Inverse Gas Chromatography Method Research Articles

Investigation of the surface properties of dibutyl amine modified poly(styrene) based polymer by inverse gas chromatography method

In the present study, poly(vinyl benzyl chloride) (PVBC) was prepared by the radical polymerization method. Then, PVBC was reacted with dibutyl amine to obtain tertiary amine-modified poly(styrene) based polymer (PVBC-Dibutyl amine) and the resulting polymer was characterized. Surface properties of the polymer were investigated by inverse gas chromatography method at infinite dilution region. For this purpose, the retention diagrams of carefully selected polar and non-polar solvents (probes) on PVBC-Dibutyl amine were obtained over a temperature range from 30 to 50 $$^\circ{\rm C}$$ . By using the diagrams, the dispersive component of the surface free energy of the polymer surface was calculated for the studied temperatures by two different methods. The specific enthalpy of adsorption and the specific component of the adsorption free energy of solvents on PVBC-Dibutyl amine which are adsorption thermodynamic parameters were determined for each solvent used. Using the adsorption data, Lewis acid and Lewis base parameters of PVBC-Dibutyl amine surface were calculated. The obtained parameters reflected that surface of PVBC-Dibutyl amine exhibited a basic behavior. Considering the values in the literature, the effect of dibutyl amine moieties in the structure of poly(styrene) based polymer PVBC-Dibutyl amine on the dispersive surface free energy and acid–base parameters of poly(styrene) was discussed.

Design principles for synthesizing high grade activated carbons for adsorption heat pumps

This study presents a thermodynamic formulation to capture the relationship between the adsorption interaction energy and adsorbent-morphological properties, which can be further extended into surface coverage. Employing the inverse gas chromatography method, the adsorbate uptakes are measured in Henry's law region, from which the energetic behaviors of a single component adsorbate-adsorbent system are calculated in terms of enthalpy and entropy of the adsorbed phase in very low-pressure regions. A thermodynamic formulation is established between the specific entropy and Henry's law constant, including the pore volume of the adsorbents, and one can predict the isosteric heats and adsorbent's pore size for activated carbon + ethanol system by extending the proposed linear trend. These findings could significantly contribute towards tailoring the adsorbent materials for the design of an adsorption bed with a minimal or maximum driving force depending on the types of heat transformation applications.

Thermodynamic studies on tert-amine modified polystyrene based polymer/solvent systems by inverse gas chromatography method

In the present work, vinyl benzyl chloride (VBC) was polymerized by using free radical polymerization. The obtained PVBC was reacted with dibutyl amine to obtain tertiary amine modified polystyrene based polymer (PVBC-Dibutyl amine). The inverse gas chromatography (IGC) method was used to examine the thermodynamic properties of the polymer. Firstly, the retention diagrams of some polar and non-polar solvents on PVBC-Dibutyl amine were obtained over a temperature range from 135 to 160° C. Then, the thermodynamic parameters, including Flory–Huggins interaction parameter, weight fraction activity coefficient, partial molar heat of sorption, and partial molar heat of mixing were determined via interactions between the polymer and selected solvents at infinite dilution. The results reveal that the alkanes are poor solvents for the polymer whereas n-butyl acetate, i-butyl acetate, ethyl acetate, n-propylbenzene, i-propylbenzene, and ethylbenzene are moderately solvents in the studied temperature range.

Clarification on "Critical Comments on 'Assessment of the Thermodynamic Properties of DL-p-Mentha-1,8-diene, 4-isopropyl-1-methylcyclohexene (DL-Limonene) by Inverse Gas Chromatography (IGC)'".

A clarification is given regarding recent polemic over our original published study. The author of this polemic has claimed a few issues about the computations and data listed in our work such as choosing the wrong temperature unit and the incorrect calculation of molar heat of vaporization. Here it is elaborated the complete data and computations that are not included in the original paper, and list out also the parameters, which may be the source of difference in reported molar heat of vaporization through inverse gas chromatography methods and other conventional methods. It is showed that there are no wrong calculations or reports of molar heat of vaporization in our published paper.

