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Surface Properties of Sepiolite from Amboseli, Tanzania, and Its Catalytic Activity for Ethanol Decomposition

Published online by Cambridge University Press:  02 April 2024

A. J. Dandy  and
M. S. Nadiye-Tabbiruka
A. J. Dandy
Affiliation:
School of Natural Resources, University of the South Pacific, Suva, Fiji
M. S. Nadiye-Tabbiruka
Affiliation:
Department of Chemistry, Makerere University, Kampala, Uganda
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Abstract

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The catalytic activity of sepiolite from Amboseli, Tanzania, for the dehydration and dehydrogenation of ethanol at 150°–300°C has been studied using a flow reactor. Both reactions occur, but the catalyst activity decreases with use. The products include water, carbon dioxide, ethene, ethanal (acetaldehyde), diethyl ether, but-1,3-diene, but-2-enal (crotonaldehyde), and an unidentified aromatic compound. The proportions change with temperature, the dehydrogenation reaction being favored at the higher temperatures. The BET surface areas of the sepiolite are 316 m2/g (nitrogen adsorption at — 197°C) and 212 m2/g (ethanol vapor adsorption at 25°C, assuming a molecular cross-sectional area of 24.6 Å2), indicating a possible greater penetration of pores and channels by nitrogen compared with ethanol vapor under these conditions. The pore-size distribution reveals that approximately 55% of the surface area measured by nitrogen adsorption is contributed by micropores.

Резюме

Резюме

Резюме—Исследовалась каталитическая активность сепиолита из Амбосели, Танзания, на дегидра-тацию и дегидрирование этаноля при 150°–300°С при помощи проточного реактора. Обе реакции происходят, но активность катализатора уменьшается со временем его использования. Продукты включают: воду, углекислоту, этен, этаноль (ацетальдегид), двухэфир, бут-1,3-диен, бут-2-енал, и неопределенное ароматическое соединение. Пропорции изменяются с температурой, реакция деги-дрирования преобладает при больших температурах. Площади поверхности сепиолита, определен-ные методом БЭТ, равны 316 м2/г (адсорбция азота при–197°С) и 212 м2/г (адсорбция пара этаноля при 25°С), предполагая, что площадь молекулярного поперечного сечения равна 24,6 Å2. Это указывает на возможное большое проникание азота в поры и каналы сепиолита по сравнению с прониканием пара этаноля при таких же условиях. Распределение пор по размерам указывает на то, что приблизительно 55% площади поверхности, измеренной адсорбцией азота, принадлежит микропорам. [E.C.]

Resümee

Resümee

Die katalytische Wirkung des Sepiolith von Amboseli, Tanzania, bei der Dehydratation und Dehydrierung von Äthanol bei 150°–300°C wurde unter Verwendung eines Durchflußreaktors untersucht. Beide Reaktionen treten ein, aber die katalytische Wirkung nahm mit der Zeit ab. Die Produkte waren Wasser, Kohlendioxid, Äthylen, Äthanal (Acetaldehyd), Diäthyläther, But-1,3-Dien, But-2-Enal (Crotonaldehyd), und eine unidentifizierte aromatische Verbindung. Die Mengenverhältnisse veränderten sich mit der Temperatur, die Dehydrierungsreaktion wurde bei höheren Temperaturen begünstigt. Die BET-Oberfiäche des Sepiolith beträgt 316 m2/g (Stickstoffadsorption bei -197°C) und 212 m2/g (Äthanoldampf-Adsorption bei 25°C), was auf eine molekulare Querschnittsfläche von 24,6 Å2 schließen läßt. Außerdem deutet dies daraufhin, daß unter den gegebenen Bedingungen Stickstoff weiter in Poren und Kanäle eindringen kann als Äthanoldampf. Die Verteilung der Porengröße zeigt, daß etwa 55% der durch Stickstoffadsorption gemessenen Oberfläche von Mikroporen stammt. [U.W.]

