Nanoscale graphene oxide(NGO)sheets were synthesized and used as carbocatalysts for effectiveoxidation of benzylic alcohols and aromatic aldehydes.For oxidation of alcohols in the presence ofH2O2at80°C,the NGOs(2...Nanoscale graphene oxide(NGO)sheets were synthesized and used as carbocatalysts for effectiveoxidation of benzylic alcohols and aromatic aldehydes.For oxidation of alcohols in the presence ofH2O2at80°C,the NGOs(20%mass fraction)as carbocatalysts showed selectivity toward aldehyde.The rate and yield of this reaction strongly depended on the nature of substituents on the alcohol.For4‐nitrobenzyl alcohol,<10%of it was converted into the corresponding carboxylic acid after24h.By contrast,4‐methoxybenzyl alcohol and diphenylmethanol were completely converted into thecorresponding carboxylic acid and ketone after only9and3h,respectively.The conversion ratesfor oxidation of aromatic aldehydes by NGO carbocatalysts were higher than those for alcohol oxidation.For all the aldehydes,complete conversion to the corresponding carboxylic acids wasachieved using7%(mass fraction)of NGO at70°C within2–3h.Possible mechanisms for NGOcarbocatalyst structure‐dependent oxidation of benzyl alcohols and structure‐independent oxidationof aromatic aldehydes are discussed.展开更多
The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied fo...The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied for manufacturing the resid hydrotreating catalysts. The influence of different TiO2 contents and calcination temperatures on specific surface area, pore volume and pore size distribution of complex supports was studied. TEM and SEM were employed to characterize the Al2O3-TiO2 complex supports. Test results revealed that the specific surface area of Al2O3-TiO2 complex supports was the largest at a TiO2 mass fraction of 20%, and when the calcination temperature was in the range between 300 ℃ to 700 ℃, the pore distribution of the complex support was stable. Characterization of the complex support by TEM and SEM demonstrated that TiO2 was homo- geneously distributed in the complex support, which was in favor of carrying active components. The Al2O3-TiO2 complex supports can function as the best catalyst support for resid hydrotreating catalysts.展开更多
文摘Nanoscale graphene oxide(NGO)sheets were synthesized and used as carbocatalysts for effectiveoxidation of benzylic alcohols and aromatic aldehydes.For oxidation of alcohols in the presence ofH2O2at80°C,the NGOs(20%mass fraction)as carbocatalysts showed selectivity toward aldehyde.The rate and yield of this reaction strongly depended on the nature of substituents on the alcohol.For4‐nitrobenzyl alcohol,<10%of it was converted into the corresponding carboxylic acid after24h.By contrast,4‐methoxybenzyl alcohol and diphenylmethanol were completely converted into thecorresponding carboxylic acid and ketone after only9and3h,respectively.The conversion ratesfor oxidation of aromatic aldehydes by NGO carbocatalysts were higher than those for alcohol oxidation.For all the aldehydes,complete conversion to the corresponding carboxylic acids wasachieved using7%(mass fraction)of NGO at70°C within2–3h.Possible mechanisms for NGOcarbocatalyst structure‐dependent oxidation of benzyl alcohols and structure‐independent oxidationof aromatic aldehydes are discussed.
文摘The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied for manufacturing the resid hydrotreating catalysts. The influence of different TiO2 contents and calcination temperatures on specific surface area, pore volume and pore size distribution of complex supports was studied. TEM and SEM were employed to characterize the Al2O3-TiO2 complex supports. Test results revealed that the specific surface area of Al2O3-TiO2 complex supports was the largest at a TiO2 mass fraction of 20%, and when the calcination temperature was in the range between 300 ℃ to 700 ℃, the pore distribution of the complex support was stable. Characterization of the complex support by TEM and SEM demonstrated that TiO2 was homo- geneously distributed in the complex support, which was in favor of carrying active components. The Al2O3-TiO2 complex supports can function as the best catalyst support for resid hydrotreating catalysts.