Examining the surface properties of waste printed circuit boards rejects using inverse gas chromatography

Flotation is a physicochemical process utilizing the difference in surface properties of particles for their separation. One of the common methods to study the surface properties of the particle is by using Inverse gas chromatography (IGC). It can be used to estimate the surface energies, surface energy heterogeneity, work of adhesion, and index of hydrophilicity of a given sample, thus predicting their flotation behavior.This paper utilizes the IGC method to determine the surface energy heterogeneity of waste printed circuit boards (PCB) rejects, also known as the nonmetal fraction (NMF). The test was performed to observe if any differences exist in the surface energy of NMF particles that might provide preliminary information regarding their response to flotation. The results showed that the distribution of surface energies is narrow and reached a plateau by 10% surface coverage. It suggests that approximately 10% of all the available particle surfaces have relatively higher surface energy compared to other particles that would report to the tailings (remain in water) if subjected to flotation without any reagent and further grinding.

Development of Abraham model correlations for short-chain glycol-grafted imidazolium and pyridinium ionic liquids from inverse gas-chromatographic measurements

Infinite dilution activity coefficients and gas-to-liquid partition coefficients are herein reported for more than 45 organic solutes of varying polarity and hydrogen-bonding character dissolved within the ether-grafted ionic liquids 1-ethyl-3-(2-methoxyethyl)imidazolium bis(trifluoromethylsulfonyl)imide and N-(2-methoxyethyl)pyridinium bis(trifluoromethylsulfonyl)imide. Experimental values were determined in 10 K intervals from 323.15 to 373.15 K using the method of inverse gas chromatography. Measured infinite dilution activity coefficients were then used to determine the partial molar excess Gibbs free energies, enthalpies, and entropies associated with the dissolution of these model solutes into these two short-chain glycol-grafted ionic liquids. Finally, based on the measured infinite dilution activity coefficient data, Abraham model correlations have been established for solute transfer into these ionic liquids, including the calculation of cation-specific equation coefficients. The derived Abraham model correlations were found to back-calculate the observed partition coefficients to within 0.09 to 0.13 log units.

Adsorption of Phenol and Chlorophenols by HDTMA Modified Halloysite Nanotubes.

The adsorption of phenol, 2-, 3-, 4-chlorophenol, 2-, 4-dichlorophenol and 2-, 4-, 6-trichloro-phenol on halloysite nanotubes modified with hexadecyltrimethylammonium bromide (HDTMA/halloysite nanocomposite) was investigated in this work by inverse liquid chromatography methods. Morphological and structural changes of the HDTMA/halloysite nanocomposite were characterized by scanning and transmission electron microscopy (SEM, TEM), Fourier-transform infrared spectrometry (FT-IR) and the low-temperature nitrogen adsorption method. Specific surface energy heterogeneity profiles and acid base properties of halloysite and HDTMA/halloysite nanocomposite have been determined with the inverse gas chromatography method. Inverse liquid chromatography methods: the Peak Division and the Breakthrough Curves Methods were used in adsorption experiments to determine adsorption parameters. The obtained experimental adsorption data were well represented by the Langmuir multi-center adsorption model.

Characterization of the solubilizing ability of short-chained glycol-grafted ammonium and phosphonium ionic liquids

Abstract Infinite dilution activity coefficients and gas-to-liquid partition coefficients are reported for >40 organic solvents dissolved in (2-methoxyethyl) triethylphosphonium bis(trifluoromethylsulfonyl)imide, (2-methoxyethyl)tributylphosphonium bis(trifluoromethylsulfonyl)imide, and (2-methoxyethyl)triethylammonium bis(trifluoromethylsulfonyl)imide in the temperature range from 323.15 K to 373.15 K. Experimental values were determined using the method of inverse gas chromatography. Measured infinite dilution activity coefficients are used to calculate the partial molar excess Gibbs free energy, enthalpy and entropy associated with dissolution of the organic solutes into the three ionic liquid solvents. Abraham model correlations for solute transfer into each ionic liquid solvent have also been determined from the measured infinite dilution activity coefficient data.

