| Sulfonate esters are compounds that are used widely as surface active agent, ion-exchange resin, dye, pesticide and medicine. Reactions of sulfonate esters have played an important role in the development of many of the fundamental concepts on which modern organic chemistry. By quotation of a lot of papers, the preparation and some kinds of important reactions of sulfonate esters have been described in this paper. The theorical studies on the pyrolytic reactions of sulfonate esters, which is the central reaction in this paper, have also been discussed in detail.Based on the size and composing of reaction system, density functional theory and semi-empirical method are applied to investigate the mechanism of ethyl-2-pyridine sulfonate, ethyl-8-quinoline sulfonate, isopropyl-8-quinoline sulfonate, isobutyl methylsulfonate and neopentyl methylsulfonate, and an authentic and useful conclusion has been drawn. It is the first time that intimate ion-pair transition state has been brought forward in this kind of the reaction.The results obtained show that the process for the gas-phase pyrolysis of these sulfonate esters occur via an intimate ion-pair transition state, where the p-hydrogen atom of ethyl carbocation facilitates C-O bond cleavage, and the cleavage of C-O bond is rate determining. On the pyrolysis of isobutyl methylsulfonate, rearrangement reactions are detected, in which the methyl group is transferred from p-C atom to O atom of sulfonic group. Furthermore, the left 2-pyridine sulfonic acid or 8-quinoline sulfonic acid processes intramolecular acid-base neutralization.In addition, theoretical studies on the mechanism of three reactions (1.Gas-phase Pyrolytic Reactions of N-Ethyl, N-Isopropyl and N-t-Butyl Substituted 2-Aminopyrimidine; 2.Gas-phase Pyrolytic Reactions of N-Ethyl, N-Isopropyl and N-t-Butyl Substituted 2-Aminopyrazine; 3.Gas-phase Elimination of 2-Bromopropionic acid) have been done, and some significant results have also been gotten.
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