Esterification reactions of ethenyl,,benzene and its derivatives were carried out with acetic acid. A strong acid, sulphuric acid, was used as a catalyst. A study was made on influence of temperature, catalyst concentration and type of substituted radical have on the conversion of all studied compounds. From the obtained results it can be deduced the following conclusions: an increase in temperature and catalyst concentration positively influences the conversion of the corresponding olefins. The substituted radical and the occupied position on the aromatic ring ("meta" or "para") exerts a very important influence on the reaction conversion. For identical substitute type, the substituted derivatives in position "para" present a bigger reactivity and olefin conversion than substituted derivatives in position "meta". Finally, a thermodynamic and kinetic study has been done with the calculation of the corresponding parameters.