Abstract
The dispersion of supported Pt and Pt–Ir reforming catalysts have been studied, after treatment with oxidative and reducing atmosphere. Methylcyclohexane dehydrogenation reaction in the absence of hydrogen was used as a test reaction. An attempt was made to relate the behavior of the catalysts upon subject to reaction, to the dispersion of the same type of catalysts upon treatment with similar atmosphere and temperatures which appeared in literature. The total conversion of reaction can be explained by a change in metal dispersion. Thus, methylcyclohexane dehydrogenation reaction appears to be a really “structure sensitive” reaction.The toluene yield increases as the oxidation temperature increases over the studied catalyst RG-402, RG-412, RG-422 and RG-432 respectively and reached a maximum value at 550°C. Above 550 the conversion decreases due to the effect of catalyst sintering.
No significant change were observed for reduction temperature range 400-600°C for the above studied catalysts. The selectivity order for the studied catalysts and for reduction treatment experiments arranged as follows:RG-422> RG-432> RG-412> RG-402
References
[1] Fung, A.S., Kelley, M.J., Koningsberger and Gates, B.C., “γ-Al2O3-Supported Re-Pt Cluster Catalyst Prepared from [Re2Pt(CO)12]: Characterization by Externded X-Ray Absorption Fine Structure Spectroscopy and Catalysis of Methylcyclohexane Dehydrogenation”, J. Am. Chem. Soc., 119, 5877 (1997).
[2] Parera, J. M., “Deactivation and Regeneration of Pt-Re/Al2O3 Catalysts”, Stud. Surf. Sci. Catal., 68, 103-10 (1991).
[3] Rajeshwer, D.; Basrur, A. G.; Gokak, D. T.; Krishnamurthy, K. R., “Method for Metal Dispersion Measurements in Bimetallic Pt-Sn/Al2O3 Catalysts”, J. Catal., 150, 135-42, (1994).
[4] Duprez, D.; Hadj-Aissa, M.; Barbier, J., “Effect of Steam on the Coking and on the Regeneration of Metal Catalysts: A Comparative Study of Alumina-Supported Platinum, Rhenium, Iridium and Rhodium Catalysts", Stud. Surf. Sci. Catal., 68, 111-8 (1991).
[5] Gonzalez-Marcos M.P., Guil J.M. Inarra B., Gutierrez-Ortiz, “Development of an Industrial Characterization Method for Naphtha Reforming Bimetallic Pt-Sn/Al2O3 Catalyst Through n-Heptane Reforming Test Reactions”, Catal. Today 107-108, 685-692, (2005).
[6] Anderson, J. R. and Avery, N.R., J. Catal., 5, 446 (1966).
[7] Fujikawa T., F.H. Ribeiro, G.A. G.A. Somorjai, J. Catal., 178, 58, (1998).
[8] Palazov A., Ch. Bonev, D. Shopov, G. Lietz, A. Sarkang, J. Volter, J. Catal., 103, 249, (1987).
[9] Burch, R., L. C. Garla, J. Catal., 71, 360, (1981).
[10] Che, M., C.O. Bennett, Adv. Catal., 36, 55, (1986).
[11] Xiaoyun Li., Ding Ma. And Xinhe Bao, “Dispersion of Pt Catalysts Supported on Activated carbon and Their catalytic Performance in Methylcyclohexane Dehydrogenation”, J. Catal., 29, 3, 259-263, (2008).
[12] Okada Y., Sasaki E., Watanabe E., Hodo S., Nishijima H. Int. J. Hydrogen Energy, 31, 10, 1348, (2006).
[13] Gonzalez-Marcos, M.P., B. Inarra, J. M. Guil, M.A. Gutierrez- Ortiz, Appl. Catal., A273, 259, (2004).
[14] Ritchie, A.W., Nixon, A.C., “Dehydrogenation of Methylcyclohexane Over a Platinum-Alumina Catalyst in Absence of Added Hydrogen”, Ind. Eng. Chem. Prod. Res. Dev. 5, 59-64 (1966).
[15] Parmaliana, A., Frusteri, F., Mezzapica, A., Giordano, N., “The Role of Chlorine in the Regeneration of Hydrogen of Coked Reforming Catalysts”, J. Catal. 111, 235-242 (1988).
[16] Straguzzi, G.I., Aduriz, H.R., Gigola, C.E., “Redispersion of Platinum on Alumina Support”, J. Catal. 66, 171-183 (1980).
[17] Dautzenberg, F. M., and H.B.M. Wolters, “State of Dispersion of Platinum in Alumina Supported Catalysts”, J. Catal. 51, 26 (1978).
