1. HYDROGENATION OF SOME ALKENES WITH NEW N-ACYL BENZOTRIAZOLE-Rh(I) COMPLEX IN IONIC LIQUID MEDIA Hakan ÜNVER1*, Filiz YILMAZ1 1Department of Chemistry, Anadolu University, 26470, Eskişehir, TURKEY.
INTRODUCTION
RESULTS
Greener chemical reaction systems have numerous advantages like environmental friendly, less toxic, energy efficiency..etc rather than conventional reaction systems [1]. Ionic liquids (ILs) are greener alternatives to conventional organic solvents due to their low vapour pressures, high thermal stability, low volatility, non-flammability, excellent solubility with many organic compounds [2]. ILs can be used not only solvent but also catalyst in catalytic reaction. Immobilisation of catalyst in ILs allows reuse for several times without any intervention to the reaction media.
In this study, we were synthesized a new N-Acyl Benzotriazole type ligand and its Rh(I) metal complex for using as catalyst in IL media (Fig. 1). Experiments were carried out at different temperatures and 10 bar H2 pressure. Also, we investigated of reusability of catalyst in this study.
The catalytic effectivity and reusability of synthesized catalyst has been investigated on styrene, 1-octene and cyclohexene hydrogenation reactions in [BMIM][BF4] ionic liquid.
STYRENE HYDROGENATION
EXPERIMENTAL
SYNTHESIS OF LIGAND AND PALLADIUM COMPLEX
Fig. 8: The effect of temperature on styrene hydrogenation
Fig. 9: Reusability of catalyst in styrene hydrogenation
* Reaction conditions: 5 mg catalyst, 100 µL styrene, 0,5 mL [BMIM][BF4], 10 Bar H2, 1h.
* Reaction conditions: 393K, 5 mg catalyst, 100 µL styrene, 0,5 mL [BMIM][BF4], 10 Bar H2, 6h.
1-OCTENE HYDROGENATION
Fig. 1: N-Acyl Benzotriazole ligand and its Rhodium (I) complex synthesis reaction.
LIGAND AND COMPLEX CARACTERISATION
FT-IR
Fig. 10: The effect of temperature on 1-octene hydrogenation.
Fig. 11: Reusability of catalyst in 1-octene hydrogenation
* Reaction conditions: 5 mg catalyst, 100 µL substrate, 0,5mL [BMIM][BF4], 1h.
* Reaction conditions: 373K, 5 mg catalyst, 100 µL 1-octene, 0,5 mL [BMIM][BF4], 10 Bar H2, 1,5 h.
CYCLOHEXENE HYDROGENATION
Fig. 3: IR spectrum of Rh complex
Fig. 2: IR spectrum of Ligand
1H-NMR Ha Hb a Hc Hd He e b d c
Fig. 4: 1H-NMR spectrum of Ligand
Fig. 5: 1H-NMR spectrum of Rh complex
Fig. 12: Cyclohexene hydrogenation at 393K
13C-NMR
* Reaction conditions: 5 mg catalyst, 100 µL cyclohexene, 1 mL [BMIM][BF4], 10 Bar H2, 6h, 393 K.
We synthesized new N-acyl benzotrıazole-Rh(I) complex. This complex is effective in styrene and 1-octene hydrogenation reactions in [BMIM][BF4] media. . For styrene, the best ethyl benzene conversition obtained at 393K for 6 h. This catalyst was reuse at least five times without significantly losing activity. Catalyst not effective on cyclohexene in [BMIM][BF4] media. h b g g i a c d f e e h d b c f g a i
Fig. 6: 13C-NMR spectrum of Ligand
Fig. 7: 13C-NMR spectrum of Rh complex
REFERENCES
[1] Centi, G., Perathoner, S., “Catalysis and sustainable (green) chemistry”, Catalysis Today, 77, 287–297, 2003
[2] T. Welton, Coordination Chemistry Reviews, 248, (2004), p.2459.
GREEN CHEMISTRY