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Using solid-state molecular organometallic (SMOM) techniques, in particular solid/gas single-crystal to single-crystal reactivity, a series of σ-alkane complexes of the general formula [Rh(Cy2PCH2CH2PCy2)(ηn:ηm-alkane)][BArF4] have been prepared (alkane = propane, 2-methylbutane, hexane, 3-methylpentane; ArF = 3,5-(CF3)2C6H3). These new complexes have been characterized using single crystal X-ray diffraction, solid-state NMR spectroscopy and DFT computational techniques and present a variety of Rh(I)···H–C binding motifs at the metal coordination site: 1,2-η2:η2 (2-methylbutane), 1,3-η2:η2 (propane), 2,4-η2:η2 (hexane), and 1,4-η1:η2 (3-methylpentane). For the linear alkanes propane and hexane, some additional Rh(I)···H–C interactions with the geminal C–H bonds are also evident. The stability of these complexes with respect to alkane loss in the solid state varies with the identity of the alkane: from propane that decomposes rapidly at 295 K to 2-methylbutane that is stable and instead undergoes an acceptorless dehydrogenation to form a bound alkene complex. In each case the alkane sits in a binding pocket defined by the {Rh(Cy2PCH2CH2PCy2)}+ fragment and the surrounding array of [BArF4]− anions. For the propane complex, a small alkane binding energy, driven in part by a lack of stabilizing short contacts with the surrounding anions, correlates with the fleeting stability of this species. 2-Methylbutane forms more short contacts within the binding pocket, and as a result the complex is considerably more stable. However, the complex of the larger 3-methylpentane ligand shows lower stability. Empirically, there therefore appears to be an optimal fit between the size and shape of the alkane and overall stability. Such observations are related to guest/host interactions in solution supramolecular chemistry and the holistic role of 1°, 2°, and 3° environments in metalloenzymes.

The isothermal vapour-liquid equilibria of R-23 + 1-hexene, R-23 + 3-methylpentane, R-116 + 1-hexene and R-116 + 3-methylpentane were measured at temperatures of between (293.1 and 313.3) K with a static-analytic apparatus. Vapour-liquid-liquid equilibria was exhibited by the R-116 + 1-hexene system. The equilibrium data was modelled with the PR EOS, modified with the MC alpha function, and the WS mixing rule with either the NRTL or the UNIQUAC activity coefficient model. Both the temperature dependent and the temperature independent forms of the models were regressed to the experimental data. The method of Ungerer et al. was used to extrapolate the subcritical co-existence data to the mixture critical loci, while the method of Heidemann and Khalil was used to estimate the critical locus curves for the systems. Each of the four systems were also categorised according to the classification system of van Konynenburg and Scott.

Equations of state for three hexane isomers, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane, have been developed based on experimental thermodynamic property data from the literature. These equations are explicit in the Helmholtz energy with independent variables of temperature and density. The temperature, pressure, and density validity ranges of the equations of state were determined by the available measured data for these three fluids. The uncertainties in densities, vapor pressures, saturated liquid and vapor densities, and caloric properties were estimated by comparisons with experimental data of these properties. The behavior of various thermodynamic properties was analyzed to assess the quality of the equations of state. Physically correct behavior within the region of validity and at extremely high temperatures and pressures, and temperatures far below the triple-point temperature, was obtained through fitting multiple constraints of various properties.

3-Methylpentane (C6H14, CAS No. 96-14-0), isomer of hexane, is a colorless liquid originating naturally from petroleum or natural gas liquids. 3-Methylpentane has been used as a solvent in organic synthesis, as a lubricant, and as a raw material for producing carbon black. There is limited information available on the inhalation toxicity of 3-methylpentane, and the aim of this study was to determine its subacute inhalation toxicity. According to OECD Test Guideline 412 (subacute inhalation toxicity: 28-day study), Sprague Dawley rats were exposed to 0, 284, 1,135, and 4,540 ppm of 3-methylpentane for 6 hr/day, 5 days/week for 4 weeks via whole-body inhalation. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, organ weights, and gross and histopathological findings were compared between control and all exposure groups. No mortality or remarkable clinical signs were observed during the study. No gross or histopathological lesions, or adverse effects on body weight, food consumption, hematology, serum chemistry, and organ weights were observed in any male or female rats in all exposure groups, although some statistically significant changes were observed in food consumption, serum chemistry, and organ weights. In conclusion, the results of this study indicate that no observable adverse effect level (NOAEL) for 3-methylpentane above 4,540 ppm/6 hr/day, 5 days/week for rats.

