Sankara Raman, S; Nampoori, V P N; Vallabhan, C P G; Ambadas, G; Sugunan, S(American Institute of Physics, 1995)
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Abstract:
The thermal diffusivity of y-alumina is determined by the photoacoustic method. The method is
calibrated by determining the thermal diffusivity of copper and aluminum. The effect of the
chemisorbed hydroxyl groups or thermal diffusivity is studied by degassing the sample at different
temperatures.
Sugunan, S; Thomas, B(American Chemical Society, 1995)
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Abstract:
The Setschenow parameter and thermodynamic parameters of transfer of 2- and 4-aminobenzoic acids
from water to salt solutions have been reported. The results are discussed in terms of the structure- breaking
effects of the ions of the salts, the localized hydrolysis model, and the internal pressure theory.
Sugunan, S; Ramankutty, C G(American Chemical Society, 1995)
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Abstract:
The enthalpies of formation of charge-transfer complexes of benzene, chlorobenzene, and 1,3-dichlorobenzene
as donors with 7,7,8,8-tetracyanoquinodimethane as acceptor were determined. The thermochemical
data show an increased stability of charge-transfer complexes of donors with permanent dipole moment.
The results confirm the importance of electrostatic forces in bonding and stabilizing weak complexes.
The approximate formation constants of the complexes are also reported.
Sugunan, S; Jalaja, J M(Indian Journal of Chemistry, March , 1995)
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Abstract:
The electron donating properties of Ce02 and its mixed
oxides with alumina have been determined from the studies
of adsorption of electron acceptors of various electron
affinities on the surface of these oxides. The catalytic
activity of these oxides towards some reactions such as
oxidation of alcohols and reduction of ketones have been
Correlated with their surface electrondonor properties. The
surface acidity/basicity of these oxides have also been
determined by titration method using a set of Hammett
indicators.
The electron-donor properties of Sm2O3 activated at 300, 500, and 800°C are reported from studies on the adsorption of electron acceptors of various electron affinities (electron affinity values in eV are given in parentheses): 7,7,8,8-tetracyanoquino-dimethane (2.84), 2,3,5,6-tetrachloro-1,4-benzoquinone (2.40), p-dinitrobenzene (1.77), and m-dinitrobenzene (1.26) in acetonitrile and 1,4-dioxane. The extent of electron transfer during the adsorption was determined from magnetic measurements. The acid-base properties of Sm2O3 at different activation temperatures are reported using a set of Hammett indicators. Electron donor-acceptor interactions at interfaces are important in elucidating the adhesion forces.
Sugunan, S; Devika Rani, G; Unnikrishnan, P A(Indian Journal of Engineering & Materials Sciences, October , 1995)
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Abstract:
Acid/base strength distribution of Y2O3 and its mixed
oxides with alumina catalysts are measured on Hammett
acidity function scale and expressed in terms of H0max
value. Basicity of Y2O3 increases with increase in activation
temperature and for mixed oxides the basicity increases
with increase in concentration of Y2O3, in the catalyst.
Sugunan, S; Benny, Thomas(Indian Journal of Chemistry, February , 1995)
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Abstract:
The Setschenow parameter and thermodynamic
parameters of transfer of 2- and 4- hydroxybenzoic acids
from water to salt solutions have been reported. The data
have been rationalised by considering the structure
breaking effects of the ions of the salts, the localized
hydrolysis model, the internal pressure theory and the
theory of water structure due to Symons.
The catalytic activity of Perovskite-type mixed oxides (LaCo03 . PrCo03 and SmCo03 ) for the
reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-Ponndorf-Verley reduction)
has been studied. The data have been correlated with the surface electron donor properties
of these mixed oxides.