Menthol

Deep eutectic solvents (DESs), renowned for their environmental compatibility and superior selectivity, have emerged as promising candidates to replace conventional organic solvents in the extraction and separation of coal tar.Despite their potential, the practical application of DESs in coal tar processing has not been thoroughly investigated.In this study, the principal components of coal tar obtained from Nao Mao Lake in Xinjiang were analyzed as representative samples.A high-throughput screening of 9,976 DES combinations was performed using the conductor-like screening model for segment activity coefficient (COSMO-SAC) model coupled with the technique for order preference by similarity to an ideal solution (TOPSIS) ranking method within a multi-criteria decision anal. framework to assess their greenness.This rigorous screening process identified an optimal DES formulation consisting of tetraethylammonium chloride (TEAC) as the hydrogen-bonding acceptor (HBA) and ethanolamine (MEA) as the hydrogen-bonding donor (HBD).The synthesized DESs exhibited remarkable selectivity for phenolic compounds, demonstrating their potential for targeted extraction processes.The extraction efficiency was systematically optimized by examining key parameters, including HBA/HBD molar ratio, extraction temperature, extraction time, solvent-to-oil ratio, cycling performance, and water content of the DESs.Under optimized conditions a temperature of 25°C, the volume ratio of the extractant to the model oil was 1:1, and an extraction time of 20 min the TEAC/MEA (1:3) system achieved an extraordinary phenol extraction efficiency of 99.93%.Notably, the efficiency remained above 99.60% even after five consecutive extraction cycles, highlighting the systems exceptional stability and reusability.Addnl., the optimal conditions for neutral oil removal were established as extraction temperature of 25°C and an n-hexane dosage at a volume ratio of 8:1.To elucidate the underlying mechanisms, d. functional theory (DFT) calculations were employed to investigate the interactions between DESs and phenolic compoundsThe results indicated that strong hydrogen bonding interactions were dominant between DESs and phenolic compounds, while only weak hydrogen bonding was observed with toluene.A strong correlation was identified between the hydrogen bonding strength and extraction efficiency, providing a theor. foundation for the exceptional performance of the selected DESs in extracting phenolic compounds from coal tar.This study not only advances the understanding of DESs in coal tar extraction but also provides a robust framework for their application in sustainable separation processes.

The seafood industry generates large volumes of waste, responsible for serious environmental hazards and high disposal costs.Bioconversion and biorefinery approaches offer effective management of seafood waste, preserving valuable nutrients and supporting sustainable seafood productionShrimp shells are a rich source of polyunsaturated fatty acids and carotenoids, mainly astaxanthin (AST), whose recovery by means of green strategies represents a challenging goal.In this work, the potential of equimolar binary mixtures of menthol and alkanoic acids (ME:AA) as green solvents for AST recovery from shells of Aristaeomorpha foliacea (Risso, 1827) shrimp has been explored, by evaluating both the yield and the stability of the extracted carotenoid.All tested ME:AA exhibited high efficiency for fast AST extraction in mild conditions, while the mixtures containing acetic (ME:C2) and decanoic (ME:C10) acids ensured the maximum stability of the pigment.HPLC anal. highlighted a variety of extracted AST derivatives, mainly consisting of mono- and diesters of fatty acids with variable side chains.Their overall amount allowed to identify mediterranean A. foliacea as a shrimp species particularly capable of AST uptake and storage.ATR-FTIR measurements pointed out partial deprotonation of the alkanoic acid component following the extraction process, in agreement with the alkalinity of the CaCO3-rich matrix.Interestingly, the antioxidant capacity of the extracts exceeded the predicted one, based on the AST content, suggesting the co-extraction of addnl. antioxidant compoundsFinally, α-cyclodextrin was successfully employed as emulsifying agent to prepare stable ME:C10-in-water microemulsions, which drastically enhanced the chem. stability of extracted AST under standard environmental conditions.