Methyl hydroperoxide

Now that the allylic oxidation problem has been solved adequately, the next task includes the introduction of the epoxide at C-l and C-2. When a solution of 31 and pyridinium para-tolu-enesulfonate in chlorobenzene is heated to 135°C, the anomeric methoxy group at C-l 1 is eliminated to give intermediate 9 in 80% yield. After some careful experimentation, it was found that epoxy ketone 7 forms smoothly when enone 9 is treated with triphenyl-methyl hydroperoxide and benzyltrimethylammonium isopropoxide (see Scheme 4). In this reaction, the bulky oxidant adds across the more accessible convex face of the carbon framework defined by rings A, E, and F, and leads to the formation of 7 as the only stereoisomer in a yield of 72%. 

The methyl radical reacts further to form either formaldehyde CH2O or methyl hydroperoxide CH3OOH, depending upon the nitric oxide NO concentration ... 

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 only accident that involves a saturated ester is the result of an attempt to extract an organic residue containing hydrogen peroxide with ethyl acetate. The latter was mixed with methanol and refluxed with the residue and hydrogen peroxide in an aqueous solution. A second extraction was carried out with acetate and the liquid was then evaporated. The small quantity of the compound that remained after the evaporation detonated violently. It was thought that this detonation was the result of the violent decomposition of methyl hydroperoxide, peracetic acid and/or ethyl peracetate. 

Organic material was extracted from a sample with methanol, and after evaporation the small residue was refluxed with aqueous peroxide. Extraction with ethyl acetate, separation and evaporation gave a residue which was scarcely visible but which exploded violently when the flask was moved. Several peroxidic species, including methyl hydroperoxide, peroxyacetic acid or its ethyl ester, may have been involved. See Ethyl acetate... 

Aqueous cyanide effluent containing a little methanol in a 2 m3 open tank was being treated to destroy cyanide by oxidation to cyanate with hydrogen peroxide in the presence of copper sulfate as catalyst. The tank was located in a booth with doors. Addition of copper sulfate (1 g/1) was followed by the peroxide solution (27 1 of 35 wt%), and after the addition was complete an explosion blew off the doors of the booth. This was attributed to formation of a methanol vapour-oxygen mixture above the liquid surface, followed by spontaneous ignition. It seems remotely possible that unstable methyl hydroperoxide may have been involved in the ignition process. 

Methylhexahydrophthalic anhydride (MHHPA) hardener, 10 17 Methyl hydroperoxides, decomposition hazards of, 18 490... 

Methyl groups, as hydrocarbon surface species, vibrational spectra, 42 214—219 Methylheptane, ring closure, 25 154 3-Methylhexane dehydrocyclization, 30 13 isomerization, 30 7, 14, 39-40 Methylhexane, ring closure, 25 155 Methyl hydroperoxide, catalytic decomposition, 35 161... 

V-Nitrosodimethylamine was the major product of ozonation of 1,1-dimethylhydrazine in the dark. Hydrogen peroxide, methyl hydroperoxide, and methyl diazene were also identified (HSDB, 1989). 

Methylhexanoic acid, see 5-Methylhexane Methyl hydrogen phthalate, see Dimethyl phthalate Methyl hydroperoxide, see 1,1-Dimethylhydrazine Methylhydroquinone, see 2-Methylphenol... 

Lind, J.A. and Kok, G.L. Henry s law determination for aqueous solutions of hydrogen peroxide, methyl hydroperoxide, and peroxyacetic acid, J. Geophys. Res., 91(D7) 7889-7895, 1986. 

FIGURE 33. Transition structures [B3LYP/6-31+G(d,p)] for the oxidation of dimethyl sulfide with (a) monomeric CH3O—OH and (b) dimeric methyl hydroperoxide... 

There is reported enthalpy of formation data for methyl hydroperoxide. The enthalpy of formation of the methyl derivative for any functional group, MeZ, is expected to deviate somewhat from the linear relationship established by the n-alkyl members of the homologous series with the same Z. It is unclear where the best straight line lies for the n-alkyl hydroperoxides and so the extent of deviation for methyl hydroperoxide is likewise unclear. However, methyl hydroperoxide, like other methyl derivatives with electron-withdrawing functional groups, should exhibit an enthalpy of formation that is more positive than other members of the series. 

The b value for peroxides was not evaluated in the original publication, but we can do so here from the experimental enthalpies of vaporization that are available. There are three such for the alkyl hydroperoxides 35 kJmor for methyl hydroperoxide, 43.1 kJmol for ethyl hydroperoxide and 47.7 kJmol for tert-butyl hydroperoxide. The corresponding b values are 27.3, 30.8 and 29.8 kJmol , respectively. The mean value, 29.0 4=... 

For the comparison of hydroperoxides with methyl ethers (equation 2), we find there is enthalpy of formation data only for dimethyl ether, isopropyl methyl ether and t-butyl methyl ether (again ignoring the ethyl and propyl hydroperoxides). The enthalpies of formal reaction 2 for R = Me, i-Pr and f-Bu (two gas phase enthalpies of formation for f-BuOOH) are —53.1, —54.9 and —37.6 or —48.6 kJmoU, respectively, in the gas phase. In the liquid phase, the enthalpies of reaction are —7.4, —35 (from the estimated enthalpy of formation of isopropyl hydroperoxide) and —20.0 kJmoU, respectively. Because the enthalpy of formation deviations from linearity for dimethyl ether and methyl hydroperoxide might not be identical, the reaction enthalpy might not be consistent with those... 

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. 

Methyl-9-(/J-formylphenyloxycarbonyl) aciidinium trifluromethanesulfonate, 643 Methyl hydroperoxide (MHP)... 

Both methyl hydroperoxide (CH3OOH) and peracetic acid (CH3C(0)00H) have been shown to oxidize S(IV)... 

O Sullivan, D. W., M. Lee, B. C. Noone, and B. G. Heikes, Henry s Law Constant Determinations for Hydrogen Peroxide, Methyl Hydroperoxide, Hydroxymethyl Hydroperoxide, Ethyl Hydroperoxide, and Peroxyacetic Acid, . /. Phys. Chem., 100, 3241-3247 (1996). 

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