Abstract: The dehydrogenation of tetralin over Ni-Mo/A1_2O_3,Fe_2O_3/Al_2O_3,Fe_2O_3 and FeS_2 has been shown inthis investigation to be a typical consecutive reversible reaction,with a small amount of 1,2-dihydronaph-thalene as an intermediate.On the less active catalyst Fe_2O_3,a few percent of 1,4-dihydronaphthalene(DHN)is also formed—the more active the catalyst,the lower the concentration of DHN.The rate of dehydrogena-tion rises with an increase of the partial pressure of tetralin,and declines with an increase of the partialpressure of hydrogen.It was observed that DHN is much more active than tetralin and naphthalene,andin the presence of a catalyst,it can be converted rapidly into naphthalene and tetralin.The fact that hydrogencan accelerate the hydrogenation of DHN is thought to be the main reason for its inhibiting the dehydroge-nation of tetralin.In the presence of a catalyst,1,4-DHN it unstable and can be isomerized into 1,2-DHNvery fast.These different catalysts have almost the same order of activities for dehydrogenation of tetralin,conversion of DHN and hydrogenation of naphthalene.On the hypothesis that the reaction is a consecutiveone on the catalyst surface and that the adsorbed DHN is a very active intermediate,a reaction model hasbeen deduced.The equilibrium constants of adsorption and the rate constants of the catalytic reaction werecalculated.The curves so calculated fit the experimental data very well,thus showing the validity of thismodel.Certain experimental results were explained in the light of this model and the related parameters.