TUGAS 2TEKNIK REAKSI KIMIA LANJUT Disusun Oleh : Fatoni Nugroho Dosen Pengampu: Dr. Istadi, S.T., M.T. JURUSAN TEKNIK KIMIA FAKULTAS TEKNIK’ UNIVERSITAS DIPONEGORO SEMARANG 2014 Develop reaction rate law appropiate with this reaction we ask what qualitative conclusions can be drawn from the data about the dependence of the rate of disappearance of i-octene. Suggest a mechanism consistent with the above experimental data 3. -r A on the partial pressures of i-octene. hydrogen. Table 1. and (c) if desorption controlling 2. Develop a reaction rate law appropriate with this reaction (possibility controlling mechanism: (a) if adsorption controlling. 1) Dependence on the product i-octane . Answer : Reaction i-octene + hydrogen A + B i-octane C 1. (b) if surface reaction controlling. Usage of Polymath software was recommended to solve the fitting. Evaluate the reaction rate law model parameters according to the above experimental data. and i-octane.The following data for the hydrogenation of i-octene to form i-octane were obtained using a differential reactor operated at 200°C. Experimental Data 1. we observe that in the low concentration. or 1 and 6. With combining equation (1) suggests that the rate law may be of the form 3) Dependence on i-octene. 8 and 10. rate increases with increasing concentration of i-octene. A rate expression in which the i-octane partial pressure appears in the denominator could explain this dependency: The type of dependence of -r A on PC given by Equation (1) suggests that ioctane is adsorbed on the clinoptilolite surface. We can assume that only low concentration of i-octene will absorbed on surface. So we can conclude that hydrogen is adsorbed on the surface. With combining equation (2) suggests that the rate law may be of the form We now propose a mechanism for the hydrogenation of i-octene. increasing concentration i-octene will decreasi the rate. We assume that i-octene and hydrogen is adsorbed on the surface and then reacts to produce i-octane adsorbed on the surface. In runs 2 and 4. 2.S . we observe that rate increases with increasing concentration of hydrogen.In runs 1. The rate law can be : a. adsorption controlling There are 2 reactan that adsorbed on surface A + S A. But in runs 1 and 7. it can disturb reaction. if high concentration of ioctene. we observe that for fixed concentrations (partial pressures) of i-octene and hydrogen the rate decreases with increasing concentration of i-octane. 2) Dependence on hydrogen In runs 2 and 3. i-octaneis then desorbed from the surface. desorption controlling C. Mechanism consistent with the above experimental data Since approximately 75% of all heterogeneous reaction mechanisms are surface reaction limited rather than adsorption or desorption limited. we see that we need to replace CAS CBS. we use the adsorption rate Equation (4) to obtain CAS and eq. In Equation (8) by quantities that we can measure.S c.(5) for CBS : . and CCS that we can measure.S + B.S C. surface reaction controlling A. we begin by assuming the reaction between adsorbed i-octene and hydrogen to be reaction rate limited.B + S B. For surface reaction mechanism.S C + S 2. For surface-reaction-limited mechanisms.S b. (10). and (11) to (12). CBS. (8) to obtain the rate law for the case of surface-reaction control: By neglecting the reserve reaction we have Then substitute eq.(7) to obtain CCS The total concentration Substitute eq. Evaluation of the rate law model parameter . we obtain : Substitution the substitute for CAS. (13) 3.And we use desorption rate eq. (9).and CCS in eq. The data from experiment were entered into the POLYMATH and use Nonlinier regression : Figure 1 . Model in Polymath Enter Model parameter Table 2. 14) were entered in Polymath : Figure 2. Model Parameter Model parameter Initial guess k 1 KA 1 . Input data (Polymath) The rates of reaction ( eq. Variabel in Polymath Solve the problem The Polymath Results are given in Figure 3 : Figure 4. . KB 1 KC 1 Definite variable in Polymath must be like this : Figure 3. Polymath report So we have. Figure 5. Graph Result .
Report "Tugas_2_Teknik Reaksi Kimia Lanjut_Fatoni Nugroho"