Peroxide diisopropyl

Alkyl peroxides Di-ferf-butyl peroxide 2,5-Dimethyl-2,5-di-fcrf-butylperoxy-hexyne-3 Diisopropyl peroxide... 

The thermal decomposition of S5mrmetrical dialkyl peroxides such as diisopropyl peroxide in solution has been shown to involve a competition between monomolecular homolysis k ) and an electrocyclic reaction yielding acetone and hydrogen ( h) cf Eq. (5-59) [564]. 

The flrst study of the disproportionation-to-combinadoii ratio of alkoxyl radicals with NO was made by McMillan (1961), who photolyzed diisopropyl peroxide at 230-290 nm in the presence of NO. From the ratio of (CH3)2CO to 1-C3H7ONO produced he could deduce His values are given in Table 8. 

Table 20-1. Half-Lives and Activation Energies of Decomposition of Some Free Radical Initiators AI BN, Azobisisobutyronitrile BPO, Dibenzoyl Peroxide MEKP, Methyl Ethyl Ketone Peroxide IPP, Diisopropyl Peroxide Dicarbonate Dicup, Dicumyl Peroxide CuHP, Cumyl Hydroperoxide...

A second dangerous property of ethers is the ease with which they undergo oxi dation in air to form explosive peroxides Air oxidation of diisopropyl ether proceeds according to the equation... 

Ethers are relatively stable and unreactivc in many respects, but some ethers react slowly with the oxygen in air to give peroxides, compounds that contain an 0-0 bond. The peroxides from low-molecular-weight ethers such as diisopropyl ether and tetrahydrofuran arc explosive and extremely dangerous, even in tiny amounts. Ethers are very useful as solvents in the laboratory, but they must always be used cautiously and should not be stored for long periods of time. 

Laboratory studies have generally focused on the diisopropyl, dicyclohexyl and di-t-butyl derivatives. These and the. s-butyl and 2-cthylhcxyl derivatives arc commercially available.189 The rates of decomposition of the peroxydicarbonates show significant dependence on the reaction medium and their concentration. This dependence is, however, less marked than for the diacyl peroxides (36) (see 3.3.1.1.4). Induced decomposition may involve a mechanism analogous to that described for diacyl peroxides. However, a more important mechanism for primary and secondary peroxydicarbonates involves abstraction of an cx-hydrogen (Scheme 3.31).190... 

Diisopropyl ether that is peroxidised detonated many times by stirring, unscrewing the cap, impact. All accidents are fatal due to the violence of the detonations. It peroxidises in a few hours and forms complex mixtures, which are highly dangerous. The following peroxides have been identified ... 

Dining distillation of 2-propanol recovered from the reduction of crotonaldehyde with isopropanol/aluminium isopropoxide, a violent explosion occurred. This was attributed to peroxidised diisopropyl ether (a possible by-product) or to peroxidised crotonaldehyde. An alternative or additional possibility is that the isopropanol may have contained traces of a higher secondary alcohol (e.g. 2-butanol) which would be oxidised during the Meerwein-Ponndorf reduction procedure to 2-butanone. The latter would then effectively sensitise the isopropanol or other peroxidisable species to peroxidation. 

During reflux of a mixture to produce malonoyl chloride, vivid sparks were seen in the flask, and the reaction was closed down without mishap. No explanation is apparent, but the diisopropyl ester structure appears likely to be susceptible to autoxidation on storage, and peroxides may possibly have been involved in the phenomenon. 

Diisopropyl peroxydicarbonate, 3034 1 -Hydropcroxy-1 -hydroxydicyclohexyl peroxide, 3555 2-Pheny 1-2-propyl hydroperoxide, 1387... 

