Oxidation Decomposition Products

Because of the lower oxidation stability of the EC2 complex compared to the EC-BF4 complex, the oxidation-induced decomposition of EC2 was investigated [36]. While the lowest barrier and most exothermic path yielded CO2 and OC2H3 radical cations, a higher barrier path led to formation of oligo(ethylene carbonate). 

Because of a high barrier for the reaction leading to oligo(ethylene carbonate) formation, this reaction is expected to be slnggish with a low yield. It is consistent with the formation of a thin passivation layer on the cathode surface. Poly(ethylene carbonate) formation on cathode surfaces as a result of the oxidation-induced decomposition of an EC-based electrolyte was also recently suggested from experimental studies [46]. 

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The Beckstead-Derr-Price model (Fig. 1) considers both the gas-phase and condensed-phase reactions. It assumes heat release from the condensed phase, an oxidizer flame, a primary diffusion flame between the fuel and oxidizer decomposition products, and a final diffusion flame between the fuel decomposition products and the products of the oxidizer flame. Examination of the physical phenomena reveals an irregular surface on top of the unheated bulk of the propellant that consists of the binder undergoing pyrolysis, decomposing oxidizer particles, and an agglomeration of metallic particles. The oxidizer and fuel decomposition products mix and react exothermically in the three-dimensional zone above the surface for a distance that depends on the propellant composition, its microstmcture, and the ambient pressure and gas velocity. If aluminum is present, additional heat is subsequently produced at a comparatively large distance from the surface. Only small aluminum particles ignite and bum close enough to the surface to influence the propellant bum rate. The temperature of the surface is ca 500 to 1000°C compared to ca 300°C for double-base propellants. 

The relative thicknesses of the fuel and the oxidizer slab are determined by the stoichiometry of the particular propellant formulation. At the surface of the oxidizer slab, the solid oxidizer is assumed to vaporize, producing the gaseous oxidizer decomposition products. At the fuel surface, a similar assumption is made. 

Oils. Among many investigated oils, soy oil, middle-chain triglycerides (MCT), safflower oil, and cottonseed oils are favoured for use as the oil phase due to their low incidence of toxic reactions. Purity is regarded as an important criterion for parenteral use. Undesirable contaminants such as hydrogenated oil, saturated fatty materials, pigments, or oxidative decomposition products should be minimized. 

Vesicants produce acidic products including hydrogen chloride (HC1), hydrogen bromide (HBr), or hydrogen fluoride (HF), and ethanolamines, thioglycols, or thioethers when hydrolyzed. Arsenous oxide decomposition products from HL (C03-A010) are toxic and may also have vesicant properties. HL will also produce acetylene at higher pH. 

Possibly, cellular thiols may be oxidized by the inactive adduct of nitric oxide and oxygen to regenerate a nitrosothiol or related species with EDRF activity. Some of the inconsistent results observed in bioassay systems may be due to the secondary and nonenzymatic formation of a nitrosothiols or other species capable of regenerating nitric oxide, which are leached into perfusion cascades. Consequently, bioassay systems should not be the gold standard to distinguish whether nitric oxide is the EDRF, because secondary reactions of nitric oxide decomposition products may regenerate nitric oxide. 

The determination of quinicine, the oxidative decomposition product of quinine, has been reported by polarography [74]. Quinicine was determined in the presence of a 1000-fold excess of quinine in quinine salts and injectibles. The assay was rendered specific for quinicine in the presence of quinine by the... 

Polyethylene (PEI. In an unpublished study, pouches were made from paper/foil/PE laminates, and headspace gas was taken from the bag after incubation at 60° C for 20 minutes and analyzed by a gas chromatograph. Three major components were identified as acetaldehyde, allyl alcohol and acrolein. When odorous bags were compared with non-odorous bags, there showed a direct correlation between odor, acetaldehyde and allyl alcohol levels. Those compounds were considered to be thermal oxidative decomposition products of polyethylene (Baxter, J. A., W. Grayson and Assoc., Ltd., unpublished data). 

The presence of the heterocyclic disulfides in the aroma mixture is easy to understand and can be generally postulated as oxidative decomposition products of the corresponding monomers. Even air oxidation of the monomers may result in dimerization without effort. 

Fichera MA, Braun U, Schartel B, Sturm H, Knoll U, Jager C, Solid-state NMR investigations of the pyrolysis and thermo-oxidative decomposition products of a polystyrene/red phosphorus/magnesium hydroxide system. J. Anal. Appl. Pyrolysis 2007 78 378-386. 