Consistent vapor–liquid equilibrium (VLE) data for the ternary systems 3-methylpentane + ethanol + methylcyclohexane and ethanol + tert-butyl alcohol (TBA) + methylcyclohexane are reported at 101.3 kPa. The VLE data have been correlated by Wilson, UNIQUAC and NRTL equations. The ternary systems do not present azeotrope and are well predicted from binary interaction parameters.

The isomerization on sulphated zirconias of the 3-methyl(3-13C)pentane, molecule chosen to distinguish between the methyl and ethyl migrations, is studied. The products distribution shows 0% for the 3-methylpentane isotopomers (not detected? or not formed?), what makes the interpretations difficult. Supposing these molecules formed in low proportions but not detected, a reaction pathway involving protonated cyclopropanes is proposed: the isotopomers are obtained from one- two- or three-step reactions. However, it is envisaged the possible non-formation of these molecules and a reaction pathway involving protonated cyclopropanes, cyclobutanes and bicyclopropanes is suggested: the 13C-label scrambling would be a two-step isomerization and the other isotopomers would be formed via a one-step reaction. The relative proportions of methyl migration (MM) and ethyl migration (EM) are assessed. The MM/EM ratio could be appreciated as an intrinsic characteristic of the catalyst because of correlations with, e.g. the crystalline structure, the sulphate content and the activity. Such correlations knowledge could help preparing catalysts with high activity and selective reactivity.

The influence of the loading on the self-diffusion of 3-methylpentane within silicalite-1 has been studied with Positron Emission Profiling technique. A monotonous decrease in the self-diffusivities of alkane was observed with zeolite loading, which could be approximated by a stretched exponential. As a consequence, the apparent activation energy increases with partial pressure.

Measurements of excess molar enthalpies at the temperature 298.15 K in a flow microcalorimeter, are reported for the two ternary mixtures { X 1 C 4 H 8 O + X 2 CH 3 CH 2 CH(CH 3 )CH 2 CH 3 + (1− X 1 − X 2 )CH 3 (CH 2 ) v −2 CH 3 } with v =8 and 10. Smooth representations of the results are described and used to construct constant-enthalpy contours on Roozeboom diagrams. It is shown that useful estimates of the ternary enthalpies can be obtained from the Liebermann–Fried model, using only the physical properties of the components and their binary mixtures.

Measurements of excess molar enthalpies at 25°C in a flow microcalorimeter are reported for the two ternary mixtures 2-methyltetrahydrofuran + 3-methylpentane + n-decane and di-n-butyl ether + 3-methylpentane + n-decane. Smooth representations of the results are described and used to construct constant-enthalpy contours on Roozeboom diagrams. It is shown that useful estimates of the ternary enthalpies can be obtained from the Liebermann–Fried model using only the physical properties of the components and their binary mixtures.

The reactivity of 3-methylpentane (3MP) and hexane (H) on HZSM-5 at 120–160 °C changes from gas (H > 3MP) to liquid phase (3MP > H), as does product selectivity. The liquid phase reactivity ratio is similar on HZSM-5 and in trifluoromethanesulfonic acid (TFMSA), where the reaction involves initiation by oxidation to allyl cations. In both cases, olefins are intermediates, but do not appear in the products. Because hydride transfer catalysis is absent in the reaction of H and the steric requirements for hydride transfer are smaller than for cracking, the mechanism involving protonation of sigma bonds, as in liquid superacids, does not operate in zeolites. The H:3MP reactivity ratio does not measure steric constraints in cavities.

Consistent vapor–liquid equilibria (VLE) at 101.3 kPa has been determined for the ternary system 3-methylpentane+diisopropyl ether (DIPE)+methylcyclohexane and the binary subsystems 3-methylpentane+methylcyclohexane and DIPE+methylcyclohexane in the temperature range from 336 to 374 K. According to the experimental results, the systems exhibit slight positive deviation from ideal behavior and no azeotrope is present. The VLE data have been correlated with the composition using the Wilson, UNIQUAC and NRTL relations. These models allow good prediction of the VLE properties of the ternary system from those of the pertinent binary subsystems.

