Acidities of lipophilic compounds, such as various ligands or catalysts, in systems consisting of an aqueous phase at equilibrium with a water-immiscible phase (lipid bilayers, phase transfer catalysis, sensor membranes, to name just few) are typically approximated by the aqueous p values. Our research shows that such approximations can lead to seriously biased estimations of the acidities as the bulk of solvated H ions reside in the aqueous phase, while the lipophilic species─both neutral acid and anion─predominantly reside in the organic phase. Therefore, the use of aqueous p in such situations is not justified. In this work, we provide a more accurate description of the acidities of acids in such systems by applying the biphasic p concept. Biphasic p values (p values) of 35 acids of various structures and chemical properties were determined in a 1-octanol:water system. We provide detailed descriptions of the UV-vis and NMR measurement methods. The directly obtained (apparent) p values depend on concentration. Concentration-independent values were obtained by extrapolating the apparent values to zero concentration using a Debye-Hückel model.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.analchem.1c05510 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Biphasic Coacervation Controlled by Kinetics as Studied by De Novo-Designed Peptides.
Langmuir
January 2025
Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Coacervation is generally treated as a liquid-liquid phase separation process and is controlled mainly by thermodynamics. However, kinetics could make a dominant contribution, especially in systems containing multiple interactions. In this work, using peptides of (XXLY)SSSGSS to tune the charge density and the degree of hydrophobicity, as well as to introduce secondary structures, we evaluated the effect of kinetics on biphasic coacervates formed by peptides with single-stranded oligonucleotides and quaternized dextran at varying pH values.
View Article and Find Full Text PDFCorrelation of Phase Structure, Defect Relaxation, and Microwave Dielectric Properties in Low-Loss MgTiO Ceramic Systems.
ACS Appl Mater Interfaces
January 2025
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
Low-loss microwave dielectrics are of significant importance for the miniaturization and integration of microwave devices. In this paper, the ceramics of nominal composition MgTiO ( = 3-6) are synthesized, and the correlations among their phase compositions, defect behaviors, and microwave dielectric properties are systematically investigated. The analyses indicate that the MgTiO ceramics are a biphasic system consisting of hexagonal ilmenite-structured MgTiO and cubic spinel-structured MgTiO.
View Article and Find Full Text PDFFacile Fabrication of Monodisperse Vinyl Hybrid Core-Shell Silica Microsphere with Short Range Radial Channel in bi-phase System.
Small
January 2025
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China.
The development of monodisperse hybrid silica microspheres with highly regular pore structure and uniform distribution of functional groups have significant value in the biomolecular separation field. In this work, the short range ordered pore channels are precisely constructed onto the non-porous silica microsphere surface by a bi-phase assembly method, and the cylindrical silica channel introduced a plethora of vinyl groups by "one-pot" co-condensation to form vinyl hybrid silica shell. As hydrophilic interaction chromatography (HILIC) stationary phase, the vinyl hybrid core-shell silica microsphere is simply modified with zwitterion glutathione (SiO@SiO-GSH), in which the HILIC enrichment process is significantly shortened due to its specific porous characteristics.
View Article and Find Full Text PDFMechanistic origins of temperature scaling in the early embryonic cell cycle.
bioRxiv
December 2024
Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat, 49, Leuven, Belgium.
Temperature profoundly impacts organismal physiology and ecological dynamics, particularly affecting ectothermic species and making them especially vulnerable to climate changes. Although complex physiological processes usually involve dozens of enzymes, empirically it is found that the rates of these processes often obey the Arrhenius equation, which was originally derived for single-enzyme-catalyzed reactions. Here we have examined the temperature scaling of the early embryonic cell cycle, with the goal of understanding why the Arrhenius equation approximately holds and why it breaks down at temperature extremes.
View Article and Find Full Text PDFStudy of the hydrodynamic parameters in an internal flat-plate airlift reactor for the increased degradation of newspaper by .
Environ Technol
January 2025
Colegio de Postgraduados, Posgrado de Edafología, Microbiología de Suelos, Montecillo, Estado de México, México.
The aim of our study was to characterize the hydrodynamics and mass transfer in a novel internal flat-plate airlift cylindrical reactor to increase the biodegradation of newspaper. We evaluated the degradation kinetics of newspaper in a batch culture with . Gas holdup, mixing time, the Reynolds number, and volumetric mass transfer coefficient () properties were characterized in biphasic and triphasic systems in order to optimize their operational conditions.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!