Cobalt diiodide

Formula C0I2 MW 312.74 also forms a hexahydrate, Col2 6H20, MW 420.83 Synonyms cobaltous iodide cobalt diiodide... 

Following the intense work on the carbonylation reaction during the 1920s by BASF and British Celanese [1], Reppe and his research group discovered that cobalt diiodide operating at 680 bar and 250 °C catalyzes this reaction [2, 3]. But it was necessary to solve harsh corrosion problems, until 1950, when highly resistant molybdenum/nickel alloys (whose trademark is Hastelloy ) were discovered and commercialized [1]. The process developed by BASF in 1960 was not selective as the yield in acetic acid was 90% based on methanol and 70% based on CO [4] due to the large amounts of CO2 coproduced by the water-gas shift (WGS) reaction (Eq. 20.2). 

Pyrazolin-5-ones react with salts of various metals to form compounds in which the pyrazolinone has reacted in its enolic form with replacement of the enolic hydrogen to give a salt and having semipolar bonds formed by donation of electrons to the metal by the nitrogen atoms393 394 Usually these compounds contain the number of pyrazolinone residues corresponding to the valence of the metal atom. Such salts as cuprous iodide, ferric iodide, cobaltous iodide, silver iodide and silver diiodide participate in such reactions.393,394 In addition, complexes may be formed in which there has been no elimination of a small molecule between the reactants and no formation of ionic bonds.432... 

Methanol carbonylation. BASF employ a cobalt catalyst, with iodide promoter, for the carbonylation of methanol to acetic acid under severe conditions (250°C, over 300 atm.). The mechanism is ill defined. Monsanto showed that rhodium again allows much milder conditions. In the following scheme the oxidative addition of methyl iodide to the rhodium(I) dicarbonyl diiodide anion appears to be rate-controlling ... 

The dibromides of cobalt(II), nickel(II) and manganese(II), vanadium(III) bromide, as well as the diiodides of cobalt (II) and nickel (II) are completely... 

Cl iH2 6Cli,CoN502Zn, D-/32-(SSS)-(Triethylenetetramine-(S)-prolinato)-cobalt(III) tetrachlorozincate, 35B, 660 C11H30C0I2N5OH, L(-)589-j32 (RRS)-(Triethylenetetramine-(S)-prolin-ato)cobalt(III) diiodide dihydrate, 35B, 658 Cl 2H1 gBrCoNgOi, D-Histidinato-L-histidinatocobalt(III) bromide, 43B,... 

C21H34C0I2N5O2, 2,12-Di-2-pyridyl-3,7,11-triazatrideca-2,11-diene-(methyl)cobalt(III) diiodide dihydrate, 43B, 1323 C21H52CO2N12O5 f ( + )-fac-Tris(meso-2,4-pentanediamine)cobalt(III) hexacyanocobaltatedll) pentahydrate, 44B, 944 C2 2H8CdMn2N20,0 f M (1f10-Phenanthrolinecadmium)-bis(pentacarbonyl-manganese) (2Cd-Mn), 40B, 906... 

CbH22C0I2N5O2 0.84 H2O, Ammineglycinato(1,4,7-triazacyclononane)-cobalt(III) diiodide hydrate, 46B, 1169 CbH2 4C12CuN<,Ob, Bis( 1, 3-diaminobutane)copper (II) perchlorate, 38B, 975... 

We expected the synthesis of kingianin J to parallel that of kingianin H. However, when we applied Manchand reaction to the diiodide derived from diol 48, we obtained products that appeared to have lost the A-3,4 olefin. Likewise, the reductive cobalt-mediated procedure of Cheng did not show the anticipated olefinic protons in the NMR spectrum of the cmde product. We concluded that the C-1 side chain in compounds in the J series is situated very close to the double bond between carbons 3 and 4 and that reactive intermediates at this position may participate in intramolecular reactions with that double bond. 

Samarium diiodide serves as an effective reductant for a variety of functional groups. Conjugated double bonds are readily reduced by Sml2 in the presence of proton donors such as methanol (Kagan and Namy, 1986). Inanaga (1990) has shown that alkynes are reduced efficiently to alkenes by samarium diiodide in the presence of catalytic amounts of cobalt (Co) complexes. Selective synthesis of (Z)-alkenes is possible due to the chemoselective nature of... 

Thus, when the diiodide derivative was used in combination with MMAO (300 < Al/Co < 1000), turnover frequencies of ethylene polymerization of up to 630 TON h were obtained, the catalyst being moreover stable for hours at RT. The analysis of the catalytic properties of this compound led to the conclusion that the catalyst resting state is a cobalt alkyl complex and not a cobalt alkyl ethylene complex. Thus, the cationic methyl acetonitrile or arylnitrile species were active for the polymerization of ethylene and, not requiring the presence of MMAO as under related reaction conditions, they led to polyethylene products with similar molecular weights and branching levels as compared to the polyethylene produced with the diiodide species. 

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