[18] Fiedorow, R.M.J.; Chahar, B. S.; and S. E. Wanke, “The Sintering of Supported Metal Catalysts. 2. Comparison of Sintering Rates of Supported Pt, Ir, and Rh Catalysts in Hydrogen and Oxygen”, J. Catal. 51, 193–202 (1978).
[19] Graham, A.J. and S. E. Wank, “The sintering of Supported Metal Catalysts. 3. The Thermal Stability of Bimetallic Pt–Ir Catalysts Supported on Alumina”, J. Catal. 68, 1–8 (1981).
[20] Lieske, H., Lietz, G., Spindler, H., Volter, J., “Reactions of Platinum in Oxygen-and Hydrogen-Treated Pt/g-Al2O3 Catalysts. 1-Temperature Programmed Reduction, Adsorption, and Redispersion of Platinum”, J. Catal. 81, 8-16 (1983).
[21] Straguzzi, G.I., Aduriz, H.R., Gigola, C.E., “Redispersion of Platinum on Alumina Support”, J. Catal. 66, 171-183(1980).
[22] Lee, T. J., Kim, Y.G., “Dispersion of Supported Platinum Catalysts in Oxygen. 1- Experimental Evidences of Redispersion. KJChE 2, 55-61 (1985).
[23] Hassan, S.A., Khalil, F.H., El-Gamal, F.G., “The Effect of Different Atmospheres on The Sintering of Pt/Al2O3 Catalysts”, J. Catal. 44, 5-14 (1976).
[24] Lietz, G., Lieske, H., Spindler, H., Hanke, W., Volter, J., “Reactions of Platinum in Oxygen-and Hydrogen-Treated Pt/g-Al2O3 Catalysts. 2-Ultaviolet-Visible Studies, Sintering of Platinum, and Soluble Platinum”, J. Catal. 81, 17-25 (1983).
[25] McHenry, K.W; R.J. Bertolacini; H.M. Brennan; Wilson, J. L. and H.S. Seeling, “The Nature of Platinum Dehydrocyclization Catalyst”, in Proc. 2nd Int. Cong. Catal. (Paris), 2295-2311(1961).
[26] Aben, P.C., Platteeuw, J.C., Stouthamer, B., in Proc. 4th Int. Cong. Catal. (Moscow) 1, 395 (1971).
[27] Dautzenberg, F.M., Platteuw, J.C., J. Catal. 24, 364- (1972).
[28] Lee, T.J., Kim, Y.G., “Dispersion of Supported Platinum Catalysts in Oxygen. 1- Experimental Evidences of Redispersion. KJChE 2, 55-61(1985).
[29] Ramaswamy, A.V., Ratnasamy, P., Sivasanker, S., Leonard, A.J., “Structure, and Catalytic Properties of Bimetallic Reforming Catalysts”, in Proc. 6th Int. Cong. Catal. (London), 855-862 (1977).
[30] Smith, D.J., White, D., Bird, T., Fryer, J.R., “The Characterization of a model Platinum/Alumina Catalyst by High Resolution Electron Microscopy”, J. Catal., 81, 107-118 (1983).
[2] Parera, J. M., “Deactivation and Regeneration of Pt-Re/Al2O3 Catalysts”, Stud. Surf. Sci. Catal., 68, 103-10 (1991).
[3] Rajeshwer, D.; Basrur, A. G.; Gokak, D. T.; Krishnamurthy, K. R., “Method for Metal Dispersion Measurements in Bimetallic Pt-Sn/Al2O3 Catalysts”, J. Catal., 150, 135-42, (1994).
[4] Duprez, D.; Hadj-Aissa, M.; Barbier, J., “Effect of Steam on the Coking and on the Regeneration of Metal Catalysts: A Comparative Study of Alumina-Supported Platinum, Rhenium, Iridium and Rhodium Catalysts", Stud. Surf. Sci. Catal., 68, 111-8 (1991).
[5] Gonzalez-Marcos M.P., Guil J.M. Inarra B., Gutierrez-Ortiz, “Development of an Industrial Characterization Method for Naphtha Reforming Bimetallic Pt-Sn/Al2O3 Catalyst Through n-Heptane Reforming Test Reactions”, Catal. Today 107-108, 685-692, (2005).
[6] Anderson, J. R. and Avery, N.R., J. Catal., 5, 446 (1966).
[7] Fujikawa T., F.H. Ribeiro, G.A. G.A. Somorjai, J. Catal., 178, 58, (1998).
[8] Palazov A., Ch. Bonev, D. Shopov, G. Lietz, A. Sarkang, J. Volter, J. Catal., 103, 249, (1987).
[9] Burch, R., L. C. Garla, J. Catal., 71, 360, (1981).
