Studies of the Formation of Inclusion Complexes Derivatives of Cinnamon Acid with α-Cyclodextrin in a Wide Range of Temperatures Using Conductometric Methods |
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Authors: | Zdzisł aw Kinart,Renato Tomaš |
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Affiliation: | 1.Department of Physical Chemistry, Faculty of Chemistry, University of Lodz, Pomorska 163/165, 90-236 Lodz, Poland;2.Department of Physical Chemistry, University of Split, Ruđera Boškovića 35, HR-21000 Split, Croatia; |
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Abstract: | The electrical conductivities of aqueous solutions of sodium salts of trans-4-hydroxycinnamic acid (trans-p-coumaric acid), trans-3,4-dihydroxycinnamic acid (trans-caffeic acid), trans-4-hydroxy-3-methoxycinnamic acid, (trans-ferulic acid) and trans-3-phenylacrylic acid (trans-cinnamic acid) with α-cyclodextrin were measured in the temperature range of 288.15 K–318.15 K. For the first time in the literature, using the limiting molar conductivity obtained from conductivity measurements, the values of the complexation constants (Kf) of the salts of phenolic acid derivatives with α-cyclodextrin were determined using a modified low concentration chemical model (IcCM). An attempt was also made to analyze the individual thermodynamic functions , and describing the complexation process as a function of temperature changes. The obtained results show that the process of formation of inclusion complexes is exothermic and is spontaneous. |
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Keywords: | electric conductivities, α -cyclodextrin, aqueous solutions of sodium salts of phenolic acids, complex constants, thermodynamic function |
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