Dielectric relaxation study of amines in 2,3-butanediol mixture using picosecond time domain reflectometry technique

Swami, M. B.; Pawar, V.P.; Hudge, P. G.; Kumbharkhane, A.C.

doi:10.1016/j.molliq.2013.11.012

Cited by 6 publications

(5 citation statements)

References 20 publications

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“…As previously proposed [33], solvents such as methanol or ethanol, which possess dielectric constants (e) 32.6 and 24.3, respectively, may favour the extraction of polyphenols, such as anthocyanins. Glycerol and butanediol have dielectric constants of 42.5 [34] and 21.26 [35], respectively, and could greatly enhance the extraction of the polyphenols occurring in APP, which are otherwise sparingly soluble in water. Based on the e values reported above, 50 % (v/v) butanediol and 50 % (v/v) ethanol would be expected to display similar behaviour, hence the almost identical Y TP(s) determined.…”

Section: Extraction Kineticsmentioning

confidence: 99%

A Comparative Evaluation of Bio-solvents for the Efficient Extraction of Polyphenolic Phytochemicals: Apple Waste Peels as a Case Study

Blidi

Bikaki

Grigorakis

et al. 2015

Waste Biomass Valor

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Apple peels were used as a model solid matrix for the comparative evaluation of aqueous mixtures of three biosolvents, including ethanol, 2,3-butanediol (butanediol) and glycerol, with regard to polyphenol recovery. The evaluation process was based on a step-by-step optimisation of the extraction, taking into consideration basic factors, including solvent composition, liquid-to-solid ratio and temperature. A further detailed description of the extraction capacity of each solvent was carried out using kinetics. Optimal solvent concentrations were 50 % (v/v), 50 % (v/v) and 70 % (w/v) for ethanol, butanediol and glycerol, respectively, while optimal liquid-to-solid ratio and temperature were 100 mL g -1 and 80°C for all solvents tested. The kinetic assay showed that extraction yields in total polyphenols obtained with these solvent systems displayed no statistical difference, although the overall extraction rate constant and diffusion coefficient were significantly higher for the extraction performed with 50 % (v/v) butanediol. The liquid chromatography-mass spectrometry examination of the extracts obtained under optimised conditions revealed that their polyphenolic profile was composed, in total, of 12 principal substances, but some qualitative differences among the extracts were also observed. The reducing power of the extract obtained with 50 % (v/v) ethanol was significantly higher, a finding attributed to possible synergistic effects among polyphenols.List of symbols C solv Solvent concentration (%, v/v or w/v) C TP Total polyphenol concentration (mg GAE L -1 ) dDensityEffective diffusion coefficient (m 2 s -1 ) h Initial extraction rate (mg g -1 min -1 ) kExtraction rate constant (g mg -1 min -1 ) P R Reducing power (lmol AAE g -1 ) R Particle radius (m) R L/S Liquid-to-solid ratio (mL g -1 ) t Time (min) t R Time required to enter the regular regime (min) T Temperature (°C) Y TP Yield in total polyphenols (mg GAE g -1 ) Y TP(s) Yield in total polyphenols at saturation (mg GAE g -1 )Greek letters e Dielectric constant (dimensionless)

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Section: Extraction Kineticsmentioning

confidence: 99%

A Comparative Evaluation of Bio-solvents for the Efficient Extraction of Polyphenolic Phytochemicals: Apple Waste Peels as a Case Study

Blidi

Bikaki

Grigorakis

et al. 2015

Waste Biomass Valor

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“…The frequency dependent dielectric parameters were measured in the frequency width 10 9 -10 12 Hz. The measurement techniques are discussed in detail in our earlier works [17][18][19][20][21]. The reported values of ε * are fit with values α=0, β=1 obtained by Debye fit using following Havirliak-Negami equation [22][23][24]…”

Section: Dielectric Measurement and Data Analysismentioning

confidence: 99%

Dielectric dispersion, relaxation and molecular interaction of pyrazine binary mixtures

et al. 2018

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The dielectric depressiveness, absorption and orientation behavior is investigated in relation to solution properties of pyrazine with water, methanol and ethanol for varying temperature and mole fraction. This behavior is discussed in terms of inter molecular bonding. Orientation effects and their dielectric properties are indicated by surface dipole potential charges by displacement of oriented solvent. The charge dependence of polar solvents with organic molecular orientation can be qualitatively evolved and can be calculated in terms of its own dielectric properties, relaxation time, and correlation factor and thermodynamical behavior of solvent mixtures. The macroscopic and optical spectroscopic properties of pyrazine+water and pyrazine+alcohol mixtures are also studied.

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“…The complex permittivity spectra were obtained by using time domain reflectometry technique. [4][5][6][7] Tektronix model number DSA8200 Digital Serial Analyzer sampling mainframe along with the sampling module 80E08 has been used for the TDR technique. A repetitive fast rising voltage pulse with 18 ps incident rise time was fed through coaxial line system of impedance 50 Ω.…”

Section: Experimental Techniquementioning

confidence: 99%

Complex permittivity spectra of binary polar liquids using time domain reflectometry

Tabassum¹,

Pawar²

2018

J. Adv. Dielect.

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The study of complex properties in a binary mixture of polar liquids has been carried out in the frequency range of 10[Formula: see text]MHz to 30 GHz at 293[Formula: see text]K and 298[Formula: see text]K temperatures using time domain reflectometry. The complex properties of polar liquids in binary mixture give information about the frequency dispersion in the dielectric permittivity ([Formula: see text]) and dielectric loss ([Formula: see text]). The information regarding the orientation of electric dipoles in a polar liquid mixture is given by Kirkwood parameters. The Bruggeman parameters are used as the indicator of liquid1 and liquid2 interaction. Molar entropy ([Formula: see text]) and molar enthalpy ([Formula: see text]) are also discussed at the end of the paper.

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Dielectric relaxation study of amines in 2,3-butanediol mixture using picosecond time domain reflectometry technique

Cited by 6 publications

References 20 publications

A Comparative Evaluation of Bio-solvents for the Efficient Extraction of Polyphenolic Phytochemicals: Apple Waste Peels as a Case Study

A Comparative Evaluation of Bio-solvents for the Efficient Extraction of Polyphenolic Phytochemicals: Apple Waste Peels as a Case Study

Dielectric dispersion, relaxation and molecular interaction of pyrazine binary mixtures

Complex permittivity spectra of binary polar liquids using time domain reflectometry

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