Performance of Gold Nanoparticles Supported on Carbon Nanotubes for Selective Oxidation of Cyclooctene with Use of O2 and TBHP

Abstract

Gold nanoparticles supported on multi-walled carbon nanotubes (Au/CNTs) were developed for the selective epoxidation of cyclooctene with oxygen and small amount of tert-butyl hydroperoxide (O 2 -TBHP). We found that the Au/CNTs could provide the best combination of selectivity and conversion in comparison with the supported gold catalysts with several other carriers like active carbon, graphite, TiO 2 , SiO 2 and Al 2 O 3 . The conversion of cyclooctene and the selectivity to epoxide increased with the amount of TBHP, but both reached almost maxima when the TBHP amount was higher than 5.0 mol% of cyclooctene. The CNTs-supported gold nanoparticles with mean sizes ranging from 3.1 to 15.0 nm could be prepared by using sol-immobilization method. The Au/CNTs catalysts with smaller gold particle size were related to higher epoxide yield, indicating a size effect of gold nanoparticles on the catalytic performance. The results suggested that the epoxidation of cyclooctene over the Au/CNTs with use of O 2 -TBHP would be structuresensitive.

Dendritic porous yolk@ordered mesoporous shell structured heterogeneous nanocatalysts with enhanced stability

“…When HAuCl 4 was used as a catalyst for cyclooctene epoxidation, it showed poor performance (<10% cyclooctene conversion) in terms of conversion and selectivity. Note that this selectivity is higher than many values reported in the literature, 45,46 while the conversion remains to be great. Furthermore, the epoxidation of styrene was investigated to understand the product distribution vs. reaction temperature and time (Fig.…”

Remarkable effect of ordered mesoporous carbon support in tantalum oxide-catalyzed selective epoxidation of cyclooctene

“…Most of the catalyst systems above mentioned utilised porous siliceous oxide or other metal oxide supports (e.g., MCM-41 and SBA-15), which caused drawbacks in catalytic activity and selectivity. Although this problem has been overcome by introducing hydrophobic organic groups onto the oxide supports [14][15][16][17][18][19], limited reports have been focused on the utilisation of carbon support [20][21][22], which is expected to provide hydrophobic reaction environments without the need for any organic modification. One carbon material used here was carbon nanotubes [21,22], which can provide unique catalytic performance albeit irregular in structure.…”

“…Although this problem has been overcome by introducing hydrophobic organic groups onto the oxide supports [14][15][16][17][18][19], limited reports have been focused on the utilisation of carbon support [20][21][22], which is expected to provide hydrophobic reaction environments without the need for any organic modification. One carbon material used here was carbon nanotubes [21,22], which can provide unique catalytic performance albeit irregular in structure. Alternatively, mesoporous carbon, recently invented carbon materials with high surface area and ordered pore structures in nm size [23][24][25][26], has potential usage as catalyst supports for the olefin epoxidation.…”

Halloysite Nanotubes Supported Gold Catalyst for Cyclohexene Oxidation with Molecular Oxygen

“…Unfortunately, as for the Au/C catalyst, it has good catalytic performance only with the addition of special organic solvent [20]. The performance of Au/CNTs catalyst is influenced by the amount of TBHP [21]. Compared Au/C and Au/CNTs, we can see that the structure of the carrier has great effect on the catalytic performance of supported gold.…”

“…Supported gold catalysts have been extensively studied for a wide range of oxidation reactions including CO oxidation [13], propylene epoxidation [14], the direct synthesis of hydrogen peroxide from oxygen and hydrogen [15,16], oxidation of cyclohexane to KA oil [17][18][19], etc.. Particularly, the partial liquid-phase cyclohexene oxidation using gold catalysts including Au/C and Au/CNTs makes gold even more attractive [20,21]. Unfortunately, as for the Au/C catalyst, it has good catalytic performance only with the addition of special organic solvent [20].…”