Compressibility studies of some copper (I) and tetraalkylammonium salts in binary mixtures of triethylphosphite with acetonitrile, benzonitrile and pyridine at 298.15 K

摘要

Ultrasonic velocity (u) and density (p) of tetrabenzonitrile copper (1) perchlorate (CuClO(4)4C(6)H(5)CN), tetrabutylammonium tetraphenylborate (Bu4NBPh4) and tetrabutylammonium perchlorate (Bu4NClO4) have been measured at different salt concentrations in the concentration range 0.002-0.28 mol kg(-1) in binary mixtures of triethylphosphite (TEP) with acetonitrile (AN), benzonitrile (BN) and pyridine (PY) containing 0, 20, 40, 60 and 80 mol % TEP. The isentropic compressibility (K-S) and apparent molal isentropic compressibility (K-Stheta) in various solvent systems have been calculated. Limiting apparent molal isentropic compressibilities (K-Stheta(0)) for various salts have been evaluated and split into contributions of individual ions i.e. into (K-Stheta(0))(+/-) values. The variation of (K-Stheta(0))(+/-) values with solvent composition shows that Cu+ indicates strong solvation in AN + TEP, BN + TEP and PY + TEP mixtures over the entire solvent composition range and the solvation with TEP is relatively stronger than that with AN, BN and PY. ClO4- is better solvated in AN + TEP mixture by having some interaction with AN but is poorly solvated in BN + TEP and PY + TEP mixtures. Both Bu4N+ and Ph4B- show some interaction with TEP in the TEP-rich region of all the solvent systems. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 22]