Preparation, characterisation and testing of catalytic polymeric membranes in the oxidation of benzene to phenol

Liquid-phase catalytic oxidation of benzene to phenol has been studied under mild conditions using catalytic polymeric membranes. They were prepared by dissolving the polymer polyvinylidene fluoride (PVDF) in different solvents, (dimethylacetammide (DMAc), dimethylformammide (DMF) and 1-methyl- 2-pyrrolidone (NMP)) and filled with two types of copper oxides catalysts. Membranes were characterised morphologically by scanning electron microscopy (SEM), pore size distribution, contact angle measurements and BET surface area. It was found that DMAc was the best solvent and that membranes filled with the CuO nanopowder catalyst presented an improved wettability to reacting mixture. Reactivity tests, performed at contact time in the range 4-19.4 s between reagents and catalyst, showed a higher phenol concentration using the PVDF membrane filled with the CuO nanopowder rather than CuO powder catalysts. Phenol productivity of 72.5 gphenol gcat 1 h1 and a phenol yield of 2.3% were obtained in a single pass using a contact time with the catalyst of 19.4 s at 358 C in presence of ascorbic acid.