II sulfoxylate

Co(C2H302)2 + NaaSaO CoSjO + 2NaC2H302 C0S2O4 + NaHCOa + xYliO CoS02-a H20 + NaHSOs + CO2 

Checked by Bubi. E. Bbtant, Nobman Dittbick, and Thomas Gaowt 

Cobalt(II) sulfoxylate, CoS02 a H20, is the only known salt of the unstable sulfoxylic acid, H2SO2. Scholder and Denk prepared this compound by the reaction of cobalt (II) acetate with sodium dithionite in the presence of a weak base. The following procedure is based on their method. 

To determine cobalt, it is merely necessary to ignite the compound in an electric furnace to about 825° for one hour and weigh the residue as C03O4. To analyze for sulfur, 0.3 to 0.4 g. of the compound is placed in 200 ml. of distilled water, and a few drops of bromine are added. When all the cobalt (II) sulfoxylate has reacted, the excess bromine is boiled off and the sulfur is precipitated as barium sulfate. Anal Calcd. for CoS02-2H20 Co, 37.07 S, 20.13. Found Co, 36.93 S, 19.62. By checkers Co, 36.7 S, 19.3. The Co S ratio here is 1.00 0.98. Because of the variability of the water content, the Co S ratio is more useful than either analysis alone. 

Cobalt (II) sulfoxylate is a brown powdery hygroscopic solid, which is obtained with varying water of hydration. It decomposes when attempts are made to convert it into the sulfoxylates of other metals. It is easily oxidized by agents such as nitric acid, bromine, or chlorine or when heated in the presence of air. It is insoluble in water and all common organic solvents. 

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The most successful method developed for the production of a general-purpose synthetic rubber was the emulsion copolymerization of butadiene and styrene (SBR), which still represents the main process in use today (Blackley, 1975 Hofmann, 1989 Blow, 1971 Brydson, 1981 Bauer, 1979 Sun and Wusters, 2004 Demirors, 2003). The general principles of copolymerization will be discussed in a later section, but it is instructive at this point to examine the other main features of this system. The types of recipes used are seen in Table 2.5 (Bauer, 1979). The recipes shown are to be considered only as typical, as they are subject to many variations. It should be noted that the initiator in the 50°C recipe (hot rubber) is the persulfate, whereas in the 5°C recipe (cold mbber) the initiator consists of a redox system comprising the hydroperoxide-iron(II)-sulfoxylate-EDTA. In the latter case, the initiating radicals are formed by the reaction of the hydroperoxide with the ferrous iron, whose concentration is... 

Bauer, H. Organic compounds in chemotherapy. II. The preparation of fmnaldehyde sulfoxylate derivatives of sulfanilamide and of amino compounds. J.Am. Chem. Soc. 1939, 61, 617-618. 

The rate of dissociation into radicals is accelerated by addition of reducing agents such as sodium hydrogensulfate (NaHSOs), sodium disulfite (metabisulfite) (Na2S205), sodium thiosulfate (NazSzOs) or sodium formaldehyde sulfoxylate (NaHSOz CH2O 2H2O). Activators are also added in the form of iron salts such as iron(II) sulfate (FeS04 THzO) or ammonium iron(II) sulfate (Fe(NH4)2(S04)2). 

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