Cerium methanesulfonate

Several examples have been described on Lewis acid and base catalyzed Michael additions. Cyclopentanone-2-carboxylic acid ethylester was added at room temperature to methyl vinyl ketone using 2 mol% FeCl3 -6 H20 as catalyst yielding > 90% of the addition product (Scheme 11) [31]. Cerium(III) chloride in the presence of sodium iodide [32] and trifluoro-methanesulfonic acid have been used as catalysts as well [33]. 

The use of electricity in reactions is clean and, at least in some cases, can produce no waste. Toxic heavy metal ions need not be involved in the reaction. Hazardous or expensive reagents, if needed, can be generated in situ where contact with them will not occur. The actual oxidant is used in catalytic amounts, with its reduced form being reoxidized continuously by the electricity. In this way, 1 mol% of ruthenium(III) chloride can be used in aqueous sodium chloride to oxidize benzyl alcohol to benzaldehyde at 25°C in 80% yield. The benzaldehyde can, in turn, be oxidized to benzoic acid by the same system in 90% yield.289 The actual oxidant is ruthenium tetroxide. Naphthalene can be oxidized to naphthoquinone with 98% selectivity using a small amount of cerium salt in aqueous methanesulfonic acid when the cerium(III) that forms is reoxidized to cerium(IV) electrically.290 Substituted aromatic compounds can be oxidized to the corresponding phenols electrically with a platinum electrode in trifluoroacetic acid, tri-ethylamine, and methylene chloride.291 With ethyl benzoate, the product is a mixture of 44 34 22 o/m/fhhy-... 

Spotnitz, R.M., Kreh, R.P, Lundquist, J.T. and Press, PJ. (1990) Mediated electrosynthesis with cerium(rV) in methanesulfonic acid. Journal of Applied Electrochemistry, 20, 209-215. 

In the zinc/cerium system, methanesulfonic acid has been widely used as a supporting electrolyte. It is less corrosive than sulphuric acid, and its sufficient acid strength can dissolve a high concentration of cerium ions. Moreover, researchers suggested that the zinc dendritic growth can be inhibited by the methanesulfonic acid [50]. 

Methanesulfonic acid is preferentially used as the electrolyte on both sides to increase the solubility of the metal cations [111]. Zinc-cerium chemistries enable a very high cell voltage. However, the concomitant parasitic reactions such as HER and OER must be avoided or minimized to achieve acceptable cell efliciencies. 

Cerium(IV) methanesulfonate 307 7. Indirect and catalytic reactions with ceri- ... 

Kreh et al. discovered that cerium(III) and cerium(IV) have a high solubility in aqueous methanesulfonic acid (Kreh and Spotnitz, 1987a, 1987c Kreh et al., 1989 Spotnitz et al., 1990). When the concentration of methanesulfonic acid is between 1.5 and 9 molar the sol-... 

---