Abstract:

Two-dimensional nanosheets have the characteristics of large specific surface area and high porosity, which allow them to support more active centers, thus improving the catalytic performance of the material. For example, Cu-TCPP nanosheets have large specific surface area and can be loaded with Pd nanoparticles （NPs）, Pt NPs and Au NPs to obtain X NPs/Cu-TCPP nanosheets （X=Pd NPs, Pt NPs and Au NPs）. In this work, Cu-TCPP nanosheets were synthesized by hydrothermal method, in which Cu（NO₃） ₂·3H₂O was used as the metal salt, TCPP （4-carboxyporphyrin） was used as the organic ligand, and a mixed solution of DMF and CH₃CH₂OH （V_DMF/V_CH3CH2OH=3∶1） was used as the solvent. Then Au NPs were loaded onto Cu-TCPP nanosheets by reduction method to form Au NPs/Cu-TCPP nanosheets, which were employed to catalyze the selective oxidation of menthol. In the reaction, with tert-butyl hydroperoxide （TBHP） as oxidant, acetonitrile （MeCN） as solvent, and the amino acid imidazolium ionic liquid [C₄mim]Cys as cocatalyst, Au NPs/Cu-TCPP catalyzed the selective oxidation of menthol to obtain menthone. After reacting at 50 ℃ for 18 h, the conversion of menthol was up to 70.2%, the selectivity and yield of menthone could reach 99.9% and 69.5%. This method not only highly selectively convert menthol to menthone, but also was easy to operate and environmentally friendly, which could meet the current development requirements of the green chemical industry.

Key words: two-dimensional nanosheet, Au NPs/Cu-TCPP nanosheet, menthol, selective oxidation, menthone