Cerium ratio effect

During the addition of the cerium(IV) solution up to the equivalence point, its only effect will be to oxidise the iron(II) (since K is large) and consequently change the ratio [Fe3+]/[Fe2 + ], When lOmL of the oxidising agent have been added, [Fe3+]/[Fe2 + ] = 10/90 (approx.) and... 

Results and Discussion. Of the 12 samples of starch graft copolymer synthesized, half were hydrolyzed to anionic polyelectrolytes. Synthesis data on these 6 samples are given in Table 2. These particular samples were chosen for hydrolysis because the samples can be intercompared to see the effect of synthesis variables on ultimate product properties. Samples 5, 8, and 11 have the same mole ratio of cerium ion to starch backbone, N, in their reaction mixture. Samples 7, 8, and 9 all have the same refctable mass per starch molecule,... 

Rare earth stabilization, as it relates to zeolite performance, has already been discussed. However, catalyst performance also varies depending on how the rare earths are deposited within the zeolite and the matrix, and also on how the ratio of individual species (such as lanthanum, cerium, and the other rare earths) are distributed. Yttrium can also be used to enhance zeolite catalyst performance and stability. These also seem to help mitigate the detrimental effect of vanadium, the most common and controversial contaminant. 

Sugi and coworkers have reported detailed results on the effect of Si02/Al203 ratio of mordenite on naphthalene isopropylation with propylene [Kim et al., 1995a]. They analyzed not only the bulk of the reaction products, but also the products trapped in the pores of mordenite after the isopropylation. The results reveal that inside the mordenite pore channel 2,6-diisopropylnaphthalene was formed in a much higher selectivity than 2,7-diisopropylnaphthalene, but the external surface sites contribute more to the non-selective reactions as well as coke formation. The same group also reported that the impregnation of cerium is an effective method for... 

Platinum is an effective oxidation catalyst for carbon monoxide and the complete oxidation of hydrocarbons. Palladium also promotes the oxidation of carbon monoxide and hydrocarbons but is more sensitive to poisoning than platinum in the exhaust environment. Both platinum and palladium promote the reduction of nitric oxide but are less effective than rhodium. In addition to the noble metals, three-way catalysts contain the base metal cerium and possibly other additives such as lanthanum, nickel or iron. These base metal additives are believed to improve catalyst performance by extending conversion during the rapid air-fuel ratio perturbations and help to stabilize the alumina support against thermal degradation. 

Human hemoglobin oxidation with Fe(lll)-heme formation as a result of the vanadyl ion effect was observed using Mossbauer spectroscopy [ 105]. Partial oxidation of rat hemoglobin after 70 days of rats feeding with cerium chloride was detected by Mossbauer spectroscopy [106]. An attempt to study hemoglobin from patients with diabetes was done in Ref. 107. However, poor statistical rates, a low signal-to-noise ratio, and a low velocity resolution in these studies did not permit the authors to extract more detailed and exact information. 

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