Bell, A. T. J. Mol. Catal. A 2007, 276, 8) and, in particular, the effect of temperature on the ratio of p-to m-toluic acid, the effects of H 2 O and the partial pressure of CO on the loss of catalyst activity, and the effect of Rh concentration on the formation of a catalytically inactive Rh dimer species.

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Section: Resultsmentioning

confidence: 98%

Theoretical Analysis of the Mechanism for the Oxidative Carbonylation of Toluene to p-Toluic Acid by Rhodium Complexes

Zheng

Bell

2008

J. Phys. Chem. C

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“…FeC 2 O 4 , (NH 4 ) 6 Mo 7 O 24 , (NH 4 )VO 3 , and V 2 O 5 in combination with O 2 were also shown to work effectively as oxidants for both Pd and Rh [7]. The reoxidation of Pd could also be achieved using MnO 2 but in the absence of O 2 [8]. While Pd was found to be more active than Rh, the selectivity to p-toluic acid was highest for Rh.…”

Section: Introductionmentioning

confidence: 97%

“…In subsequent studies, Kalinovskii and coworkers have shown that the oxidative carbonylation of arenes can also be catalyzed using rhodium(III) or palladium(II) cations [6][7][8][9], and they have proposed a mechanism for the synthesis of toluic acid from toluene [9]. Since Rh(III) is reduced to Rh(I) and Pd(II) is reduced to Pd(0) in the course of the reaction, it was necessary to provide a means for reoxidizing the reduced metal.…”

Section: Introductionmentioning

confidence: 99%

Oxidative carbonylation of toluene to p-toluic acid catalyzed by rhodium in the presence of vanadium and oxygen

Zakzeski

Bell

2007

Journal of Molecular Catalysis A: Chemical

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“…Several studies have demonstrated that p-toluic acid can be synthesized by oxidative carbonylation of toluene catalyzed by Rh(III) cations in the presence of trifluoroacetic acid (TFAH) and its anhydride (TFAA) together with a vanadium oxo co-catalyst and molecular oxygen. 1,2 The active center in this system is thought to be Rh(CO) x (TFA) 3 (x = 1 or 2). [1][2][3][4] Kalinovskii and co-workers have proposed that Rh(CO) x (TFA) 3 reacts with toluene to form an aryl-rhodium complex Rh(CO)(TFA) 3 (Ph).…”

Section: Introductionmentioning

confidence: 99%

“…1,2 The active center in this system is thought to be Rh(CO) x (TFA) 3 (x = 1 or 2). [1][2][3][4] Kalinovskii and co-workers have proposed that Rh(CO) x (TFA) 3 reacts with toluene to form an aryl-rhodium complex Rh(CO)(TFA) 3 (Ph). 3 Migratory insertion of CO into the arene-metal bond forms PhCO-Rh(TFA) 3 , which then undergoes reductive elimination to form the mixed anhydride of toluic and trifluoroacetic acids.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic investigation of the species involved in the rhodium-catalyzed oxidative carbonylation of toluene to toluic acid

Zakzeski

Burton

Behn

et al. 2009

Phys. Chem. Chem. Phys.

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A spectroscopic investigation of complexes used to catalyze the oxidative carbonylation of toluene to p-toluic acid was conducted. Rhodium complexes were analyzed by (103)Rh and (13)C NMR, UV-visible spectroscopy, and infrared spectroscopy. In the presence of vanadium and oxygen, the resting state of the Rh-catalyst was found to exist as a Rh(III) complex with carbonyl and trifluoroacetate ligands, consistent with the structure Rh(CO)(2)(TFA)(3). The (13)C NMR spectrum of Rh((13)CO)(2)(TFA)(3) complex exhibited a carbonyl peak with an unusual degree of shielding, which resulted in the appearance of the carbonyl peak at an unprecedented upfield position in the (13)C NMR spectrum. This shielding was caused by interaction of the carbonyl group with the trifluoroacetate ligand. In the absence of oxygen, the Rh(III) complex reduced to Rh(I), and the reduced form exhibited properties resembling the catalyst precursor. Structures and spectroscopic properties calculated using density functional theory agreed closely with the experimental results. The vanadium co-catalyst used to reoxidize Rh(I) to Rh(III) was similarly characterized by (51)V NMR and UV-visible spectroscopy. The oxidized species corresponded to [(VO(2))(TFA)](2), whereas the reduced species corresponded to (VO)(TFA)(2). The spectroscopic results obtained in this study confirm the identity of the species that have been proposed to be involved in the Rh-catalyzed oxidative carbonylation of toluene to toluic acid.

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Cited by 12 publications

References 4 publications

Theoretical Analysis of the Mechanism for the Oxidative Carbonylation of Toluene to p-Toluic Acid by Rhodium Complexes

Theoretical Analysis of the Mechanism for the Oxidative Carbonylation of Toluene to p-Toluic Acid by Rhodium Complexes

Oxidative carbonylation of toluene to p-toluic acid catalyzed by rhodium in the presence of vanadium and oxygen

Spectroscopic investigation of the species involved in the rhodium-catalyzed oxidative carbonylation of toluene to toluic acid

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