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Synlett 2004(4): 746-747  
DOI: 10.1055/s-2004-817756
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

1-Butyl-3-methylimidazolium Tetrafluoroborate as a Green Reaction Medium

Yogesh R. Jorapur*
Department of Chemistry, Medicinal Chemistry Lab, Inha University, 253,Yonghyundong Namgu, Inchon, 402-751, Republic of Korea
Fax: +82(32)8675604; e-Mail: yogesh_inhauni@yahoo.co.in;
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Publikationsdatum:
10. Februar 2004 (online)

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Introduction

Ionic liquids [1] as green high tech reaction media of the ­future are considered as environmentally friendly sub­stitutes for volatile organic solvents, because of their low vapor pressures and their ability to act as catalysts. They also possess several other attractive properties, [2-4] including chemical and thermal stability, non-flammability, high ionic conductivity, a wide electrochemical potential window, and are 100% recyclable solvent media for synthesis and catalytic processes.

Ionic liquids first described in 1914, [5] consist of inorganic anions and nitrogen containing organic cations whose chemical and physical properties can be finely tuned for a range of applications by varying the cations or anions.4

Ionic liquid, [bmim][BF4], can be easily prepared [6] from N-methylimidazole. The crude 1 obtained was purified by filtering through silica gel followed by washing with ­saturated Na2CO3 to give pure 1 (Scheme 1), which is now commercially [7] available. It showed enhanced reactivity and selectivity in reactions like hydrogenation, [8] coupling, [9] carbonylation, [10] and cycloaddition [11] in comparision with several other ionic liquids.

The toxicological and/or eco-toxicological effects [12] of 1 in comparision with volatile organic solvents is uncertain.