42714-70-5Relevant articles and documents
The metathesis of α-olefins over supported Re-catalysts in supercritical CO2
Selva, Maurizio,Perosa, Alvise,Fabris, Massimo,Canton, Patrizia
experimental part, p. 229 - 238 (2010/04/22)
At 35 °C, in the presence of supercritical carbon dioxide (80-150 bar) as a solvent, α-olefins (RCHCH2, R = C4-C6) undergo highly selective self-metathesis catalyzed by supported Re-oxide (7%). To the best of our knowledge, this is the first procedure for the metathesis of alkenes, in which heterogeneous catalysts are combined with the use of dense CO2. The intrinsic eco-compatibility and the unique physicochemical properties of this medium offer both environmental and synthetic advantages: not only conventional toxic solvents (e.g. n-heptane and toluene) can be replaced, but the reaction is faster. For instance, after 2 h, the average conversion of 1-octene is 67% and 40% in scCO2 and n-heptane, respectively. The product of self-methatesis, 7-tetradecene, can be isolated in yields up to 68%. At 90 bar, the reaction is rather sensitive to the mole fraction of the olefin (in scCO2); though, the enhancement of the pressure (and the density) of the supercritical medium does not induce significant effects on either the rate or the selectivity of the process. The nature of the catalytic support also greatly affects the reaction outcome: Re-oxide shows good activity if dispersed over γ-Al2O3, while silica-based systems are ineffective.
Metathesis of unsaturated fatty acids: Synthesis of long-chain unsaturated-α,ω-dicarboxylic acids
Ngo, Helen L.,Jones, Kerby,Foglia, Thomas A.
, p. 629 - 634 (2007/10/03)
The self-metathesis of readily available monounsaturated FA has the potential of being an important pathway for the synthesis of symmetrical long-chain unsaturated-α,ω-dicarboxylic acids (C18-C 26). Previous studies on the self-metathesis of monounsaturated FA esters using ruthenium catalysts in solution, however, suffered from low conversions as a result of the thermodynamic control of the reaction. We have found that the secondgeneration Grubbs catalyst can effectively catalyze the solventfree self-metathesis of monounsaturated FA of varying purity (from 90 to 99%) to afford two important products-monounsaturated dicarboxylic acids and hydrocarbons-in very high molar conversions (>80%). This solvent-free self-metathesis reaction also works for monounsaturated FA containing additional functional groups. Reactions were conducted at catalyst loadings as low as 0.005 mol%, and turnover numbers as high as 10,800 could be obtained. This discovery represents an attractive approach to the large-scale production of useful monounsaturated-α,ω-dicarboxylic acids and long-chain unsaturated hydrocarbons by means of this solvent-free ruthenium-catalyzed self-metathesis of readily available monounsaturated FA. Copyright
