Green oxidation protocol: Selective conversions of alcohols and alkenes to aldehydes, ketones and epoxides by using a new multiwall carbon nanotube-based hybrid nanocatalyst via ultrasound irradiation

•First ultrasound-MWCNTs/TiO2 synergistic effects selective oxidation is reported.•The best sonication conditions were obtained in 40kHz frequency and 250W power.•Some advantages include excellent results, easy operation and simple work-up procedure.•Average nanoparticles size distribution in the hybrid nanostructure was about 80nm.•The heterogeneous nanocatalyst was simply recovered and reused several times. In this work, design and development of a new economically-efficient and environmentally-benign sonochemical-assisted oxidation protocol by using multiwall carbon nanotubes (MWCNTs) and TiO2 hybrid nanostructure catalyst is reported. The structure, morphology and particle size of the nanostructure catalyst and the products were characterized by various methods such as FT-IR, FE-SEM, EDX, XRD, DTA, GC and GC–MS analyses. The selective oxidations of alcohols to aldehydes, ketones and epoxidation were studied in the presence of MWCNTs/TiO2 at room temperature under ultrasonic irradiation conditions in excellent conversions. This is the first design, preparation, characterization and application of the present nanomaterial and also the first ultrasound-irradiated green oxidation. This novel protocol offers several advantages such as environmentally-benign, high yields, selective oxidations, short reaction times, easily isolation of the products, simple preparation, recoverability and reusability of the nanocatalyst without significant decrease in its activity.