Current Topics and Emerging Issues in Chemical Science Vol. 1

Oil-in-Water (O/W) emulsions based on lecithin have numerous applications in the food and cosmetic sectors. The stability and physicochemical properties of food grade emulsion play a key role in determining the application of the emulsion. The stability of an O/W emulsion is determined by the emulsifying solution's characteristics as well as the presence of ionic contaminants. The current experiment clearly demonstrated the importance of polyvalent Lewis acid salt solution in creating emulsion stability.  Lewis acid salts solutions of NaCl, KNO₃ BaCl₂ MgCl₂, Al₂(SO₄)₃ and FeCl₃ were implemented in the production of lecithin based O/W emulsion. The ionic activity coefficient measured  from Debye-Hückel limiting law (DHLL) for Lewis metal ions Na⁺, K⁺, Ba²⁺, Mg²⁺, Al³⁺ and Fe³⁺ were found to decrease the pH value of the ionic solutions. As the ionic activity coefficient falls, the conductance of an ionic solution rises. The lecithin O/W emulsion is severely destabilized by these patterns, which also reveal a substantial order in the breakage times of various emulsion systems.  Microscopic analysis accurately predicted the influence of ionic activity coefficient on emulsion instability. Droplet diameter was measured for monovalent and divalent metal ions ranging from 12-160 micrometers, and the number of larger droplets increased with increasing valence. Higher valence Al³⁺ and Fe³⁺ ionic solutions, on the other hand, completely shatter the emulsion with fast separation of the oil and water layers and lower activity coefficients. Thus, the emulsifying solution's enhanced valence and conductance, reduced ionic activity coefficient, and pH value considerably destabilize the soy lecithin-based O/W emulsion by increasing interfacial tension and retarding the emulsifier's binding capacity.

In our previous work (Indian J Phys., 93(9):1113-1122 (2019)), utilizing Density Functional Theory (DFT), some essential properties of 3-Amino-4-(Boc-amino) pyridine (Henceforth referred to as the analyzed molecule) were investigated, including its molecular geometry, electronic properties, vibrational frequencies, and nonlinear optical performance. In this study, the molecular docking study is also carried out to investigate protein-ligand interactions between the analyzed molecule and the target protein amyotrophic lateral sclerosis. The findings shows that the lowest binding energy for the analyzed molecule is -5.25 Kcal/mol. By depending on docking results, the analyzed molecule could be an effective drug candidate for amyotrophic lateral sclerosis.

Partial molar volumes (\(\varphi^0\)_v) of glycine (c=0.02-0.22 mol^.dm^-3) in aqueous electrolyte solutions (NaCl and KCl, c=0.15, 0.45 and 0.60 mol^.dm^-3) and non-electrolyte solutions (sucrose, c=0.15, 0.45 and 0.60 mol^.dm^-3)  were determined at 298.15 K. Partial molar volume of transfer (\(\Delta\)_tr\(\varphi^0\)_v) of glycine from aqueous to aqueous electrolyte and non-electrolyte solutions has been calculated and interpreted in terms of different interactions. Dominating hydrophilic-hydrophilic or ion-hydrophilic interactions are observed in present systems and these interactions strengthen with increase in concentration of salts and sucrose. Hydration behavior of glycine perturbs in presence of salts and sucrose through solvation and hydrogen bonding effects of co-solutes and resulted in the overall enhancement of water structure.

This chapter evaluate the Physical Parameters of the Raw Sand Mixture, Significant for its Washing Treatment. Mixing and dispersing are one of the most energy-intensive and expensive operations used in bulk material classifiers, machines designed for washing sand and separating clay and other equipment in the relevant field. Therefore, the rational hardware design of these processes has a significant impact on the economy not only of such auxiliary processes as preparation for the use of construction sand, but also on the overall product cost.

The parameters of the rate of discharge of clay extraction and the power consumed for washing sand do not change linearly depending on the geometric parameters of the working volume, and the parameter of the speed of rotation of the liquid with untreated sand has a linear character of change.

The linear change in the rotation speed of the liquid with uncleaned sand is provided that when filling the working volume with liquid, the diameter formed by the rotational movement of the liquid flow is equal to the diameter of the working volume of the washing machine.

When constructing an automatic control system for sand washing, it is necessary to ensure stabilization by such basic indicators as the required sand-clay ratio, the humidity of the cleaned sand, power consumption, etc.

