HEAT-CAPACITIES, SELF-ASSOCIATION AND COMPLEX-FORMATION IN ALCOHOL ESTER SYSTEMS
DSpace at IIT Bombay
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Title |
HEAT-CAPACITIES, SELF-ASSOCIATION AND COMPLEX-FORMATION IN ALCOHOL ESTER SYSTEMS
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Creator |
DESHPANDE, DD
PATTERSON, D ANDREOLIBALL, L COSTAS, M TREJO, LM |
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Subject |
picker flow calorimeter
mixtures thermodynamics |
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Description |
The apparent molar heat capacity, phi-c, its associative part, phi-c(assoc), and the excess heat capacity, C(p)E, have been obtained at 25-degrees-C through the concentration range for methanol, hexan-1-ol and decan-1-ol in a series of proton acceptor solvents: methyl acetate, ethyl acetate, octyl acetate, methyl octanoate, decyl acetate and methyl tetradecanoate. The results are explained quantitatively by the Tresczanowicz-Kehiaian (TK) association model and the Flory lattice model in terms of alcohol self-association into tetramers, characterized by an OH-OH equilibrium constant and enthalpy, and by alcohol-ester complex formation characterized by an OH-COO equilibrium constant and enthalpy, each independent of alcohol and ester chain length. As predicted, phi-c(assoc) at infinite alcohol dilution is independent of the choice of alcohol, but increases with increasing ester chain length. With increasing alcohol concentration phi-c(assoc) passes through a maximum which is much reduced compared with the inert solvent case. For each alcohol, C(p)E increases with increasing ester chain length, while for the same ester, C(p)E decreases with increasing alcohol chain length. dC(p)E/dT is positive for mixtures of methanol and methyl acetate, as predicted by the TK model. It is negative for decanol with methyl acetate, contrary to the TK model, but consistent with a non-random distribution of alcohol tetramers in the solution.
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Publisher |
ROYAL SOC CHEMISTRY
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Date |
2011-08-28T11:38:31Z
2011-12-26T12:58:01Z 2011-12-27T05:46:55Z 2011-08-28T11:38:31Z 2011-12-26T12:58:01Z 2011-12-27T05:46:55Z 1991 |
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Type |
Article
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Identifier |
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 87(8), 1133-1139
0956-5000 http://dx.doi.org/10.1039/ft9918701133 http://dspace.library.iitb.ac.in/xmlui/handle/10054/11730 http://hdl.handle.net/10054/11730 |
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Language |
en
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