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Bimetallic Au/Pd nanoparticles were prepared and used to catalyze oxidation of alcohols in the poly(ethylene glycol) (PEG)/CO2 biphasic system using O2 as the oxidant without adding any base.The catalytic activity of Au/Pd bimetal with different mole ratios was studied using benzyl alcohol as the substrate.It was found that bimetallic Au/Pd nanoparticles with Au:Pd=1:3.5 had higher catalytic activity than monometallic Au,Pd and the bimetallic Au/Pd nanoparticles with other molar ratios.The effect of CO2 pressure on the oxidation of benzyl alcohol and 1-phenylethanol in PEG/CO2 was investigated.It was demonstrated that CO2 pressure could be used to tune the conversion and selectivity of the reactions effectively.α,β-Unsaturated alcohols were also studied and found to be more reactive than benzyl alcohol and 1-phenylethanol.Recycling experiments showed that the Au/Pd/PEG/CO2 catalytic system could be recycled at least four times without reducing the activity.In addition,the catalytic system is clean and the products can be separated easily.
Bimetallic Au / Pd nanoparticles were prepared and used to catalyze oxidation of alcohols in the poly (ethylene glycol) (PEG) / CO2 biphasic system using O2 as the oxidant without adding any base. The catalytic activity of Au / Pd bimetal with different mole ratios was studied using benzyl alcohol as the substrate. It was found that bimetallic Au / Pd nanoparticles with Au: Pd = 1: 3.5 had higher catalytic activity than monometallic Au, Pd and the bimetallic Au / Pd nanoparticles with other molar ratios. The effect of CO2 pressure on the oxidation of benzyl alcohol and 1-phenylethanol in PEG / CO2 was investigated. It was previously demonstrated that CO2 pressure could be used to tune the conversion and selectivity of the reactions. Α, β-Unsaturated alcohols were also studied and found to be more reactive than benzyl alcohol and 1-phenylethanol. Recycling experiments showed that the Au / Pd / PEG / CO2 catalytic system could be recycled at least four times without reducing the activity. In addition, the catalytic s ystem is clean and the products can be separated easily.