.Cobalt nanoparticles in hollow mesoporous spheres as a highly efficient and rapid magnetically separable catalyst for selective epoxidation of styrene with molecular oxygen
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Corresponding authors
a
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, China
E-mail: liyirong@lzu.edu.cn
Fax: +86 0931 891 2582
Tel: +86 0931 891 2311
E-mail: liyirong@lzu.edu.cn
Fax: +86 0931 891 2582
Tel: +86 0931 891 2311
b
The Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering Lanzhou University, Lanzhou 730000, China
RSC Adv., 2014,4, 47-53
DOI: 10.1039/C3RA45383A
Uniform rattle-type hollow mesoporous spheres (HMS) with large cavities have been successfully prepared by the colloidal carbon spheres as templates. The spheres are well monodispersed and nearly uniform in dimension with particle size of ca. 150 nm. Co nanoparticles composed of HMS were found to be a highly efficient catalyst for selective epoxidation of styrene under mild reaction conditions. The catalysts can be easily separated from the reaction mixtures by an external magnet, and reused five times without significant loss of catalytic activity.
STYRENE OXIDE
EXTRAS FROM NET
Chiral GC
Column: Supelco (#24301):
-DEX
110 30 m capillary columnCarrier Gas: Helium
Pressure: 22 psi
Split Ratio: 50:1
Detector: Flame Ionization Detector (FID)
Styrene Oxide Analysis:
Oven Temperature: 100 °C
Retention times of the two enantiomers: 10.3 and 10.6 min
Typical percentages of the two enantiomers using catalyst synthesized using L-Tartaric acid: 92.7% (10.3 min RT), 7.3% (10.6 min RT)
Typical percentages of the two enantiomers using catalyst synthesized using D-Tartaric acid: 2.7% (10.3 min RT), 97.2% (10.6 min RT)
1-Phenyl-1,2-ethanediol Acetonide Analysis:
Oven Temperature: 130 °C
Retention time of the two enantiomers: 9.6 and 9.9 min
Typical percentages of the two enantiomers using catalyst synthesized using L-Tartaric acid: 4.7% (9.6 min RT), 95.3% (9.9 min RT)
Typical percentages of the two enantiomers using catalyst synthesized using D-Tartaric acid: 96.0% (9.6 min RT), 4.0% (9.9 min RT)
Optical Rotation
Jacobsen reports that the R enantiomer of styrene oxide is the major one remaining using the (R,R) catalyst. (This is the catalyst produced using the L-Tartaric acid.) For a sample with >99% ee he reports: [
]23D
+28.6° (neat).Jacobsen reports that the S enantiomer of the diol is the major one produced using the (R,R) catalyst. (This is the catalyst produced using the L-Tartaric acid.) For a sample with 95% ee he reports: [
]23D
+38.4° (c 4.38, EtOH).tirupati, india
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