Oxidation of Saturated Hydrocarbons to Alkyl Hydroperoxides by a ‘H2O2/Titanosilicalite-1/NaOH/MeCN’ System

Shul’pin, Georgiy B.; Kirillova, Marina V.; Sooknoi, Tawan; Pombeiro, Armando J. L.

doi:10.1007/s10562-008-9406-8

Cited by 22 publications

(11 citation statements)

References 100 publications

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“…Bearing in mind that various metal‐free oxidation reactions can proceed more efficiently in the presence of a metal promoter,7, 13 we have screened a series of Cu, Fe, Cr, V, Mn, Zn, Co and Mo containing salts, oxides and coordination compounds (known catalysts for the oxidative functionalization of alkanes10,11f,12) for a potential promoting effect in the aqueous medium carboxylation of cyclohexane (Table 1). Although the majority of the selected metal compounds promote the carboxylation (see below), some Mo, V, Cr, Zn and Co species exhibit an inhibiting effect, leading to inferior yields of C 6 H 11 COOH in comparison with the metal‐free system (Table 1, entries 2–6).…”

Section: Resultsmentioning

confidence: 99%

“…Although the majority of the selected metal compounds promote the carboxylation (see below), some Mo, V, Cr, Zn and Co species exhibit an inhibiting effect, leading to inferior yields of C 6 H 11 COOH in comparison with the metal‐free system (Table 1, entries 2–6). This observation would be somehow unexpected taking into consideration that for example, H 4 [PMo 11 VO 40 ]⋅34 H 2 O and Cr(OH) 3 ⋅2.5 H 2 O11f are catalysts for the carboxylation of gaseous alkanes in TFA10b and for the peroxidative oxidation of cycloalkanes in MeCN/H 2 O,11f respectively. However, it reflects the dependence of the catalytic activity on the composition of the system and on the experimental conditions.…”

Section: Resultsmentioning

confidence: 99%

“…All chemicals were obtained from commercial sources and used as received. Compound 1 12 and the other tested promoters11f,12,21 were prepared according to published procedures. GC analyses were performed on a Fisons Instruments GC 8000 series gas chromatograph with a DB WAX (J&W) capillary column (P/N 122–7032; 30 m×0.25 mm×0.25 μm; helium was the carrier gas) and the Jasco‐Borwin v.1.50 software.…”

Section: Methodsmentioning

confidence: 99%

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Metal‐Free and Copper‐Promoted Single‐Pot Hydrocarboxylation of Cycloalkanes to Carboxylic Acids in Aqueous Medium

Kirillova¹,

Kirillov²,

Pombeiro³

2009

Adv Synth Catal

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A simple and effective method for the transformation, under mild conditions and in aqueous medium, of various cycloalkanes (cyclopentane, cyclohexane, methylcyclohexane, cis-and trans-1,2-dimethylcyclohexane, cycloheptane, cyclooctane and adamantane) into the corresponding cycloalkanecarboxylic acids bearing one more carbon atom, is achieved. This method is characterized by a singlepot, low-temperature hydrocarboxylation reaction of the cycloalkane with carbon monoxide, water and potassium peroxodisulfate in water/acetonitrile medium, proceeding either in the absence or in the presence of a metal promoter. The influence of various reaction parameters, such as type and amount of metal promoter, solvent composition, temperature, time, carbon monoxide pressure, oxidant and cycloalkane, is investigated, leading to an optimization of the cyclohexane and cyclopentane carboxylations. The highest efficiency is observed in the systems promoted by a tetracopper(II) triethanolaminate-derived complex, which also shows different bond and stereoselectivity parameters (compared to the metalfree systems) in the carboxylations of methylcyclohexane and stereoisomeric 1,2-dimethylcyclohexanes. A free radical mechanism is proposed for the carboxylation of cyclohexane as a model substrate, involving the formation of an acyl radical, its oxidation and consequent hydroxylation by water. Relevant features of the present hydrocarboxylation method, besides the operation in aqueous medium, include the exceptional metal-free and acid-solvent-free reaction conditions, a rare hydroxylating role of water, substrate versatility, low temperatures (ca. 50 8C) and a rather high efficiency (up to 72% carboxylic acid yields based on cycloalkane).

