Lactic acid is widely used in the food, cosmetic, pharmaceutical, and chemical industries and has received increased attention for use as a monomer for the production of biodegradable poly(lactic acid).we select the reactive extraction for the recovery of the lactic acid because it is the cheapest method to recovery of lactic acid than the other processes where the mass transfer and reaction are carried out in one unit .In this case study there different parameters are used such as effect of diluents, effect of the initial concentration of lactic acid in aquoeus phase, effect of the concentration of TBP in organic phase and effect of temperature and we studied the kinetic studies of the reaction of lactic acid with TBP dissolved in di ethyl ether