Molar excess enthalpies of ternary mixtures of non-electrolytes

Molar excess enthalpies, H^E_ijk(T₁, x_i, x_j), for methylenebromide (i)+pyridine (j)+β-picoline (k); pyridine (i)+β-picoline (j)+cyclohexane (k); benzene (i)+toluene (j)+1,2-dichloroethane (k); benzene (i)+o-xylene (j)+1,2-dichloroethane (k); and benzene (i)+p-xylene (j)+1,2-dichloroethane (k) mixtures have been measured calorimetrically as a function of temperature and composition. The data have been analysed in terms of the Sanchez and Lacombe theory and using an approach employing the “graph theoretical” concept of connectivity parameters to characterize its pure components. It has been observed that the H^E_ijk (T, x_i, x_j) data calculated from the “graph theoretical” approach using ³ξ values based on δ^v considerations (that take into consideration the valency of individual atoms of the molecular graph constituent components) best reproduces the corresponding experimental H^E_ijk data.     

Molar excess volumes of ternary mixtures of nonelectrolytes

Molar excess volumes V^E_ijk of methylenebromide i + pyridine j + β-picoline (k, cyclohexane (i) + pyridine (j) + β-picoline(K), benzene(i)+toluene(j)+1,2-dichloroethane(k), benzene(i) + 0-xylene(j) + 1,2-dichloroethane(k) and benzene(i) + p-xylene(j) + 1,2-dichloroethane(k) mixtures have been determined dilatometrically at 298.15 K. The data have been examined in terms of Sanchez and Lacombe theory and the graph-theoretical approach, and it is found that they are described well by the latter. Self- and cross-volume interaction coefficients V_jk, V_jjk and V_jkk, etc., have also been evaluated and the values utilised to study molecular interactions between the jth and kth molecular species in the presence of the ith in these i + j + k mixtures.     

Thermodynamic and spectroscopic evidence in binary mixtures of nonelectrolytes

Nigam, R.K. and Aggarwal, S., 1986. Thermodynamic and spectroscopic evidence in binary mixtures of nonelectrolytes. Fluid Phase Equilibria, 26: 181–200.Molar excess enthalpies H^E_m of 1,2-dichloroethane (1)+pyridine (2), + α-picoline (2),+n-hexane (2), +n-heptane (2), n-heptane (1)+pyridine (2), +α-picoline (2), +γ-picoline (2), aniline (1)+pyridine 92), +α-picoline (2) and +γ-picoline (2) mixtures have been measured calorimetrically at 298.15 and 308.15 K.The data have been examined in terms of the Lacombe and Sanchez theory and the graph theoretical approach. It was found that these were described better by the graph theoretical approach. The NMR studies on 1,2-dichloroethane (1)+α-picoline (2), aniline (1)+pyridine (2) and aniline (1)+γ-picoline (2) mixtures have also been used to lend credence to the nature and extent of interaction in these mixtures.     

Topological and thermodynamic investigations of molecular interactions in binary mixtures: Molar excess volumes and molar excess enthalpies

Molar excess volumes and molar excess enthalpies of butyl acetate (i) with cyclohexane or benzene or toluene or o-, m- or p-xylene (j) binary mixtures have been measured dilatometrically and calorimetrically over the entire composition range at 308.15 K. The observed data have also been analyzed in terms of graph theoretical approach. The analysis of V^E data by graph theoretical approach suggests that butyl acetate in pure state exists as associated entity and (i + j) mixtures are characterized by the presence of (i–j) molecular entity. It has further been observed that V^E and H^E values calculated by this approach agree well with the corresponding experimental values. The presence of molecular entity is further confirmed by IR study of (i + j) mixture.     

