Different combinations of cations (imidazolium, pyridinium, pyrrolidinium, phosphonium, and ammonium) and anions (basic anions, sulfate, phosphate, and borate) were studied based on the COSMO volume and quantum chemical parameters such as highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energies, HOMO-LUMO energy gap, global hardness and softness, electronegativity, electrophilicity index, and chemical potential using the density functional theory (DFT) method. Further, the sigma profile and sigma potential for the selected cations and anions were generated using a COSMO-RS model. The activity coefficient at infinite dilution was also studied for the butanol-water system to find a greater degree of nonideality. A feasible entrainer for the azeotrope breaker for a butanol-water system is proposed.
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http://dx.doi.org/10.1021/acsomega.0c02086 | DOI Listing |
J Chromatogr A
December 2024
School of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, PR China; Key Laboratory of Traditional Chinese Medicine Classical Theory, Ministry of Education, Shandong University of Traditional Chinese Medicine, Jinan 250355, PR China. Electronic address:
Countercurrent chromatography (CCC) is an efficient technique for purifying bioactive natural compounds, but selecting the solvent system can be a time-consuming and crucial process for successful separation. This paper discussed the HPLC-assisted mathematical prediction method for the n-hexane/alcohol solvents/water (HAWat) and ethyl acetate/n-butanol/water (EBuWat) systems and designed an intelligent online selection system to simplify the separation process. First, the applicable rage of HAWat and EBuWat solvent systems were quantified by the methanol concentration at the column inlet when template molecules peak in a HPLC analysis (B%).
View Article and Find Full Text PDFDrug Deliv Transl Res
December 2024
Thiomatrix Forschungs- Und Beratungs GmbH, Trientlgasse 65, 6020, Innsbruck, Austria.
The aim of this study was to develop an alternative strategy to sufficiently increase the lipophilicity of anionic model macromolecules (MM) without the use of cationic counterions. Enoxaparin (ENO), insulin (INS) and poly-L-glutamic acid (PLG) were ion paired with anionic surfactants (sodium decanoate (DEC), sodium dodecyl sulfate (SDS), sodium stearate (SS) and sodium octadecyl sulfate (SOS)), mediated by divalent cations such as magnesium, calcium and zinc. Complexes were evaluated regarding their precipitation efficiency and logD.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
February 2025
Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, China; Guangxi Key Laboratory of Optoelectronic Information Processing, School of Optoelectronic Engineering, Guilin University of Electronic Technology, Guilin 541004, China. Electronic address:
The co-solvent system of tert-butanol and water is commonly employed in the field of freeze-drying pharmaceuticals. Investigating the phase composition and behavior of this system at low temperatures contributes to furthering its applications. In this study, THz-TDS was used to investigate the melting process of the frozen tert-butanol-water binary system for the first time.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
October 2024
Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, 22 Xiong Road, Yangling 712100, Shaanxi, China. Electronic address:
The process of counter-current chromatography (CCC) separation for natural products typically necessitates the use of multiple solvent systems to accommodate constituents with a wide range of polarities. However, the incompatibility between these different solvent systems often results in unsuccessful online 2D successive separations. In this study, a 2D CCC system was developed, featuring an interface for online-storage, dilution, and mixing.
View Article and Find Full Text PDFPhytochem Anal
August 2024
School of Pharmacy, Gansu University of Traditional Chinese Medicine, Lanzhou, China.
Introduction: Astragaloside IV (AS-IV) is an index for the quality evaluation of the traditional Chinese medicine Astragalus and an important material basis for Astragalus to exert its medicinal effects, and it is difficult to obtain a single AS-IV by ordinary separation methods.
Objective: To find a new isolation method that can prepare AS-IV quickly and efficiently.
Methodology: AS-IV was isolated from Astragalus membranaceus extract by high-speed countercurrent chromatography using a two-phase solvent system consisting of ethyl acetate/n-butanol/water (4.
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