Perfluoroalkyl-substituted arylphosphanes as ligands for homogeneous catalysis in supercritical carbon dioxide
Perfluoroalkyl-substituted arylphosphanes as ligands for homogeneous catalysis in supercritical carbon dioxide
复制标题
DOI：
10.1002/anie.199716281
复制
发表时间：
1997-08-18
期刊：
影响因子：
--
通讯作者：
Leitner, W
中科院分区：
文献类型：
--
作者：
Kainz, S;Koch, D;Leitner, W
超临界状态的二氧化碳(ScC0)是一种有趣的反应介质，最近被应用于过渡金属络合物的均相催化。与传统的有机溶剂相比，scC0提供了一种无毒和生态友好的替代方案。此外，scC0与许多气态反应物高度相容，从而避免了气/液反应中经常遇到的扩散过程的速度限制。还讨论了在超临界介质中通过特殊的溶剂效应来提高选择性和活性的可能性。最后，由于scC0的溶剂性质可以通过改变压力和温度来调节，因此直接从反应混合物中进行选择性分离是可能的。具有讽刺意味的是，到目前为止，scC0的溶剂性质一直是其作为反应介质在均相催化中广泛应用的主要障碍。在第一近似值中，scC0具有与饱和碳氢化合物相当的溶剂性质；这导致催化剂的选择受到严重限制。特别是含有芳基膦配体(如Ph，P，Ph，P(CH，)，PPh，4，5-双[(二苯基膦)甲基]-2，2-二甲基-I，3-二氧杂环戊烷)的配合物
Carbon dioxide in the supercritical state (scC0,) is an interesting reaction medium that has recently been established for application in homogeneous catalysis with transition metal complexes.['] Compared to conventional organic solvents, scC0, provides a nontoxic and ecologically benign alternative. Furthermore, scC0, is highly miscible with many gaseous reactants, thus avoiding rate limitations by diffusion processes, as is often encountered with gas/liquid-phase reactions. A possible increase in selectivity and activity through special solvent effects in the supercritical medium has also been discussed. Finally, since the solvent properties of scC0, can be tuned by variation of pressure and temperature,[21 selective separation directly from the reaction mixture seems possible. Ironically, the solvent properties of scC0, have up to now represented the major obstacle for its wide application as a reaction medium in homogeneous catalysis. In a first approximation scC0, possesses solvent properties comparable to those of saturated hydrocarbons; this leads to severe limitations for the choice of catalysts. Especially complexes containing arylphosphane ligands (such as Ph, P, Ph, P (CH,), PPh,, 4, 5-bis [(diphenylphosphanyl) methyl]-2, 2-dimethyl-I, 3-dioxolan