Thermodynamics of molecular interactions in binary mixtures of non-electrolytes. Molar excess volumes

Molar excess volumes, V^E, for pyridine (A) + α-picoline (B), + β-picoline (B) and + γ-picoline (B) and benzene (A) + toluene (B), + o-xylene (B) and + p-xylene (B) and carbon tetrachloride (A) + n-heptane (B) have been measured dilatometrically as a function of temperature and composition and have been utilized to study B—B and B—B—B interactions in the presence of A via the Mayer—McMillan approach. A model has also been presented to account for these B—B and B—B—B interactions. The V^E data at 308.15 K have also been analysed in terms of the “graph theoretical” approach which describes the V^E data well for all these mixtures at 308.15 K. The “graph theoretical” approach has further been extended to successfully evaluate V^E data for a mixture at any temperature, T₂, when the V^E data at T₁ are known.     

Topological and thermodynamic investigations of binary mixtures: Molar excess volumes, molar excess enthalpies and isentropic compressibility changes of mixing

Molar excess volumes, V^E, molar excess enthalpies, H^E, and speeds of sound, u, of o-toluidine (i) + cyclohexane or n-hexane or n-heptane (j) binary mixtures have been determined over entire range of composition at 308.15 K. Speeds of sound data have been utilized to predict isentropic compressibility changes of mixing, of (i + j) mixtures. The observed V^E, H^E and data have been analyzed in terms of Graph theory. The analysis of V^E data by Graph theory reveals that o-toluidine exists as an associated molecular entity and (i + j) mixtures contain 1:1 molecular complex. It has been observed that V^E, H^E and values calculated by Graph theory compare well with their corresponding experimental values. The observed data have also been analyzed in term of Flory theory.     

Isentropic Compressibility Changes of Mixing for 1,3-Dioxolane or 1,4-Dioxane + Water + Propanol Ternary Mixtures

Speed of sound data, u_ijk, of 1,3-dioxolane or 1,4-dioxane(i) + water(j) + propan-1-ol or propan-2-ol(k) ternary mixtures and their sub-binary mixtures, u_ij, of 1,3-dioxolane or 1,4-dioxane(i) + water or propan-1-ol or propan-2-ol(j) and water(i) + propan-1-ol or propan-2-ol(j) mixtures have been measured over the entire composition range at 308.15 K. Isentropic compressibility changes of mixing, (κ_s^E)_ij and (κ_s^E) _ijk, for the binary and ternary mixtures have been determined by employing the observed speeds of sound data and densities (calculated from their molar excess volumes data). The (κ_s^E) _ij and (κ_s^E) _ijk values have also been predicated by the graph theoretical approach and the Flory theory. It has been observed that (κ_s^E) _ij and (κ_s^E) _ijk predicted by the graph theoretical approach compare well with their corresponding experimental values.     

Topological and thermodynamic investigations of molecular interactions of aniline and o-toluidine with chloroform

Molar excess volumes, V^E, molar excess enthalpies, H^E, and speeds of sound data, u, of chloroform (i) + aniline or o-toluidine (j) binary mixtures have been measured as a function of composition at 308.15 K. Isentropic compressibility changes of mixing, have been determined by employing speed of sound data. Topological investigations of V^E data reveals that aniline, chloroform and o-toluidine are associated entities and these (i + j) mixtures contain a 1:1 molecular complex. The IR studies lend further support to the nature and extent of interaction for the proposed molecular entity in the mixtures. H^E and values have also been calculated by employing Moelwyn-Huggins concept [Polymer 12 (1971) 387] taking topology of the constituents of the mixtures. It has been observed that calculated H^E and values compare well with their corresponding experimental values. The observed V^E, H^E and data have also been analyzed in terms of Flory theory.     

Topological Investigations of Some Cyclic Ether-Water-Alkanol Ternary Mixtures: Molar Excess Volumes

Molar excess volumes, V_ijk^E, of 1,3-dioxolane or 1,4-dioxane (i) + water (j) + propan-1-ol or + propan-2-ol (k) ternary mixtures have been determined dilatometrically over the entire composition range at 308.15 K. The resulting data have been analyzed in terms of (1) the graph theoretical approach (which involves the topology of the mixture constituents), (2) the Sanchez and Locombe theory and (3) the Flory theory. It was observed that V_ijk^Evalues predicted by the graph theory compare reasonably well with their corresponding experimental values. However, although V_ijk^E values calculated by the Sanchez and Lacombe and Flory theories are of same sign and magnitude, the qualitative agreement is poor.     

