The thermodynamic characteristics of adsorption and retention of adamantane derivatives on graphitized carbon black under the conditions of gas-adsorption chromatography

Yashkin, S. N.; Novoselova, O. V.; Svetlov, D. A.

doi:10.1134/s0036024408050270

Cited by 5 publications

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“…The Δ( -S°1 ,C ) s (theor) values calculated by formula (5) in terms of the dimeric ideal gas model for many various methyladamantanes are listed in Table 3 values decreases monotonically with an increase in the molecular weight. We have earlier 40 shown that simi lar regularity in the series of mono , di , and trisubstitut ed adamantane derivatives can indicate that the cen ter of gravity of the adsorbed molecule shifts in fact to the most substituted cyclohexane ring, which directly con tacts with the planar adsorbent surface. The difference between the theoretical and experimental Δ( -S°1 ,C ) s val ues for the molecules with the most favorable arrangement of substituents relative to the planar surface (4, 6, 7, 14, and 17) is noticeably smaller than that for other com pounds considered, which is well consistent with the above conclusions drawn on the basis of the dependence of the Δ -C s 1,p values on the molecular structure of methyl adamantanes.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

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

et al. 2008

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“…It was found that that the adsorption potential markedly depended on the cyclohexane fragment (Yashkin et al, 2008).…”

Section: Other Applicationsmentioning

confidence: 99%

Carbon‐based sorbents in chromatography. New achievements

Cserháti

2009

Biomedical Chromatography

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The newest results in the employment of carbon-based composites in various chromatographic techniques such as gas-liquid chromatography, high-performance liquid chromatography and electrically driven separation techniques for the separation, quantitative determination and identification of a wide variety of compounds in complicated matrices are compiled. The results are concisely described and critically evaluated. The future trends in the application of carbon-based compounds in the chromatographic separation methods are briefly discussed.

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Molecular size and shape properties of diamondoid molecules occurring in crude oil

Jiménez-Cruz

García-Gutiérrez

2020

Arabian Journal of Chemistry

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The thermodynamic characteristics of adsorption and retention of adamantane derivatives on graphitized carbon black under the conditions of gas-adsorption chromatography

Cited by 5 publications

References 2 publications

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

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

Carbon‐based sorbents in chromatography. New achievements

Molecular size and shape properties of diamondoid molecules occurring in crude oil

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