Abstract
K-saturated kaolinite was titrated in 13 different solvents with tetrabutylammonium hydroxide using a combination electrode for potentiometric determination. The titer of base required to reach the final potentiometric endpoint was dependent on the solvent and increased according to the following solvent order in both the presence and absence of excess neutral salt: methanol ⩽ water < ethanol ⩽ 1-propanol < 1-butanol < 2-propanol < DMF < t-butanol < DMSO < pyridine ⩽ acetonitrile ⩽ methylethyl ketone < acetone. With the protic solvents, titratable acidity increased according to decreasing dielectric constant of the solvent and increasing size and/or branching of the aliphatic constituent. The largest titratable acidities were obtained in the dipolar aprotic solvents with negligible basic character (e.g., acetonitrile, acetone, methylethyl ketone). These results are discussed in terms of solvent properties, solvation characteristics of ions in the solvents, and acid-base behavior of crystalline edge sites.
Резюме
Каолинит, насыщенный К, был титрован в тринадцати различных растворителях с гидроокисью тетрабутиламмония с использованием комбинированного электрода для потенциометрического определения. Титр основания, необходимый для достижения окон-чательной потенциометрической границы, зависел от растворителя и возрастал соглас-но следующему порядку растворителей в присутствии и отсутствии избыточной нейтра-ной соли: метанол≤вода<этанол≤1-пропанол<1-бутанол<2-пропанол<Т-бутанол<диметил-сульфоксид<пиридин≤ацетонитрит≤метилэтилкетон<ацетон. С протонными растворами ти-трационная кислотность возрастала в соответствии с уменьшением диэлектрической постоянной растворителя и возрастанием размера и/или разветвлением алифатического компонента. Наибольшие титрационные кислотности были получены в дипольных апро-тонных растворителях с незначительным основным характером.(т.е. ацетонитрил, аце-тон, метилэтилкетон). Эти результаты обсуждаются в отношении свойств растворителей, характеристик сольватации ионов, кислотно-основного поведения некоторых частей кристаллических граней.
Kurzreferat
Ein mit Kalium gesättigtes Kaolinit wurde in dreizehn verschiedenen Lösungsmitteln mit Tetrabutylammoniumhydroxyd titriert, indem eine Kombinationselektrode für potentiometrische Bestimmungen benutzt wurde. Die Menge von Alkali, die nötig war, um den potentiometrischen Endpunkt zu erreichen, war vom Lösungsmittel abhängig und nahm in der folgenden Lösungsmittelreihenfolge zu, sowohl in Anwesenheit wie auch in Abwesenheit eines Überschusses an neutralen Salzen: Methanol≤ Wasser< Äthanol≤ 1-Propanol< 1-Butanol< 2-Propanol< DMF< t-Butanol< DMSO< Pyridin≤ Acetonitril≤ Methyläthylketoní Aceton. Mit den protischen Lösungsmitteln nimmt die titrierbare Azidität mit abnehmender Dielektrizitätskonstante des Lösungsmittels und mit zunehmender Länge und/oder Verzweigung des aliphatischen Anteils zu. Die höchsten titrierbaren Aziditäten wurden in den dipolaren, aprotischen Lösungsmitteln mit unbedeutendem basischen Charakter (z.B. Acetonitril, Aceton, Methyläthylketon) erhalten. Diese Resultate werden hinsichtlich der Eigenschaften der Lösungsmittel, Solvatationscharakteristiken der Ionen in den Lösungsmitteln und Säure-Basen Benehmen der kristallinen Randstellen diskutiert.
Résumé
Une kaolinite saturée de K a été titrée dans treize solvants différents avec de l’hydroxide de tétrabutylammonium utilisant une électrode de combinaison pour la détermination potentiométrique. Le titre basique nécessaire pour parvenir au point potentiométrique final dépendait du solvant, et augmentait, à la fois en la présence et l’absence d’un excès de sel neutre, dans l’ordre de solvants suivant: méthanol ≤ eau < éthanol ≤ 1-propanol < l-butanol < 2-propanol < DMF < t-butanol < DMSO < pyridine ≤ acétonitrile ≤ méthyléthyl cetone < acétone. Pour les solvants protiques, l’acidité titrable augmentait selon la constante diélectrique décroissante du solvant, et selon la taille et/ou le branchement croissant du constituant aliphatique. Les plus grandes acidités titrables étaient obtenues dans les solvants dipolaires aprotiques à caractère basique négligible (c.à.d. acétonitrile, acétone, méthyléthyl cetone). Ces résultats sont discutés selon les proprétés des solvants, les caractéristiques de dissolution des ions dans les solutions, et le comportement vis à vis des acides et des bases des sites de bords de cristaux.
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References
Bates, R. G. (1973) Determination of pH; Theory and Practice: Wiley, New York.
Brown, T. L. and Rogers, M. T. (1957) The integrated intensity of the O-H stretching band in aliphatic alcohols: J. Am. Chem. Soc. 70, 577–578.
Connick, R. E. and Fiat, D. N. (1963) Coordination numbers of beryllium and aluminum ions in aqueous solutions: J. Chem. Phys. 39, 1349–1351.