The volatile peroxides, other oxidation decomposition products, and odiferous compounds form reduced-boiling point azeotropes with water in the steam, at high temperatures, 250-260°C/482-500°F, and very low absolute pressures ( 3 mbar). This is above the smoke point of soybean oil, but below the flash point, and oxygen must be excluded. Considerable heat bleaching of yellow-red carotenoids also occurs at this temperature. Typically the deodorization process requires 20-40 min after come-up time, uses 0.5-2.0 percent spaiged steam (the higher level if tocopherols are recovered), operates at between 2 and 4 mbar, and produces a product with about 0.03-0.05 percent FFA.143... 

A mechanism has been reported for the formation of trithlolane from the reaction of aldehydes with hydorgen sulfide (51). The identification of 3-methyl-5-butyl-l,2,4-trithiolane and 3-methyl-5-pentyl-1,2,4-trithiolane in food flavor suggests that pentanal and hexanal were Involved in the formation of these compounds (Figure 5). Pentanal and hexanal are major thermal and oxidative decomposition products of lipids. 

Likewise, Julian and Barnes succeeded in separating benzatiilide (XXIV, R = phenyl) from the oxidative decomposition products of XXIII, R = phenyl. This reaction also occurred spontaneously, and rapidly, in air. 

Modifications of the palladium-phenothiazine derivative complex procedure of Ryan ° have been applied to the quantitative analysis of propiomazine hydrochloride successfully. j The colorimetric procedure is based on the reaction of palladium with propiomazine in an aqueous solution buffered at about pH 3 to form a colored complex which is spectrophotometrically measured at U65 m/u. Since this complex formation is based on an electron transfer from the sulfur moiety to the palladium ions, the procedure provides a method to assay propiomazine in the presence of its corresponding sulfoxide oxidative decomposition product. 

Thermai decomposition products % at 475°C Thermal-oxidative decomposition product % at 430°C (approximate)... 

Ufheil J., Wiirsig A., Schneider O. D., Novak P. Acetone as oxidative decomposition product in propylene carbonate containing battery electrolyte, Electrochem. Commun. 2005, 7,... 

Ufheil, J. Wursig, A. Schneider, O. D. Novak, P., Acetone as Oxidative Decomposition Product in Propylene Carbonate Containing Battery Electrolyte. Electrochem. Commun. 2005, 7,1380-1384. 

Separation of tocopherols from their decomposition products. Silica gel lends itself conveniently to the separation of a-tocopherol from its oxidized decomposition products, including a-tocopherylquinone, a-tocopherylhydroquinone, and various partly characterized monomeric and dimeric compounds. These compounds can be prepared by in vitro oxidation, but some of them have also been detected by TLC in biological materials, e.g. rat liver (60). 

The quinone forms of a-, P-, and y-tocopherol have also been chromatographed on silica gel together with plastoquinones and various plant prenylquinones (61). A mixed sorbent consisting of alumina-zinc carbonate has been used for the TLC separation of various oxidized decomposition products of tocopherols (61). 

Dangerous fire hazard when exposed to heat or flame. Stable under normal conditions of temperature and pressure. Keep away from oxidizers. Decomposition products may include toxic and corrosive fumes of fluorides. 

The reaction of a-tocopherol with peroxyl radicals in vivo (see further D) leads to a number of oxidative decomposition products (5,6) (Fig. 2), of which a-tocopherolquinone (a-TQ) has been the most widely studied (7). 

Table 13 chemical shifts of papaverine and several oxidative decomposition products Compound DMSO-de TFA-d CDCI3 CD3OD ... 

As an alternative method for the above mentioned food items we proved the formation of N -carboxymethyllysine (CML) in a model system of several sugars and lysine (24) or casein, respectively. CML, an oxidative decomposition product of e-fructoselysine was identified for the first time in 1985 (25) in biological material and later also in food items (26, 27). This new compound can be detected... 

Initially, common phthalate plasticizers were included in die extremely hazardous substances list (Section 311) of Title III SARA, but this has since been corrected. But many usual plastics compounding ingredients still remain Usted and must be reported. For example, EPA denied a petition from a vinyl stabilizer company to de-list antimony tris(isooctylmercaptoacetate), a well known PVC stabilizer, since it considers the oxide decomposition products to be possible carcinogens. 

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