This article has no abstract. Keywords: 2-methylpentane; isohexane; 3-methylpentane; 2,2-dimethylbutane; neohexane; 2,3-dimethylbutane; gas chromatography; GC; double capillary technique; adsorption on charcoal; workplace measurement; air analysis; occupational monitoring; analytical method; hazardous substance; measurement procedure; expanded uncertainty; personal sampling; stationary sampling

Pure-component vapor pressure of 3-methylpentane and vapor–liquid equilibrium (VLE) for the binary systems of 3-methylpentane with methyl 1,1-dimethylethyl ether (MTBE) and with methyl 1,1-dimethylpropyl ether (TAME) at 101.3 kPa have been measured. Both systems exhibit small positive deviations from ideality. They can be described as regular solutions and do not present azeotrope. The activity coefficients and boiling points of the solutions were correlated with its composition by Wilson, UNIQUAC, NRTL, and Wisniak–Tamir equations.

Vapour pressures of n -butanol with 2-methylpentane and 3-methylpentane between 283.15 and 313.15 K were measured at 5 K intervals by a static method. Excess enthalpies and excess volumes, at 298.15 K, were also measured. Experimental excess volumes are compared with predictions of an extended real associated solution (ERAS) model. The model reproduces qualitatively the experimental curves of V E and gives a good description of the experimental results of G E at 298.15 K.

The (vapour + liquid) equilibria of (3-methylpentane + heptane) at T = 308.15 K, 318.15 K, and 328.15 K; of (3-methylpentane + octane) at T = 338.15 K; and of (toluene + octane) at T = 333.15 K, have been obtained by using a dynamic still, and excess volumes of these mixtures have been measured at T = 298.15 K using an Anton-Paar densitometer. The VLE results were analysed by applying the maximum-likelihood principle and are well correlated by the Wilson, NRTL, and modified UNIQUAC equations. They are also compared satisfactorily with a group-contribution equation of state.

Experimental time-average conversions and selectivities for reactions of 3-methylpentane and 2-methylpentane have been measured on USHY at 400[degrees]C to provide additional confirmation of the proposal that initiation of the cracking of saturated compounds takes place via the protolysis of a feed molecule and is always followed by some degree of conversion via a bimolecular, carbenium-ion-induced chain process. 11 refs., 4 tabs.

The standard ( p o = 0.1 MPa) molar enthalpy of formation of the crystalline complex of iron(III) with 3-methylpentane-2,4-dione (HMe acac ) was determined at the temperature 298.15 K, by solution-reaction calorimetry as −(1360.3 ± 5.8) kJ · mol −1 . The enthalpy of sublimation at the temperature 298.15 K, determined by microcalorimetry, was found to be (164.5 ± 2.8) kJ · mol −1 . From the standard molar enthalpy of formation of the gaseous complex, the mean molar bond-dissociation enthalpy, 〈 D m 〉(Fe-O), was derived as (172 ± 11) kJ · mol −1 .

The standard ( p o = 0.1 MPa) molar enthalpy of combustion in oxygen at 298.15 K of liquid 3-methylpentane-2,4-dione (HMe acac ) was measured by static bomb calorimetry as −(3353.2±1.7) kJ · mol −1 . The standard molar enthalpy of formation of the crystalline copper(II) complex with 3-methylpentane-2,4-dione was determined, at the temperature 298.15 K, by solution-reaction calorimetry. The vapour pressures of the complex were measured as function of temperature by the Knudsen-effusion technique, and the standard molar enthalpy of sublimation Δ g cr H o m (396.70 K)/(kJ · mol −1 ) = 130.7 ± 1.0, was derived by the Clausius-Clapeyron equation. From this value, the standard molar enthalpy of sublimation was calculated as Δ g cr H o m (298.15 K)/(kJ · mol −1 ) = 135.6 ± 1.0. Measurement of the standard molar enthalpy of sublimation using a direct microcalorimetric method, confirmed the value from the Knudsen technique.

