Oxidation excess

After epoxidation, propylene oxide, excess propylene, and propane are distilled overhead. Propane is purged from the process propylene is recycled to the epoxidation reactor. The bottoms Hquid is treated with a base, such as sodium hydroxide, to neutralize the acids. Acids in this stream cause dehydration of the 1-phenylethanol to styrene. The styrene readily polymerizes under these conditions (177—179). Neutralization, along with water washing, allows phase separation such that the salts and molybdenum catalyst remain in the aqueous phase (179). Dissolved organics in the aqueous phase ate further recovered by treatment with sulfuric acid and phase separation. The organic phase is then distilled to recover 1-phenylethanol overhead. The heavy bottoms are burned for fuel (180,181). 

The amount of sodium hypochlorite in a bleach solution can be determined by using a given volume of bleach to oxidize excess iodide ion to iodine CIO- is reduced to Cl-. The amount of iodine produced by the redox reaction is determined by titration with sodium thiosulfate, Na2S203 I2 is reduced to I-. The sodium thiosulfate is oxidized to sodium tetrathionate, Na2S406. In this analysis, potassium iodide was added in excess to 5.00 ml of bleach d = 1.00 g/cm3). If 25.00 mL of 0.0700 MNa2S203 was required to reduce all the iodine produced by the bleach back to iodide, what is the mass percent of NaCIO in the bleach ... 

INORGANIC FILMS Oxide films Air oxidation Excessive heating O2 in deposition equipment Oxidative cleaning processes... 

The nitration of propane is operated at 370-450 C and at about 10 atm. The use of about a fourfold excess of propane, 60-70% nitric acid, and short residence time ensures good temperature control.199 The conversion of nitric acid to nitroalkanes is less than 50% (the balance are nitrogen oxides). Excess propane is usually recycled to achieve about 60-80% yield of nitroalkanes. Under these conditions nitropro-panes are the main products. 

Failure to add a HBr quencher may lead to the partial hydrolysis of the tin alkoxide and a lower yield in the selective oxidation. Excess of molecular sieves or stannylating agent employed in the formation of the tin alkoxide may operate as HBr quenchers during the tin alkoxide oxidation. 

Moreover, XPS data also indicate that this Os reduction may be accompanied by oxidative degradation of the polymer. Not only the Os speciation but also the oxidant preference seem different for Herrmann s Os/PVP catalyst. Only H2O2 was an effective oxidant even in this case, extreme oxidant excesses were applied to convert the olefins ... 

The first step in the analysis of antioxidant phytochemicals is extraction of the compounds Ifom the plant matrix. The means by which the samples are prepared for extraction is very important because, if it is not carefully performed, compounds can be chemically altered or degraded during the process. In general, sample preparation conditions should avoid oxidation, excessive exposure to high temperatures, enzymatic reactions, and other chemical changes to the target compounds. The first step is to select a representative sample of plant material that has been collected as recently as possible. If extraction cannot be performed immediately, it is recommended that samples be stored at refrigeration... 

The oxidation of thiols to disulfides is a very facile process and many reagents function as oxidants. Ease of oxidation usually decreases in the following order ArSH > n-RSH > s-RSH > t-RSH. The use of vigorous conditions such as strong oxidants, excess oxidants, higher temperatures and longer reaction times etc. usually results in further oxidation of initially produced disulfides to give a mixture of several... 

Non-stoichiometric oxides may contain either an excess of metal (e.g. zinc oxide, Zni+jO) or a deficiency of metal (e.g. nickel oxide, Ni,.jO). Some metal oxides (e.g. titanium oxide) may be prepared as either excess-metal or metal-deficit oxides. Excess metal is incorporated in the structure as interstitial cations together with the electrons removed through ionization. In metal-deficit or excess-oxygen oxides, excess oxygen is incorporated in the structure by formation of cation vacancies and positive holes, which may be achieved by oxidation of cations, e.g. 

Bartlett et al. 191) reported the use of oxidative demethylation of LTA. When 21-deoxyajmaline-l7-( -acetate (304) was oxidized with LTA (1 equiv) in acetic anhydride, 2-hydroxy-21-deoxyajmaline-17-O-ace-tate (305) was produced. However, LTA oxidation (excess of the oxidant) in benzene of the acetate 304 proceeded via oxidative demethylation to give l-demethyl-A -2I-deoxyajmaIine-17-O-acetate (306), which was also... 

Under most conditions, oxygen release into rhizosphere should be adequate to oxidize excessive levels of reduced compounds in order for wetland plants to survive soil anaerobiosis. Release of oxygen into the rhizosphere is demonstrated by the observation of oxidation of Fe + to Fe + and precipitation on the root surface, oxidation of carbonaceous compounds, and nitrification of ammonium nitrogen. A detailed discussion on the fate of oxygen in the rhizosphere is presented in Chapter 6. 

Peroxodisulfate anion, S208 , oxidizes excess Fe2+ in part D. Write a balanced net ionic equation describing this redox reaction. To predict the correct sulfur-containing product, you must consider both the pH of the solution and that sulfur undergoes no change of oxidation state. 

For n-type oxides, excess metal ions exist in interstitial positions of the oxide lattice, and it is these, together with electrons, that migrate during oxidation... 

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