A Thermodynamic Study of Complex Formation between 15-Crown-5 with Mg2+, Ca2+, Sr2+ and Ba2+ in Acetonitrile Methanol Binary Mixtures Using Conductometric Method
The complexation reactions between Mg2+, Ca2+, Sr2+ and Ba2+ metal cations with 15-crown-5 (15C5) were studied in acetonitrile (AN)-methanol (MeOH) binary mixtures at different temperatures using conductometric method. 15C54 forms 1:1 complexes with Mg2+, Ca2+ and Sr2+ cations in solutions. The Ma2+...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
2001-12-01
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| Series: | Iranian Journal of Chemistry & Chemical Engineering |
| Subjects: | |
| Online Access: | http://www.ijcce.ac.ir/article_9974_d3433a9c8922af5c580458fccac63f9d.pdf |
| Summary: | The complexation reactions between Mg2+, Ca2+, Sr2+ and Ba2+ metal cations with 15-crown-5 (15C5) were studied in acetonitrile (AN)-methanol (MeOH) binary mixtures at different temperatures using conductometric method. 15C54 forms 1:1 complexes with Mg2+, Ca2+ and Sr2+ cations in solutions. The Ma2+ cation forms a 2:1 complex (ratio of lighand to cation) in solutions. A linear relation was observed for variation of logKf of 15C5-Ca2+ and 15C5-Sr2+ complexes vs the composition of An-MeOH binary systems, but a non-linear behavior was observed in the case of 15C5-Mg2+ complex in these binary mixtures. Selectivity of 15C5 for Mg2+, Ca2+ and Sr2+ cations is sensitive to solvent composition. In some cases and in certain compositions of the mixed solvent systems, the selectivity order is changed. The values of thermodynamic parameters (DH0c , DS0c ) for formation of 15C5-Mg2+ , 15C5-Ca2+ and 15C5-Sr2+ complexes were obtained from temperature dependence of stability constants and the results show that the thermodynamics of complexation reactions is affected by the nature and composition of the mixed solvents. |
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| ISSN: | 1021-9986 1021-9986 |