Peroxide formed percentage

ORR Apparent Electron-Transfer Number and the Formed Percentage of Peroxide Measured by RRDE Technique 221... 

The first free radical initiated copolymerization was described by Brubakerl) in a patent. A variety of peroxides and hydroperoxides, as well as, 02, were used as initiators. Olefins that were copolymerized with CO included ethylene, propylene, butadiene, CH2=CHX (X—Cl, OAc, CN) and tetrafluoroethylene. A similar procedure was also used to form terpolymers which incorporated CO, C2H4 and a second olefin such as propylene, isobutylene, butadiene, vinyl acetate, tetrafluoroethylene and diethyl maleate. In a subsequent paper, Brubaker 2), Coffman and Hoehn described in detail their procedure for the free radical initiated copolymerization of CO and C2H4. Di(tert-butyl)peroxide was the typical initiator. Combined gas pressures of up to 103 MPa (= 15,000 psi) and reaction temperatures of 120—165 °C were employed. Copolymers of molecular weight up to 8000 were obtained. The percentage of CO present in the C2H4—CO copolymer was dependent on several factors which included reaction temperature, pressure and composition of reaction mixture. Close to 50 mol % incorporation of CO in the copolymer may be achieved by using a monomer mixture that is >70 mol% CO. Other related procedures for the free radical... 

A number of volatile compounds are obtained apart from the crosslinked products in the final oxidation process. With polyolefines, water, formaldehyde, acetaldehyde, acetone, methanol, hydrogen peroxide, carbon monoxide, and carbon dioxide were identified [Refs. 75, 76, 122, 292, 424, 425, 449, 487, 560, 608]. Table 5 shows the percentage content of particular volatile products formed during the photo-oxidative degradation of polypropylene [122]. 

Ihe key point in this type of reactions is that hydroxyl radicals should not be attached to the redox center, but they should reach the state of free radicals diffusing to the aqueous phase away from the center from which it was formed. For instance, metal oxides and particularly iron oxides can act also as catalysts of the peroxide decomposition, but OH- radicals become attached to the iron atom forming iron hydroxide and only a small percentage of the total peroxide decomposition is useful to attack organic compounds in water (Scheme 3.26). It seems that the chemical stability derived from the strength of the n orbitals in G is responsible for the low reactivity of G materials against hydroxyl radicals. 

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