Self-diffusion coefficients and viscosities for the saturated hydrocarbons having six carbon atoms such as hexane, 2-methylpentane (2MP), 3-methylpentane (3MP), 2,2-dimethylbutane (22DMB), 2,3-dimethylbutane (23DMB), methylcyclopentane (McP) and cyclohexane (cH) were measured at various constant temperatures; obtained results were discussed in connection with their molar volumes, molecular structures and thermodynamic properties. The values of self-diffusion coefficients as the microscopic property were inversely proportional to those of viscosities as the macroscopic property. The order of their viscosities was almost same to those of their melting temperatures and enthalpies of fusion, which reflect the attractive interactions among their molecules. On the other hand, the order of the self-diffusion coefficients inversely related to the order of the melting temperatures and the enthalpies of the fusion. Namely, the compound having the larger attractive interaction mostly shows the less mobility in its liquid state, e.g., cyclohexane (cH), having the largest attractive interaction and the smallest molar volume exhibits an extremely large viscosity and small self-diffusion coefficient comparing with other hydrocarbons. However, a significant exception was 22DMB, being most close to a sphere: In spite of the smallest attractive interaction and the largest molar volume of 22DMB in the all samples, it has the thirdly larger viscosity and the thirdly smaller self-diffusion coefficient. Consequently, the dynamical properties such as self-diffusion and viscosity for the saturated hydrocarbons are determined not only by their attractive interactions but also by their molecular structures.

Shear viscosity and dynamic light scattering measurements as well as ultrasonic spectrometry studies of the nitroethane/3-methylpentane mixture of critical composition have been performed at various temperatures near the critical temperature, T(c). A combined evaluation of the shear viscosity and mutual diffusion coefficient data yielded the amplitude, xi(0), of the fluctuation correlation length, xi, assumed to follow power law, and the relaxation rate, Gamma, or order parameter fluctuations. The latter was found to follow power law with the theoretical universal exponent. The amplitudes xi(0) = 0.23 +/- 0.02 nm and Gamma(0) = (125 +/- 5) x 10(9) s(-1) nicely agree with literature values. Using the relaxation rates resulting from the viscosity and diffusion coefficient data, the scaling function has been calculated assuming the ultrasonic spectra to be composed of a critical part and a noncritical background contribution. The experimental scaling function fits well to the predictions of the Bhattacharjee-Ferrell dynamic scaling model with scaled half-attenuation frequency, Omega(BF)1/2= 2.1. The amplitude of the sonic spectra yields the amount |g| = 0.26 of the adiabatic coupling constant, g, in fair agreement with -0.29 from another thermodynamic relation.

The deactivation of two platinum black samples caused by pulses of 3-methylpentane introduced into atmospheres with different hydrogen pressures was determined by relating yields obtained in subsequent pulses to those observed over freshly regenerated catalyst. The remaining catalytic activity could be related to the amount of hydrocarbon retained on the surface as determined by radiotracer studies. The selective deactivation for isomerization and C 5 -cyclization as well as hydrogenolysis was interpreted in terms of multiple sites for these processes deactivated by their partial covering with carbonaceous residues formed in the first moment of reaction with hydrocarbons.

Pulse radiolysis of bis (2-ethylhexyl)sulfosuccinate (AOT) solutions in 3 methylpentane (3 MP) at 77 K leads to the formation of a species absorbing at around 450 nm. This absorption is believed to result from the scavenging of electrons by AOT inverted micelles. The electron scavenging capacities of an AOT solution depend on the aggregation number of the micelles. The addition of water leads to less efficient electron capture which is explained by an increase of the aggregation number. This increase is of the same order of magnitude as measured by other techniques at room temperature.

Reactions of 3-methylpentane, 3-methyl-1-pentene, cis - and trans -3-methyl-2-pentenes have been studied over a platinum black catalyst, in a pulse-microcatalytic system, in the presence of carrier gases with different hydrogen contents. The yields of dehydrogenation of 3-methylpentane, C 5 -cyclization, skeletal isomerization, and benzene formation are discussed in detail as a function of hydrogen pressure. An enhanced reactivity of the terminal olefinic double bond has been observed under hydrogen-deficient conditions: this manifested itself as benzene formation (presumably in bond-shift type dehydro-isomerization reaction) as well as in “non-hydrogenative” C 5 -cyclization resulting in 1-methylcyclopentene. On the other hand, “hydrogenative” mechanisms of C 5 -cyclization and C 5 -cyclic isomerization have been found to prevail in the presence of more hydrogen; a common half-hydrogenated intermediate for both saturated and unsaturated hydrocarbons and a “dual-site” mechanism has been proposed for this process.

