Investigations of the alkylation of substituted aromatic hydrocarbons by an alcohol and 70-- 857$ sulfuric acid1V2 hare led to the belief, but apparently without definite proof in some cases, that the normal orientation effects of alkyl groups are always exerted when this procedure is used. Thus, i-propylbenzene has been reported to yield 1, 2, 4- triisopropylbenzene, and the dialkylbenzenes obtained from benzene or toluene have ...
[Olah, George A.; Shamma, Tatyana; Burrichter, Arwed; Rasul, Golam; Prakash, G. K. Surya Journal of the American Chemical Society, 1997 , vol. 119, # 52 p. 12923 - 12928]