Enhanced selectivity in the preparation of linear alkylbenzenes using hexagonal mesoporous silica supported aluminium chloride

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