The pyrolysis of two C6 alkanes, n-hexane and 3-methylpentane, was investigated in a conventional static apparatus at 420°C and 133 mbar, at low extents of reaction. The primary reaction products were identified and measured by gas chromatography and the corresponding stoichiometric equations were determined. Our experimental results are interpreted by a long-chain radical mechanism ofthe Rice-Herzfeld type, and clearly show the influence of the structure (linear- or branched-chain) on the yields of ethylene. They provide a useful basis for modelling the reaction at higher temperature.

Excess volumes were measure over the entire composition range with a Sodev vibrating-tube densimeter for cyclohexane + 2-methylpentane, + 3-methylpentane, and + methylcyclo-pentane. Measurements are reported at 298.15 K for the first two, and at 283.15, 298.15, and 313.15 K for the last. Measurements over a limited composition range are also reported for cyclohexane + 2,3-dimethylbutane at 298.15 K. The V E results are correlated with the geometry of the molecules.

Using the pulse radiolysis method the excimer formation of diphenyl derivatives in low temperature 3-methylpentane was investigated. For diphenyls two emission bands are found in the temperature range 140 – 230 K. The band at 320 nm is due to monomer fluorescence, whereas the second at 380 – 390 nm is as an excimer emission.

The products from the reaction of pentane-2,4-dione (acac H) with the anion [Fe(CN) 5 (NO)] 2− in the presence of alkali are [Fe(acac) 3 ], [Fe(CN) 6 ] 4− , NO, and the oxime HONC(COCH 3 ) 2 . A reaction mechanism is proposed involving formation of an adduct of [Fe(CN) 5 (NO)] 2− and the carbanion, metal-to-ligand charge transfer, loss of NO and ligand rearrangement. A similar reaction occurs with 3-methylpentane-2,4-dione.

Excess volumes for nitroethane + 3-methylpentane have been measured at 298.596, 300.153, 303.150, and 313.176 K. The excess volume is positive at these temperatures, has a maximum near x(C2H5NO2) = 0.25, and is unusually flat at compositions approaching pure nitroethane. The results are compared with excess volume measurements on other mixtures of nitroethane + hydrocarbon. Measurements of coexisting densities reported by Wims, McIntyre, and Hynne (J. Chem. Phys.1969, 50, 616) are reanalyzed and a value of the critical exponent β = 0.33 is obtained.

Autoxidation of 3-methylpentane in the presence of tert-butyl hydroperoxide gives, after reduction with triphenylphosphine, 3-methyl-3-pentanol and 3-methyl-2-pentanol as the major reaction products. The overall rate constant for reaction of (CH3)3COO· with this substrate at 30 °C is 0.008 ± 0.001 M−1 s−1 which consists of k/tertiary C—H = 0.007 ± 0.001 M−1 s−1 and k/secondary C—H = 0.0002 ± 0.0001 M−1 s−1. The products from cooxidation of cumene and 3-methylpentane in the presence of tert-butyl hydroperoxide are formed in yields which are consistent with these rate constants relative to a value of 0.16 M−1 s−1 for cumene. The Arrhenius equations for reaction of (CH3)3COO• with the t-C—H and s-C—H of 3-methylpentane relative to the Arrhenius equation for reaction of (CH3)3COO• with cumene (log (k10/M−1 s−1) = (8.7 ± 0.3) − (13.2 ± 0.4)/θ) are[Formula: see text]respectively, where θ = 2.303 RT kcal mol−1.

The destructive alkylation reaction of benzene with 3-methylpentane to give ethylbenzene in the presence of aluminum chloride was investigated. When 3-methylpentane-1-14C was employed, radioactive ...