Résumé

Résumé

On a étudié avec un réacteur à flot l'activité catalytique de la sepiolite d'Amboseli, Tanzanie, pour la déshydration et la déshydrogènation d’éthanol à 15°–300°C. On observe les deux réactions, mais l'activité catalyste décroit avec l'emploi. Les produits comprennent l'eau, le carbone dioxide, l’éthène, l’éthanal (acétaldéhyde), l’éther diethyl, but-l,3-diène, but-2-énal (crotonaldéhyde), et un composé aromatique non-identifié. Les proportions changent avec la température, la réaction de déshydrogènation étant favorisée à de plus hautes températures. Les aires de surface de la sépiolite sont 316 m2/g (adsorption de nitrogène à — 197°C) et 212 m2/g adsorption (de vapeur d’éthanol) à 25°C, en supposant que l'aire moléculaire d'une section transversale est 24,6 Å2, indiquant possiblement une plus grande pénétration possible de nitrogène dans les pores et les canaux en comparaison avec la vapeur d’éthanol sous les mêmes conditions. La distribution de tailles de pores révèle qu'approximativement 55% de la surface mesurée par l'adsorption par le nitrogène est contribué par des micropores. [D.J.]

Keywords

AdsorptionCatalysisEthanolPore sizeSepioliteSurface area
Type
Research Article
Information
Clays and Clay Minerals , Volume 30 , Issue 5 , October 1982 , pp. 347 - 352
Copyright
Copyright © 1982, The Clay Minerals Society

