Copper-catalyzed oxidative decarboxylation of aliphatic carboxylic acids

Agterberg, F.P.W.; Driessen, Willem L.; Reedijk, Jan; Oeveringb, H.; Buijs, Wim

doi:10.1016/s0167-2991(08)63458-8

Cited by 14 publications

(8 citation statements)

References 17 publications

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“…Reaction of sodium phenylacetate with 0.20 molal CuCl 2 resulted in higher conversion (85% conversion after 0.17 h) compared to the acid (68% after 0.17 h), which further suggests participation of a deprotonated form of the acid in the reaction, but not necessarily the freely solvated phenylacetate ion. The reaction is reminiscent of the known decarboxylations of benzoic and other carboxylic acids that are catalyzed by copper(I) and copper(II) salts, , and, in particular, oxidative decarboxylations of carboxylic acids where copper(II) is the oxidizing reagent. − Based on the previously proposed mechanisms of copper(II) decarboxylations and also the speciation calculations described above, a plausible mechanism for the phenylacetic acid reaction can be proposed, Scheme .…”

Section: Resultsmentioning

confidence: 99%

Organic Oxidations Using Geomimicry

et al. 2015

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Oxidations of phenylacetic acid to benzaldehyde, benzyl alcohol to benzaldehyde, and benzaldehyde to benzoic acid have been observed, in water as the solvent and using only copper(II) chloride as the oxidant. The reactions are performed at 250 °C and 40 bar, conditions that mimic hydrothermal reactions that are geochemically relevant. Speciation calculations show that the oxidizing agent is not freely solvated copper(II) ions, but complexes of copper(II) with chloride and carboxylate anions. Measurements of the reaction stoichiometries and also of substituent effects on reactivity allow plausible mechanisms to be proposed. These oxidation reactions are relevant to green chemistry in that they proceed in high chemical yield in water as the solvent and avoid the use of toxic heavy metal oxidizing reagents.

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Section: Resultsmentioning

confidence: 99%

Organic Oxidations Using Geomimicry

et al. 2015

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“…This type of structure may thus be the catalytically active species in the copper(II)-catalyzed oxidation of carboxylic acids. In fact, the rate-determining step in oxidative decarboxylation of copper(II) carboxylates in carboxylic acids is known to be the inner-sphere electron transfer from a coordinated carboxylate ligand to a copper(II) ion . This electron transfer then occurs in the paddle-wheel structure, the second copper ion facilitating the electron transfer.…”

Section: Discussionmentioning

confidence: 99%

“…During our investigations of the copper(II)-catalyzed oxidation of carboxylic acids, it was found that dinuclear copper(II) carboxylates are present under catalytic reaction conditions…”

Section: Introductionmentioning

confidence: 99%

Dinuclear Paddle-Wheel Copper(II) Carboxylates in the Catalytic Oxidation of Carboxylic Acids. Unusual Polymeric Chains Found in the Single-Crystal X-ray Structures of [Tetrakis(μ-1-phenylcyclopropane-1-carboxylato-O,O‘)bis(ethanol-O)dicopper(II)] and catena-Poly[[bis(μ-diphenylacetato-O:O‘)dicopper](μ₃-diphenylacetato-1-O:2-O‘:1‘-O‘)(μ₃-diphenylacetato-1-O:2-O‘:2‘-O‘)]

et al. 1997

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The X-ray structures and spectroscopic and magnetic properties of [tetrakis(&mgr;-1-phenylcyclopropane-1-carboxylato-O,O')bis(ethanol-O)dicopper(II)], 1, and catena-poly[[bis(&mgr;-diphenylacetato-O:O')dicopper](&mgr;(3)-diphenylacetato-1-O:2-O':1'-O')(&mgr;(3)-diphenylacetato-1-O:2-O':2'-O')], 2, two extended-chain copper(II) carboxylates with dinuclear paddle-wheel subunits, are reported. 1 crystallizes in the triclinic space group P&onemacr;, with a = 6.8873(3) Å, b = 11.7367(6) Å, c = 13.7899(7) Å, alpha = 107.076(4) degrees, beta = 93.545(4) degrees, gamma = 103.967(4) degrees, Z = 1. The Cu.Cu distance is 2.6009(4) Å, and the Cu.carboxylate O distances are in the range 1.937(2)-1.962(2) Å. The ethanol at the apex forms an unsymmetrical bifurcated H bond to two carboxylate oxygens of another dinuclear unit with O.O distances 2.980(3) and 3.108(3) Å, thereby extending the structure along the a-axis. The magnetic structure consists of isolated antiferromagnetically coupled dinuclear copper units, with a -2J value of 242 cm(-)(1), in concurrence with the EPR parameters, viz., g(x)() = 2.03(1), g(y)() = 2.07(1), g(z)() = 2.35(1), A( parallel) = 0.064(2) cm(-)(1), D = 0.316(15) cm(-)(1), E = 0.005(1) cm(-)(1). The -2J value is the smallest value measured for dinuclear copper carboxylates with oxygen-donor ligands at the axial position and no electron-withdrawing carboxylate R groups. 2 crystallizes in the monoclinic space group P2(1)/c, with a = 15.953(2) Å, b = 5.385(6) Å, c = 28.322(10) Å, beta = 120.22(3) degrees, Z = 2. The compound contains tetrakis(diphenylacetato)dicopper(II) units, forming a polymeric structure along the b-axis by axial coordination of a carboxylate oxygen to copper of a subsequent dinuclear unit, at 2.323(11) Å. The intradimer Cu.Cu distance is 2.594(4) Å; the interdimer Cu.Cu distance is 3.425(5) Å. The -2J value of 321 cm(-)(1) was interpreted as originated from isolated antiferromagnetically coupled dinuclear copper units. The EPR parameters are g(x)() = 2.07(1), g(y)() = 2.02(1), g(z)() = 2.33(1), D = 0.347(10) cm(-)(1), E = 0.0034(5) cm(-)(1). The dinuclear subunits are likely candidates for the catalytically active Cu species in copper(II)-catalyzed oxidation of carboxylic acids.

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“…A possible mechanism that would account for the significant TOC losses that occurred due to direct oxidation of SSW organics by Cu(NO 3 ) 2 and CuO in the absence of oxygen is copper catalysed decarboxylation. Copper is a well known catalyst for decarboxylation reactions of compounds such as keto acids and aliphatic carboxylic acids [23,24]. To the best of our knowledge this mechanism has not previously been proposed to occur during CWO of wastewaters using homogenous copper salts.…”

Section: Cu(no 3 ) 2 Catalysed Oxidation Of Ssw In Absence Of Oxygenmentioning

confidence: 96%