Autoxidations of cyclohexane and its autoxidation products

Hendry, Dale G.; Gould, Constance W.; Schuetzle, Dennis; Syz, Martin G.; Mayo, Frank R.

doi:10.1021/jo00863a001

Cited by 67 publications

(29 citation statements)

References 6 publications

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“…However, it has been previously reported that less sec. alcohol than ketone species is found in both oxidised liquid hydrocarbons and in g-irradiated polyethylene [13,30]. This is clearly confirmed by our data (cf.…”

Section: Discussionsupporting

confidence: 92%

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Mallégol

Carlsson

Deschênes

2001

Polymer Degradation and Stability

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Vitamin E was found to be a very effective antioxidant both in a model, liquid alkane, (teradecane) and in HDPE when oxidations at close to room temperature were initiated with g-radiation. FTIR was used to follow changes in vitamin E in oxidising tetradecane and HDPE, even at very low concentrations of the antioxidant. Formation of isolated hydroperoxide groups as a direct result of the vitamin E-peroxyl radical reaction were clearly visible. Quinone products from vitamin E were formed during g-irradiation, but different quinones were formed depending on the vitamin E concentrations. Vitamin E quite effectively retarded the oxidation of HDPE during g-irradiation and so should be useful in polyethylene intended for radiation sterilisation, as packaging materials or medical devices. Crown

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Section: Discussionsupporting

confidence: 92%

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Mallégol

Carlsson

Deschênes

2001

Polymer Degradation and Stability

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“…This deviation could be explained by either the occurrence of nonterminating ketone producing reactions or by an increased rate of initiation at higher conversions. Possible nonterminating ketone producing reactions could be a-attack of peroxyl radicals on hydroperoxides [ll], reaction (ll), direct molecular decomposition of hydroperoxides to yield ketone and water [12], reaction (12), molecular decomposition assisted by some oxidation product (M = carboxylic acid, ketone, etc.) [13], reaction (13), or direct reaction of oxygen with alkoxyl radicals, reaction (14) [14].…”

Section: Determination Of Kl From Rate Of Formation Of Termination Prmentioning

confidence: 99%

Initiation in hydrocarbon autoxidation at elevated temperatures

Jensen

Korček

Zinbo

et al. 1990

Int J of Chemical Kinetics

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Kinetic and mechanistic investigations of liquid phase autcxidation of hexadecane at 120 to 190°C have shown that, in the early stages of oxidation, the initiation process involves homolytic decomposition of hydroperoxides. The values of a composite first order rate constant for this decomposition, k l , have been determined in stirred flow reactor experiments from the rate of formation of termination products and in batch reactor studies using inhibitor methods.Arrhenius parameters derived from these studies (log (A/s-') = 8.5 and E, = 26 kcal mol-') allow calculation of k l as a function of temperature. This permits determination of the rate of initiation as a function of hydroperoxide concentration and facilitates determination of absolute rate constants for other oxidation reactions occurring in this system.

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“…Prior to performing GLC analysis, isomeric methyl 2 , methyl 4 , methyl 5 , and methyl 6 hydroperoxy hexanoates, as well as methyl 2,3 dihydroperoxyhex anoate, were converted to the corresponding hydroxyl derivatives by treating them with triphenylphosphine [16,17]. Thereafter, methyl 2 , methyl 4 , and methyl 5 hydroperoxyhexanoates were analyzed on a column packed with 15% silicone rubber Carbowax 6000 on Chromatone N AW DMCS using methyl tetrade canoate as the internal standard.…”

Section: Methodsmentioning

confidence: 99%

Reactivity of the C-H bonds of methyl hexanoate toward the tert-butylperoxy radical

et al. 2012

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155Carboxylic acid esters resulting from the liquid phase oxidation of hydrocarbons and their oxygen derivatives [1,2] can enter into free radical chain pro cesses involving both the acyl and alkoxyl moieties [1,3,4]. The electron withdrawing functional group affects the mechanisms of formation and transforma tion of the intermediates (peroxyl radicals and hydro peroxides) and also the reactivity of the C-H bonds nearest to this functional group [1,3,4]. It was shown for the reactions of tert butylperoxy radicals with cyclohexyl acetate at 333 K [5] that the ester group activates the α C-H bonds and substantially deacti vates the β and γ C-H bonds of the alkoxyl moiety with respect to the peroxyl radicals. Although there have been many works devoted to ester oxidations (see monograph [1] and review [3]), the influence of the functional group on the reactivity of various types of C-H bonds in the acyl moiety remains unclear. The discovery of a new mechanism and new products of the oxidation of carbonyl containing compounds at the β C-H bonds [6-8] makes disputable the results of an earlier study [9] in which the relative reactivity of the C-H bonds of methyl hexanoate were determined from the composition of the alcohols that resulted from the reduction of the oxidation products of this ester with lithium aluminum hydride at 413 K.The purpose of the present work is to determine, using methyl hexanoate as an example, the reactivity of the main types of C-H bonds in the acyl moiety of the ester toward the tert butylperoxy radical at 373 K. EXPERIMENTALMethyl hexanoate (analytical grade) was purified by vacuum distillation in flowing argon. According to GLC data, the product contained 99.5 ± 0.1% methyl hexanoate.tert Butyl hydroperoxide (TBHP) was synthesized and purified by a standard procedure [10]. As deter mined by iodometry, the synthesized compound con tained at least 99.3 ± 0.2% hydroperoxide. Peroxide compounds were quantified by a colorimetric method using a reagent containing Fe 2+ ions and N,N dime thyl para phenylenediamine [11].The reference substances necessary for gas chro matographic identification of methyl hexanoate oxi dation products were synthesized using standard methods. 2 Hydroxyhexanoic acid was obtained by the hydrolysis of 2 bromohexanoic acid [12]. Accord ing to GLC data, the 2 hydroxyhexanoic acid content of the product was 99.3 ± 0.2%. Methyl 6 hydroxy hexanoate was obtained by heating ε caprolactone with water in a sealed tube followed by the esterifica tion of the carboxyl groups with diazomethane. 2 Hexenic acid was synthesized by the Knoevenagel condensation of butanal and propanedioic acid in the presence of pyridine [13] and was purified by consec utive recrystallization from water and an ethanolwater (1 : 1) mixture. The melting point of the product was 32°С (reference value: 32-33°С [13]). 2,3 Epoxy hexanoic acid was obtained by treating 2 hexenic acid with a 30% aqueous solution of hydrogen peroxide in the presence of Na 2 WO 4 [14]. The purity of the result ing acid, according ...

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Autoxidations of cyclohexane and its autoxidation products

Cited by 67 publications

References 6 publications

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Initiation in hydrocarbon autoxidation at elevated temperatures

Reactivity of the C-H bonds of methyl hexanoate toward the tert-butylperoxy radical

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