کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
217541 1426337 2006 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic study of (alkyl esters + α,ω  -alkyl dihalides) II: HmE and VmE for 25 binary mixtures {xCu − 1H2u − 1CO2C2H5 + (1 − x)α,ω-BrCH2(CH2)v − 2CH2Br}, where u = 1 to 5, α = 1 and v = ω = 2 to 6
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Thermodynamic study of (alkyl esters + α,ω  -alkyl dihalides) II: HmE and VmE for 25 binary mixtures {xCu − 1H2u − 1CO2C2H5 + (1 − x)α,ω-BrCH2(CH2)v − 2CH2Br}, where u = 1 to 5, α = 1 and v = ω = 2 to 6
چکیده انگلیسی

Excess molar enthalpies HmE, and excess molar volumes VmE, have been determined experimentally at constant conditions of atmospheric pressure and a temperature of T = 298.15 K, for a set of 25 binary mixtures, composed of ethyl alkanoate (methanoate to pentanoate) with each of the α,ω  -dibromoalkanes (1,2-dibromoethane to 1,6-dibromohexane), presenting the values of excess quantities YmE as a function of the ester composition x  . Most of the mixtures presented VmE>0, except those formed by 1,5-dibromopentane and 1,6-dibromohexane with propanoate, butanoate and ethyl pentanoate, for which VmE<0. The five mixtures of (ethyl methanoate + α,ω-dibromoalkanes) are all endothermic, although, in the other systems this endothermicity decreases slightly with the increase in the ester acid chain length, producing sigmoidal curves that reflect exo/endothermic effects in the mixing process. The results are explained on the basis of a structural model that considers the existence of several effects, some positive and some negative, which produce the previously mentioned variations in excess quantities.In all cases, the experimental values are correlated with a suitable polynomial equation. Finally, predictions of HmE are made using two versions of the UNIFAC group contribution model. The version proposed by Dang and Tassios produces unacceptable estimations, while the version of Gmehling et al. produces results closer to experimentals.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Chemical Thermodynamics - Volume 38, Issue 5, May 2006, Pages 585–598
نویسندگان
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