Search results for "inverse gas chromatography"
showing 8 items of 8 documents
Thermodynamic Interaction Parameters of Tetra-n-undecylcalix[4]resorcinarenes with Selected Solvents Studied by Inverse Gas Chromatography
2004
The basic thermodynamic parameters, characterising intermolecular interactions of tetra-n-undecylcalix[4]resorcinarene and its octaacetate derivative with simple organic solutes, were calculated by using the inverse gas chromatography method. Free energy, enthalpy and entropy of sorption were determined.
1,3,5-triisopropylbenzene diffusion in polystyrene solutions
1996
Self-diffusion coefficients of 1,3,5-triisopropylbenzene (TIB) in binary solutions with polystyrene and ternary mixtures comprised of TIB, toluene, and polystyrene have been measured by static gradient nuclear magnetic resonance (SG-NMR) techniques. These data, as well as mutual-diffusion coefficient data measured by capillary column inverse gas chromatography (CCIGC), have been analyzed here with the Vrentas-Duda free-volume diffusion model. Although both binary and ternary diffusion coefficient data can be accurately correlated with the model, the results contradict those of an earlier investigation, which suggested that TIB diffuses as a single unit in polystyrene solutions. The new data…
Inverse gas chromatography study of acid-base properties of cation resin used as catalysts of Bisphenol A synthesis
2001
The inverse gas chromatography method have been used for estimation of relative number of acid and base active centres for two type cation exchangers that are used as catalysts of Bisphenol A industrial synthesis. It was stated that after a few weeks of the continuous work of reactors filled with the catalysts, the acid-base properties of the latter have undergone significant changes. The number of acid centres decreased while the number of base centres increased. Simultaneously, the decreased of the yield of the synthesis product was observed.
Badanie właściwości inkluzyjnych p-tert-butylokaliksarenów metodą inwersyjnej chromatografii gazowej
2007
Metodą QSRR scharakteryzowano właściwości inkluzyjne p-tert-butylokaliksarenów o 4, 6 i 8 merach w cyklu oraz ich octanów, wykorzystując do tego celu inwersyjną chromatografię gazową. W badaniach zastosowano przy tym dwa szeregi homologiczne solutów - alkohole alifatyczne oraz benzen i jego homologi. Stwierdzono, że zdolności inkluzyjne w znacznym stopniu zależą od wymiarów luki molekularnej cyklomeru. Zamiana w kaliksarenach grup wodorotlenowych na octanowe nie wywiera natomiast istotnego wpływu na możliwości tworzenia kompleksów typu gość-gospodarz. Wyniki uzyskane metodą QSRR potwierdzono wyznaczonymi wartościami indeksów Kovátsa.
Badanie metodą inwersyjnej chromatografii gazowej wpływu wielkości podstawnika na właściwości inkluzyjne kaliksarenów
2009
Badano wpływ wielkości alifatycznego podstawnika na zdolności inkluzyjne kaliksarenów {kaliks[4]arenu(K4), p-izopropylokaliks[4]arenu (IPK4) i p-tert-butylokaliks[4]arenu (TBK4)}. Oceny wpływu dokonywano za pomocą metody QSRR przy użyciu inwersyjnej chromatografii gazowej. W charakterze solutów użyto szeregu alifatycznych alkoholi, homologów benzenu i homologów pirydyny. Na podstawie indeksów retencji Kovatsa i wykresów zależności właściwej objętości retencji od temperatury wrzenia [Vg=f(Tw)] stwierdzono, że tylko podstawione kaliksareny wykazują właściwości inkluzyjne w stosunku do niższych alkoholi.
On what terms and why the thermodynamic properties of polymer solutions depend on chain length up to the melt
2003
Theoretical considerations based on chain connectivity and conformational variability of polymers have lead to an uncomplicated relation for the dependence of the Flory-Huggins interaction parameter, chi, on the volume fraction of the polymer, phi, and on its number of segments, N. The validity of this expression is being tested extensively by means of vapor pressure measurements and inverse gas chromatography (complemented by osmotic and light scattering data from literature) for solutions of poly(dimethylsiloxane) in the thermodynamically vastly different solvents n-octane (n-C8), toluene (TL), and methylethylketone (MEK) over the entire range of composition for at least six different mol…
1984
By means of data from critical demixing and vapour pressure measurements and by inverse gas chromatography, including the results of published light scattering measurments, a consistent picture is obtained for the entire dependence of the Flory-Huggins parameter χ on the weight fraction w2 of the polymer and on the temperature T for the system tert-butyl acetate/polystyrene. Within the entire T-range (ca. 0°C – 140°C), χ increases stronger than exponentially with w2, the rise being the larger the larger χH (the enthalpy contribution to χ) becomes in the limit of infinite dilution. At sufficiently high temperatures (≳ 50°C), χH changes its sign from negative to positive as w2 is raised. This…
Thermodynamic Interaction Parameters of Tetra-n-undecylcalix[4]resorcinarenes with Selected Solvents Studied by Inverse Gas Chromatography
2004
The basic thermodynamic parameters, characterising intermolecular interactions of tetra-n-undecylcalix[4]resorcinarene and its octaacetate derivative with simple organic solutes, were calculated by using the inverse gas chromatography method. Free energy, enthalpy and entropy of sorption were determined.