Polyoxides

Polypyrrole hybrids [Fig. 13(e)], electrogenerated from solutions containing the monomer and a salt of an inorganic macroion or a polyoxide.90-92... 

SL Khursan. Organic Polyoxides. Thesis Dissertation, Institute of Organic Chemistry, Ufa, 1999. 

The major groups of acyclic organic peroxides may be obtained by successively substituting H atoms in H2O2 with alkyl, aryl, acyl, alkoxycarbonyl or heteroatom substituents (Figure 3). A formal O insertion into the 0—0 bond provides polyoxides, i.e. compounds with at least three O atoms in a row. Substituents R have the potential to modify the... 

One of the significant differences between sulfur and oxygen chemistry is the relnctance of oxygen to form long chains of the type RO—0 —OR (n > 0, R,R = H, alkyl, aryl). The earliest reports on the preparation and characterization of the smallest polyoxo compound H2O3 dates back to 1963. The synthesis, structural characterization and exploration of this chemistry has made tremendous progress within the last decades and has opened a new area in peroxide chemistry, which is associated with the qnestion on the maxi-mnm possible chain length of a polyoxide chain before the system escapes spectroscopic characterization based on its lability . 

Poly(methylstyrene peroxide) radical polymerization, 707 stmcmre, 709 Polyolefins oxidized, 673 unsamrated, 740 Polyoxides... 

Unfortunately, two planned chapters did not materialize, on polyoxides and on structural chemistry of organometallic and heteroatomic peroxides. The literature coverage is mostly up to the end of 2004. 

Table V gives the bond strengths in some interesting polyoxide molecules and free radicals. The calculations were based on the reasonable assumption that group additivity is obeyed.

The constant awareness that the propellant chemist must keep for small amounts of impurities can be illustrated by the effects of the small quantities of peroxide that can be found in the polyoxide polymers. Small quantities of peroxide lead to chain scission at elevated temperatures and result in depolymerization. 

Conformational energies of the first four members (y = 1-4) of the polyoxide series CH30 (CH2ly-0-)x-CH3 are calculated using semiempirical potential energy functions. 

Monte-Carlo simulations based on the RIS models are used to generate distribution functions for the end-to -end separation of polyoxide chains having the repeat unit -(CH2)... 

From my estimates on the thermodynamic properties of peroxy and polyoxide molecules and radicals, we can estimate that the bond dissociation energy of the tetroxide is about 5 kcal. Thus, at room temperature, or even at dry ice temperature, the tetroxide is extremely unstable and should redissociate into the more stable (from a thermodynamic point of view) peroxy radicals. The competing step would be a concerted decomposition into an RO and an R03 (Step 14) radical, which would be uphill by 20 kcal., or else a concerted decomposition into 2 RO radicals and 02 (Step 14 ). The latter is almost thermoneutral. If we take the current data at face value, it provides, from the reported activation energy at least, strong evidence that the propagating interaction of two alkylperoxy radicals proceeds in a concerted fashion. 

Benson SW, Shaw R (1970) Thermochemistry of organic peroxides, hydroperoxides, polyoxides, and their radicals. In Swern D (ed) Organic peroxides, vol I. Wiley, New York, pp 105-139 Berdnikov VM, Bazhin NM, Fedorov VK, Polyakov OV (1972) Isomerization of the ethoxyl radical to thea-hydroxyethyl radical in aqueous solution. KinetCatal (EngITransI) 13 986-987 Besler BH, Sevilla MD, MacNeille P (1986) Ab initio studies of hydrocarbon peroxyl radicals. J Phys Chem 90 6446-6451... 

Nangia PS, Benson SW (1979) Thermochemistry of organic polyoxides and their free radicals. J Phys Chem 83 1138-1142... 

Plesnicar B (1983) Organic polyoxides. In Chemistry of Peroxides. Patai S (ed) Wiley, London, p 483... 

In Table 6.10 the influence of functional groups on the Ym(CH2) increments are given m = 0 means no functional goups in aliphatic carbon chains and m = 1 means with one functional group, like in polycaprolactams, polyoxides, etc.(see Fig. 6.7a). 

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