Solubility and Surface Thermodynamics of Conducting Polymers by Inverse Gas Chromatography, IV: Polypyrrole/Titanium Oxide

A wealth of physico-chemical information has been obtained on an insoluble and crystalline polypyrrole/titanium oxide (PPY/TiO2) using the Inverse Gas Chromatography Method (IGC). Twenty-five solvents (test compounds) with different specific interactions were used. PPY/TiO2 was synthesized and characterized by FTIR and DSC methods. The following characteristics of PPY/TiO2 were explored: changes in morphology, the strength of solvent–PPy/TiO2 interactions, dispersive surface energy, percent crystallinity, solvents and PPy/TiO2 solubility parameters, and molar heat of sorption, mixing and evaporation ($$\Delta H_{1}^{s}$$, $$\Delta H_{1}^{\infty }$$, $$\Delta H_{1}^{v}$$). Interaction parameters were corrected to be free from the solvents’ chemical nature. Nonane, propyl acetate, and methyl ethyl ketone showed stronger interactions and a higher affinity to PPy/TiO2; yet, none of these solvents can dissolve PPy/TiO2. IGC showed that PPy/TiO2 has 59.34 mJ/m2 dispersive surface energy at 100 °C and 98% crystalline at 60 °C. Comprehensive solvents and PPy/TiO2 solubility parameters were obtained and comparted with that of soluble and insoluble polymers. Inverse Gas Chromatography (IGC) along with DSC and FTIR methods investigated the morphology, surface energy, degree of crystallinity and the thermodynamics of conducting polypyrrole/TiO2. The solubility parameters were calculated for 27 solvents.

Is Inverse Gas Chromatography (IGC) a Convenient Method to Determine Compatibility of Rubber Materials?

Compatibility is a key factor in formulation of polymeric compounds. Having sufficient data about solubility of components may help to create novel engineered materials. Solubility parameter has been used as a tool for predicting the compatibility of materials. In this study, the solubility parameter of natural rubber and styrene–butadiene rubber is determined through inverse gas chromatography. The 3D solubility parameter sphere for each rubber has been depicted using three components of the Hansen solubility parameter. In addition, the reliability of the procedure has been confirmed through scanning electron microscope (SEM) micrographs and Fourier-transform infrared spectroscopy (FTIR-ATR) spectra of samples. Results demonstrate NR and SBR solubility parameters to be 23.58 and 21.98 (J/cm3)0.5 at room temperature. Also, this study aimed to verify if the inverse gas chromatography method is a reliable method to be used in polymer industries as a prediction tool before compounding. Finally, results confirmed that inverse gas chromatography is a promising method in the field of rubbers.

Measuring the specific surface area (SSA) of freeze-dried biologics using inverse gas chromatography

The specific surface area (SSA) of freeze-dried biologics (FD) is usually measured via a Brunauer–Emmett–Teller (BET) analysis of volumetric nitrogen adsorption isotherms. However, this technique has accuracy limitations for materials <0.5 m2/g, requires dry samples, must be measured at 77 K and has slow sample preparation times (drying/degassing). Inverse gas chromatography (IGC) is chromatographic characterization technique which can be used to analyse the SSA (down to ≈0.1 m2/g) of various solid-state materials including powders using organic molecules such as octane at ambient temperatures/pressure for a range of relative humidities. This study presents a comprehensive comparison between the N2 BET adsorption versus octane BET adsorption using IGC methods for determining the SSA’s for a range of freeze dried biological materials. These include IgG 5% w/w, an influenza antigen standard, sucrose 5% w/w and trehalose 5% w/w. IGC provided comparable SSA values to the N2 BET method with better reproducibility (lower RSDs %). Large variations in average SSA within manufactured FD batches were observed for both IGC and volumetric determinations. IGC was also used to measure the change in SSA with increasing humidity, with FD cakes shrinking and losing their structural integrity with increasing moisture content. Such information highlights the importance of moisture content in determining the physical stability of FD cakes as exemplified by their SSA. In conclusion, IGC is a suitable alternative method for determining the SSA of freeze-dried biological materials which are generally strongly dependent on their moisture content.

