Experimental investigation for stability and surface properties of TiO2 and Al2O3 water-based nanofluids

Journal of Thermal Analysis and Calorimetry - Nanofluids have gained recent attention because of their potential applications in diverse engineering fields like enhancing thermal transport,...     

Versatile ligands for high-performance liquid chromatography: An overview of ionic liquid-functionalized stationary phases

Ionic liquids (ILs), a class of unique substances composed purely by cation and anions, are renowned for their fascinating physical and chemical properties, such as negligible volatility, high dissolution power, high thermal stability, tunable structure and miscibility. They are enjoying ever-growing applications in a great diversity of disciplines.     

On the effects of bath composition and ultrasound on structure and properties of Cu thin films

Copper thin films were prepared by sono-electrodeposition method at different acid concentrations in the electrolyte. A potential of ?450 mV (100 mV negative than the Nernst potential) was selected for the deposition procedure for all the conditions. The thickness of films was found to be in the range of 100–600 nm. Electrochemical analysis was performed by chronoamperometry. Films were characterized by XRD, SEM, AFM, and study of the mechanical properties was done by nanoindentation.     

Facile conversion of para-benzoquinones to para-alkoxyphenols with primary/secondary alcohols and amberlyst-15: a process showing novel reducing property of such alcohols

A new efficient methodology has been developed for the synthesis of para-alkoxyphenols, an important group of anti-melanoma compounds, by heating alcoholic solutions of para-benzoquinones in the presence of amberlyst-15. The most notable feature here is the behaviour of the used primary or secondary alcohol as an effective reducing agent.     

Analytic structure of ρ meson propagator at finite temperature

We analyse the structure of one-loop self-energy graphs for the ρ meson in real time formulation of finite temperature field theory. We find the discontinuities of these graphs across the unitary and the Landau cuts. These contributions are identified with different sources of medium modification discussed in the literature. We also calculate numerically the imaginary and the real parts of the self-energies and construct the spectral function of the ρ meson, which are compared with an earlier determination. A significant contribution arises from the unitary cut of the π ω loop, that was ignored so far in the literature.     

Kinetics of unusual photoinduced currents in the solid state of some ferrocene derivatives

Kinetics of change in photoinduced currents (during illumination and after switching off light source) in the solid state of some ferrocene derivatives, namely, ferrocenecarboxylic acid, acetylferrocene, ferrocenecarbaldehyde, hydroxymethyl ferrocene have been studied in dry nitrogen gas atmosphere. Unusual/anomalous photocurrent versus time profiles were observed in some ferrocene derivatives at certain cell temperatures. The kinetics of current changes under photoexcitation and after switching off the light source have been observed to be complicated in nature. Temperature-dependent behavior of the studied kinetics indicates that charge carrier trapping/detrapping and recombination processes are significantly temperature dependent. These processes have an important role in causing the temperature dependent unusual/anomalous photocurrent versus time profiles in the ferrocene derivatives studied.     

Transition Metal-Catalyzed Hydroalkoxylation of Alkynes: An Overview

Oxygen-bearing motifs, mainly the congener heterocycles are ubiquitous due to their presence in various natural products and bioactive scaffolds. Although in literature, several strategies have been developed for their synthesis, hydroalkoxylation of alkynes has come forward as a method of choice and has been used extensively. In particular, hydroalkoxylation of alkynes has gained enormous attention from the synthetic community due to the rapid access to a very useful and reactive synthetic intermediate like ‘enol ether’. Furthermore, to manifold the utility of these methods, reports have been developed elaborating the generation of ‘enol ether’ using hydroalkoxylation and their usage in various reactions in cascade or tandem manner. This review focuses on recent development on the hydroalkoxylation of alkynes for the synthesis of oxygen-containing entities.     

Copolymer-grafted silica phase from a cation–anion monomer pair for enhanced separation in reversed-phase liquid chromatography

This work reports a new imidazolium and l-alanine derived copolymer-grafted silica stationary phase for ready separation of complex isomers using high-performance liquid chromatography (HPLC). For this purpose, 1-allyl-3-octadecylimidazolium bromide ([AyImC₁₈]Br) and N-acryloyl-l-alanine sodium salt ([AAL]Na) ionic liquids (IL) monomers were synthesized. Subsequently, the bromide counteranion was exchanged with the 2-(acrylamido)propanoate organic counteranion by reacting the [AyImC₁₈]Br with excess [AAL]Na in water. The obtained IL cation–anion monomer pair was then copolymerized on mercaptopropyl-modified silica (Sil-MPS) via a surface-initiated radical chain-transfer reaction. The selective retention behaviors of polycyclic aromatic hydrocarbons (PAHs), including some positional isomers, steroids, and nucleobases were investigated using the newly obtained Sil-poly(ImC₁₈-AAL), and octadecyl silylated silica (ODS) was used as the reference column. Interesting results were obtained for the separation of PAHs, steroids, and nucleobases with the new organic phase. The results showed that the Sil-poly(ImC₁₈-AAL) presented multiple noncovalent interactions, including hydrophobic, π–π, carbonyl–π, and ion–dipole interactions for the separation of PAHs and dipolar compounds. Only pure water was sufficient as the mobile phase for the separation of the nucleobases. Ten nucleosides and bases were separated, using only water as the mobile phase, within a very short time using the Sil-poly(ImC₁₈-AAL), which is otherwise difficult to achieve using conventional hydrophobic columns such as ODS. The combination of electrostatic and hydrophobic interactions are important for the effective separation of such basic compounds without the use of any organic additive as the eluent on the Sil-poly(ImC₁₈-AAL) column.