Synthesis Of Polyethylene Glycol Functionalized Ionic Liquids And Their Application To Promote The Hydrogenation Of Rhodium And

Catalyst system of ionic liquids/transistion metal complexes has been successfully applied in the hydrosilylation reactions. Using ionic liquids can not only improve the activity but also increase the selectivity of adducts, meanwhile the catalyst system can be recycled.On the base of former’s research results, a series of polyethylene glycol-functionalized imidazolium ionic liquids have been designed and synthesized. The catalytic systemformed with ionic liquids and transition metal rhodium or platinum have been preparedand applied in hydrosilylation of alkenes. It is found that these ionic liquids as ligands or promoters could promote the catalytic activity of rhodium complexes in the hydrosilylationof styrene. With the increasing of molecular weight of polyethylene glycol, the catalytic activity of rhodium increase. When polyethylene glycol(400) functionalized imidazolium ionic liquid was used as ligand, the conversion of styrene and the selectivity of the β-adduct is 100% and 83.1%, respectively. Next, effect of the different of anions on the hydrosilylation recction of alkeneshas been investigated. Using the ionic liquid with PF6- anion, the catalyst system showed the best catalytic activity. Further, catalyst system of Rh(PPh3)3Cl/ different N-alkyl chain of ionic liquid had also been investigated. The ratio of the β-adduct to α-adduct is increased with increasing length of N-alkyl chain, the best was 25.4. At last, we also investigated the repeatability of the catalyst system. The catalyst system could be separated and recycled from the reaction mixture easily. Among the catalyst systems, Rh(PPh3)3Cl/4a could recycle many times without obviously decreasing of activity.In this thesis, we also investigated the effect of these ionic liquids on the hydrosilylation recction catalyzed by platinum catalyst. It found that the ionic liquids were not promoting the platinum catalyst obviously, however, the catalyst system could be recyclied many times. Among the catalyst systems, H2 Pt Cl6/4c could be recycled 13 times, the conversion of styrene was above 80% with selectivity of β-adduct above 90% after repeated 15 runs.