Search

Your search keyword '"Minceva, Mirjana"' showing total 438 results
Start Over Author "Minceva, Mirjana"
438 results on '"Minceva, Mirjana"'

22. Estimating the nonideality of eutectic systems containing thermally unstable substances.

Author

Alhadid, Ahmad, Jandl, Christian, Nasrallah, Sahar, Kronawitter, Silva M., Mokrushina, Liudmila, Kieslich, Gregor, and Minceva, Mirjana

Subjects
EUTECTIC reactions, ACTIVITY coefficients, HYDROGEN bonding interactions, X-ray powder diffraction, ION-ion collisions, OSMOTIC coefficients
Abstract

Eutectic systems design requires an in-depth understanding of their solid–liquid equilibria (SLE). Modeling SLE in eutectic systems has as prerequisites, the melting properties and activity coefficients of components in the liquid phase. Thus, due to the unavailable melting properties of thermally unstable substances, it is impossible to estimate their activity coefficients from experimental SLE data and model the SLE phase diagram of their eutectic systems. Here, we evaluate the activity coefficients of thermally unstable constituents in the liquid phase, which were calculated independent of their melting properties by correlating the SLE data of their cocrystals. Differential scanning calorimetry and powder x-ray diffraction were employed to obtain the SLE phase diagram of three eutectic systems, i.e., tetramethylammonium chloride/catechol, tetraethylammonium chloride/catechol, and betaine/catechol systems, and identify the formation of nine cocrystals. The non-random, two-liquid equation was used to calculate the activity coefficients of the components in the liquid phase. The substantial negative deviation from ideality in the three studied systems indicated strong hydrogen bonding interactions in the liquid solution. Furthermore, modeling ion–ion interactions in eutectic systems containing ionic constituents is of utmost importance for understanding their nonideality. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

36. Modeling Extraction for Better Taste and Aroma: Espresso Coffee Extraction and Supercritical Fluid Extraction

Author

Briesen, Heiko (Prof. Dr.), Briesen, Heiko (Prof. Dr.);Minceva, Mirjana (Prof. Dr. habil.), Pannusch, Verena Bernadette, Briesen, Heiko (Prof. Dr.), Briesen, Heiko (Prof. Dr.);Minceva, Mirjana (Prof. Dr. habil.), and Pannusch, Verena Bernadette

Abstract

In this publication-based dissertation, mechanistic modeling of extraction processes was applied to predict the extraction kinetics of different components contributing to the taste and aroma of the extract. Two common use cases were investigated: (1) espresso coffee extraction (articles 1, 2, and 3), and (2) supercritical CO2 extraction of essential oil from hops (article 4). Both extraction processes were investigated regarding various operating conditions and molecules., In dieser publikationsbasierten Dissertation wurde mechanistische Modellierung von Extraktionsprozessen dazu genutzt die Extraktionskinetiken verschiedener geschmacks- und geruchsaktiver Komponenten vorherzusagen. Zwei übliche Anwendungsfälle wurden behandelt: (1) Espresso-Kaffee-Extraktion (Artikel 1, 2 und 3) und (2) Extraktion ätherischer Öle mittels überkritischem CO2 aus Hopfen (Artikel 4). Beide Prozesse wurden hinsichtlich verschiedener Prozessbedingungen und Moleküle untersucht.

Published
2024

42. Modeling the liquid‐liquid chromatography separation of cannabinoids from hemp extracts.

Author

Luca, Simon Vlad, Gerigk, Melanie, Arshad, Ahmad Adeel, and Minceva, Mirjana

Subjects
CANNABINOIDS, COUNTERCURRENT chromatography, HEMP, CHROMATOGRAPHIC analysis, CANNABIDIOL, TETRAHYDROCANNABINOL, CANNABINOID receptors
Abstract

The separation of cannabinoids from hemp materials is nowadays one of the most promising industrial applications of liquid‐liquid chromatography (LLC). Despite various experimental research efforts to purify cannabinoids, there are currently few works on process modeling. Thus, this study aimed to explore a straightforward approach to model the LLC separation of cannabinoids from two hemp extracts with different compositions. The feed materials were simplified to mixtures of preselected key components (i.e., cannabidiol, tetrahydrocannabinol, cannabigerol, and cannabinol). The elution profiles of cannabinoids were simulated using the equilibrium‐cell model with an empirical nonlinear correlation. The model parameters were derived from the elution profiles of single‐solute pulse injections. For the validation of the proposed approach, LLC separations with the two hemp extracts were performed in descending mode with the solvent system composed of hexane/methanol/water 10/8/2 (v/v/v). The injected sample concentrations were gradually increased from 5 to 100 mg/mL. The results showed that the approach could describe reasonably well the elution behavior of the cannabinoids, with deviations of only 1–2 min between simulated and experimental elution times. However, to improve the prediction accuracy, the model parameters can be refitted to the elution profiles of 3–4 systematically selected pulse injections with specific hemp extracts. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results