Excess volumes for binary liquid mixtures of trichloroethylene with anisole,pyridine, quinoline and cyclohexane at 298.15 and 308.15 K

Dilatometric measurements of excess volumes V^E have been made for binary liquid mixtures of trichloroethylene (CHClCCl₂) with anisole, pyridine, quinoline and cyclohexane at 298.15 and 308.15 K. At both temperatures, and values of V^E have been found to be slightly negative for CHClCCl₂ + anisole, CHClCCl₂ + pyridine, highly negative for CHClCCl₂ + quinoline, and highly positive for CHClCCl₂ + cyclohexane. The negative values of V^E for the systems CHClCCl₂ + anisole, CHClCCl₂ + pyridine, and CHClCCl₂ + quinoline, have been explained as due to the existence of specific interaction of CHClCCl₂ with anisole, pyridine and quinoline in the liquid state.     

Thermodynamics of complex formation reactions in non-aqueous solvents: Part I. Reactions of silver(I) with pyridine and related ligands in acetone

Log β_i,ΔH_iand ΔS_i values have been determined in acetone solution at 25°C using the entropy titration procedure for the stepwise formation of AgL⁺₂ where L = pyridine, α-picoline, quinoline and 2,2'-bipyridine. The complexes formed under these conditions are all enthalpy stabilized, except for the Ag(bipyr)⁺ complex which is both enthalpy and entropy stabilized.     

Excess Isentropic Compressibilities for 1,3-Dioxolane or 1,4-Dioxane <Emphasis Type="Italic">+</Emphasis> Water <Emphasis Type="Italic">+</Emphasis> Formamide or N,N-Dimethylformamide Ternary Mixtures at 308.15 K

Speeds of sound, u_ijk, of 1,3-dioxolane or 1,4-dioxane (i) + water (j) + formamide or dimethylformamide (k) ternary mixtures and of their binary subsystems, u_ij, of 1,3-dioxolane or 1,4-dioxane (i) + formamide or dimethylformamide (j), and water (i) + formamide or dimethylformamide (j) have been measured over the entire composition range at 308.15 K. The experimental data have been used to evaluate the excess isentropic compressibilities of binary (κ_s^E)_ij and ternary (κ_s^E)_ijk mixtures using their densities calculated from molar excess volume data. The Moelwyn-Huggins concept [M. L. Huggins, Polymer 12, 389 (1971)] of interaction between the surfaces of components of a binary mixture has been employed to evaluate the excess isentropic compressibilities (using the concept of connectivity parameter of third degree of a molecule, ³ξ, which in turn depends on its topology) of binary mixtures, and this method has been extended to predict excess compressibilities of ternary mixtures. Values of (κ_s^E)_ij and (κ_s^E)_ijk have also been calculated by the Flory theory. It was observed that (κ_s^E)_ij and (κ_s^E)_ijk predicted by the Moelwyn-Huggins approach compare well with calculated and experimental values.     

Interaction of cyclopentane with benzene,carbon tetrachloride and cyclohexane

Heats of mixing cyclopentane + benzene, + carbon tetrachloride, + cyclohexane at 308.15 K and for cyclohexane + carbon tetrachloride at 298.15 K have been determined in an adiabatic calorimeter. The data have been examined for current theories (McGlashan, Flory and Barker) of solutions and show that McGlashan's theory predicts values for H^E and G^E that are in good agreement with their corresponding experimental values. Interaction energy between the components of these mixtures has also been determined.     

