A catalyst composition suitable for the conversion of n-butane to butenes. The same catalyst composition that with chlorination is further suitable, when used in the conversion of n-butane, for the production of an increased amount of BTX (benzene-toluene-xylene) and greater selectivity to the production of isobutylenes than attained with the unchlorinated catalyst. A process for the preparation of catalyst compositions suitable for the conversion of n-butane. Use of the catalyst compositions in processes for the conversion of n-butane.