ENHANCED SELECTIVITY IN THE PREPARATION OF LINEAR ALKYLBENZENES USINGHEXAGONAL MESOPOROUS SILICA-SUPPORTED ALUMINUM-CHLORIDE

For decades sulphonated linear alkylbenzenes have been one of the worl ds most important detergents. Industrially, their preparation involves the use of either aluminium chloride or hydrogen fluoride as catalyst s in the alkylation stage of the reaction. The use of these catalysts presents severe problems in terms of both their environmental impact a nd their lack of selectivity towards the desired product. Solid acids, such as zeolites, can overcome these problems but at the expense of a ctivity, It has now been discovered that by chemically supporting alum inium chloride on a MCM-41 type silica a reuseable catalyst is produce d. It can be easily separated from the products and is environmentally benign, In addition, the new catalyst exhibits significant improvemen ts in selectivity towards both the monoalkylated product and the prefe rred 2-phenyl isomer, Selectivity can be further increased by maximizi ng the relative activity of the catalytic sites situated within the po res of the catalyst.