UN/VIS DIFFUSE REFLECTANCE SPECTROSCOPIC<BR>(DRS) STUDY OF COBALT-CONTAINING Y ZEOLITES DEHYDRATED AT ELEVATED TEMPERATURES

Han JD; Woo SI

Korean Journal of Chemical Engineering, Vol.8, No.4, 235-239, October, 1991

UN/VIS DIFFUSE REFLECTANCE SPECTROSCOPIC
(DRS) STUDY OF COBALT-CONTAINING Y ZEOLITES DEHYDRATED AT ELEVATED TEMPERATURES

Han JD, Woo SI

The coordination changes of Co²⁺ in Y-zeolite prepared by ion-exchange and dehydrated at various temperatures, have been investigated by UV/VIS diffuse reflectance spectroscopy. Fully hydrated zeolites show an octahedral coordination of [Co(H₂O)₆]²⁺ in the supercage with some inter-action with the framework. During dehydration at high temperatures, Co²⁺ in Y-zeolite changes its coordination, first from a symmetric to distorted tetrahedral and, successively, to an octahedral coordination. Fully hydrated sample of impregnated cobalt nitrate in Y-zeolite shows an octahedral coordination of Co(H₂O)₆(NO₃)₂. During dehydration at high temperature, the cobaltous nitrate decomposes to the cobalt oxide. However, the small amount of cobalt ions in cobalt nitrate are ion-exchanged simultaneously.

[References]

Gallezot P, BenTaarit Y, Imelik B, J. Catal., 26, 295 (1972)
Klier K, Adv. Chem. Ser., 101, 480 (1971)
Rabo JA, "Zeolite Chemistry and Catalysis," ACS Monograph vol. 171 (1976)
Kim JC, Woo SI, Appl. Catal., 39, 107 (1988)
Egerton TA, Hagan A, Stone FS, Vickerman JC, J. Chem. Soc.-Faraday Trans., 68, 723 (1972)
Zhang Z, Wong TT, Sachtler WMH, J. Catal., 128, 13 (1991)
Egerton TA, Stone FS, J. Chem. Soc.-Faraday Trans., 69, 22 (1973)
Gallezot P, BenTaarit Y, Imelik B, J. Catal., 26, 481 (1972)
Gallezot P, Imelik B, J. Chem. Phys., 72, 155 (1974)
Han JD, Woo SI, J. Chem. Soc.-Faraday Trans., to be published (1991)
Klier K, Catal. Rev.-Sci. Eng., 1(2), 207 (1967)
Diegruber H, Plath PJ, "Metal Microstructures in Zeolites," Jacobs, P.A., Ed., Elsevier, p. 23 (1982)
Hathaway BJ, Lewis CE, J. Chem. Soc., 1183 (1969)
Ashley JH, Mitchell PCH, J. Chem. Soc., 2821 (1968)
Budavari S, O'Neil MJ, "The Merck Index," 11th ed., Merck & Co., Inc., Rahway (1989)
Hutta PJ, Lunsford JH, J. Chem. Phys., 66(10), 4716 (1977)
Cotton FA, Goodgame DML, Goodgame M, J. Am. Chem. Soc., 83, 4690 (1961)
Klier K, Kellerman R, Hutta PJ, J. Chem. Phys., 61, 4224 (1974)
Cotton FA, Wilkinson G, "Advanced Inorganic Chemistry," 4th ed., John Wiley & Sons, New York, p. 766 (1980)

[1] Gallezot P, BenTaarit Y, Imelik B, J. Catal., 26, 295 (1972)

[2] Klier K, Adv. Chem. Ser., 101, 480 (1971)

[3] Rabo JA, "Zeolite Chemistry and Catalysis," ACS Monograph vol. 171 (1976)

[4] Kim JC, Woo SI, Appl. Catal., 39, 107 (1988)

[5] Egerton TA, Hagan A, Stone FS, Vickerman JC, J. Chem. Soc.-Faraday Trans., 68, 723 (1972)

[6] Zhang Z, Wong TT, Sachtler WMH, J. Catal., 128, 13 (1991)

[7] Egerton TA, Stone FS, J. Chem. Soc.-Faraday Trans., 69, 22 (1973)

[8] Gallezot P, BenTaarit Y, Imelik B, J. Catal., 26, 481 (1972)

[9] Gallezot P, Imelik B, J. Chem. Phys., 72, 155 (1974)

[10] Han JD, Woo SI, J. Chem. Soc.-Faraday Trans., to be published (1991)

[11] Klier K, Catal. Rev.-Sci. Eng., 1(2), 207 (1967)

[12] Diegruber H, Plath PJ, "Metal Microstructures in Zeolites," Jacobs, P.A., Ed., Elsevier, p. 23 (1982)

[13] Hathaway BJ, Lewis CE, J. Chem. Soc., 1183 (1969)

[14] Ashley JH, Mitchell PCH, J. Chem. Soc., 2821 (1968)

[15] Budavari S, O'Neil MJ, "The Merck Index," 11th ed., Merck & Co., Inc., Rahway (1989)

[16] Hutta PJ, Lunsford JH, J. Chem. Phys., 66(10), 4716 (1977)

[17] Cotton FA, Goodgame DML, Goodgame M, J. Am. Chem. Soc., 83, 4690 (1961)

[18] Klier K, Kellerman R, Hutta PJ, J. Chem. Phys., 61, 4224 (1974)

[19] Cotton FA, Wilkinson G, "Advanced Inorganic Chemistry," 4th ed., John Wiley & Sons, New York, p. 766 (1980)