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The Partial Hydrogenation of Benzene to Cyclohexene by Nanoscale Ruthenium Catalysts in Imidazolium Ionic Liquids
Author(s) -
Silveira Edson T.,
Umpierre Alexandre P.,
Rossi Liane M.,
Machado Giovanna,
Morais Jonder,
Soares Gabriel V.,
Baumvol Israel J. R.,
Teixeira Sergio R.,
Fichtner Paulo F. P.,
Dupont Jairton
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200305765
Subject(s) - cyclohexene , ionic liquid , benzene , hexafluorophosphate , catalysis , ruthenium , tetrafluoroborate , chemistry , inorganic chemistry , nanoparticle , trifluoromethanesulfonate , solubility , materials science , organic chemistry , nanotechnology
The controlled decomposition of an Ru 0 organometallic precursor dispersed in 1‐ n ‐butyl‐3‐methylimidazolium hexafluorophosphate (BMI⋅PF 6 ), tetrafluoroborate (BMI⋅BF 4 ) or trifluoromethane sulfonate (BMI⋅CF 3 SO 3 ) ionic liquids with H 2 represents a simple and efficient method for the generation of Ru 0 nanoparticles. TEM analysis of these nanoparticles shows the formation of superstructures with diameters of ≈57 nm that contain dispersed Ru 0 nanoparticles with diameters of 2.6±0.4 nm. These nanoparticles dispersed in the ionic liquids are efficient multiphase catalysts for the hydrogenation of alkenes and benzene under mild reaction conditions (4 atm, 75 °C). The ternary diagram (benzene/cyclohexene/BMI⋅PF 6 ) indicated a maximum of 1 % cyclohexene concentration in BMI⋅PF 6 , which is attained with 4 % benzene in the ionic phase. This solubility difference in the ionic liquid can be used for the extraction of cyclohexene during benzene hydrogenation by Ru catalysts suspended in BMI⋅PF 6 . Selectivities of up to 39 % in cyclohexene can be attained at very low benzene conversion. Although the maximum yield of 2 % in cyclohexene is too low for technical applications, it represents a rare example of partial hydrogenation of benzene by soluble transition‐metal nanoparticles.