Diethyl peroxide

Nearly all peroxides decompose readily, and many of the lower members are explosive. The decomposition of diethyl peroxide has been studied under both non-explosive and explosive conditions [99—102(b)]. The reaction is first-order and the variation of rate coefficient with temperature (uncorrected for any self-heating) is represented by fe = 1.6 x 10 exp(—34,000/i T) sec . At around 200 °C the course of the slow reaction may be represented by [102(a)] 

This reaction is exothermic AH = —47 kcal. mole ) and at 180 °C and above is accompanied by self-heating. 

Above a critical pressure (about 8 torr at 180 °C falling to about 2 torr at 200 °C) diethyl peroxide explodes spontaneously, emitting a flash of blue light. This explosion, which is preceded by an induction period 

All the major products of both the slow decomposition and explosive reaction can be accounted for qualitatively by reactions of the ethoxy radicals formed in the initial step which involves fission of the 0—0 bond. The reaction scheme is 

At about 500 °K disproportionation is favoured as the products are mainly ethanol and acetaldehyde. Explosion leads to higher temperatures, and more ethoxy radicals decompose yielding more ethane and formaldehyde. 

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Ether so obtained is anhydrous, and almost entirely free from other impurities. On standing, however, it undergoes slight atmospheric oxidation, with the formation of traces of diethyl peroxide, (CaH jaOa. The formation of this peroxide can be largely checked, however, by storing the distilled ether over fresh sodium wire, preferably in the dark. 

The thermal decompositions described above are unimolecular reactions that should exhibit first-order kinetics. Under many conditions, peroxides decompose at rates faster than expected for unimolecular thermal decomposition and with more complicated kinetics. This behavior is known as induced decomposition and occurs when part of the peroxide decomposition is the result of bimolecular reactions with radicals present in solution, as illustrated below specifically for diethyl peroxide. 

Dimethyl peroxide Diethyl peroxide Di-t-butyl-di-peroxyphthalate Difuroyl peroxide Dibenzoyl peroxide Dimeric ethylidene peroxide Dimeric acetone peroxide Dimeric cyclohexanone peroxide Diozonide of phorone Dimethyl ketone peroxide Ethyl hydroperoxide Ethylene ozonide Hydroxymethyl methyl peroxide Hydroxymethyl hydroperoxide... 

Dimethyl peroxide Diethyl peroxide Di-t-butyl-di-peroxyphthalate Difuroyl peroxide Dibenzoyl peroxide Dimeric ethylidene peroxide Dimeric acetone peroxide Dimeric cyclohexanone peroxide Diozonide of phorone Dimethyl ketone peroxide Ethyl hydroperoxide Ethylene ozonide Hydroxymethyl methyl peroxide Hydroxymethyl hydroperoxide 1-Hydroxyethyl ethyl peroxide 1 -Hydroperoxy-1 -acetoxycyclodecan-6-one Isopropyl percarbonate Isopropyl hydroperoxide Methyl ethyl ketone peroxide Methyl hydroperoxide Methyl ethyl peroxide Monoperoxy succinic acid Nonanoyl peroxide (75% hydrocarbon solution) 1-Naphthoyl peroxide Oxalic acid ester of t-butyl hydroperoxide Ozonide of maleic anhydride Phenylhydrazone hydroperoxide Polymeric butadiene peroxide Polymeric isoprene peroxide Polymeric dimethylbutadiene peroxide Polymeric peroxides of methacrylic acid esters and styrene... 

The meta- and para-isomers of the phosphoranes (FC6H4)3P(OEt)2 have been prepared from the corresponding phosphines and diethyl peroxide. From their F chemical shifts it was concluded that the groups... 

The phosphoranes (4) and (5) have been obtained from the corresponding phosphines and diethyl peroxide. From the variable temperature n.m.r. spectrum of (5), below - 51 °C the phenyl group is locked in an equatorial position as in (5), between — 51 and 30 °C the pseudorotation (5) (6) is rapid on the n.m.r. time scale, and above 30 °C the pseudorotation (6) (7) is rapid. In the latter pseudorotation the strain involved in... 

When ether is allowed to stand for some time in contact with air and exposed to light, slight oxidation occurs with the formation of the highly explosive diethyl peroxide, The danger from this unstable... 

Diethoxytriphenylphosphorane (the product of insertion of triphenylphosphine into diethyl peroxide) finds use as a mild, neutral reagent which initiates cyclodehydration of N- and C-substituted g-aminoalcohols to form aziridines in excellent yield,... 

