Organic peroxy compounds

More than 200 structures from X-ray diffraction studies of acyclic organic peroxides have been disclosed in the literature since 1983. Structural information prior to 1983 was reviewed in an earlier book chapter and therefore has been omitted from this synopsis. Emphasis has been laid on a documentation of the most important structural information. The survey, however, remained incomplete since a considerable number of structures had been disclosed in the literature and/or the CSD database without providing the associated atomic coordinates. Further, structures with unusually short or long 0—0 connectivities have been omitted from the statistics for the reasons outlined in Section II. 

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In the organic chemicals industry, H2O2 is used in the production of epoxides, propylene oxide, and caprolactones for PVC stabilizers and polyurethanes, in the manufacture of organic peroxy compounds for use as polymerization initiators and curing agents, and in the synthesis of fine chemicals such as hydroquinone, pharmaceuticals (e.g. cephalosporin) and food products (e.g. tartaric acid). 

Figure 6 shows the variation of peroxide concentration in methyl ethyl ketone slow combustion, and similar results, but with no peracid formed, have been found for acetone and diethyl ketone. The concentrations of the organic peroxy compounds run parallel to the rate of reaction, but the hydrogen peroxide concentration increases to a steady value. There thus seems little doubt that the degenerate branching intermediates at low temperatures are the alkyl hydroperoxides, and with methyl ethyl ketone, peracetic acid also. The tvfo types of cool flames given by methyl ethyl ketone may arise from the twin branching intermediates (1) observed in its combustion. 

The first report of the polymerization of tetrafluoroethylene was by Plunkett in 1941, who had a cylinder of tetrafluoroethylene cut open to see why the expected amount of gas was not released when the valve was opened. His perspicacity led to the discovery of an inert, white, opaque solid with a waxy feel. Various methods of polymerization were tried after the adventitious discovery and the preferred methods for polymerization now involve aqueous media and super-atmospheric pressures. Suitable initiators (Hanford and Joyce) include ammonium, sodium, or potassium persulfate, hydrogen peroxide, oxygen, and some organic peroxy compounds. Oxidation-reduction initiation systems involving the use of persulfate with either ferrous ion or bisulfite or the use of bisulfite with ferric ion are also useful and have been discussed by Berry and Peterson. 

The danger associated with organic peroxy compounds makes it essential to maintain the safety precautions described in the Section on Hydroperoxides and peroxides by autoxidation. The behavior of an untested olefin on oxidation must be tested on a small sample before larger amounts are brought into reaction. Reaction mixtures must be worked up only after destruction or extraction of the excess of peroxy acid by alkali hydroxide solutions (danger of explosion ). 

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