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  • 1
    Electronic Resource
    Electronic Resource
    Determination of thermodynamic functions of sorption for cyclohexyl-, piperidyl-, morpholyl-, and thiomorpholyl-n-alkanes by capillary gas-liquid chromatography (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 1925-1927 
    Details
    ISSN: 1573-9171
    Keywords: capillary gas-liquid chromatography ; N-alkyl-substituted piperidines ; morpholines and thiomorpholines ; cyclohexyl-n-alkanes ; partial molar free energy ; enthalpy and entropy of sorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The values of partial molar free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of sorption in the homologous series ofN-alkylpiperidines,N-alkylmorpholines,N-alkyl thiomorpholines, and alkylcyclohexanes were determined. It was found that the free energy of sorption is determined to a greater extent by the enthalpy term than by the entropy one. The free energy of sorption of the first homolog decreases when then-alkyl chain is attached directly to the carbon atom of the cycle and increases in the case ofN-alkylsubstituted heterocycles. The influence of the heteroatom nature on intermolecular interactions of homologs with the nonpolar stationary phase was quantitatively estimated on the basis of thermodynamic data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01457778
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  • 2
    Electronic Resource
    Electronic Resource
    Thermodynamic characteristics of sorption of heterocyclic compounds m capillary gas chromatography (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 1928-1933 
    Details
    ISSN: 1573-9171
    Keywords: capillary gas chromatography ; thermodynamic characteristics of sorption ; heterocyclic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dependences of sorption energies of sulfur-, oxygen-, and nitrogen-containing heterocyclic compounds on the nature of heteroatoms, structure of substituents and their position in the ring were studied. The contributions of heteroatoms, functional and alkyl groups to the energy of dispersive interaction of position isomers with nonpolar stationary phases were determined for imidazoles, piperidines, morpholines, thiomorpholines, dioxalanes, oxathiolanes, dithiolanes, thiophenes, and furans. The nonequivalence of contributions of the same substituents to the sorption energy of each of the heterocyclic compounds, depending on the nature of the heteroatom and position of the substituent, was shown. The obtained values of contributions of heteroatoms and substituents can be used for apriori calculation of retention indices of position isomers of five- and six-membered heterocycles containing one or two heteroatoms in the ring.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01457779
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  • 3
    Electronic Resource
    Electronic Resource
    Sorption characteristics ofN-alkylimidazoles under conditions of capillary chromatography (1995)
    Springer
    Russian chemical bulletin 44 (1995), S. 300-304 
    Details
    ISSN: 1573-9171
    Keywords: capillary gas chromatography ; homologous series ; alkyl substitutedN-alkylimidazoles ; retention indices ; equations ; contributions of alkyl groups at the C and N atoms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The retention indices forN-n-alkyl (C1-C5) substituted imidazoles with Me, Et, Pr, and Bu groups in different positions of the cycle were determined. Two capillary columns with OV-101/KF and PEG-40M/KF were used. The two nitrogen atoms of the imidazole molecule were shown to have different effects on the contributions of the alkyl groups to the retention indices. The maximum and minimum contributions are observed for the substituents at the 5 and 4 positions of the imidazole cycle, respectively. An increase in a size of the C m H2m+1 substituent attached to the N(1) atom has a notable effect only on the contributions of the alkyl groups at the 2 and 5 positions. The retention indices values for a homologous series with ann-alkyl group attached to the N or C(2) atom were described by a universal type equation. The obtained equations can be used for predicting the retention indices of new homologs and identification ofN-alkylimidazoles in complex mixtures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702140
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  • 4
    Electronic Resource
    Electronic Resource
    Possibility of using Kovac indices in gas-chromatographic analysis on polar phases (1967)
    Springer
    Russian chemical bulletin 16 (1967), S. 176-177 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. Kovac indices can be used to characterize the gas-Chromatographic behavior of substances on the highly polar phase β,β'-oxydipropionitrile. 2. The size of the sample of the calibrating hydrocarbons must be equivalent to 0.002–0.007 μ1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00907126
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  • 5
    Electronic Resource
    Electronic Resource
    The influence of an alkaline treatment of the carrier on residence times in gas chromatography (1967)
    Springer
    Russian chemical bulletin 16 (1967), S. 2038-2039 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The treatment of a carrier with an alkali increases the “polarity” of the stationary phase. 2. The hypothesis has been put forward that there is donor-acceptor interaction — in particular, the formation of hydrogen bonds — both with the substance undergoing analysis and with the liquid phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00909617
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of base treatment of the support on the temperature dependence of retention indices of organic bases (1968)
    Springer
    Russian chemical bulletin 17 (1968), S. 656-657 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The temperature dependence of the values of the retention indices for n-amyl-, isoamyl-, dipropyl-, and triethylamines, piperidine, and pyridine on a column of 10% Apiezon-L and 5% NaOH suspended on “Novator” detergent was studied. 2. The obtained data confirm the hypothesis voiced earlier about the donor-acceptor interaction of primary and secondary amines with base suspended on the surface of the absorbent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00911637
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  • 7
    Electronic Resource
    Electronic Resource
    The quantitative proportion of amines in the volatile substances from sturgeon grain and salmon roe, dutch and russian cheeses (1968)
    Springer
    Russian chemical bulletin 17 (1968), S. 888-890 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. A large number of organic bases in the volatile components of natural food products which contain protein of animal origin were detected for the first time by gas Chromatographic analysis. 2. The quantitative analysis of the organic bases in the volatile components of Russian and Dutch cheeses and grain and salmon roes by gas chromatography is presented. 3. The qualitative composition of the organic bases in the food products we studied is rather similar; the specificity of the product appears in the quantitative ratio of the components. 4. A proposal was made on the basis of the data we obtained that alkylation reactions participate in the formation of the secondary and tertiary amines which are present in the aromatic constituents of the food products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00905780
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  • 8
    Electronic Resource
    Electronic Resource
    Quantitative gas chromatographic determination of the heterocyclic bases in the odor of Russian cheese (1969)
    Springer
    Russian chemical bulletin 18 (1969), S. 2407-2409 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The change during storage of the qualitative composition and of the quantitative proportion of the amines in the volatile components of Russian cheese manufactured in the springtime was studied by GLC. 2. The qualitative composition of the amines changes insignificantly during storage, however, a sharp increase in the contents of some of the nitrogenous bases, especially piperidine and α-picoline, takes place. 3. The piperidine, α-picoline, pyridine, and triethylamine concentration in the odor of four-and 10-month-old cheese was determined by an absolute calibration method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00906522
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