Durene, sulfonation

Jacobsen Rearrangement. When a polyalkylated benzene is allowed to remain in contact with sulfuric acid, a rearranged polylalkylbenzene sulfonic acid is often obtained. Reactions of this kind are usually called Jacobsen rearrangements.54 The reaction of durene with sulfuric acid is an example ... 

Rearrangement appears to be a property of the sulfonic acids themselves and not of the hydrocarbons, since durenesulfonic acid rearranges in contact with phosphorus pent oxide, but durene itself will not.55 Similarly, the sulfonic acid from pentamethylbenzene will rearrange in a desiccator over sulfuric acid, whereas the hydrocarbon will not.54... 

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