Investigation of the Specific Retention Volume of the Probe Volume and the Effects on the Polymer-Probe System by Inverse Gas Chromatography

In this study, the effects of probe quantities on retention volume and the physical and thermodynamic results of polymer-probe systems were investigated. For this purpose, by using inverse gas chromatographic method. Alcohols and alkanes with different chemical and physical properties were injected as probes on homopolymer (2-cyclohexylidene-1,3-dioxolane-4-yl-methyl methacrylate) (CHMMA). Probe quantities of 0.3, 0.6, and 0.9 μl were selected, and an injection was made at every 10°C between 40 and 150°C. In addition, 3 μl volume probes were tried but reproducible results were not obtained in these volumes and the detector was observed to be out of order after several injections. It has been observed that the specific retention volume of alcohols and alkanes partially increased by increasing the injection amount. A linear relationship was observed between probe quantities and specific retention volume. This linear relationship is apparent from the specific retention volume values, where the probes are independent of the physical and chemical structures. It was observed that the results obtained in all three injections were close to each other and within acceptable limits. The glass transition temperature of the polymer was determined to be a Tg of 60°C. The thermodynamic data calculated for the injection of different amounts of probes were close to each other.

Solubility Parameter of Ionic Liquids: A Comparative Study of Inverse Gas Chromatography and Hansen Solubility Sphere

The solubility parameters of four ionic liquids (ILs), 1-ethyl-3-methylimidazolium methyl sulfate ([EMIM][MeSO4]), 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO4]), 1-hexyl-3-methylimidazolium methyl sulfate ([HMIM][MeSO4]), and 1-octyl-3-methylimidazolium methyl sulfate ([OMIM][MeSO4]), were estimated using two complementary methods. The first is an inverse gas chromatography (IGC) method, which determined the Hildebrand solubility parameters of four ILs based on a series of formulaic calculations. The second is the Hansen solubility sphere method, which determined the Hansen solubility parameters (HSPs) of the four ILs based on solubility testing of four ILs in 30 pure solvents. The results showed that the Hansen solubility sphere method provides higher values of the solubility parameters, while the IGC method presents lower values. In addition, the miscibilities of ILs in various solvents were evaluated by the method of IGC, and the results exhibit good agreement with those derived from the Hansen solubility sphere method. It is confirmed that the IGC and Hansen solubility sphere methods can be used to determine the solubility parameters of the ILs and were useful for solvent selection.

Intermolecular interactions between polyarylenephthalides surface and organic compounds of different nature by inverse gas chromatography data

