Disclosed herein is a process and catalyst for producing a monoalkylated aromatic compound from a polyalkylated aromatic compound, comprising the step of contacting an alkylatable aromatic compound with a polyalkylated aromatic compound under at least partial liquid phase conditions in the presence of a zeolite beta catalyst having a phosphorus content in the range of 0.001 wt. % to 10.0 wt. % of said catalyst, to provide a product which comprises a monoalkylated aromatic compound.