This chapter highlights about Corrosion inhibition verification of fresh extracts from matured seed of Persea americana var. Americana on mild steel in 0.5 M H₂SO₄ using gravimetric and electrochemical methods. Avocado pear (Persea americana Mill.) crop is cultivated and highly demanded internationally because of the growing demand for fruit and food products. Gravimetric methods were conducted on mild steel coupons of stated dimensions. The tests were carried out at room temperature for 24 hours, and also for higher temperature from 40^oC to 70^oC for 1 hour. The results showed that the seed extracts have appreciable corrosion inhibition potentials which decreased with increase in temperature. Inhibition efficiency varied considerably with temperature. The Langmuir isotherm, which is a sign that the extract constituents were adsorbed on the steel surface, was compatible with the experimental data. The general increase in the Arrhenius equations suggests that physisorption rather than chemisorption is more common.  The values of the heat of adsorption are all negative for temperatures at 40^oC, indicative of the fact that inhibition efficiency decreases with rise in temperature, a proof that the inhibition trend was physisorption. Increase in inhibitor concentration leads to a corresponding increase in inhibition efficiency, though the values are less than the case of the experiment at room temperature. The adsorption of natural corrosion inhibitors on metal surfaces is influenced by a number of factors including nature of metal, testing media, chemical structure of inhibitor, nature of substituents present in the inhibitor, presence of additives, solution temperature, and solution concentration. At temperatures of 70^oC, the values are mixed, some negative and some positive.  This indicates that both physisorption and chemisorptions abound at higher temperatures. According to the results of potentiodynamic tests, a mixed inhibitor is implied by a decrease in current potential when the inhibitor is present at both concentrations.  

This research clarifies a mechanistic insight into scavenging of superoxide radical anion (O₂^•-) by (2E)-3-(3,4-dihydroxyphenyl)prop-2-enoic acid (caffeic acid), classified as a hydroxycinnamic acid (HCA) derivatives. With the aid of density functional theory (DFT) calculations, the reactivity of caffeic acid toward electrogenerated O₂^•- was examined using cyclic voltammetry, in situ electrolytic electron spin resonance spectrometry, and in situ electrolytic ultraviolet-visible spectrometry in N,N-dimethylformamide (DMF). Caffeic acid appears to modify the quasi-reversible redox of dioxygen/ O₂^•-, indicating that it scavenges O₂^•-  by proton-coupled electron transfer.  Experimental evidence from comparison studies with other HCAs has shown that the ortho-diphenol (catechol) moiety rather than the acryloyl group mediates the reactivities of caffeic acid toward O₂^•-. The electrochemical and DFT measurements in DMF indicated that the catechol moiety serves as the intermediary in a coordinated two-proton-coupled electron transfer pathway. This method exemplifies the better kinetics of caffeic acid's O₂^•- scavenging.

This chapter provides a comprehensive and systematic review of the current status of Ir-iTMC-based LEECs using the archetypal complex [Ir(ppy)2(bpy)]PF6 as a reference emitter. Cyclometallated iridium complexes possess fascinating electrochemical and photophysical properties that make them excellent candidates for various photonic and optoelectronic applications. In place of traditional organic light-emitting diodes, light-emitting electrochemical cells (LEECs) based on iridium-containing ionic transition-metal complexes (Ir-iTMCs) show promise.  The advantages of LEECs based on Ir-iTMCs include a simpler device structure, solution processability, and reduced manufacturing costs compared with conventional light-emitting diodes. Here, the device fundamentals and important photophysical parameters are discussed, then key strategies for tuning the emission characteristics and device stability through LUMO and HOMO stabilization/destabilization are presented using numerous examples from the literature. It has concentrated on ligand modification with hydrophobic, electron-withdrawing, and electron-donating substituents, -stacking interactions, alternative ancillary ligand skeletons, and cyclometallated ligands.  Comprehensive data tables summarizing the photophysical and LEEC properties of the various classes of iridium complexes reported to date are also provided. The presence of steric hindrance increases the intercomplex distance, thereby minimizing the non-radiative decay in the solid state. Thus, a low IL concentration in the emissive layer is sufficient for improving the device efficiency, as an excessive IL concentration could increase the intercomplex distance even further and lead to reduced electronic communication between the iridium complexes and lower LEEC efficiency. It is concluded that potential directions for future research by reporting the current champion iridium complexes for fabricating state-of-the-art LEECs and discussing the merits and limitations of existing approaches.

The current review paper goes deeply into the chemistry of saponin, specifically triterpenoid saponin.  Saponin is a naturally occurring bioorganic molecule with a high molecular weight that is isolated from medicinal plants. It has an aglycone nucleus with 27 to 30 carbon atoms and one or two sugar moieties with at least 6 or 12 carbon atoms each. Saponins were considered as a starting precursor for the semi-synthesis of steroidal drugs in the pharmaceutical industry. Many scientists and researchers may regard saponin chemistry's complexities as a gap in their understanding of the relationship between the chemical structure and its medicinal or medical function. The need for saponin applications has lately expanded due to a variety of biological, medicinal, and pharmacological benefits. The topics covered were classifications, chemical structure, potential classical techniques of isolation, qualitative and quantitative saponin testing. Examples of hederagenin and oleanolic acid with mono- and bidesmosidic structures are also provided. Triterpenoid, steroid, and alkaloid glycoside structural distinctions were established based on their atoms, rings, and functional groups.