It is used as a reagent in sulfonation and sulfomethylation agent. Sulfur trioxide is an essential reagent in sulfonation reactions. Sulfonic acids are produced by the process of sulfonation. Several methods exist for this conversion, which can lead to varying degree of sulfonation. Tppts is synthesized by sulfonation of triphenylphosphine. TsOH is prepared on an industrial scale by the sulfonation of toluene. It is used in chemical manufacturing as a sulfonation and sulfomethylation agent. It is produced by the sulfonation of benzene with sulfuric acid and oleum. The sulfonation with fuming sulfuric acid gives benzenesulfonic acid. Many method have been developed for introducing sulfonate groups aside from direction sulfonation. Further sulfonation gives 1,5-naphthalene-disulfonic acid. Peptides frequently have post-translational modifications such as phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation and disulfide formation. Arylsulfonic acids are susceptible to hydrolysis, the reverse of the sulfonation reaction. For example, sulfa drugs are sulfonamides derived from aromatic sulfonation. Further sulfonation gives The 1,3,5-trisulfonic acid derivative.