Enthalpies of solution and transfer enthalpies.  An analysis of the pure base calorimetric method for the determination of hydrogen bond enthalpies

Spencer, J. N.; Gleim, Jeffrey E.; Blevins, Charles H.; Garrett, Robert C.; Mayer, Fred J.

doi:10.1021/j100473a004

Cited by 40 publications

(13 citation statements)

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“…Previously reported pure base enthalpies (15) for the hydrogen bonded complexes of N-methylaniline with ethyl acetate and DMF corrected according to ref. 16 are -1.6 and -2.3 kcal mol-I respectively. The NMF complexes with ethyl acetate and DMF have hydrogen bond enthalpies of -2.3 and -2.9 kcal mol-I respectively, which indicates that the NMF N-H is a 0.6-0.7 kcal mol-' better proton donor than the amine N-H.…”

Section: Resultsmentioning

confidence: 94%

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Amide hydrogen bonding in organic medium

Spencer¹,

Garrett²,

Mayer³

et al. 1980

Can. J. Chem.

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Can. J. Chem. 58, 1372 (1980. Thermodynamic parameters for the self-association of N-methylformamide and N-methylacetamide in CCI, solvent have been determined by infrared spectroscopy. The pure base calorimetric method was used to determine the enthalpy of hydrogen bond complex formation of N-methylformamide and N-methylacetamide with N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and dioxane. Comparison of the calorimetric and spectroscopic results show that the dimers of N-methylformamide and N-methylacetamide are linear with hydrogen bond enthalpies of -2.9 and -3.9 kcal mol-' respectively. The carbonyl group of N-methylacetamide was found to be a better proton acceptor than the carbonyl of N-methylformamide in agreement with theoretical predictions. N-methylacetamide was found to be a better proton donor than N-methylformamide in disagreement with theoretical predictions. The dimer self-association constants appear to be larger than previously reported.

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Section: Resultsmentioning

confidence: 94%

“…The pure base enthalpies corrected for differences in enthalpies of solution between acid and model compound as outlined previously (16) are also given in Table 2.…”

Section: Resultsmentioning

confidence: 99%

Amide hydrogen bonding in organic medium

Spencer¹,

Garrett²,

Mayer³

et al. 1980

Can. J. Chem.

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“…The methylene increment in PFDC is less exothermic than in any of the other solvents we have Methylene Increment examined. The rather small increment in DMF can The methylene increment in AH(v+S) represents reasonably be attributed to a highly endothermic the enthalpy difference between an endothermic sol-cavity formation term in this strongly associated vent cavity formation term and exothermic contribu-solvent (7,9). This is clearly not the case in a perCan.…”

Section: Methodsmentioning

confidence: 93%

Enthalpies of interaction of polar and nonpolar solutes with a perfluoro solvent

Fuchs¹,

Peacock²,

Das³

1980

Can. J. Chem.

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RICHARD FUCHS, L. ALAN PEACOCK, and KAMALENDU DAS. Can. J. Chem. 58,2301Chem. 58, (1980. Enthalpies of solution of 51 polar and nonpolar organic solutes have been determined in the solvent perfluoro-l,3-dimethylcyclohexane. The values have been combined with solute enthalpies of vaporization to give the enthalpies of transfer from vapor to solvent. These solvation enthalpies are for most solutes substantially less exothermic than those measured in other solvents. Polar interactions appear to be stronger than with hydrocarbon solvents; but this may result, in part, from incomplete dissociation of strongly associated solutes in the perfluoro solvent.RICHARD FUCHS, L. ALAN PEACOCK et KAMALENDU DAS. Can. J. Chem. 58,2301Chem. 58, (1980. On a dktermine les enthalpies de solution de 51 solutCs organiques polaires et non polaires dans le perfluorodimethyl-1.3 cyclohexane. On a combine les valeurs obtenues avec les enthalpies de vaporisation des solutes pour obtenir les enthalpies de transfert de la vapeur au solvant. Dans la plupart des solutCs, ces enthalpies de solvatation sont substantiellement moins exothermiques que celles mesurees dans d'autres solvants. Les interactions polaires semblent itre plus fortes que celle internenant dans les solvants hydrocarbonks, mais ceci peut provenir en partie d'une dissociation incomplete des solutes fortement associes dans le solvant perfluore.[Traduit par le journal]The unusual solvent properties of completely fluorinated alkane derivatives (perfluoroalkanes) were first recognized more than three decades ago (1). These compounds show limited miscibility with nonpolar alkanes, and even less miscibility with polar liquids. On the other hand, the solubility of nitrogen (2) and of oxygen are greater than that in other solvents, and there has been wide interest in perfluorocarbons and perfluorocarbon derivatives as components of blood extenders.The boiling points of perfluorocarbons are generally lower than those of the analogous hydrocarbons, as are the heats of vaporization (AH,) in the few cases where comparison data are available (3). The fluorocarbon polarizability is slightly greater, and at equal separation the dispersion forces should be larger (4). The molar volume and mean radius are much larger, however, and at the greater distance the effective dispersion forces are smaller than in hydrocarbons.We have recently measured the heats of solution (AH,) of some polar molecules (5, 6) and nonpolar hydrocarbons (7) in the solvents cyclohexane, benzene, methanol, and dimethylformamide, and some additional hydrocarbon values (8) in acetic acid and in hexane. Values of AH, have been combined with experimental (5) or literature (3) heats of vaporization (AH,) to give enthalpies of transfer from vapor to solvent [AH(v+S:)] (the solvation enthalpy). Comparison of AH(v+S) for polar compounds and nonpolar model compounds has provided an estimate of the polar solute-solvent interactions (5-7). It is our eventual objective to evaluate the contributions of various types of intermolecular...

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“…It is highly inert towards ordinary temperature at an electrophile or nucleophile. Non-polar being cyclohexanone is not expected to be involved in any strong interaction with the other components of the mixture [5,6]. However, types of dispersive interactions between them are possible.…”

Section: Introductionmentioning

confidence: 99%

Acoustical properties of molecular interactions in 1-propanol, 1-butanol and 1-pentanol with tetrahydrofuran in cyclohexanone at various temperatures

Ubagaramary¹,

Enoch²,

Mullainathan³

et al. 2018

biomedicalresearch

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Enthalpies of solution and transfer enthalpies. An analysis of the pure base calorimetric method for the determination of hydrogen bond enthalpies

Abstract: The rate constants for benzene and toluene were found to be nearly equal In any given alcohol except methanol, for which the experimental scatter was large. We have therefore taken the average value, k1 = 1,3 X 106 M"1 s'1, for both benzene and toluene in methanol at 299 K. (23) E.

Cited by 40 publications

References 5 publications

Amide hydrogen bonding in organic medium

Amide hydrogen bonding in organic medium

Enthalpies of interaction of polar and nonpolar solutes with a perfluoro solvent

Acoustical properties of molecular interactions in 1-propanol, 1-butanol and 1-pentanol with tetrahydrofuran in cyclohexanone at various temperatures

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