Abstract
Phenol is an important industrial chemical that was manufactured by the Hock process. The sulphuric acid used in the Hock process to break cumene hydroperoxide into phenol and acetone suffers from environmental problems along with low selectivity towards the desired products. There are several solid acid catalysts have been tried in cumene hydroperoxide decomposition into an ecofriendly process. In the present work, an efficient environmentally friendly and economically benefitted zeolite-based catalyst was synthesized and tested for breaking cumene hydroperoxide (CHPO) into phenol and acetone. Beta zeolite and ZSM-5 zeolite were synthesised with nano crystalline geometry by hydrothermal method and tested their efficiency to break CHPO. The morphology and structure of nanocrystalline zeolite materials was investigated by Dynamic Light Scattering (DLS), X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) methods. From DLS studies it is documented that the zeolite particle size is tuneable as evidenced from particle size growths with the ageing time under hydrothermal treatment process. XRD analysis confirms the zeolite Beta and ZSM-5. The mean crystal size of Beta and ZSM-5 obtained from SEM analysis are 45 nm and 18.3 nm respectively. The optimization of reaction conditions for CHPO decomposition such as catalyst quantity and initial concentration of CHPO has been done using nanocrystalline Beta catalyst. The optimum catalyst amount and concentration of CHPO are 0.03 g and 15 mmol respectively. The results showed that the nanocrystalline Beta zeolite catalyst exhibits exceptional activity with 100% conversion of CHPO and yielded exclusively phenol and acetone at room temperature. No other by-products are detected. Also, the catalyst is stable and exhibits high product selectivity for phenol and acetone. The nature of the enhanced activity at room temperature for the decomposition of CHPO is suggested that higher accessibility of the active sites that are proposed to be associated with the zeolite with nano configuration with higher surface area and short distances for diffusion inside the channels in the nanocrystalline zeolite particles. The possibility of commercialization of beta zeolite is proved by complete conversion of CHPO with selective formation of phenol and acetone.