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Metal‐Free and Copper‐Promoted Single‐Pot Hydrocarboxylation of Cycloalkanes to Carboxylic Acids in Aqueous Medium

Kirillova¹,

Kirillov²,

Pombeiro³

2009

Adv Synth Catal

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“…However, the selectivity reached in all cases is still far from the desired values for an industrial application; this lower selectivity in absence of sodium hydroxide has been widely documented [24][25][26][27][28].…”

Section: Resultsmentioning

confidence: 99%

“…The NHPI method is applicable in a broad variety of organic syntheses via carbon radical intermediates [12][13][14][15][16]. Nonetheless, some authors have described the use of NHPI in hydrocarbon autoxidation, in which it acts as a catalyst and does not require the presence of a transition metal compound [16,17] In present industrial practice, ethylbenzene oxidation to its hydroperoxide is performed without solvent, using air as a source of oxygen, at temperatures ranging from 400 to 443 K, and slightly over atmospheric pressure to keep ethylbenzene in liquid phase (0.2 to 1.0 MPa) [24][25][26][27][28][29]. Another common practice is the addition to the reaction mixture of minute quantities of alkaline metals, such as sodium [24][25][26][27], alkaline-earth compounds, in particular barium [29,30], or organic salts [31] to increase the yield to hydroperoxides.…”

Section: Abstract: Autoxidation Organocatalysis Homogeneous Catalysmentioning

confidence: 99%

Ethylbenzene oxidation to its hydroperoxide in the presence of N-hydroxyimides and minute amounts of sodium hydroxide

Toribio

Gimeno-Gargallo

Capel-Sanchez

et al. 2009

Applied Catalysis A: General

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Copper(II) Complexes with Schiff Bases Containing a Disiloxane Unit: Synthesis, Structure, Bonding Features and Catalytic Activity for Aerobic Oxidation of Benzyl Alcohol

Soroceanu¹,

Cazacu²,

Shova³

et al. 2013

Eur J Inorg Chem

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Mononuclear copper(II) salen‐type Schiff base complexes, CuIIL1–5 [H2L1 to H2L5 = tetradentate N,N,O,O ligands derived from 2‐hydroxybenzaldehyde, 2,4‐dihydroxybenzaldehyde, 3,5‐dibromo‐2‐hydroxybenzaldehyde, 2‐hydroxy‐5‐nitrobenzaldehyde, 5‐chloro‐2‐hydroxybenzaldehyde and 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane, respectively] were prepared in situ in the presence of a copper(II) salt or by direct complexation between a copper(II) salt and a presynthesised Schiff base. The compounds {CuL1, CuL1·0.5Py, CuL2·0.375CH2Cl2, (CuL3)[Cu(4‐Me‐Py)4Cl]Cl·2H2O, CuL4, CuL4·CHCl3 and CuL5, as well as the isolated ligand H2L3} were characterised by elemental analysis, spectroscopic methods (IR, UV/Vis, 1H NMR, EPR) and X‐ray crystallography. The formation of a 12‐membered central chelate ring in these complexes is effected by the tetramethyldisiloxane unit, which separates the aliphatic chains, thus significantly reducing the mechanical strain in such a chelate ring. We dub this a “shoulder yoke effect” by analogy with the load‐spreading ability of such an ancient device. The coordination geometry of copper(II) in CuIIL1–5 can be described as tetrahedrally distorted square‐planar. Maximum tetrahedral distortion of the coordination geometry expressed by the parameter τ4 was observed for CuL1 (0.460), while distortion was minimal for the two crystallographically independent molecules of CuL2 (0.219 and 0.284). The Si–O–Si bond angle varies markedly between 169.75(2)° for CuL1 and 154.2(3)° for CuL4·CHCl3. Charge‐density and DFT calculations on CuL1 indicate high ionic character of the Si–O bonds in the tetramethyldisiloxane fragment. The new copper(II) complexes bearing the disiloxane moiety have been shown to act as catalyst precursors for the aerobic oxidation of benzyl alcohol to benzaldehyde mediated by the TEMPO radical, reaching yields and TONs up to 99 % and 990, respectively, under mild and environmentally friendly conditions (50 °C; MeCN/H2O, 1:1).

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Oxidation of Saturated Hydrocarbons to Alkyl Hydroperoxides by a ‘H2O2/Titanosilicalite-1/NaOH/MeCN’ System

Cited by 22 publications

References 100 publications

Metal‐Free and Copper‐Promoted Single‐Pot Hydrocarboxylation of Cycloalkanes to Carboxylic Acids in Aqueous Medium

Metal‐Free and Copper‐Promoted Single‐Pot Hydrocarboxylation of Cycloalkanes to Carboxylic Acids in Aqueous Medium

Ethylbenzene oxidation to its hydroperoxide in the presence of N-hydroxyimides and minute amounts of sodium hydroxide

Copper(II) Complexes with Schiff Bases Containing a Disiloxane Unit: Synthesis, Structure, Bonding Features and Catalytic Activity for Aerobic Oxidation of Benzyl Alcohol

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