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Yashkin, S. N.; Kurbatova, S. V.; Petrova, E. I.; Buryak, А. К.

doi:10.1023/a:1011398823938

Cited by 3 publications

(4 citation statements)

References 2 publications

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“…[18][19][20] Under the HPLC conditions, analogous results for these compounds were obtained 21 when the graphite like adsorbent Hypercarb was used as a stationary phase. The molecular statistical calculations of the thermodynamic characteristics of adsorption of the adamantane derivatives on the surface of the basal graphite face showed their good agreement with the experimental gas chromatographic data deter mined on the GTC.…”

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confidence: 65%

“…The molecular statistical calculations of the thermodynamic characteristics of adsorption of the adamantane derivatives on the surface of the basal graphite face showed their good agreement with the experimental gas chromatographic data deter mined on the GTC. [18][19][20][21][22][23] This served as a reliable basis for the prediction of thermodynamic retention conditions on the GTC of many adamantane derivatives, a considerable part of which represented stereoisomers similar in proper ties. 20 The accumulated vast experimental material on the retention values on the GTC in combination with molecular statistical calculations was successfully used for the identification of particular isomers in complicated synthetic 24 and natural 25 mixtures.…”

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confidence: 99%

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Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Yashkin

Svetlov²,

Murashov³

2010

Russ Chem Bull

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The thermodynamic characteristics of adsorption (TCA) on the basal face of graphite have been calculated in terms of the semiempirical molecular statistical theory of adsorption for molecules of O , S , and Se containing heteroadamantanes of different structure and isostructural cyclohexane derivatives. The influence of the nature, number, and position of heteroatoms in the adamantane framework on the TCA values was studied in detail, which made it possible to predict the retention of the compounds considered on the surface of graphitized thermal carbon black under the conditions of equilibrium gas adsorption chroma tography. The introduction of each subsequent heteroatom into a polyheteroadamantane molecule makes a non additive contribution to the TCA values. The contributions of various fragments to the total adsorption energy were calculated by the TCA of isostructural heterocyclohexane molecules, and the most preferential orientations of the framework molecules of the adsorbates relative to the planar graphite surface were determined.

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confidence: 65%

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confidence: 99%

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Yashkin

Svetlov²,

Murashov³

2010

Russ Chem Bull

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“…The isomers with the Me groups in the nodal positions (4 and 14) are characterized by the lowest TCA values among the isomers with the corresponding composition. The excep tion (see Table 2) is only a cis 1,3,4 trimethyladamantane molecule (16), which is evidently due to specific features of its spatial arrangement in the planar GTCB surface. The low adsorption potential of methyladamantane mole cules with nodal Me groups is probably related to the "cage effect" characteristic of the highly symmetric adamantane structure.…”

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confidence: 99%

Experimental and molecular statistical study of alkyladamantane adsorption on graphitized thermal carbon black

et al. 2008

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Experimental measurements and molecular statistics methods were used to calculate ther modynamic characteristics of adsorption (TCA) of alkyladamantanes of different structure on the surface of hydrogen treated graphitized thermal carbon black (GTCB) Carbopack C HT. High selectivity of separation of isomeric alkyladamantanes on GTCB is due to specific features of their geometry and electronic structure. The influence of the spatial structure of adsorbates on the TCA was established. Special attention was given to analysis of the heat capacities of adsorption. The best agreement between the experimental TCA and those calculated by the molecular statistics methods is achieved when the "cage effect" in the adamantane ring is taken into account. The corresponding corrections are introduced into the parameters of the atom atomic potential function of pair intermolecular interaction of the Me groups with the carbon atoms of the basal face of graphite, which are localized in the nodal positions of the lattice. The critical parameters for a large group of alkyladamantanes were calculated in terms of the addi tive group Lydersen method. A set of various topological indices used further for constructing structure-retention correlations on GTCB was obtained.At present the single natural source of adamantane and its alkyl derivatives is petroleum. 1-8 Alkyladamantanes of certain molecular weight are usually presented by mixtures of many isomers differed by both the structure of the alkyl group and the number and position of substituents in the adamantane skeleton. Isomeric alkyladamantanes often differ insignificantly from each other by physicochemical properties, which impedes their analysis and separation. There are a number of methods of isolating and concen trating alkyladamantanes such as thermodiffusion separa tion, formation of adducts with thiocarbamide, azeotropic distillation with steam or with tri(perfluorobutyl)amine. 2-4 A leading role belongs to preparative GLC followed by identification of isomers by high performance capil lary GLC on stationary phases (SP). 2,9-14 However, in spite of achieved success in studying the chromatographic behavior of this group of compounds under the GLC con ditions, a series of questions related to efficient separation and identification of some isomers with similar structure even in relatively narrow fractions remains unanswered so far. 2-5,10,12-14 The influence of specific features of the molecular structure of the adamantane framework on the chromato graphic behavior of adamantane derivatives under the con ditions of gas chromatography was studied by many au thors. It was found 15-19 by gas adsorption chromatogra phy (GAC) of adamantyl containing compounds on graphitized thermal carbon black (GTCB) that a possible reason for the different adsorption behavior of 1 and 2 functional adamantane derivatives is the "cage effect" in the adamantane system resulting in adsorption nonequiv alence of the substituents in the nodal and bridging posi tions of the adamantane framework. Analo...

