Synthesis and performance of a composite photocatalyst based on polyester-supported carbon nitride nanosheets for selective oxidation of anisyl alcohol

Heterogeneous photocatalysis represents an essential organic synthesis strategy for the sustainable development of new routes to the highly efficient production of fine chemicals. This work describes a coating method using polyester fibre (PES) to support carbon nitride nanosheets (GCN-TS). PES surface was treated with HNO3 aqueous solutions with different concentrations (0.2 - 5% v/v), which enhanced the adhesion of the GCN-TS on PES fibres. The surface of coated PES treated with 1% v/v HNO3 results in a homogeneous deposition of the photocatalyst and increased hydrophilicity. The photocatalytic synthesis of p-anisaldehyde by oxidation of anisyl alcohol in an aqueous solution assisted by 417 nm visible light-emitting diodes resulted in 95% yield operating in batch mode. The prepared material could be reused, maintaining its photocatalytic performance during five consecutive tests. Aiming at industrial processing, the synthesis of anisaldehyde was performed using the same catalyst in a continuous flow photocatalytic reactor. The performance of the process depends on the residence time of the mixture containing the reactant, as the contact with the immobilised photocatalyst determines the yield.