Methods are provided for producing alkylbenzenes, such as propylbenzene, from aromatics, such as toluene, and alkenes, such as ethylene. Such methods comprise combining the toluene with about 100 ppm to about 350 ppm water and alkali metal catalyst, activating the catalyst at about 180° C. to about 220° C., adding the ethylene and conducting the synthesis reaction at about 130° C. to about 150° C.