Current Physical Chemistry - Volume 13, Issue 3, 2023

Previous studies provide substantial evidence that catechins, polyphenol bioactive compounds, exhibit medicinal benefits. These polyphenols are found in abundance in green teas, including a combination of the four major types of catechins: (-)-Epicatechin (EC), (-)-Epicatechin-3-gallate (ECG), (-)- Epigallocatechin (EGC), and (-)- Epigallocatechin-3-gallate (EGCG). Although all four exhibit medicinal benefits, the catechin cited in the literature the most is EGCG, so derivatives of this catechin were selected for these studies. Literature searches identified catechins as biologically active compounds for a diverse set of diseases ranging from cancer, metabolism, neurological, and neuromuscular ailments. A diverse set of potential protein targets for docking with catechin derivatives was first identified as a list (n = 48). The targets were then selected based on the presence of 3D protein coordinates for these targets provided by the Rutgers Consortium for Structural Biology (RCSB) Protein Data Bank (PDB) (n = 10). The surfaces of the 3D protein targets were evaluated with computational methods to identify potential binding sites for the EGCG catechin derivatives. Static and flexible docking was done using target protein binding sites performed with the catechin derivatives followed by molecular dynamics (MD). MD protocols were run to confirm binding in the physiological range and environment. In summary, the results of computational protocols confirmed predicted binding by docking with MD of several catechin derivatives to be used as scaffolds once validated in lab-based assays. Possible changes to these scaffolding molecules that could result in tighter, more specific binding is discussed.

Aims: Oxidation of p-anisaldehyde by Quinolinium dichromate (QDC) in the aqueous acetic acid medium in the presence of sulphuric acid using surfactants. Background: The oxidation studies of anisaldehyde is very important as the oxidized products are used as a synthetic intermediate for the preparation of a variety of drugs. Quinolinium dichromate (QDC) has emerged as a very useful and versatile oxidant. Micellar medium enhances the reaction rate. Objective: 1. To study the kinetics of the reaction, which includes the determination of order, rate, and activation parameters. 2. Spectral characterization of QDC by NMR and the kinetic study of the reaction mechanism is done through UV – A visible spectrophotometer. 3. Solvent effect for the oxidation of anisaldehyde by QDC. 4. Determination of critical micelle concentration (CMC) of used surfactants (CTAB and SDS). Methods: The reactions were followed at constant temperature and were followed by monitoring the UV – Visible spectrophotometer (Double Beam – 2203) in a quartz cuvette of 1 cm path length by following the absorbance decay of Cr (VI) at 440 nm. Results: KINETIC RESULTS: 1. The reaction follows first-order dependence on panisaldehyde and QDC. 2. The reaction is found to be acid-catalysed. A plot of log [k] versus log [H⁺] was found to be a straight line with a slope of 1.07. EFFECT OF SOLVENT: The rate of reaction increases with the increase in acetic acid proportion in the medium, which suggests that the reactions were of the ion–dipole type. MICELLAR EFFECT: 1. Experimental results demonstrated that anionic surfactant SDS catalysed and accelerated the study more effectively than CTAB, which is a cationic surfactant, and the rate of reaction increases with an increase in the concentration of the SDS while in the case of CTAB, the rate decreases with an increase in its concentration. 2. CMC values of CTAB and SDS were 3.9 mM and 8.2 mM, respectively. Conclusion: The value of negative ΔS (entropy of activation) and positive ΔH (enthalpy of activation) suggests the formation of more ordered activated complexes, and the transition state is highly solvated. SPECTROSCOPIC ANALYSIS 1.NMR characterisation of synthesised QDC shows a resemblance with pure QDC. 2. Effect of oxidant QDC, panisaldehyde and acid was studied by considering the spectra of the reaction mixture and varying their concentration.

Introduction: Two key features of an emulsion, stability and viscosity, are not only considered dependent on ingredient quantities but also delicately affected by emulsification conditions, such as pH, temperature, and mixing conditions. Methods: In the laboratory, we formulated an O/W emulsion made up of 41% water, 9.8% silicon (polydimethylsiloxane), 22.1% liquid sucrose (700 mg/ml), 22.1% light liquid paraffin, and 1.5 to 5% paraffin emulsifier by volume % purposed for large-scale production as a rubber coating for decorative purposes. Results: This emulsion became faulty after large-scale production, while it was fine on the laboratory scale. This study investigated the probability of a complicated interaction among pH, temperature, solutes, and agitation intensity on the stability and viscosity of our emulsion by focusing on sugar degradation effects on these parameters. This emulsion was made in two different temperatures and agitation rates, and the emulsification time was 20 minutes for all samples. The critical roles of appropriate pH regulators or buffers in the stability were also investigated. Conclusion: It was found that applying intense agitations at 1500 rpm during emulsifications in high temperatures may lead to absurdly high emulsion viscosity, accompanied by a sharp pH fall.

Background: Historically, the coincidence of classical thermodynamic entropy and statistical entropy is based on an assumption (the so-called Boltzmann-Planck relation). The study shows that the Boltzmann-Planck relation is not valid in general. Aims: The study demonstrates that thermodynamic entropy is a physical entity distinct from statistical entropy. Methods: Initially, the entropy of ideal gases is examined and demonstrated to be independent of the gas volume. The ideal gas's true entropy is then expressed correctly. Results: The Boltzmann-Planck entropy equation is demonstrated to be incapable of describing the thermodynamic entropy of ideal gases. Conclusion: In general, the Boltzmann-Planck entropy cannot be considered a statistical interpretation of the thermodynamic entropy. The two entropies represent two different physical quantities. The physical quantity that enters the second law of thermodynamics is the thermodynamic entropy, not the statistical entropy. The study advocates for a fundamental rethinking of today's statistical understanding of thermodynamics.

Background: Organic synthesis, under environment-friendly circumstances, has a great impact on sustainable development. In this perspective, visible light photocatalysis has emerged as a green model, as this offers an energy-efficient pathway towards organic conversion. Light has been used as an energy source in this study, which is also a green approach to a sustainable environment. Methods: An investigation of the effects of various physical parameters, like the amount of complex, catalyst dose, and varying polarity of solvent methanol-benzene, on the photocatalytic degradation of surfactant as copper (II) mustard 2-amino 6-methyl benzothiazole complex has been carried out under the UV-visible light source. Biocidal activities of Staphylococcus aureus have also been studied in this work. Results: The rate of percent degradation has been found to increase with an increase in the range of parameters. Conclusion: This study provides a deeper experimental knowledge of the photocatalysis processes as well as microbial activities of the copper (II) mustard 2-amino 6-methyl benzothiazole complex. This article deals with advances in photocatalytic methods under non-aqueous media over the past few years.