References

Aldhouse, S. T. E., Howman, E. J., andMcGrath, B. P. (1969) 4-Methyl-2-pentene: Patent Brit. 1,173,906 (Chetn. Abstr. 72, 66351, 1970).Google Scholar
Barrer, R. M., Mackenzie, N. and Macleod, D. M., 1954 Sorption by attapulgite. II. Selectivity shown by attapulgite, sepiolite and montmorillonite for n-paraffins J. Phys. Chem. 58 568–572.CrossRefGoogle Scholar
Bodor, E. E., Older, I. and Skalny, J. J., 1970 An analytical method for pore structure analysis J. Colloid Interface Sci. 32 367–369.CrossRefGoogle Scholar
Brindley, G. W., 1959 X-ray and electron diffraction datafor sepiolite Amer. Mineral. 44 495–500.Google Scholar
Brunauer, S., Emmett, P. H. and Teller, E. J., 1938 Adsorption of gases in multimolecular layers J. Amer. Chem. Soc. 60 309–319.CrossRefGoogle Scholar
Brunauer, S., Mikhail, R Sh and Bodor, E. E., 1967 Pore structure analysis with a pore shape model J. Colloid Interface Sci. 24 451–463.CrossRefGoogle Scholar
Dandy, A. J., 1968 Sorption of vapors by sepiolite J. Phys. Chem. 72 334–339.CrossRefGoogle Scholar
Dandy, A. J., 1969 The determination of the surface area of sepiolite from carbon dioxide adsorption isotherms J. Soil Sci. 20 278–287.CrossRefGoogle Scholar
Dandy, A. J., 1971 Zeolitic water content and adsorptive capacity for ammonia of microporous sepiolite J. Chem. Soc. 2383–2387.CrossRefGoogle Scholar
Dandy, A. J. and Nadiye-Tabbiruka, M. S., 1975 The effect of heating in vacu. on the microporosity of sepiolite Clays & Clay Mineral. 23 428–430.CrossRefGoogle Scholar
de Boer, J. H., Lippens, B. C., Linsen, B. G., Broekhoff, J. C. P., van den Heuval, A. and Osinga, Th J, 1966 The t-curve of multimolecular N2-adsorption J. Colloid Interface Sci. 21 405–414.CrossRefGoogle Scholar
Fenoll Hach-Ali, P. and Martin Vivaldi, J. L., 1970 Thermal behaviour of vermiculite and sepiolite complexes with normal aliphatic alcohols An. Quim. 66 141–148.Google Scholar
Fernandez-Alvarez, T., 1978 Effect of dehydration on the adsorbant properties of palygorskite and sepiolite Clay Miner. 13 325–335.Google Scholar
Hagymassy, J. Jr. and Brunauer, S., 1970 Pore structure analysis by water vapor adsorption. II. Analysis of five silica gels J. Colloid Interface Sci. 33 317–327.CrossRefGoogle Scholar
Hayashi, H., Otsuka, R. and Imai, N., 1969 Infrared study of sepiolite and palygorskite on heating Amer. Mineral. 53 1613–1624.Google Scholar
Hougen, O. A. and Watson, K. M., 1943 Solid catalysts and reaction rates—general principles Ind. Eng. Chem. 35 529–541.CrossRefGoogle Scholar
Inooka, M., Kasuya, M., and Matsuda, M. (1978a) Three-stage hydrocracking of fuel oils: Japan. Koka. 78,101,004 (Chem. Abstr. 90, 57732, 1979).Google Scholar
Inooka, M., Nakamura, M., and Morimoto, T. (1978b) Two-stage hydrodesulfurization of heavy fuel oils: Japan. Koka. 78,098,308 (Chem. Abstr. 90, 74251, 1979).Google Scholar
Ioka, M., Wakabayashi, M., and Oguchi, Y. (1978) Hydrogenation catalysts for hydrocarbon oil: Japan. Koka. 78,034,691 (Chem. Abstr. 89, 8724, 1978).Google Scholar
de Lopez-Gonzalez, J. D., Valenzuela Calahorro, C., Jiminez Lopez, A., Ramurez Saenz, A. and Reinoso, R., 1978 Retention of n-butylamine on activated sepiolite. II. Retention isotherms An. Quim. 74 220–224.Google Scholar
Madeley, J. D. and Sing, K. S. W., 1959 Adsorption of ethyl alcohol vapor by silica gel Chemy. Ind. 289–290.Google Scholar
Manara, G. and Taramasso, M., 1972 Sieving effects of hormites in gas-adsorption chromatography J. Chromatog. 65 349–353.CrossRefGoogle Scholar
Martin Vivaldi, J. L., Fenoll Hach-Ali, P. and Mackenzie, R. C., 1969 Palygorskites and sepiolites (hormites) Differential Thermal Analysis London Academic Press 553–573.Google Scholar
Mikhail, R Sh, Brunauer, S. and Bodor, E. E., 1968 Investigations of a complete pore structure analysis. I. Analysis of micropores J. Colloid Interface Sei. 26 45–53.CrossRefGoogle Scholar
Nagata, H., Shimoda, S. and Sudo, T., 1974 On dehydration of bound water of sepiolite Clays & Clay Mineral. 22 285–293.CrossRefGoogle Scholar
Niiyama, H. and Echigoya, E., 1972 Hydrogen transfer reaction between alcohols and acetone Bull. Chem. Soc. Jap. 45 938–939.CrossRefGoogle Scholar
Niiyama, H., Morii, S. and Echigoya, E., 1972 Butadiene formation from ethanol over silica-magnesia catalysts Bull. Chem. Soc. Jap. 45 655–659.CrossRefGoogle Scholar
Pines, H. and Manassen, J., 1966 The mechanism of dehydration of alcohols over alumina catalysts Adv. Catalysis 16 49–93.Google Scholar
Schwab, G. M. and Schwab-Agallidis, E., 1949 Selective catalysis J. Amer. Chem. Soc. 71 1806–1816.CrossRefGoogle Scholar
Sema, C. and Fernandez-Alvarez, T., 1975 Adsorption of hydrocarbons on sepiolite. II. Surface properties An. Quim. 71 371–376.Google Scholar
Serna, C., Vanscoyoc, G. E., Mortland, M. M. and Farmer, V. C., 1979 Infrared study of sepiolite and palygorskite surfaces in Proc. Int. Clay Conf., Oxford, 1978 Amsterdam Elsevier 197–206.Google Scholar
Serratosa, J. M., Mortland, M. M. and Farmer, V. C., 1979 Surface properties of fibrous clay minerals (palygorskite and sepiolite) Proc. Int. Clay Conf., Oxford, 1978 Amsterdam Elsevier 99–109.Google Scholar
Stoessel, R. K. and Hay, R. L., 1978 The geochemical origin of sepiolite and kerolite at Amboseli, Kenya Contrib. Mineral. Petrol. 65 255–267.CrossRefGoogle Scholar
Whittam, T. V. (1977) Catalyst mass for removal of hetero atoms from hydrocarbons: Ger. Offen. 2,655,879 (Chem. Abstr. 87, 91415, 1977).Google Scholar
Williams, L. A. G. (1972) Geology of the Amboseli area: Geol. Survey Keny. 90, 86 pp.Google Scholar