The excess molar volumes of (hydrocarbon + branched chain ether) systems at 298.15 K and 308.15 K, and the application of PFP theory

The excess molar volumes, V_m^E, have been calculated from measured density values over the whole composition range at the temperatures 298.15 K and 308.15 K and under atmospheric pressure for the 12 mixtures {hydrocarbon (heptane, 2,2,4-trimethylpentane, 1-heptene or toluene) + branched chain ether (methyl 1,1-dimethylethyl ether, ethyl 1,1-dimethylethyl ether or methyl 1,1-dimethylpropyl ether)}. The excess volumes of all the mixtures except (toluene + ether) are positive over the whole composition range. The experimental results have been correlated and compared with the results from Prigogine-Flory-Patterson (PFP) theory.     

Phase equilibria in the ternary system hexane+ethyl 1,1-dimethylethyl ether+heptane

Consistent vapor–liquid equilibrium data at 94 kPa have been determined for the ternary system hexane+ethyl 1,1-dimethylethyl ether+heptane. The results indicate that the system deviates positively from ideality and that no azeotrope is present. The ternary system were predicted with the composition by the Redlich–Kister, Wilson, NRTL, UNIQUAC and UNIFAC models using only the parameters of the constituent binaries. Most of the models allow a very good prediction of the phase equilibrium of the ternary system. In addition, the Wisniak–Tamir relations were used for correlating bubble-point temperatures.     

Characterization and modelling of a gasoline containing 1,1-dimethylethyl methyl ether (MTBE), diisopropyl ether (DIPE) or 1,1-dimethylpropyl methyl ether (TAME) as fuel oxygenate based on new isothermal binary vapour–liquid data

Experimental isothermal P–x data at T=313.15 K for seven binary systems (1,1-dimethylethyl methyl ether (MTBE)+2,2,4-trimethylpentane); (1,1-dimethylethyl methyl ether (MTBE)+toluene); (toluene+2,2,4-trimethylpentane); (toluene+1-hexene); (toluene+cyclohexane); (2,2,4-trimethylpentane+1-hexene) and (2,2,4-trimethylpentane+cyclohexane) are reported. Data reduction by Barker’s method provides correlations for G^E using the Margules equation, Wilson, NRTL and UNIQUAC models, which have been applied successfully. We have compared the behaviour in the vapour–liquid equilibrium of the aromatic compounds benzene and toluene and the paraffins heptane and 2,2,4-trimethylpentane. And finally we have modelled a gasoline of five components using the Wilson model, and we have compared the influence of three different ethers used as oxygenated additives in gasolines.     

Phase equilibria in the ternary system ethyl 1,1-dimethylethyl ether+heptane+octane

Vapor–liquid equilibrium at 94 kPa has been determined for the ternary system ethyl 1,1-dimethylethyl ether (ETBE)+heptane+octane. The system deviates slightly from ideality and no azeotrope is present. The ternary activity coefficients and the boiling points of the system have been correlated with the composition using the Redlich–Kister, Wilson, NRTL, UNIQUAC, UNIFAC, and Wisniak–Tamir relations. Most of the models allow a very good prediction of the activity coefficients of the ternary system from those of the pertinent binary systems.     

First synthesis of nitro-substituted bicyclo[1.1.0]butane derivatives and new method for generation of tricyclo[4.1.0.0<Superscript>2,7</Superscript>]hept-1(7)-ene

Successive treatment of 1-phenylsulfonyltricyclo[4.1.0.0^2,7]heptane with butyllithium and ethyl nitrate leads to the formation of 7-nitro-7′-phenylsulfonyl-1,1′-bi(tricyclo[4.1.0.0^2,7]heptane) through intermediate tricyclo[4.1.0.0^2,7]hept-1(7)-ene which is generated by 1,2-elimination of benzenesulfinic acid from the initial compound. Analogous treatment of 1-phenyltricyclo[4.1.0.0^2,7]heptane gives 1-nitro-7-phenyltricyclo[4.1.0.0^2,7]heptane.     

Reaction of gem-dibromocyclopropanes with diphenylphosphide ion

Diphenylphosphide ion undergoes a photostimulated reaction with 7,7-dibromobicyclo[4.1.0]heptane and 1,1-dibromo-2,2,3,3-tetramethylcyclopropane involving both ionic and radical steps to afford cyclopropyldiphenylphosphines resulting from substitution and reduction.     

Phase Diagrams of Ternary and Quaternary Systems Containing Heptane,Toluene, Dimethylsulfoxide,Methanol, and Ethanol at 298.15 K

Russian Journal of Physical Chemistry A - Liquid–liquid equilibrium of the ternary and quaternary systems (heptane + toluene + dimethyl sulfoxide), (heptane + toluene + dimethylsulfoxide +...     

Application of the flory and sanchez-lacombe theories to the excess enthalpy and excess volume of ether + hydrocarbon systems

Excess volume measurements for 2,5-dioxahexane + heptane and + octane, for 3,5-dioxaheptane + heptane and for isopropyl ether + heptane at 298.15 K are reported. The changes in excess volume observed in this work and described in the literature, as well as the reported excess enthalpy data for chain aliphatic ether+alkane systems as a function of composition are discussed in terms of the new Flory and the Sanchez-Lacombe theories. The interaction parameters for this class of mixtures have been correlated with the oxygen-atom surface fraction in the ether molecule.     

