کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
215140 1426226 2015 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Energetics of pairwise interaction between glycidol enantiomers in (dimethylformamide + water) mixtures rich in water at T = 298.15 K
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Energetics of pairwise interaction between glycidol enantiomers in (dimethylformamide + water) mixtures rich in water at T = 298.15 K
چکیده انگلیسی


• Dilution enthalpies of glycidols in (DMF + water) mixtures were determined by ITC.
• Enthalpic pairwise interaction coefficients (hXX) of each compound were evaluated.
• The hXX values are all positive and decrease gradually with the mass fraction of DMF.
• The pairwise interaction of S–S pair is slightly stronger than that of R–R pair.
• The addition of DMF favours endothermic pairwise interactions of these compounds.

Successive dilution enthalpies (ΔH(mN-1→mN)ΔH(mN-1→mN)) of glycidol enantiomers (R-(+)-glycidol, S-(−)-glycidol) and the racemate (R/S-(±)-glycidol) in (dimethylformamide (DMF) + water) mixtures rich in water (mass fractions of DMF, wDMF = 0 to 0.25) have been determined respectively by isothermal titration calorimetry (ITC) at T = 298.15 K. The corresponding homotactic enthalpic pairwise interaction coefficients (hXX) of each compound have been evaluated from the framework of McMillan–Mayer theory. Across the studied composition range of (DMF + water) mixtures the hXX values of these compounds are all positive, and decrease gradually with the mass fraction of DMF by the order hRR > hRS ≈ hMM > hSS > 0 (M represents the racemate R/S-(±)-glycidol, and hRS is the estimated value for the heterochiral pair R–S). The positive values of hXX indicate that pairwise interactions of these compounds are endothermic and unfavourable from the point of view of enthalpy. The interaction of S–S pair is considered to be slightly stronger than M–M, R–S and R–R pairs since the former absorbs less heat than the latter in pairwise interactions. The addition of cosolvent (DMF) is in favour of pairwise interactions of these compounds in the mixtures rich in water.

Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Chemical Thermodynamics - Volume 87, August 2015, Pages 8–12
نویسندگان
, , , , ,