Authors: Silvia Porcedda Maurizio Leo Marianna Usula Alessandra Piras
Publish Date: 2016/05/21
Volume: 125, Issue: 2, Pages: 607-615
Abstract
Molar heat of mixing and volume change of mixing coinciding with molar excess enthalpies H E and molar excess volumes V E respectively of binary mixtures composed by a linear saturated aliphatic acid of general formula CH3CH2u2–CO2H u = 2 3 4 5 6 7 8 + diisopropyl ether CH32CH−2O have been measured in the whole range of mole fraction at 29815 K and 010 MPa The H E experimental determinations have been realized by means of a mixing flow calorimetric apparatus and V E have been calculated from density data acquired by using a vibrating tube densitometer Mixing is exothermic for all investigated systems The values at equimolar composition H x=05 E are in the range −385 ± 1 to −140 ± 4 J mol−1 The more negative value is attributable to butanoic acidcontaining mixture then H E decrease in absolute value as the alkyl chain of the acid increases For the same systems the V E trends are different the value at equimolar composition V x=05 E always negative increase regularly in absolute value as the alkyl chain length of the acid increases from –112 × 10−6 m3 mol−1 for mixtures containing ethanoic acid to −175 × 10−6 m3 mol−1 for octanoic acidcontaining mixtures
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