Thermodynamics of biofuels: Excess enthalpies for binary mixtures involving ethyl 1,1-dimethylethyl ether and hydrocarbons at different temperatures using a new flow calorimeter

Excess molar enthalpies for the binary systems: (ethyl 1,1-dimethylethyl ether + heptane); (ethyl 1,1-dimethylethyl ether + cyclohexane); (ethyl 1,1-dimethylethyl ether + toluene); (cyclohexane + toluene), and (toluene + heptane) have been measured at T = (298.15 and 313.15) K using a new isothermal flow calorimeter developed in the laboratory. The technique was previously checked by measuring test systems. The experimental results have been correlated with the Redlich–Kister polynomial equation. The mixing effects observed and the influence of the temperature are discussed.     

Isobaric Vapor-Liquid Equilibria in the Systems Ethyl 1,1-Dimethylethyl Ether + Hexane and + Heptane

Abstract

Pure-component vapor pressure of ethyl 1,1-dimethylethyl ether and vapor-liquid equilibrium for the binary systems of ETBE with hexane and with heptane have been measured at 94kPa. Both systems deviate slightly from ideal behavior, can be described as regular solutions and do no present an azeotrope. The activity coefficients and boiling points of the solutions were correlated with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak-Tamir equations.     

Isothermal vapor-liquid equilibria of bromochloroalkanes with heptane or cyclohexane: Measurement and analysis in terms of group contributions

Isothermal vapor-liquid equilibria (VLE) have been measured for liquid bromochloromethane + heptane or cyclohexane at 25‡C and 40‡C, and for 1-bromo-chloroethane + heptane or cyclohexane at 40‡C. These experimental results, along with our previous ones on excess enthalpies, as well as literature data on activity coefficients at infinite dilution, are interpreted in terms of the DISQUAC group contribution model, and are compared with UNIFAC predictions.     

Caged phosphorane with P-C bond based on chloral and 4,5-dimethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphospholane

The key methods of caged phosphoranes synthesis are analyzed. Reaction of 4,5-dimethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphospholane (prepared from the meso-form of 2,3-butanediol) with chloral has yielded the caged phosphorane containing a phosphorus-carbon bond: 1,1-(1,2-dimethylethylenedioxy)-3,4-diphenyl-6-trichloromethyl-2,5,7,1-trioxaphosphabicyclo[2.2.1^1,4]heptane; spatial structure of the product has been elucidated with X-ray diffraction analysis.

     

Geometry and bonding in substituted silacyclopropanes

Minimum energy geometries for silirane, 1; 1,1-difluoro-, 1; 1;1-difluorotetramethyl-, 3; 1,1-dimethyl-, 4; hexamethylsilirane, 5; 7-siladispiro[2.0.2.1]heptane, 6; and its 7,7-dimethyl derivative, 7, have been calculated using the CNDO/2 approximation. Good agreement has been obtained between the predicted structure for 7 and an experimental structure for a related compound. The calculations indicate that the enhanced stability observed for the spirocyclopropyl compounds such as 6 or 7 is due for the most part to increased overlap in the σ framework of the silirane ring resulting from increased contributions of the $\text{s}$ orbitals of the spiro carbon atoms to the bonding. Hyperconjugation between filled Walsh orbitals of the spirocyclopropyl rings and acceptor orbitals on silicon does not contribute as much to the stabilization of 6 and 7 as does the increased σ overlap. The calculations predict that the 1,1-difluorosiliranes, 2 and 3, should have thermodynamic stability comparable to or greater than the other siliranes, but much higher reactivity due to charge separation.     

A novel entry to dispiropyrrolo-bicyclo[2.2.1]heptanes through sequential 1,3-dipolar and Diels-Alder cycloaddition reactions

The synthesis of novel dispiroheterocycles containing a bicyclo[2.2.1]heptane ring system through sequential [3+2] and [4+2] cycloadditions is described.     

Preparation and crystal structure of 1,1-tetramethylethylenedioxy-3,4-diphenyl-6-trichloromethyl-2,5,7,1-trioxaphosphabicyclo[2.2.1<Superscript>1,4</Superscript>]heptane and 2-(1-hydroxy-2,2,2-trichloroethoxy)-4,4,5,5-tetramethyl- 2-oxo-1,3,2-dioxaphospholane

The state of the art of chloral applications in the chemistry of tricoordinate phosphorus derivatives has been analyzed. The highly stereoselective reaction of 4,4,5,5-tetramethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphospholane with chloral has been shown to afford a caged phosphorane with the phosphorus–carbon bond, 1,1-tetramethylethylenedioxy-3,4-diphenyl-6-trichloromethyl-2,5,7,1-trioxaphosphabicyclo- [2.2.1^1,4]heptane. Structure of the phosphorane and its hydrolysis product, 2-(1-hydroxy-2,2,2-trichloroethoxy)- 4,4,5,5-tetramethyl-2-oxo-1,3,2-dioxaphospholane, has been elucidated by X-ray diffraction analysis.     