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“…However, our results (see Table 2) indicate that although an increase in I with an increase in the stationary phase polarity is a characteristic feature of AdH it is observed also for bicyclic trans decalin and cis hydrindane mol ecules, and that contradicts the above mentioned as sumption. [12][13][14][15][16][17] The retention indices on OV 210 increase compared to the less polar phase OV 1, while the heats of sorption of all cyclic hydrocarbons on fluoromethylsiloxane de crease by 3-4 kJ mol -1 (see Table 1). …”

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Influence of the chemical nature of siloxanes on the thermodynamic characteristics of sorption for a series of linear and cyclic saturated hydrocarbons

Roshchina

Shepeleva

2005

Russ Chem Bull

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The thermodynamic characteristics of sorption (Henry´s constants of sorption equilibrium K sorp , heats of sorption q, and standard entropies of sorption ∆S°) were studied by gas chroma tography to describe the behavior of linear and cyclic saturated hydrocarbons on phenyl methylsiloxane HP 5, fluoromethylsiloxane OV 210, and methylsiloxane OV 1. The K sorp and q values and, correspondingly, the energy of dispersion interactions decrease in the series HP 5 > OV 1 > OV 210. The difference in structures of adamantane, trans decalin, and decane molecules has almost no effect on the heats of sorption. Henry´s constants increase on going from decane to trans decalin and, further, to adamantane. This effect becomes more pronounced with an increase in the sorbent polarity (OV 1 < HP 5 < OV 210). The entropy factor can play a key role in sorption processes on siloxanes.Siloxanes are used as stationary phases for gas chro matography. 1-4 The thermodynamic characteristics of sorption (TCS) in systems involving siloxanes are studied in few publications only.Linear alkanes are testing compounds commonly used for the quantitative estimation of the energy of dispersion interaction with the stationary phase (both liquid and solid). 1,5 Contributions of the specific interaction to the Gibbs energy and heat of sorption are determined on the basis of the sorption values of n alkanes. 6 Chromato graphic data for n alkanes are necessary to determine the Kovats retention indices and to calculate relative charac teristics of sorption in gas chromatography. 1 The latter is one of the main methods for determining linear and cy clic alkanes in various objects, including oil and petro leum refining products. 7, 8 The physicochemical properties of adamantane (AdH) and its derivatives, including sorption behavior, are in tensely studied due to the wide use of this class of com pounds in medicine, their potential biological activity, 9,10 and, especially, the unique features of the AdH struc ture. 7,11 The number of publications on the relations of the retention parameters of AdH and its derivatives to the stationary phase nature has substantially increased in re cent time. 12-17 Nevertheless, the retention parameters of AdH in a wide temperature range remain virtually un known and, hence, the TCS of these compounds were not determined.In this work, we used gas chromatography to study the influence of the chemical nature of siloxanes (methyl siloxane, phenylmethylsiloxane, and fluoromethylsil oxane) on the TCS (constants, heats, and standard entro pies) of several linear and cyclic alkanes. ExperimentalStationary phases were 5% phenylmethylsiloxane HP 5 -[Si(Ph) 2 -O-] n -[Si(Me) 2 -O-] m -(thickness of the grafted phase 0.25 µm; the density of the grafted phase was assumed to be ρ = 1 g mL -1 ), 2 fluoromethylsiloxane OV 210 -[(CF 3 (CH 2 ) 2 )Si(Me)-O-] n -with the 50% content of trifluoropropyl groups (10% on Chromaton NAW, Russia; particle size 0.16-0.25 mm), and methylsiloxane OV 1 -[Si(Me) 2 -O-] n -(10% on Gas Chrom Q, USA; particle s...

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Cited by 3 publications

References 2 publications

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Experimental and molecular statistical study of alkyladamantane adsorption on graphitized thermal carbon black

Influence of the chemical nature of siloxanes on the thermodynamic characteristics of sorption for a series of linear and cyclic saturated hydrocarbons

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