Cerium -sulfate

Analytical thin-layer chromatography was performed on E. Merck silica gel 60 F254 plates (0.25 mm) and compounds were visualized by dipping the plates in a cerium sulfate-ammonium molybdate solution followed by heating. 

Fig. 5.1.4 (A) TEM and (B) SEM of rodlike particles of basic cerium sulfate prepared by...

Cerium sulfate Potentiometric titration, using Fe2+ 1,10-phenanthroline as indicator Cioroi449... 

Gasolines contain a small amount of sulfur which is emitted with the exhaust gas mainly as sulfur dioxide. On passing through the catalyst, the sulfur dioxide in exhaust gas is partially converted to sulfur trioxide which may react with the water vapor to form sulfuric acid (1,2) or with the support oxide to form aluminum sulfate and cerium sulfate (3-6). However, sulfur storage can also occur by the direct interaction of SO2 with both alumina and ceria (4,7). Studies of the oxidation of SO2 over supported noble metal catalysts indicate that Pt catalytically oxidizes more SO2 to SO3 than Rh (8,9) and that this reaction diminishes with increasing Rh content for Pt-Rh catalysts (10). Moreover, it was shown that heating platinum and rhodium catalysts in a SO2 and O2 mixture produces sulfate on the metals (11). 

The easily visualized Belousov Zhabotinsky (BZ) reaction is now a classic example of the emergence of temporal and spatio temporal dissipative struc tures in homogeneous chemical systems. The reaction was discovered by Soviet military chemist B. P. Belousov in 1951 when he was studying homo geneous oxidation of citric acid by potassium bromide, KBrOq, in the presence of cerium sulfate Ce(S04)2 as the catalyst for redox processes. In the dissolved mixture of these compounds under certain process conditions, Belousov discovered a time-oscillating synchronous reduction of cerium(4+) ions ... 

The solubilities of several solids as a function of temperature. Note that although most substances be come more soluble in water with increasing temperature, sodium sulfate and cerium sulfate become less... 

CERIC SULPH.ATE CERIUM DISULFATE CERIUM SULFATE CERIUM(4+) SULFATE SULFURIC ACID, CERIUM SALT (2 1)... 

It is interesting to consider which factors are important in the formation of cerium sulfates. The presence or absence of Pt had little effect, showing that ceria is able to oxidize SO2 without an additional catalyst [42]. Furthermore, the oxidation of SO2 to S04 occurs on ceria to some extent without the addition of gas-phase O. obviously with the simultaneous reduction of ceria [40]. Finally, bulk sulfates were only formed when the ceria samples were exposed to SO2 at temperatures above 250"C. 

Ceria Cerium Sulfate Cerium Sulftde Supported-Metal Catalysts Oxygen-Storage Capacity Water-Gas Shift Steam Reforming SO H2S. 

Ammonium cerium sulfate (ceric ammonium sulfate), (NH4)2Ce-(804)4 2(NH4)2S04 2H20, converts aromatic polynuclear hydrocarbons into quinones [429]. 

Tungsten hexafluoride, WF (mp 2.5 °C, bp 17 °C) [529], resembles M0F5 and M0OCI3 in its oxidative properties. However, less exotic reagents such as ozone, ammonium cerium sulfate, or zinc dichromate may be used for a similar purpose. 

Sodium bromate, NaBrOs, a white crystalline compound, converts acyloins into a-diketones under forcing conditions [740]. More often, this reagent is used as a reoxidant of ammonium cerium nitrate [421], cerium sulfate [741], or ruthenium trichloride [741] in oxidations of alcohols to aldehydes [421] or carboxylic acids [741]. 

Other REDOX reagents include iodine (I2), either by itself in a forward titration or in a back titration with sodium thiosulfate (Na2S2Os), and complex salts of the metal cerium (such as ammonium cerium sulfate,... 

---