[10] Che, M., C.O. Bennett, Adv. Catal., 36, 55, (1986).
[11] Xiaoyun Li., Ding Ma. And Xinhe Bao, “Dispersion of Pt Catalysts Supported on Activated carbon and Their catalytic Performance in Methylcyclohexane Dehydrogenation”, J. Catal., 29, 3, 259-263, (2008).
[12] Okada Y., Sasaki E., Watanabe E., Hodo S., Nishijima H. Int. J. Hydrogen Energy, 31, 10, 1348, (2006).
[13] Gonzalez-Marcos, M.P., B. Inarra, J. M. Guil, M.A. Gutierrez- Ortiz, Appl. Catal., A273, 259, (2004).
[14] Ritchie, A.W., Nixon, A.C., “Dehydrogenation of Methylcyclohexane Over a Platinum-Alumina Catalyst in Absence of Added Hydrogen”, Ind. Eng. Chem. Prod. Res. Dev. 5, 59-64 (1966).
[15] Parmaliana, A., Frusteri, F., Mezzapica, A., Giordano, N., “The Role of Chlorine in the Regeneration of Hydrogen of Coked Reforming Catalysts”, J. Catal. 111, 235-242 (1988).
[16] Straguzzi, G.I., Aduriz, H.R., Gigola, C.E., “Redispersion of Platinum on Alumina Support”, J. Catal. 66, 171-183 (1980).
[17] Dautzenberg, F. M., and H.B.M. Wolters, “State of Dispersion of Platinum in Alumina Supported Catalysts”, J. Catal. 51, 26 (1978).
[18] Fiedorow, R.M.J.; Chahar, B. S.; and S. E. Wanke, “The Sintering of Supported Metal Catalysts. 2. Comparison of Sintering Rates of Supported Pt, Ir, and Rh Catalysts in Hydrogen and Oxygen”, J. Catal. 51, 193–202 (1978).
[19] Graham, A.J. and S. E. Wank, “The sintering of Supported Metal Catalysts. 3. The Thermal Stability of Bimetallic Pt–Ir Catalysts Supported on Alumina”, J. Catal. 68, 1–8 (1981).
[20] Lieske, H., Lietz, G., Spindler, H., Volter, J., “Reactions of Platinum in Oxygen-and Hydrogen-Treated Pt/g-Al2O3 Catalysts. 1-Temperature Programmed Reduction, Adsorption, and Redispersion of Platinum”, J. Catal. 81, 8-16 (1983).
[21] Straguzzi, G.I., Aduriz, H.R., Gigola, C.E., “Redispersion of Platinum on Alumina Support”, J. Catal. 66, 171-183(1980).
[22] Lee, T. J., Kim, Y.G., “Dispersion of Supported Platinum Catalysts in Oxygen. 1- Experimental Evidences of Redispersion. KJChE 2, 55-61 (1985).
[23] Hassan, S.A., Khalil, F.H., El-Gamal, F.G., “The Effect of Different Atmospheres on The Sintering of Pt/Al2O3 Catalysts”, J. Catal. 44, 5-14 (1976).
[24] Lietz, G., Lieske, H., Spindler, H., Hanke, W., Volter, J., “Reactions of Platinum in Oxygen-and Hydrogen-Treated Pt/g-Al2O3 Catalysts. 2-Ultaviolet-Visible Studies, Sintering of Platinum, and Soluble Platinum”, J. Catal. 81, 17-25 (1983).
[25] McHenry, K.W; R.J. Bertolacini; H.M. Brennan; Wilson, J. L. and H.S. Seeling, “The Nature of Platinum Dehydrocyclization Catalyst”, in Proc. 2nd Int. Cong. Catal. (Paris), 2295-2311(1961).
[26] Aben, P.C., Platteeuw, J.C., Stouthamer, B., in Proc. 4th Int. Cong. Catal. (Moscow) 1, 395 (1971).
[27] Dautzenberg, F.M., Platteuw, J.C., J. Catal. 24, 364- (1972).
[28] Lee, T.J., Kim, Y.G., “Dispersion of Supported Platinum Catalysts in Oxygen. 1- Experimental Evidences of Redispersion. KJChE 2, 55-61(1985).
[29] Ramaswamy, A.V., Ratnasamy, P., Sivasanker, S., Leonard, A.J., “Structure, and Catalytic Properties of Bimetallic Reforming Catalysts”, in Proc. 6th Int. Cong. Catal. (London), 855-862 (1977).
[30] Smith, D.J., White, D., Bird, T., Fryer, J.R., “The Characterization of a model Platinum/Alumina Catalyst by High Resolution Electron Microscopy”, J. Catal., 81, 107-118 (1983).
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