CATALYTIC AND NONCATALYTIC OXIDATIVE DEHYDROGENATION OF N-BUTANE

The thermal pyrolysis and the catalytic and non-catalytic oxydehydroge nation of n-butane were investigated. It was found that, under optimum conditions, the non-catalyzed reaction can be very efficient and sele ctive. The effect of temperature, butane/oxygen ratio and residence ti me was studied and it was concluded that high selectivity in butenes c an be achieved at relatively low temperatures and low butane/oxygen ra tios. Conversion of n-butane up to 90%, at 580 degrees C, and 1.8 s re sidence time with an overall alkenes C-2-C-4 selectivity exceeding 55% were observed. Based on experimental results, it is suggested that ox ygen participates in the reaction mechanism of butane decomposition no t only in the initiation steps but in the propagation steps as well. O xidative dehydrogenation was also examined in the presence of mixed ox ide catalyst comprising 30 wt% V2O5 and 70 wt% MgO. It was observed th at the catalyst is very active and quite selective in desirable produc ts at reaction temperatures (540-580 degrees C), similar to those appl ied in non-catalytic experiments. Very promising results were obtained when n-butane and oxygen were fed over a catalytic bed (VMgO catalyst ) combined in series with a void volume (post-catalytic). High convers ion of n-butane was achieved with high C-2-C-4 selectivity and relativ ely low COx selectivity. (C) 1998 Elsevier Science B.V. All rights res erved.