Contact of ether with ozonised oxygen produces some of the explosive diethyl peroxide. 

Diethoxytriphenylphosphorane, (C6H5),P(OC2H5)2 (1). The phosphorane is obtained by reaction of diethyl peroxide (caution) with triphenylphosphine at 0-70°. Cyclodehydration of dioIs to ethers. 1,3-, 1,4-, and 1,5-Diols react with 1 to... 

Di(fe/ f-butylpcroxy)butanc. 3565 Diethyl peroxide, 1699 Dimethyl peroxide, 0923 Dipropyl peroxide, 2547... 

Disproportionation reaction 7 might be expected to be thermoneutral in the gas phase and perhaps less so in the liquid phase where there is the possibility of hydrogen-bonding. Only for gas phase dimethyl peroxide is the prediction true, where the reaction enthalpy is —0.2 kJmoD. The liquid phase enthalpy of reaction is the incredible —61.5 kJmoD. Of course, we have expressed some doubt about the accuracy of the enthalpy of formation of methyl hydroperoxide. For teri-butyl cumyl peroxide, the prediction for thermoneutrality is in error by about 6 kJmor in the gas phase and by ca 9 kJmoD for the liquid. The enthalpy of reaction deviation from prediction increases slightly for tert-butyl peroxide — 14kJmol for the gas phase, which is virtually the same result as in the liquid phase, — 19kJmol . The reaction enthalpy is calculated to be far from neutrality for 2-fert-butylperoxy-2-methylhex-5-en-3-yne. The enthalpies of reaction are —86.1 kJmoD (g) and —91.5 kJmol (Iq). This same species showed discrepant behavior for reaction 6. Nevertheless, still assuming thermoneutrality for conversion of diethyl peroxide to ethyl hydroperoxide in reaction 7, the derived enthalpies of formation for ethyl hydroperoxide are —206 kJmoD (Iq) and —164 kJmoD (g). The liquid phase estimated value for ethyl hydroperoxide is much more reasonable than the experimentally determined value and is consistent with the other n-alkyl hydroperoxide values, either derived or accurately determined experimentally. 

As was the case for the alkyl hydroperoxides in reaction 4, the enthalpies of the oxy-gen/hydrocarbon double exchange reaction 8 for dialkyl peroxides are different depending on the classification of the carbon bonded to oxygen. For R = Me, Et and f-Bu, the liquid phase values are —4, 24.6 and 52.7 kJmoR, respectively, and the gas phase values are 0.1, 25.7 and 56.5 kJmoR, respectively. For the formal deoxygenation reaction 9, the enthalpies of reaction are virtually the same for dimethyl and diethyl peroxide in the gas phase, —58.5 0.6 kJ moR. This value is the same as the enthalpy of reaction of diethyl peroxide in the liquid phase, —56.0 kJ moR (there is no directly determined liquid phase enthalpy of formation of dimethyl ether). Because of steric strain in the di-ferf-butyl ether, the enthalpy of reaction is much less negative, but still exothermic, —17.7 kJmol (Iq) and —19.6 kJmol (g). 

The gas phase enthalpy of reaction 6 for bis(hydroxymethyl) peroxide is — 192 kJ mol , which deviates from the other hydrate-producing peroxides by nearly 89 kJ mol . The enthalpy of reaction 8, 145 kJmol, is likewise discrepant by some 120 kJmol from that for diethyl peroxide, ca 26 kJ mol. From the high-level calculations reported in Reference 28, the reaction enthalpy for the addition of H2O2 to formaldehyde is —59 kJ mol. A similar reaction is equation 10 for the gas phase addition of tert-butyl hydroperoxide to a carbonyl group. 

The similarity of the slopes guarantees that the enthalpies of reaction 9, which involve members of these two series, will be similar. The mean value of —46.8 2.1 kJmol is about 12 kJmol less negative than the enthalpy of reaction 9 for diethyl peroxide, mentioned in the preceding section. 

A small contribution from the chain decomposition would be difficult to detect and would lower both the A factor and the activation energy. A similar argument applies to diethyl peroxide, and the measured (11) low A factors and activation energies are convincing evidence of the chain contribution. Leggett and Thynne (16) recently measured the A factor and activation energy for the decomposition of diethyl peroxide and found them to be normal. 

Experimental Measurements of Self-Heating in the Explosive Decomposition of Diethyl Peroxide , I2thSympCombstn, Poitiers, France, July 14-20, 1968. Abstracts of Papers, pp 100-02... 

Ethyl Peroxide. See Diethyl Peroxide in Vol5 of Encycl p D1246-R... 

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