Swelling of <Emphasis Type="Italic">N</Emphasis>-vinylcaprolactam-dodecyl methacrylate gel in {heptane + toluene} mixtures

A copolymer gel has been synthesized from N-vinylcaprolactam and dodecyl methacrylate in ethanol using the free radical cross-linking polymerization method. Characterizations of the gel were performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA) techniques. Swelling behavior of the gel was investigated in heptane, toluene, and their binary mixtures with different compositions. Swelling value in toluene is higher than that in heptane and swelling value increases with the increasing initial content of toluene in the binary mixture with heptane. The swelling values are correlated by the first- and second-order differential equations, and the best model correlating the experimental results is a second-order one. Diffusion coefficients have also been calculated for heptane and toluene at each concentration by power-law and first-order equations. While the diffusion mechanism of the gel in heptane is a Fickian one, the gel swelled in toluene exhibits a non-Fickian character. Diffusion mechanisms of the gels in binary mixtures are much more complicated. Because of the higher swelling degree in toluene compared to that in heptane, selectivity of the gel in different {heptane + toluene} mixtures with selectivity close to 1 has also been taken into consideration.     

Excess Volumes of 1-Alcohol + Heptane Mixtures at 298.15 and 308.15 K-Application of An Association Model with Flory Interaction Term

Abstract

The excess volumes of 1-pentanol+, 1-hexanol+, 1-heptanol+, 1-octanol+, 1-decanol+ and 1-dodecanol + heptane mixtures were evaluated at 298.15 and 308.15 K from the density data. The excess volumes were found to decrease with the increase in the carbon chain length of alcohol molecules. The temperature coefficient for the excess volumes was also observed to show a decreasing trend from 1-pentanol + to 1-dodecanol + heptane mixtures. The excess volumes were also calculated by combining the individual physical and chemical contributions, evaluated by combining an association model with Flory's free volume theory. Reasonable agreement between the experimental and calculated excess volumes for all the mixtures at 298.15 and 308.15 K was noted.     

Thermodynamic properties of binary mixtures: Hexamethylphosphoric triamide (HMPA) with a non-polar liquid at 25°C

Excess isobaric heat capacities C _p ^E , densities and speeds of sound u of HMPA+heptane and+benzene were measured at 25°C. C _p ^E of both mixtures were positive in the range of small x and negative in the other region. The mixture containing benzene showed higher C _p ^E than the heptane mixture. They both exhibited considerably smaller C _V ^E than C _p ^E . V^E was positive for HMPA+heptane and negative for HMPA+benzene. The compressibilities K _s ^E and K _p ^E of both mixtures were negative. In both mixtures, non-random mixing is expected and [(CH₃)₂N]₃PO molecules are inhomogeneously distributed.     

A simple molecular model of adsorption chromatography. XIII. Comparison of solvation effects in liquid-solid and liquid-liquid systems

Summary R_Mvs solvent composition plots of three quinoline bases are compared for analogous liquid-liquid and liquid-solid systems. For the heptane+heptanone-2-water system for which the variation of R_M(log k′) values with concentration of heptanone-2 is due to solvation effects in the mobile phase, the slope of the plots was much smaller than in the case of the heptane + heptanone-2-silica system. This is considered as evidence that solvation in the mobile phase cannot play the decisive role in the adsorption equilibrium. On the other hand, the relationships can be interpreted in terms of competitive interactions of the solutes and polar solvent (heptanone-2) with the surface silanol groups, as the main molecular mechanism. Part XII: Ref. [1].     

Metallacycloalkanes : II. Reactions of α,α′-bipyridyl-5-nickela-3,3,7,7-tetramethyl-trans-tricyclo[4.1.0.02,4]heptane

The title compound (II) underwent reductive elimination on treatment with maleic anhydride, tetracyanoethylene or triphenylphosphite to give 3,3,6,6,-tetramethyl-trans-tricyclo[3.1.0.0^2,4]hexane (III). With triphenylphosphite bi(2,2-dimethylcyclopropyl) (V) and 1-(2,2-dimethylcyclopropyl)-3-methyl-1,3-butadiene (VI) were also formed. Acidolysis of II with either HCl, malonic acid or methanol gave V. An intermediate complex α,α′-bipyridyl(phenoxy)-3-nickel-1,1′-bi-(2,2′-dimethylcyclopropyl) (VIII) was isolated by reaction of II with phenol. Methylene dibromide reacts with II to give III and 3,3,7,7-tetramethyl-trans-tricyclo[4.1.0.0^2,4]heptane (IV). With triethylaluminum and II complete exchange of the alkyl groups occurred and V was released on hydrolysis. Trifluoroborane diethyl ether and II gave 3,3,6,6-tetramethylcyclohexa-1,4-diene in a rearrangement-displacement reaction. The cyclodimerisation of 3,3-dimethylcyclopropene (I) to III catalysed by II and the fact that II can be recovered from the reaction mixture provides strong evidence for the intermediacy of metallacyclopentanes in these transition-metal-catalysed [2π + 2π] cyclo-additions.