Oil enhanced recovery from oil reservoirs, especially from heavier oil reservoirs, due to the need of industrial countries has put the refining industries in the way of development. Low API oil will cause problems such as the production of more sulfur pollutants during the refining process, Compounds of environmental issues which also lower the burning quality of the products. Legislation of strict environmental laws for reduction of pollutant fuels dangers has made the oil companies to put the sweetening of oil products in high priority. One of the sulfuric pollutants is the mercaptans. These compounds are the most undesirable sulfur compounds in petroleum products due to their foul odor, highly corrosive nature, causing undesirable oxidation and preventing some additives activity. There are various methods to remove mercaptans but the major one is the catalytic oxidation in the presence of caustic solution and air. the catalytic oxidation of mercaptans and iecting the affecting parameters on the process are some of the most important parts of the mercaptan removal unit design. Due to lack of information about the kinetic of catalytic oxidation of light mercaptans present in the light to middle distillation products, some experiments were accomplished in this project. Useful experimental data were obtained by doing more than sixty experiments and investigating the effective parameters. These data can be used for the simulation and designing mercaptan removal units. Effective parameters such as temperature, organic to aqueous phase ratio, sodium hydroxide concentration and the nature of solvent and their effect on the rate of oxidation reaction were reported as quantitative data. Experiments were done in a semi batch bubble column reactor made of glass in witch Organic and aqueous phases were designed to be batch and gas phase to be continuous. These experiments were done in the presence of merox catalyst as the most common catalyst.So it was proved that the mercaptan oxidation reaction equation is first-order with respect to mercaptan concentration, zero-order with respect to oxygen concentration and as order of -1/2. Modeling of the packed-bed reactor of the sweetening unit was done after achieving experimental data. Being able to change the effective parameters of the bed and feed, steady-state analytical solving, high accuracy and simplicity are the advantages of the proposed modeling. Using kinetic data and solving the model, appropriate simulation was obtained. Achieved results were close to the reported results and existing unit’s data. Finally using programs written in MATLAB, effect of the parameters such as the feed flow rate, type of the existing mercaptan, sodium hydroxide concentration and unit’s temperature on the sweetening process was investigated.