Thermal decomposition of used tires was studied under atmospheric pressure and thermal heating program up to 350 °C for 110-120 min in a glass reactor. The effects of using MgO or SiO2 as catalyst in the thermal pyrolysis of tires waste on the yield ratio, reaction time, initial degree of decomposition also the contents of BTEX compounds in resulting pyrolytic oil was estimated via GC-FID. The results showed that the MgO catalyst gave a gas output in proportion of 17.063%, a liquid in a proportion of 38.245% and a solid product in proportion of 44.733%, while the SiO2 catalyst gave proportions of 14.308%, 40.161% and 45.448% for gas, liquid and solid products respectively. The results revealed that the thermal pyrolysis produced minor content of BTEX as compared with catalytic SiO2 and MgO pyrolysis, also Toluene is the highest concentration among compounds in all types of thermal decomposition while Ethyl benzene is the lowest one. he reaction time and the initial temperature were decreases by use their cofactors MgO or SiO2, also the sum of the total BTEX concentrations was increased at 17.4% and 30.8% with MgO and SiO2 respectively.
