Journal
NEW JOURNAL OF CHEMISTRY
Volume 46, Issue 13, Pages 6009-6017Publisher
ROYAL SOC CHEMISTRY
DOI: 10.1039/d1nj04812k
Keywords
-
Categories
Funding
- National Research Council of Thailand [NRCT5-RSA63015-21]
- Royal Golden Jubilee PhD Programme [PHD/0220/2557]
- Faculty of Science, Mahidol University
- Mahidol University under the National Research Universities Initiatives
- Center of Excellence for Innovation in Chemistry (PERCH-CIC), Ministry of Higher Education, Science, Research and Innovation
- CIF Grant
Ask authors/readers for more resources
In this study, amphiphilic tris(triazolyl)amines functionalized with poly(ethylene glycol) were investigated as bi-functional surfactants for copper-catalyzed aerobic alcohol oxidation in water. The results showed that NBBT550 exhibited the highest activity among the tested surfactants. However, there was significant leaching of copper ions from the catalyst system, leading to the need for additional copper catalyst after every four catalytic cycles.
Amphiphilic tris(triazolyl)amines functionalized with poly(ethylene glycol) 1-(1-R-1H-1,2,3-triazol-4-yl)-N,N-bis((1-benzy-1H-1,2,3-triazol-4-yl)methyl)methanamine [R = PEG200 (NBBT200-OH), mPEG550 (NBBT550), and mPEG2000 (NBBT2000)] were investigated as bi-functional surfactants serving as N donor ligands and surfactants for copper-catalyzed aerobic alcohol oxidation in water. The catalyst system CuBr/NMI/TEMPO/NBBTn (NMI = N-methylimidazole; TEMPO = 2,2,6,6-tetramethylpiperidine 1-oxyl, n = 200-OH, 550, 2000) shows oxidation activity toward 4-methoxybenzyl alcohol following the trend: NBBT550 > NBBT2000 > NBBT200-OH. Although UV-Vis spectrophotometric titrations suggest large binding constants between Cu2+ and NBBT550 in water (K-11 = 2.5 x 10(4) M-1 and K-21 = 6.3 x 10(3) M-1), flame atomic absorption spectroscopy (FAAS) reveals ca. 35 ppm of Cu ions from the catalyst system leaching into the EtOAc extract. As a result, in the reusability study, additional 5 mol% CuBr was added to the reaction mixture before the fourth catalytic run to achieve high conversions to the oxidized product for at least six catalytic cycles.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available