Bis(fluoroformyl) peroxide, 0625 Bis-3-(2-furyl)acryloyl peroxide, 3640 Bis(trichloroacetyl) peroxide, 1361 Bis(trifluoroacetyl) peroxide, 1367 Diacetyl peroxide, 1537 Dibenzenesulfonyl peroxide, 3499 Dibenzoyl peroxide, 3639 Di-3-camphoroyl peroxide, 3807 Dicrotonoyl peroxide, 2986 Dicyclohexylcarbonyl peroxide, 3667 Didodecanoyl peroxide, 3857 Di-2-furoyl peroxide, 3245 Dihexanoyl peroxide, 3554 Diisobutyryl peroxide, 3032 Diisopropyl peroxydicarbonate, 3034 Dimethanesulfonyl peroxide, 0931 Di-2-methylbutyryl peroxide, 3354 Di-l-naphthoyl peroxide, 3831 3,6-Dioxo-l,2-dioxane, 1445 Dipropionyl peroxide, 2442 Dipropyl peroxydicarbonate, 3035 Di-4-toluenesulfonyl peroxide, 3656 Peroxodisulfuryl difluoride, 4328 Phthaloyl peroxide, 2900 Potassium benzenesulfonylperoxosulfate, 2257 Potassium O-O-benzoylmonoperoxosulfate, 2684 (9-TriIIuoroacctyl-.S -lluorofonny 1 thioperoxide, 1050 See PEROXIDES, PEROXYCARBONATE ESTERS... 

Many incidents involving explosions have been attributed, not always correctly, to peroxide formation and violent decomposition. Individually indexed incidents are 2-Acetyl-3-methyl-4,5-dihydrothiophen-4-one, 2807 Aluminium dichloride hydride diethyl etherate, Dibenzyl ether, 0061 f 1,3-Butadiene, 1480 f Diallyl ether, 2431 f Diisopropyl ether, 2542... 

List A, giving examples of compounds which form explosive peroxides while in storage, include diisopropyl ether, divinylacetylene, vinylidene chloride, potassium and sodium amide. Review of stocks and testing for peroxide content by given tested procedures at 3-monthly intervals is recommended, together with safe disposal of any peroxidic samples. 

Apart from the conversion of peroxides to useful products, it is sometimes necessary to reduce peroxides, and especially hydroperoxides formed by auto-oxidation. Such compounds are formed especially in hydrocarbons containing branched chains, double bonds or aromatic rings, and in ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, etc. Since most peroxidic compounds decompose violently at higher temperatures and could cause explosion and fire it is necessary to remove them from liquids they contaminate. Water-immiscible liquids can be stripped of peroxides by shaking with an aqueous solution of sodium sulfite or ferrous sulfate. A simple and efficient way of removing peroxides is treatment of the contaminated compounds with 0.4 nm molecular sieves [669]. 

Diphenyl-1 -pyrenylphosphine hydroperoxide determination, 679-80 peroxide value, 659, 680 Diphenyl sulfide, peroxyacid reduction, 700-1 Dipolar intermediate, ene reaction, 853 Dipole moments, dioxiranes, 1132 DIPT (diisopropyl tartrate), 395 Dipyridamole, low-density hpoprotein antioxidant, 611 Di radicals... 

The kinetics of the zinc diisopropyl dithiophosphate-in-hibited oxidation of cumene at 60°C. and Tetralin at 70°C. have been investigated. The results cannot be accounted for solely in terms of chain-breaking inhibition by a simple electrow-transfer mechanism. No complete explanation of the Tetralin kinetics has been found, but the cumene kinetics can be explained in terms of additional reactions involving radical-initiated oxidation of the zinc salt and a chain-transfer step. Proposed mechanisms by which zinc dialkyl dithiophosphates act as peroxide-decomposing antioxidants are discussed. 

One possible problem peculiar to a quantitative study of the inhibition of oxidation of aromatic hydrocarbons by zinc dialkyl dithiophos-phates is that peroxide decomposition could yield a phenol during the initial-rate measurement. Rate curves for the zinc diisopropyl dithio-phosphate-inhibited oxidation of cumene are shown in Figure 7. In the initial presence of hydroperoxide the uninhibited rate is never reached, and the reaction soon exhibits autoinhibition, presumably caused by the... 

Pfizer has also had solvent reduction programs for diethyl ether, diisopropyl ether, hexane, and pentane, and these have all undergone either substantial reductions or in some cases total elimination. In the case of diisopropyl ether, which easily forms explosive peroxides, some journal editors will only accept papers using this solvent if a scientific justification for its usage is given, and this approach is to be applauded [7]. 

---