Fratiello, A., Lee, R. E., Miller, D. P. and Nishida, W. M. (1967) NMR studies of electrolytes in binary solvent mixtures. II. Aqueous mixtures of acetone, acetonitrile, dimethylformamide, dimethylsulf-oxide, dioxane, ethanol, methanol, N-methylformamide, tetramethylfuran, and tetramethylurea: Mol. Phys. 13, 349–359.
Fripiat, J. J., Vancompernolle, G. and Servais, A. (1960) Étude de la l’acidité de surface des silicates et alumino-silicates par titration en milieu non-aqueux. Bull. Soc. Chim. Fr. 46, 250–259.
Fritz, J. S. (1973) Acid-base Titrations in Nonaqueous Solvents: Allyn and Bacon, Inc., Boston.
Grasdalen, H. (1971) Proton magnetic resonance study of the solvation of aluminum (III) in ethanol: J. Magn. Reson. 5, 84–93.
Grasdalen, H. (1972) Proton magnetic resonance study of the solvation of aluminum (III) in n-propanol. J. Magn. Reson. 6, 336–343.
Green, R. D. and Sheppard, N. (1972) NMR study of the solvation sphere of the Mg2+ ion in acetone + water solutions in magnesium Perchlorate: J. Chem. Soc. Faraday Trans. 2 68, 821–832.
Hine, J. and Hine, M. (1952) The relative acidity of water, methanol, and other weak acids in isopropanol: J. Am. Chem. Soc. 74, 5266–5271.
Kapoor, B.S. (1972) Acid character of nontronite: permanent and pH-dependent charge components of cation exchange capacity: Clay Miner. 9, 425–433.
King, E. J. (1973) Acid-base behavior. In Physical Chemistry of Organic Solvent Systems (Edited by Covington, A. K. and Dickinson, T.), pp. 331–403. Plenum Press, London.
Kohl, R. A. and Taylor, S. A. (1961) Hydrogen bonding between the carbonyl group and Wyoming bentonite: Soil Sci. 91, 223–227.
Kolthoff, I. M. (1974) Acid-base equilibria in dipolar aprotic solvents: Anal. Chem. 46, 1992–2003.
Loeppert, R. H., Jr., Zelazny, L. W. and Volk, B. G. (1977) Acidic properties of kaolinite in water and acetonitrile: Soil Sci. Soc. Am. J. 41, 1101–1106.
Matwiyoff, N. A. and Taube, H. (1968) Direct determination of the solvation number of magnesium (II) ion in water, aqueous acetone, and methanolic acetone solutions: J. Am. Chem. Soc. 90, 2796–2800.
Mitra, R. P. and Kapoor, B. S. (1969) Acid character of montmorillonite: titration curves in water and some nonaqueous solvents: Soil Sci. 108, 11–23.
Mortland, M. M. and Raman, K. V. (1968) Surface acidity of smectites in relation to hydration, exchangeable cation, and structure: Clays & Clay Minerals 16, 393–398.
Olejnik, S., Posner, A. M. and Quirk, J. P. (1970) The intercalation of polar organic compounds into kaolinite: Clay Miner. 8, 421–434.
Orlander, D. P., Marianelli, R. S. and Larson, R. C. (1969) Solvation of aluminum (III) ion in dimethylsulfoxide- water solutions by proton magnetic resonance spectroscopy: Anal. Chem. 41, 1097–1099.
Parfitt, R. L. and Mortland, M. M. (1968) Ketone adsorption on mont-morillonite. Soil Sci. Soc. Am. Proc. 32, 355–363.
Sharp, W. R. (1972) Spectroscopic studies of ion-solvent interactions. University of Pittsburgh. Diss. Abstr. Int. B 1974 34 (10), 4860.
Shirvington, P. J. (1967) The hydrolysis of some acidic metal cations in acetonitrile containing traces of water. Aust. J. Chem. 20, 447–457.
Supran, D. and Sheppard, N. (1967) A nuclear magnetic resonance study of the solvation of aluminum Perchlorate by water and acetonitrile: separate resonances from differently hydrated aluminum ions: Chem. Commun. 832–834.
Tahoun, S. A. and Mortland, M. M. (1966) Complexes of montmorillonite with primary, secondary, and tertiary amides: II. Coordination of amides on the surface of montmorillonite: Soil Sci. 102, 314–321.
Theng, B. K. G. (1974) The Chemistry of Clay-Organic Reactions: Halstead Press, New York.
Thomas, S. and Reynolds, W. L. (1970) Proton magnetic resonance study of aluminum (III) chloride in water-DMSO solvent mixtures: Inorg. Chem. 9, 78–81.
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Loeppert, R.H., Zelazny, L.W. & Volk, B.G. Titration of pH-Dependent Sites of Kaolinite in Water and Selected Nonaqueous Solvents. Clays Clay Miner. 27, 57–62 (1979). https://doi.org/10.1346/CCMN.1979.0270107
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DOI: https://doi.org/10.1346/CCMN.1979.0270107