Measurement of astaxanthin and squalene diffusivities in compressed liquid ethyl acetate by Taylor-Aris dispersion method

abstract

An increasing demand of consumers for natural bioactive compounds has boosted the interest of the scientific community for vegetables and fruits, with many efforts being made to identify new bioactive compounds and to develop sustainable extraction methods that preserve the compounds bioactivity. Such is thicase of pressurized liquid extraction and supercritical fluid extraction using green solvents as supercritical CO2, ethanol, and ethyl acetate. The accurate design of these processes requires the knowledge of transport properties, namely, diffusion coefficients, D-12. Astaxanthin and squalene are two bioactive compounds whose D-12 values were measured in compressed liquid ethyl acetate using a chromatographic technique. For astaxanthin the D-12 values were in the range 0.817 x 10(-5) - 1.223 x 10(-5) cm(2) s(-1) (at 303.15-333.15 K and 1-100 bar) and for squalene they were in the range 1.052 x 10(-5) - 1.822 x 10(-5) cm(2) s(-1) (at 303.15-333.15 K and 1-150 bar). The influence of tem- perature, pressure and Stokes-Einstein coordinate was studied for both systems and explained with the most relevant theories of the literature.

keywords

BINARY DIFFUSION-COEFFICIENTS; SUPERCRITICAL-FLUID EXTRACTION; CARBON-DIOXIDE EXTRACTION; BIOACTIVE COMPOUNDS; SOLVENT SELECTION; INFINITE DILUTION; LENNARD-JONES; DENSE FLUIDS; HARD-SPHERE; WIDE RANGES

subject category

Engineering

authors

Bruno Zêzere, José M. Silva, Inês Portugal, José R. B. Gomes, Carlos M. Silva

our authors

acknowledgements

This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2019), financed by National Funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. Bruno Mere thanks FCT for PhD grant SFRH/BD/137751/2018.

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