Gas chromatographic study of the thermal and analytical properties of a nematic luquid crystal and its cupric complex

Berdagué, Philippe; Perez, Felix; Courtieu, Jacques; Bayle, J. P.; Abdelhadi, Ousama M.; Guermouche, S.; Guermouche, M. H.

doi:10.1002/jhrc.1240180508

Cited by 26 publications

(9 citation statements)

References 15 publications

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“…The isomers considered (~-and flcedrenes, estragol-anethol, thymol-carvacrol) are separated on nematic A, B, and A + B. It is known that limonene and eucalyptol are well separated on polar columns such as Carbowax 20M, with limonene eluting more quickly [21], but are unresolved or partially resolved on apolar columns such as SE30 [1,22]. Good separation of these compounds was obtained on A, B, and A + B.…”

Section: 'O L's 2'0 2's ~Omentioning

confidence: 85%

Thermal properties and chromatographic behavior of a mixture of two liquid crystals

Boudah¹,

Sebih²,

Guermouche³

et al. 2003

Chromatographia

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Key WardsGas-liquid chromatography Liquid crystal mixtures as stationary phases Differential scanning calorimetry Aromatic hydrocarbons and phenols SummaryThe thermal and chromatographic properties of an equimolecular mixtu re of I',,vo liquid crystals have been investigated. Differential scanning calorimetry showed that the clearing temperature of the mixture is intermediate bel',,veen the corresponding temperatures for the individual liquid crystals. The melting temperature was lower than the corresponding temperatures for the separate liquid crystals. Polarizing microscopy showed that the liquid crystal phase of the mixture was nematic. The analytical performance of the mixed liquid crystal was investigated by use of different kinds of solute (aromatic hydrocarbons, polycychc hydrocarbons, phenols, volatile aroma compounds). It seemed that the behavior of the nematic mixture was the same as that of a pure nematic liquid crystal.When separations were performed with the mixture the more elongated isomer (para for positional isomers, trans for geometric isomers) was the most retained solute.

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Section: 'O L's 2'0 2's ~Omentioning

confidence: 85%

Thermal properties and chromatographic behavior of a mixture of two liquid crystals

Boudah¹,

Sebih²,

Guermouche³

et al. 2003

Chromatographia

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“…Influence of Lateral Alkoxy Chain Length on the GC Properties of Liquid Crystals Chromatographic behavior of the five liquid crystals is comparable in the separation of volatile aroma isomers (Table 3) [18,19]. The five liquid crystals completely separate the two compounds (see Table 3).…”

Section: Comparative Analytical Applications Of Aln Compoundsmentioning

confidence: 97%

Influence of the lateral alkoxy chain length on the gas chromatographic properties of five liquid crystals

Perez

Berdagué

Courtieu

et al. 1997

J. High Resol. Chromatogr.

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SummaryThe gas chromatographic properties of five laterally substituted liquid crystals are the subject of a comparative study. These liquid crystals belong to the homologous series: 2-alkoxy-3-methyl-4-(4-ethoxybenzoyl-oxy)-4'-(4-trans-n-pentylcyclohexanecarboxyloxy) azobenzene, referred to as ALn, where n , the carbon number in the lateral alkoxy chain, is equal to 4,6,8,10, or 12 carbon atoms. Their thermal properties were established by differential scanning calorimetry (DSC). It appears that the introduction of a lateral alkoxy chain affects the nematic temperature range which decreases when the carbon number increases. The chromatographic separation abilities of AL4, AL6, AL8, AL10, and AL12 were studied using capillary glass columns. The five liquid crystals are efficient before and after solid-nematic or nematic-liquid transitions; however, the plate numbers are higher in the nematic state. Interesting analytical properties were noted in various fields: isomeric separation of alkanes, aromatics, polyaromatics, volatile aroma compounds, and cis and trans isomers. However, the chain length does not exert any great influence on the separation abilities.

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“…Methods for the preparation of LCs and their utilisation as stationary phases in gas chromatography columns have been developed [8][9][10][11][12][13][14][15][16]. In his work, Benalia et al [12] compared the gas chromatographic behaviour of three monomeric LCs that have the same basic structure (1,3,4-oxadiazole ring) but have different substituents.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, nematic LC materials based on Schiff base core have attracted considerable interest due to their unique solvent properties and potential applications in gas chromatography [4,5,[8][9][10][11][12][13][14][15][16].…”

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Synthesis and powder X-ray diffraction of new Schiff-base liquid crystal

Ghanem

Al-Hariri

2013

Liquid Crystals Today

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Liquid crystals (LCs) are soft materials that combine the fluidity of disordered liquids and the long-range orientational or positional order of crystalline solids, along one or two directions of space. A search for better stationary phases, including highly selective ones, is an important trend in chromatography development. Among the stationary phases under investigation are LC stationary phases that have been recently generated much interest. A variety of isomeric molecules were separated with high accuracy. Successfully, X-ray scattering is widely used to investigate and characterise the microscopic structure of most LCs. In this paper, a new liquid crystalline material that can be used potentially as stationary phase in gas chromatography was synthesised and characterised by means of nuclear magnetic resonance (NMR), infrared (IR) spectra, elemental analysis and X-ray diffraction.Keywords: liquid crystalline; Schiff base; nematic; X-ray diffraction; gas chromatography Introduction Liquid crystals (LCs) or mesophases are intermediate states of condensed matter; they combine long-range positional or orientational order along some directions of space (like in a crystal) and liquid-like disorder along other directions [1]. The most commonly obtained liquid crystalline phases are those with organic molecules or in solutions of surfactants.Presently, LCs can be divided into two categories: thermotropic and lyotropic according to the principal means of destroying the order in the parent solid state, probably thermotropic LC is the most widely studied category. Thermotropic LCs are formed by varying the temperature of the compounds and can be further classified as nematic (N) and smectic (S m ) structures [2,3].Since 1974, a number of studies have been centred on liquid crystalline materials with anisotropic properties. In particular, nematic LC materials based on Schiff base core have attracted considerable interest due to their unique solvent properties and potential applications in gas chromatography [4,5,[8][9][10][11][12][13][14][15][16].Increasing attention has been focused on important pollutants and phenols introduced into the environment through the discharge of industrial waste and the decomposition of various pesticides and herbicides [5][6][7]. The determination of substituted phenol isomers by ordinary stationary phases presents some difficulties, since these isomers have similar boiling points and polarities.A stationary phase able to separate on a basis other than boiling point or polarity is essential. Several studies have centred on liquid crystalline

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Gas chromatographic study of the thermal and analytical properties of a nematic luquid crystal and its cupric complex

Cited by 26 publications

References 15 publications

Thermal properties and chromatographic behavior of a mixture of two liquid crystals

Thermal properties and chromatographic behavior of a mixture of two liquid crystals

Influence of the lateral alkoxy chain length on the gas chromatographic properties of five liquid crystals

Synthesis and powder X-ray diffraction of new Schiff-base liquid crystal

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