Methyl ethyl ketone diperoxide

Ozonolysis of Tetramethylene and cis-3,4-Dimethyl- 3 -hexene. A solution of tetramethylethylene (0.503 gram, 5.98 mmoles) and cis-3,4-dimethyl-3-hexene (0.692 gram, 6.17 mmoles) in 20 ml pentane was ozonized to 63% theoretical yield at —40°C. The product mixture was analyzed by GPC using an 8-ft 10% XF-1150 column at 85°C and a flow rate of 150 ml/minute. The mixture contained 25 mg acetone diperoxide, 36.7 mg l,l,4-trimethyl-4-ethyl-2,3,5,6-tetraoxacyclohexane, and 23.2 mg methyl ethyl ketone diperoxide as determined by GPC using an internal standard. Total yield of diperoxides was 14%. The diperoxides were identified by comparing mp, infrared, NMR, and GPC data with those of authentic samples. 

The remainder of the ozonolysis mixture was distilled from 22 °C (0.4 mm) to 55°C (0.03 mm) to give 0.549 gram of product. The crude product was distilled at 27°C (0.25 mm) to give 0.376 gram of a liquid. Analysis of this material by GPC showed that 70% of it was methyl ethyl ketone diperoxide (30% yield) identified by comparison with authentic material. The diperoxide had m.p. 7°-8°C. The remainder of the product was not identified. 

By choosing olefins of comparable reactivity towards ozone this difficulty can be avoided. When approximately equimolar amounts of 7 and cis-3,4-dimethyl-3-hexene, 8, were ozonized together all three predicted diperoxides were obtained—i.e., acetone diperoxide, 9, the cross diperoxide, l,l,4-trimethyl-4-ethyl-2,3,5,6-tetraoxacyclohexane, 10, and methyl ethyl ketone diperoxide, 11. 

Figure 1. Room temperature NMR spectrum of methyl ethyl ketone diperoxide...

Fig. 1.14 Molecular structures of triacetone triperoxide (TATP), hexamethylene triperoxide diamine (HMTD), methyl ethyl ketone peroxide (MEKP) and diacetone diperoxide (DADP).

We have found it useful to prepare authentic samples of the various diperoxides encountered by using a variation of the Baeyer-Villiger oxidation conditions. Oxidation of ketones at low temperatures using peracetic acid has been reported (23) to give diperoxides instead of the esters produced under Baeyer-Villiger conditions. Authentic samples of 10 and 11, can be prepared, respectively, by the peracetic oxidation of acetone and methyl ethyl ketone jointly or methyl ethyl ketone alone. We are studying the mechanism of this interesting oxidation reaction. 

Similar stereochemical possibilities are present when 11 is obtained from trans-l,3-dimethyl-3-hexene, 13, as a cross diperoxide from the ozon-olysis of 12 or from the peracetic acid oxidation of methyl ethyl ketone. 

The most commonly used initiator for anaerobic adhesives is cumene hydroperoxide. Many other hydroperoxides have been disclosed, such as t-butylhydroperoxide (XL), p-menthane hydroperoxide (XLI), diisopropylbenzene hydroperoxide (XLII), pinene hydroperoxide (XLIII), and methyl ethyl ketone hydroperoxide (XLIV) [40]. Some diperoxides, such as di-/-butylperoxide (XLV) and dicumylperoxide (XLVI), have been claimed, but these may function only because of hydroperoxide contamination [41]. 

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