¹H NMR spectroscopic and thermodynamic studies of hydrogen bonding in liquid n-butanol + cyclohexane, tert-butanol + cyclohexane, and n-butanol + pyridine mixtures

Abstract

H NMR chemical shifts d OH of the proton in the hydroxyl group of n-butanol and tert-butanol have been measured as function of mixture composition in the binary mixtures n-butanol + cyclohexane, tertbutanol + cyclohexane, and n-butanol + pyridine at 303, 313 and 323 K. In addition the molar excess enthalpy H E of n-butanol + pyridine has been determined as a function of the mixture composition at 298 K using a flow calorimeter. The ERAS (extended real associated solution) model has been applied for describing simultaneously the data of d OH and H E for n-butanol + cyclohexane accounting for self association of n-butanol via hydrogen bonding. The mixture of n-butanol + pyridine was treated similarly using the ERAS model considering self association of n-butanol as well as cross association of n-butanol with pyridine. The results obtained indicate that self association in n-butanol and tert-butanol as well as cross association between n-butanol and pyridine play an important role in these mixtures. The ERAS model is able to describe the dependence of d OH and H E on mixture composition and temperature for all mixtures with a minimum of adjustable parameters providing a realistic insight into the liquid structure of these systems.y Electronic supplementary information (ESI) available: Experimental chemical shifts d OH of alcohol mixtures referred to TMS (Table S1) and molar excess enthalpies H E of n-butanol(1) + pyridine(2) mixtures at 298 K (Table S2). See

Application of a new theoretical procedure for calculating Kirkwood correlation factors in alkanol + hexane and alkanol + pentane mixtures

“…4. Implementation of the association into the theoretical treatment of the Kirkwood factor g K The ERAS-model [29][30][31][32][33][34][35][36][37] combines a chemical association model based on the Flory-Huggins theory for polydisperse multimers with an equation of state for flexible molecules of different size and their mixtures. In order to derive Kirkwood factors g K the chemical association involved into the ERAS-model has to be accounted for.…”

“…Since we are dealing with the simultaneous description of g K and the molar excess enthalpy H E m of alcohol + pentane and alcohol + hexane mixtures in this work the expression of the ERAS-model for H E m already derived in our previous work 36…”

“…V E m,chem is the molar excess volume and has been calculated by , respectively, accounting for the fact that this value is known to describe excess volumes of alkanol + alkane mixtures by the ERAS-model in the most appropriate way. [29][30][31][32][33][34][35][36] Finally, also the integral infrared absorbance of monomer alcohol species in the mixture A can be predicted by the theory:…”

Enthalpy of cooperative hydrogen bonding in complexes of tertiary amines with aliphatic alcohols: Calorimetric study

“…Studies of hydrogen bond formation in aliphatic alcohols have been carried out with different experimental methods, for example, vapor pressure [3,4] and calorimetric measurements [5][6][7][8], infrared (FTIR) spectroscopy [9][10][11][12][13][14] and nuclear magnetic resonance (NMR) [15][16][17][18][19] techniques. The authors attempted to solve two major tasks in these studies.…”

A Comparative Study on theNMR Relaxation of Methanol in Sub-and Super-Critical Mixtures of CO₂ and Methanol

“…Among them, spectroscopic investigations of model systems as CO2-alkanol on thermodynamic and molecular dynamic background represent a current research area. Thus far CO2-methanol fluids, a scientifically interesting and a technologically important class of mixed solvents have enjoyed the most attention, and a number of authors have reported vibrational spectroscopy [20][21][22][23] , NMR spectroscopy [24][25][26][27][28][29][30][31] , absorption and emission spectra 13 as well as molecular dynamics simulation 14 on such systems. Meanwhile, NMR spectroscopy is regarded as a very informative method to probe the properties of fluids on a microscopic level, and NMR spectroscopy at NCFs/ SCFs conditions also has potential applications in the studies of hydrogen bonds or reaction monitoring 24 as molecular structural changes induced by pressure on hydrogen bonds are also very interesting topics.…”