Search results for "isobar"
showing 10 items of 210 documents
Adsorption and diffusion of linear and dibranched C6 paraffins in a ZSM-5 zeolite
2002
The adsorption of n-hexane and 2,2-dimethylbutane on a commercial ZSM-5 zeolite is studied under isothermal and isobaric conditions. ZSM-5 exhibits two different behaviours with linear and dibranched alkanes. A substep at 4 molec.uc−1 is observed on the adsorption isotherm of n-hexane at 348 K. A singular adsorption-desorption process is evidenced on the adsorption isobar at 5.5 kPa with 2,2-dimethylbutane at a temperature close to 343 K when the sample is activated at 298 K under vacuum. The diffusivities have been determined by fitting directly the uptake curves with a numerical resolution of second Fick's law based on finite difference method. Microporous diffusion seems to be rate limit…
First experimental proof of asymmetric charge transfer in ICP-MS/MS (ICP-QQQ-MS) through isotopically enriched oxygen as cell gas
2014
The quantification of a variety of elements in the field of ICP-MS is restricted by isobaric interferences. The recent development of ICP-MS/MS (“triple quadrupole” configuration) offers a new way to solve the problem of the detection of such elements affected by interferences because the signal caused by either the analyte or the isobaric interference can be shifted to another m/z through reactions with the cell gas (oxygen, ammonia or hydrogen). This system consists of two quadrupoles (Q1 and Q2) with a collision/reaction cell in between. When using the MS/MS mode of this configuration it becomes possible to restrict the ions entering the cell to a defined m/z and therefore get a better i…
Finite-size scaling in a microcanonical ensemble
1988
The finite-size scaling technique is extended to a microcanonical ensemble. As an application, equilibrium magnetic properties of anL×L square lattice Ising model are computed using the microcanonical ensemble simulation technique of Creutz, and the results are analyzed using the microcanonical ensemble finite-size scaling. The computations were done on the multitransputer system of the Condensed Matter Theory Group at the University of Mainz.
Classical and Quantum Two-Dimensional Fluids in the Gibbs Ensemble
1994
We study the properties of model fluids in two spatial dimensions with Gibbs ensemble Monte Carlo (GEMC) techniques. In particular in the first part of the paper we study the entropy driven phase separation in case of a nonadditive symmetric hard disc fluid and locate by a combination of GEMC with finite size scaling techniques the critical line of nonadditivities as a function of the system density, which separates the mixing/demixing regions, we compare with a simple approximation. In the second part we successfully combine path integral Monte Carlo (PIMC) and GEMC techniques in order to locate the gas-liquid coexistence densities for a fluid with classical degrees of freedom and internal…
Relations between compression and thermal contraction in 1,2,4-trichlorobenzene and melting of trichlorobenzene isomers
2015
The compression and thermal expansion of crystalline 1,2,4-trichlorobenzene, C6H3Cl3, 124TCB, investigated under isobaric and isothermal conditions, are in reverse relation, as for most of crystals, however, the isochoric strain along direction c is clearly different from those along a and b. Single crystals of 124TCB have been in situ grown under isochoric and isobaric conditions, at 270 K/0.1 MPa and 295 K/0.16 GPa, and also at 100 K/0.1 MPa and 295 K/0.64 GPa, when the unit-cell volume is similar. All crystallizations yielded the same phase, of monoclinic space group P21/n, with two symmetry-independent molecules (Z′ = 2). The structure is governed by Cl⋯Cl and Cl⋯H interactions and the …
Isobaric vapor–liquid equilibria for 1-propanol+water+copper(II) chloride at 100kPa
2005
Abstract Isobaric vapor–liquid equilibria for the ternary system 1-propanol + water + copper(II) chloride has been measured at 100 kPa using a recirculating still. The addition of copper(II) chloride to the solvent mixture produced a salting-out effect of the alcohol, but the azeotrope did not tend to be eliminated when the salt content increased. The experimental data sets were fitted with the electrolyte NRTL model and the parameters of Mock's model were estimated. This model has proved to be suitable to represent experimental data in the entire range of compositions. The effect of copper(II) chloride on the vapor–liquid equilibrium of the 1-propanol + water system has been compared with …
Isobaric Vapor–Liquid–Liquid Equilibria for the Ternary Systems Ethanol + Water + Propyl Acetate and 1-Propanol + Water + Propyl acetate
2014
In order to break azeotropes appearing in mixtures of water and either ethanol or 1-propanol, an azeotropic distillation process is proposed using propyl acetate as entrainer. Therefore, isobaric vapor–liquid–liquid equilibrium (VLLE) data at atmospheric pressure have been obtained for the ternary systems ethanol + water + propyl acetate and 1-propanol + water + propyl acetate. Data correlation has been carried out in four different ways and a comparison between the results obtained in each correlation has been done. The set of parameters obtained from the best correlation has been used in the VLLE estimation. Effects of using propyl acetate as entrainer in the azeotropic distillation have …
Isobaric Vapor−Liquid Equilibria for 1-Propanol + Water + Calcium Nitrate
1999
Isobaric vapor−liquid equilibria for all of the binary and ternary mixtures of 1-propanol, water, and calcium nitrate have been measured at 100.00 kPa using a recirculating still. The addition of calcium nitrate to the solvent mixture produced an important salt effect; the azeotrope was removed at salt mole fractions higher than 0.08. The three experimental binary data sets were independently fitted with the electrolyte NRTL model (Mock, B.; Evans, L. B.; Chen, C. C. AIChE J. 1986, 32, 1655−1664), and the parameters of Mock's model were estimated for each binary system. No ternary parameter was required. These parameters were used to predict the ternary vapor−liquid equilibrium using the sa…
Isobaric Vapor−Liquid Equilibria for Water + Acetic Acid + Lithium Acetate
2001
Isobaric vapor−liquid equilibria for all of the binary and ternary mixtures of water, acetic acid, and lithium acetate have been measured at 100.00 kPa using a recirculating still. To take into account the association of the acetic acid in the vapor phase, Marek's chemical theory has been considered. The three experimental binary data sets have been independently correlated using Mock's electrolyte NRTL model, and the binary parameters estimated for each binary system have been used to predict the ternary vapor−liquid equilibrium using the same model. No ternary parameters were required. The ternary equilibrium values obtained in this way agreed well with the experimental values.
Isobaric Vapor−Liquid Equilibrium of Binary Mixtures of 1-Butanol + Chlorobenzene and 2-Butanol + Chlorobenzene at 20 and 100 kPa
1997
Isobaric vapor−liquid equilibria were obtained for 1-butanol + chlorobenzene and for 2-butanol + chlorobenzene systems at 20 and 100 kPa using a dynamic still. The experimental error in temperature was ±0.1 K, in pressure ±0.01 kPa and ±0.1 kPa for the experiments carried out at 20 and 100 kPa, respectively, and in liquid and vapor composition ±0.001. The two systems satisfy the point-to-point thermodynamic consistency test. Both systems show a positive deviation from ideality. The data were correlated with the Wilson equation.