Chemistry

Cheaper by the Half-Dozen

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Science  11 Apr 2003:
Vol. 300, Issue 5617, pp. 217
DOI: 10.1126/science.300.5617.217b

The value of many primary chemical feedstocks can be limited by the value of by-products that must also be sold. For example, the current synthesis of methanesulfonic acid (MSA) proceeds by means of the chlorine oxidation of methylmercaptan, and 6 moles of hydrochloric acid are produced for every mole of MSA. Mukhopadhyay and Bell report on a method in which methane is sulfonated directly, thereby avoiding the production of chlorine-containing byproducts. They use SO2 as the sulfate source and K2S2O8 as an oxidant; the reactions are run at high pressure in triflic acid. Various calcium salts, which have been shown to be effective catalysts in methane carbonylation, were tested, and the highest yields (22% conversion after 26 hours of reaction) were obtained with CaO2. Further efforts will be directed at replacing K2S2O8 with O2 as the oxidant.—PDS

J. Am. Chem. Soc. 10.1021/ja0281737 (2003).

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