This invention relates new and improved processes for the preparation of arylalkylsulfonic acids derived from aromatic or substituted aromatic molecules and AOS acid (generally a mixture of alkenesulfonic acid and sultones, produced from the sulfonation of alpha olefins) and to cleaning compositions comprising said arylalkylsulfonic acids. The invention involves the use of a superacid catalyst to effectuate the conversion of AOS acid and aromatic reactants to arylalkylsulfonic acid under substantially anhydrous conditions, whereby a substantial improvement in the rate of conversion of the reactants to arylalkylsulfonic acid and/or improvement in mono-alkylation selectivity is realized, as compared to methods of preparation previously disclosed. Also useful as an alkylation promoter is the arylalkylsulfonic acid reaction product itself, produced in situ or from a previous reaction (i.e., a self-catalyst heel). The new processes generally afford arylalkylsulfonic acids with substantially improved conversion yields, highly desirable lighter color, and reduced odor, as compared to previously known methods. The acids produced by the inventive process may be neutralized to form arylalkylsulfonates (i.e., a neutralized form of the acid) which are useful in a variety of end use applications as surfactants and/or emulsifiers.