Thermodynamics of organic mixtures containing amines: V. Systems with pyridines

Binary mixtures containing pyridine (PY), or 2-methylpyridine (2MPY) or 3-methylpyridine (3MPY) or 4-methylpyridine (4MPY) and an organic solvent as benzene, toluene, alkane, or 1-alkanol are investigated in the framework of DISQUAC. The corresponding interaction parameters are reported. The model describes accurately a whole set of thermodynamic properties: vapor-liquid equilibria (VLE), liquid-liquid equilibria (LLE), solid-liquid equilibria (SLE), molar excess Gibbs energies (G^E), molar excess enthalpies, (H^E), molar excess heat capacities at constant pressure () and the concentration-concentration structure factor (S_CC(0)). It is remarkable that DISQUAC correctly predicts the W-shaped curve of the of the pyridine + n-hexadecane system. The model can be applied successfully to mixtures with strong positive or negative deviations from the Raoult's law. DISQUAC improves the theoretical results from UNIFAC (Dortmund version). The replacement of pyridine by a methylpyridine leads to a weakening of the amine-amine interactions, ascribed to the steric effect caused by the methyl group attached to the aromatic ring. This explains that for a given solvent (alkane, 1-alkanol) H^E(pyridine) > H^E(methylpyridine).     

3-D indium(III)-btc channel frameworks and their ion-exchange properties (btc=1,3,5-benzenetricarboxylate)

Assembly of InCl₃ with 1,3,5-benzenetricarboxylic acid (H₃btc) and pyridine or pyridine derivatives under hydrothermal conditions produces a series of isostructural coordination polymers with the interesting frameworks: {(HL)[In₄(OH)₄(btc)₃]·L·3H₂O}_n, L=pyridine (1); L=2-picoline (2); L=4-picoline (3) and {(Hdpea)[In₄(OH)₄(btc)₃]·3H₂O}_n (4) (dpea=1,2-di(4-pyridyl)ethane). In these four complexes, carboxyl and hydroxyl oxygen atoms bridge indium(III) centers to form octahedral chain-like sinusoidal curves, which are further interlinked by btc³⁻ moieties to generate 3-D frameworks with 1-D channels. The protonated guests HL in 1-3 located at the channels can be fully exchanged by K⁺ ion or partially exchanged by Sr²⁺, and Ba²⁺ ions.     

Synthesis and characterization of mixed ligand complexes of cobalt(II) with some nitrogen and sulfur donors

Mixed ligand complexes of Co(II) with nitrogen and sulfur donors, Co(OPD)(S–S) · 2H₂O and Co(OPD)(S–S)L₂ [OPD = o-phenylenediamine; S–S = 1,1-dicyanoethylene-2,2-dithiolate (i-MNT^2?) or 1-cyano-1-carboethoxyethylene-2,2-dithiolate (CED^2?); L = pyridine (py), α-picoline (α-pic), β-picoline (β-pic), or γ-picoline (γ-pic)], have been isolated and characterized by analytical data, molar conductance, magnetic susceptibility, electronic, and infrared spectral studies. The molar conductance data reveal non-electrolytes in DMF. Magnetic moment values suggest low-spin and high-spin complexes. The electronic spectral studies suggest distorted octahedral stereochemistry around Co(II) in these complexes. Infrared spectral studies suggest bidentate chelating behavior of i-MNT^2?, CED^2?, or OPD while other ligands are unidentate in their complexes.     

Molar excess volumes and molar excess enthalpies of methylenebromide + aromatic hydrocarbon mixtures

Molar excess volumes V^e and molar excess enthalpies H^e of binary methylenebromide (i) +benzene. +toluene, and + o^?, + m^? and + p-xylene (j) mixtures have been determined at 298.15 and 308.15 K. The data have been analysed in terms of recent approaches for solutions of nonelectrolytes, and the results suggest that these mixtures are characterised by specific interactions between the components. Self-volume interaction coefficients V_iiV_jj have also been evaluated.     

Heats of mixing of some binary methylene chloride solutions

Heats of mixing of pyridine, α-picoline, aniline, o-toluidine and cyclohexane with methylene chloride have been measured at 298.15 K. The results have been considered in terms of molecular interactions between the components of these mixtures and possible structures of the complexes have been described.