Polyarylenephthalides are a promising class of polymeric materials. They are soluble in organic solvents, but remain resistant to water, as well as to acids and bases. All this makes polyarylenphthalide promising materials for the formation of films on surfaces. However, for this it is necessary to first study the ability of polyarylenephthalides to different intermolecular interactions, as well as the polarity of their surface.Therefore, it is of interest to use the inverse gas chromatography method for studying the adsorption properties of the surface of polyarylenephthalates, as well as the evaluation of its conditional polarity. Two polymers of the class of polyarylenephthalides were used as the studied samples: chlorinated (in position 4) poly phthalidylidenefluorene) (OPS-236) and poly (phthalidylidene diphenyl) (PE-259). They are distinguished by the presence of a methylene group between two benzene rings. Inert solid support Chromaton NAW was used as a solid substrate for the deposition of polyarylenphthalide films. The application was carried out from chloroform by evaporation of the solvent at a temperature of 40 ° C. The amount of the applied polymer was 1% by weight of the inert carrier. The study was conducted by the method of inverse gas chromatography. Samples were introduced as diluted vapor-air mixtures at the limit of the detector sensitivity. This made it possible to measure the retention parameters in the Henry region and consider the interactions between sorbate molecules to be negligible. The relative conditional polarity of the surface and the contributions of various intermolecular interactionsto adsorption free energy were estimated by the method of linear free energy relationship (LFER). From the obtained LFER-coefficients, the contributions of intermolecular interactions to the adsorption energy were calculated, and the relative conditional polarity of the surface was also estimated. The dispersion and specific component of the Helmholtz free energy of adsorption was calculated by the Dong method. It has been established that adsorbents based on polyarylenephthalides are able to act as stationary phases for chromatography. It is shown that polyarylenephthalide films are capable of both dispersion and various specific interactions with organic molecules. The surface of polyarylenephthalides can be attributed to stationary phases of medium polarity, more polar than porous polymers based on styrene and divinylbenzene and less polar than silica gels.

Practical Determination of the Solubility Parameters of 1-Alkyl-3-methylimidazolium Bromide ([CnC₁im]Br, n = 5, 6, 7, 8) Ionic Liquids by Inverse Gas Chromatography and the Hansen Solubility Parameter.

The physicochemical properties of four 1-alkyl-3-methylimidazolium bromide ([CnC1im]Br, n = 5, 6, 7, 8) ionic liquids (ILs) were investigated in this work by using inverse gas chromatography (IGC) from 303.15 K to 343.15 K. Twenty-eight organic solvents were used to obtain the physicochemical properties between each IL and solvent via the IGC method, including the specific retention volume and the Flory–Huggins interaction parameter. The Hildebrand solubility parameters of the four [CnC1im]Br ILs were determined by linear extrapolation to be = 25.78 (J·cm−3)0.5, = 25.38 (J·cm−3)0.5, =24.78 (J·cm−3)0.5 and = 24.23 (J·cm−3)0.5 at room temperature (298.15 K). At the same time, the Hansen solubility parameters of the four [CnC1im]Br ILs were simulated by using the Hansen Solubility Parameter in Practice (HSPiP) at room temperature (298.15 K). The results were as follows: = 25.86 (J·cm−3)0.5, = 25.39 (J·cm−3)0.5, = 24.81 (J·cm−3)0.5 and = 24.33 (J·cm−3)0.5. These values were slightly higher than those obtained by the IGC method, but they only exhibited small errors, covering a range of 0.01 to 0.1 (J·cm−3)0.5. In addition, the miscibility between the IL and the probe was evaluated by IGC, and it exhibited a basic agreement with the HSPiP. This study confirms that the combination of the two methods can accurately calculate solubility parameters and select solvents.

Surface Properties of Magnesium-Aluminium Hydrotalcite-Like Compound Characterized by Inverse Gas Chromatography

In this paper, the Mg-Al hydrotalcite-like compound (Mg-Al-HTLC) was synthesized by hydrothermal method at 373K. Structure and morphology of Mg-Al-HTLC was obtained with X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infra-red spectroscopy(FTIR). A series of polar and non-polar molecules were used for probes, surface properties of Mg-Al-HTLC was studied by inverse gas chromatography (IGC) at 353K, 363K, 373K, 383K respectively. The retention volume was utilized for evaluating the free energy of adsorption (-ΔGSP), the dispersive component of the surface energy(γsD), as well as the enthalpy and entropic component(ΔHSP, -ΔSSP). XRD results reveal that the Mg-Al-HTLC has high crystallinity and perfect layered structure. The results of IGC show that Mg-Al-HTLC would adsorb straight-chain alkanes spontaneously, and the values of γsDwere similar at all temperature. It reveals Mg-Al-HTLC is a material with particular characteristics of both acid and base. This study illustrates that, as a method to evaluate the surface properties of material , IGC method is dependable and significant.

