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28-P-16-Diffusion analysis of cumene cracking over ZSM5 using a jetloop reactor
310 2 8 - P - 1 5 - The influence of pore geometry on the alkylation of phenol with
methanol over zeolites G. Moon, K.P. M611er, W. B6hringer and C.T. O'Connor
Catalysis Research Unit, Department of Chemical Engineering, University of Cape Town, Rondebosch, South Africa - gmoon@chemeng, uct.ac.za The alkylation of phenol with methanol, in the liquid phase, has been investigated using zeolites H-ZSM-5, H-beta, H-MCM-22, H-mordenite, H-USY as well as amorphous silica alumina. At the low temperature of 200~ anisole was the major product over all the catalyst investigated, second was cresols. H-Beta, H-USY, H-ZSM-5, H-mordenite and amorphous silica alumina showed similar cresol distributions. H-MCM-22, which has the smallest pore openings and the narrowest channel system among all zeolites studied, showed the highest preference for p-cresol.
28-P-16 - Diffusion analysis of c u m e n e cracking over Z S M 5 using a jetioop reactor P. Schwan and K.P. M~ller
Department of Chemical Engineering, University of Cape Town, South Africa. Cumene is cracked in a recycle reactor over commercial H-ZSM5 extrudates during a pulse experiment. The results are compared to those obtained from steady state measurements. A linear model for diffusion, adsorption and reaction rate is applied to reactants and products. In contrast to literature it is shown that if the Thiele modulus is greater than 5, the system becomes over parameterised. If additionally adsorption dynamics are negligible or not measurable, only one lumped parameter can be extracted, which is the apparent reaction constant found from steady state experiments. The pulse experiment of cumene is strongly diffusion limited showing no adsorption dynamics of cumene. However, benzene adsorbed strongly on the zeolite and could be used to extract transient model parameters.
methanol over zeolites G. Moon, K.P. M611er, W. B6hringer and C.T. O'Connor
Catalysis Research Unit, Department of Chemical Engineering, University of Cape Town, Rondebosch, South Africa - gmoon@chemeng, uct.ac.za The alkylation of phenol with methanol, in the liquid phase, has been investigated using zeolites H-ZSM-5, H-beta, H-MCM-22, H-mordenite, H-USY as well as amorphous silica alumina. At the low temperature of 200~ anisole was the major product over all the catalyst investigated, second was cresols. H-Beta, H-USY, H-ZSM-5, H-mordenite and amorphous silica alumina showed similar cresol distributions. H-MCM-22, which has the smallest pore openings and the narrowest channel system among all zeolites studied, showed the highest preference for p-cresol.
28-P-16 - Diffusion analysis of c u m e n e cracking over Z S M 5 using a jetioop reactor P. Schwan and K.P. M~ller
Department of Chemical Engineering, University of Cape Town, South Africa. Cumene is cracked in a recycle reactor over commercial H-ZSM5 extrudates during a pulse experiment. The results are compared to those obtained from steady state measurements. A linear model for diffusion, adsorption and reaction rate is applied to reactants and products. In contrast to literature it is shown that if the Thiele modulus is greater than 5, the system becomes over parameterised. If additionally adsorption dynamics are negligible or not measurable, only one lumped parameter can be extracted, which is the apparent reaction constant found from steady state experiments. The pulse experiment of cumene is strongly diffusion limited showing no adsorption dynamics of cumene. However, benzene adsorbed strongly on the zeolite and could be used to extract transient model parameters.