Detailed studies have been carried out of the combustion of 3-ethylpentane with special reference to the chemical changes taking place in the cool-flame region, where at least 74 individual products are formed. At ca . 300 °C, the first products to appear are 3-ethylpent-1-ene and 3-ethylpent-2-ene, C 7 O -heterocycles and alkenes of carbon number less than seven; the rates of consumption of 3-ethylpentane and of formation of all products increase dramatically just before propagation of the first cool-flame but do not vary appreciably when subsequent cool-flames pass. As the temperature is raised to ca . 400 °C, the quantities of 3-ethylpentane consumed and of lower molecular mass products formed increase markedly while the amounts of most C 7 products decrease. Consideration of the analytical results indicates that alkylperoxy radical isomerization plays an important part in the primary chain-propagation cycle both in and out of the cool-flame region and at temperatures as high as 400 °C. It appears that the initial reaction of alkyl radicals with oxygen takes place, largely, if not exclusively, by direct addition to form alkylperoxy radicals. Different modes of isomerization of these radicals leads to the wide variety of products found and decomposition of the a-hydroperoxyalkyl radicals by direct loss of HO 2 is probably the sole source of the conjugate alkenes. The results also provide the first recorded evidence of ethyl group migration during alkylperoxy radical isomerization.

The low-temperature thermal properties of 3-methylpentane and 3-methylheptane were measured by adiabatic calorimetry from 10 to 330 K and 10 to 380K, respectively. Properties measured included the heat capacity of the condensed phases, enthalpy of fusion, triple point temperature, and purity of sample. The results were used to calculate the following thermodynamic functions at selected temperatures for the solid and liquid phases: − {Gs(T) − H°(0)}/T, {Hs(T) − H°(0)}/T, Hs(T) − H°(0), Ss, and Cs. The entropies in the ideal gas state at 298.15 K were computed, and methylene increments of 7.69 calth K−1 mol−1 for the liquid state and 9.23 calth K−1 mol−1 for the vapor state were derived. Crystallization of the 3-methylpentane sample was induced (apparently for the first time) by cooling the liquid through the liquid-to-glass transition temperature (about 77 K), followed by slow warming to temperatures between the transition and the triple point (110.25 K).

The variation of the critical temperature as a function of pressure in nitroethane-isooctane (N-I) and nitroethane-3-methylpentane (N-3M) mixtures has been experimentally determined. Since both mixtures exhibit components having nearly the same refractive index, special care had to be taken to see the transition. The following values were found : and For N-3M, a comparison is made of the amplitude of the diverging part of the specific heat with the renormalization group prediction.

In order to elucidate the behavior of a positive hole in irradiated alkane glasses, the effect of solutes having ionization potential lower than that of a glass matrix molecule upon the decay of a trapped electron was examined in a 3-methylpentane glass at 77°K by means of electron spin resonance. The decay was found to be explained in terms of the superposition of two exponentially decaying processes, as in the absence of a solute. Although the fast process was not affected by a solute, the slow process was further slowed by the addition of a solute. The effect of a solute is described by the empirical relation, k⁄k0=1⁄(1+fN), where k and k0 are the rate constants of the slow decay in the presence and in the absence of a solute, respectively. N is the mole fraction of a solute. The observed values of the slowing-down efficiency, f, increase in parallel with the decreasing values of ionization potential of solutes: 2-methyltetrahydrofuran, diethylether, methylvinylether, 2-methylpentene-1 and n-butylvinyl...

This paper presents a study of the influence of branching in the binary diffusion coefficients of n-heptane+n-hexane isomers, in the liquid state. The measurements have been made with the Taylor dispersion technique, at several compositions, at 283 and 298 K, for the X+n-heptane mixtures, where X=n-hexane, 3-methylpentane, 2, 3-dimethylbutane, and 2, 2-dimethylbutane. The results show a very interesting behavior of the composition dependence of the binary diffusion coefficients, presenting a maximum, for compositions about a molar fraction of n-heptane of 0.5, which increases with the increase in the degree of branching, suggesting the possibility of order~tisorder effects caused by stereochemically favored packing in the liquid phase and energetically favored segment interaction in the liquid mixtures. An attempt to apply the van der Waals model to these data could not predict the experimental binary diffusion coefficients of these systems within the experimental accuracy.

Electron transport in disordered systems has received much interest during recent years. The motion of excess electrons under the influence of an electric field has been investigated in many systems and the problems of evaluating the transport process have been pointed out recently In liquid hydrocarbons drift velocities uci of excess electrons were measured as a function of the electric field strength F. At low field strengths v