Thermodynamic Characterization of Surface and Solubility of 5-((S)-3,7-Dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol Liquid Crystal with Some Solvents

The inverse gas chromatography method was used to obtain dispersive surface energy, surface acidity or basicity constants, mole fraction activity coefficients of the solvents at infinite dilution f...

Determination of glass transition temperature and surface properties of novel chalcone modified poly (styrene) based polymer

The novel chalcone modified poly (styrene) based polymer (PVBC-DMAC) has been prepared and characterized. By using the inverse gas chromatography method, we determined glass transition temperature and surface properties of PVBC-DMAC. The obtained glass transition temperature, Tg, is a good agree with the one obtained by differential scanning calorimetry. Also considering some isomeric alcohol and acetate solvents in the temperature range from 303.2 K to 353.2 K, we investigated the polymer selectivity. The parameters KA(acidic) and KD(basic) of the PVBC-DMAC surface were calculated. The obtained KA, KD values reflected that PVBC-DMAC surface has a basic character.

Characterization of Environmentally Friendly Polymers by Inverse Gas Chromatography: II, Poly(3-hydroxybutyric acid)

The surface thermodynamics of poly(3-hydroxybutyric acid) (PHBA) as a biodegradable polymer, was characterized using the inverse gas chromatography method. Gel permeation chromatography and differential scanning calorimetry method was also used to measure the molar mass, polydispersity, glass and melting temperatures. Twenty-seven solutes (solvents) with different families having a variety of chemical natures were used to measure the strength of the interaction forces of these solutes with PHBA. All these solutes showed an endothermic interactions which varied from one family to another. All families showed a chemical dependence on the interaction coefficients, a successful correction was used to eliminate the chemical dependence which resulted in exothermic interactions. Retention diagrams of all solvents showed no crystallinity occurred at the temperature range used. The molar heat of sorption of all solutes was measured from the retention diagrams ranged from − 19.41 for acetone to − 90.38 kJ/mol for cyclohexane. The dispersive component of the surface energy of PHBA was measured using alkanes which ranged from 24.42 mJ/m2 at 80 °C to 13.94 mJ/m2 at 120 °C. The decrease in surface energy attributed to the weakening of the surface at a higher temperature due to the melt and expansion of the surface.

Investigation of thermodynamic properties of 4-decyloxybiphenyl-4′-carboxylic acid liquid crystal and preparation of polymer dispersed liquid crystal composite

In this study, firstly, retention behavior of solvents on the liquid crystalline material 4-decyloxybiphenyl-4′-carboxylic acid (DBCA) has been studied by inverse gas chromatography (IGC) technique. Liquid crystal (LC) selectivity was investigated using the acetate isomers by the IGC method at temperatures between 333.2 K and 543.2 K. Later on, the interactions of LC with n-octane, n-nonane, n-decane, undecane, dodecane, tridecane, n-propyl benzene, isopropyl benzene, ethylbenzene, chlorobenzene and toluene between 518.2 K and 543.2 K were examined. LC-solvent interaction parameters for Flory-Huggins theory, χ12∞, and equation of state theory, χ12∗, effective exchange energy parameters, Xeff, the weight fraction activity coefficent, Ω1∞, the partial molar heat of mixing at infinite dilution of the solvent, ∆H1∞, molar heat of vaporization of solvent, ∆HV and the partial molar heat of sorption of the solvent, ∆H1, s were obtained.Secondly, polymer dispersed liquid crystal (PDLC) composite film in composition 20/80 poly(methyl methacrylate) (PMMA):DBCA by weight was synthesized by solvent-induced phase separation method. The mesomorphic behavior of DBCA and PDLC composite has been investigated by differential scanning calorimetry (DSC) and optical polarizing microscopy (PM).