Copper Nanoparticles in Ionic Liquid: An Easy and Efficient Catalyst for Selective Carba-Michael Addition Reaction
- PDF / 323,875 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 56 Downloads / 216 Views
Copper Nanoparticles in Ionic Liquid: An Easy and Efficient Catalyst for Selective Carba-Michael Addition Reaction Prashant Singh Æ Kamlesh Kumari Æ Anju Katyal Æ Rashmi Kalra Æ Ramesh Chandra
Received: 21 May 2008 / Accepted: 9 September 2008 / Published online: 11 October 2008 Ó Springer Science+Business Media, LLC 2008
Abstract In this paper, we wish to report a novel synthesized copper nanoparticles in an ionic liquid employed as a catalyst for Michael addition between active methylene compound and a, b-unsaturated compounds to give corresponding compounds in excellent yield and in shorter reaction times. R1 O
O
S
O
S
R1
S
R2 HN
Copper nanooparticles in ionic liquid A
HN
O
O
HN
H
Keywords Copper nanoparticles Ionic liquid Active methylene compounds a, b––Unsatuated compounds
R. Chandra (&) Department of Chemistry, University of Delhi, Delhi 110007, India e-mail: [email protected] P. Singh A. Katyal R. Chandra Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India P. Singh A. R. S. D. College, University of Delhi, Delhi, India K. Kumari Dayal Bagh Education Institute, Agra, India R. Kalra A. N. D. College, University of Delhi, Delhi, India
R2 O
1 Introduction Recently, research has been directed towards the synthesis and application of metal nanoparticles in view of their unique properties compared to the bulk metals [1, 2]. Among various metal nanoparticles, copper and gold nanoparticles have received considerable attention because of their unusual properties and potential applications in diverse fields [3]. The various synthetic procedures for their synthesis include micro-emulsion [4], reverse micelles [5], reduction of aqueous copper salts [6], UVlight irradiation [7], physical vapor deposition [8] and impregnation methods [9, 10]. The core-shell particles are of great interest due to their potential applications in diverse fields including catalysis, drug delivery, photonics, sensors, etc. [11]. The classical Michael type reactions are certainly very importnat but need quite severe reaction conditions and thereby causing limitations [12] in their use in practice. However, these reactions require either basic or acidic catalysts [13], which seem to be detrimental to the desired synthesis. In order to overcome some of the disadvantages, a number of alternative procedures for the Michael addition have been reported over the past few years using Yb(OTf)3, InCl3, CeCl3 . 7H2O, Bi(NO)3, Bi(OTf)3, Cu(OTf)2, FeCl3 7H2O/Co(OAc)2, LiClO4 and boric acid [14–16]. Several heterogeneous catalysts, such as silica gels, copper nanoparticles, and CeCl3 7H2O/NaI system [17] have been reported. There is considerable interest in the use of ionic liquids as promising substitutes for volatile organic solvents. Copper nanoparticles are highly efficient for the aza-Michael addition and thia-Michael addition reaction and they have been used in organic solvents which are very toxic in nature [18–21]. Copper nanoparticles are particularly
123
120
P. Sin
Data Loading...
