Current Physical Chemistry - Current Issue

This research paper explores the environmental sustainability of ionic liquid-based green solvents in the extraction and purification of natural plant products, with a focus on their entire life cycle. The objectives of the study were to assess the environmental impact of ionic liquid synthesis, energy consumption, water usage, emissions, recycling rates, policy effects, and stakeholder perceptions.

Methodologically, we conducted a comprehensive Life Cycle Assessment (LCA) that involved primary data collection through field surveys and interviews with key stakeholders in the ionic liquid production and usage industry across various regions in India. The data were analyzed using specialized LCA software tools to quantify environmental impacts. Key findings include the identification of synthesis as a major contributor to environmental impact, emphasizing the need for greener synthesis methods.

The study revealed the significant carbon footprint, energy consumption, and water usage during production, highlighting opportunities for improvement. Emissions data underscored the importance of emission control measures, particularly for greenhouse gases and volatile organic compounds. Recycling and reuse were identified as environmentally friendly disposal methods. Policy compliance varied among stakeholders, indicating room for stricter regulations. Stakeholder perceptions varied, with researchers having the most positive outlook. Implications of the findings extend to sustainable chemistry practices, emphasizing interdisciplinary collaboration and the importance of considering the entire life cycle of chemical processes.

This research contributes to a deeper understanding of green solvents and provides a foundation for promoting sustainable practices in industrial processes in India and globally.

The kinetic study of Ir (III) chloride-catalyzed oxidation of methionine by hexacyanoferrate (abbreviated as HCF) III ions in aqueous alkaline medium was performed spectrophotometrically at constant ionic strength of 0.5 moldm^-3 and temperature of 35±0.1°C.

The progress of the reaction was found to be first-order rate dependence kinetics with respect to [HCF (III)], [OH^-], and [IrCl3]. The rate of reaction was found to decrease with an increased concentration of methionine. The ionic strength of the reaction mixture showed a positive salt effect on the reaction rate. Different activation parameters were also evaluated by studying the reaction at four different temperatures. The stoichiometry of the reaction showed Methionine: HCF (III) = 1:4.

The oxidation product of the reaction was found to be methionine sulphone, which was identified by an organic solvent method and IR Spectroscopy. Further, a suitable mechanism was proposed to explain all the experimental results.

It is assumed that the reaction proceeded through complex formation between substrate (oxidant) and iridium trichloride. A rate law was derived, which verified the results.

CH3-S-(CH2)²-CH (NH2)-COO^- + 4HCF (III) CH3-SO2-(CH2)²-CH-(NH2)-COO^- + 4HCF (II)

In this work, the thermal behavior and specific heat capacities of nine derivatives which were obtained via Biginellipyrimidone synthesis reaction have been experimentally determined using thermal gravimetry analysis and differential scanning calorimetry, and the obtained results have been thoroughly analyzed and discussed. The influence of the structural variation on the thermal analysis has been discussed along with the influence of the structure of the derivatives of pyrimidines on the specific heat capacity.

To date, heterocycles have successfully been switched from synthetic organic chemistry laboratory to the core of a variety of biomolecules, conducting devices and so on. Derivatives of 2-hydroxypyrimidine or pyrimidines have a wide window of pharmaceutical applications. Therefore, attempts have been made to understand the thermal response of these organic frameworks.

The main objective of this study was to explore thermal methods to understand heat-induced structural interactions as well as the specific heat capacity (Cp) as a function of temperature for the synthesized derivatives of 2-hydroxy pyrimidine or pyrimidones.

Room temperature condensation of ethyl acetoacetate, urea, and variety of aldehydes or ketones has been optimized in ionic liquids for the formation of pyrimidones. Thereafter, the thermal profiles of the synthesized derivatives of pyrimidines have been studied thoroughly and the thermal response of the synthesized derivatives of pyrimidones gives sound information about thermal stability of these heterocycles.

In the present work, the effect of substituents on the thermal behavior of the synthesized derivatives of pyrimidines has been investigated with the help of TGA-DSC analysis. Specific heat capacity (Cp) data as a function of temperature for the synthesized derivatives of pyrimidones have been reported for the first time.

The specific heat capacity data of the molecules of high commercial and biological relevance such as pyrimidines like organic frameworks play a subtle role in the development of the computational methods and molecular modelling, to comprehend the fundamentals of these molecular frameworks and effectively explore the pharmaceutical as well as materialistic potentials of these heterocyclic frameworks via simulation.

PVA/TiO2 nanocomposite membranes are prepared by solution casting technique where different phases of TiO2 nanoparticles like brookite, brookite-rutile and rutile are dispersed in PVA matrix. Sol-gel method was employed to prepare TiO2 nanoparticles, while different phases of TiO2 have been obtained by controlling the calcination temperature.

PVA/TiO2 nanocomposite membranes were characterized by XRD, FTIR, AFM, TEM, UV-visible and PL techniques. XRD results confirmed the presence of different phases of TiO2, exhibiting 3.3 nm, 8.4 nm, and 35.7 nm mean crystalline size. The XRD studies also confirmed that TiO2 nanoparticles became properly dispersed to the PVA matrix, leading to increased PVA crystallinity after doping of different phases of TiO2 nanoparticles. UV-visible analysis revealed an increase in absorption intensity and peak position shifts slightly towards longer wavelengths, which indicates that nanofillers tuned the band gap of PVA. The doping of the TiO2 (brookite) phase in the PVA matrix results in a decreased in PL intensity.

This suggests that the PVA/TiO2 (brookite) membrane exhibits a greater degree of photocatalytic activity in comparison to the other two composites. According to the FTIR investigation, the hydroxyl (OH) groups present in PVA interact with the dopants Ti+ ions via intra- and intermolecular hydrogen bonds to produce charge transfer complexes (CTC). The AFM study shows surface roughness details for PVA and PVA/TiO2 composite membranes. The average grain size of TiO2 nanoparticles calculated from TEM images is in good agreement with the grain size calculated by XRD.

By adjusting the phase of TiO2 nanoparticles into PVA matrix, composites can be developed that are optimized for a variety of applications such as water purification, UV protection, self-cleaning surfaces, lithium-ion batteries, and optoelectronic devices.

Nutraceuticals are products derived from food sources that provide extra health benefits in addition to the basic nutritional value found in foods. Spectrophotometric methods for the determination of curcumin were developed, which are simple, sensitive, selective, rapid, and reliable.

The methods are based on the reduction of iron (III) to iron (II) by 3-Methyl-2-benzothiazolinone hydrazone hydrochloride hydrate (MBTH), which is an electrophilic coupling agent and subsequent reaction with curcumin in mild hydrochloric acid medium. Spectrophotometric methods for the determination of curcumin were developed, which are simple, sensitive, selective, rapid, and reliable. The methods are based on the reduction of iron (III) to iron (II) by 3-Methyl-2-benzothiazolinone hydrazone hydrochloride hydrate (MBTH), which is an electrophilic coupling agent and subsequent reaction with curcumin in mild hydrochloric acid medium.

The reaction produces a bluish–green complex with maximum absorbance at 670 nm. The colour complex can be extracted into chloroform. The methods obey Beer’s law in the range 0.3-7.0 and 0.2-7.0 (µg mL^-1).

10 common anions and cations were added, and the method was tested, and no interference was observed. The proposed methods offered the advantages of having good reproducibility and were satisfactorily worked out to estimate the amount of curcumin in various turmeric samples.