Selective Bromination of p-Xylene via Homogeneous Catalysis: Influence of Reaction Parameters on 2,5-Dibromo- p-Xylene Formation

In general, homogeneous catalysis signifies reactions with soluble catalysts that are of the same phase as of the reactants in order to decrease the activation energy and increase the reaction rate. The aromatic halogenation substitution reaction of p-xylene to the multi-halogenated derivatives is a well-known reaction that has been studied over years. However, the recent advances in porous materials (e.g., MOFs) have re-focused the spot again on such a reaction so as to functionalize those materials. This study is concerned with the homogeneous catalytic bromination of p-xylene to 2,5-dibromo-p-xylene along with its separation and purification. Using Ferric chloride hexahydrate as catalyst, the effect of variating the bromine amount, the reaction temperature, and the reaction time have been selectively studied. The products were characterized using XRD, FTIR, and H 1 NMR Spectrometer. The best yield of 2,5-dibromo-p-xylene is at bromine/p-xylene ratio of 2:1.