Liquid-phase oxidation of benzene to phenol using CuO catalytic polymeric membranes

Catalytic polymeric membranes filled with copper oxides of different particles size were prepared and tested in the liquid phase oxidation of benzene to phenol. Polyvinylidenefluoride (PVDF) was used as polymer to make the membranes. Three different solvents, dimethylacetammide (DMAc), dimethylformammide (DMF) and 1-methyl-2-pyrrolidone (NMP) were used as polymer solvents and distilled water as a nonsolvent. The prepared membranes were characterised morphologically by scanning electron microscopy (SEM). Pore size distribution was determined using gas a permeation method. Membrane characterisation tests evidenced that DMAc was the best solvent. Permeability tests were carried out for measuring the contact time of the catalyst with the reacting mixture. Catalytic membranes were tested in the liquid phase oxidation reaction of benzene to phenol by using hydrogen peroxide as oxidant in an ultrafiltration membrane reactor. The obtained results showed a higher phenol concentration using the PVDF membrane filled with the CuO nanopowder rather than CuO powder catalysts. A phenol concentration of 2.4 g L−1 and a benzene conversion to phenol of 2.3% were obtained using a contact time with the catalyst of 19.4 s at 35°C.