Journal of Molecular Liquids最新文献

Eutectic solvents (ESs) have attracted considerable attention as CO₂ absorbents due to their tunable and unique properties. In this study, ESs based on choline chloride (ChCl) as hydrogen bond acceptor were combined with four different hydrogen bond donors (HBDs): urea, formamide, monoethanolamine and 1-aminopropan-2-ol, in different molar ratios. The impact of the primary amino group in HBD, with particular focus on the functional groups present in the vicinity, on the physicochemical and structural properties of the ESs was investigated. The CO₂ capture in these ESs was measured. ¹³C NMR, FTIR and Raman analyses were performed to provide evidence of chemical and structural changes after CO₂ capture. Quantum chemical methods were used to investigate the interaction mechanism between the ESs and CO₂. The resulting ESs were characterised by measuring their basic physicochemical properties, including melting point, density and viscosity as a function of temperature. A three-parameter correlation equation was proposed to predict the solubility of CO₂ in ChCl-based physical absorbents. It is shown that the use of the free volume parameter of ESs can help to identify alternative CO₂ absorbents.

In this paper, we present employing our own and literature data the results of investigation of the thermal behavior and ion transport properties of vinyl and alkyl imidazolium zwitterions containing an alkane sulfonic acid group and salts on their basis. For comparison, we present the results of investigation the respective vinyl and alkyl imidazolium ILs without these functional groups. The phase behavior of zwitterionic and vinyl imidazolium ionic liquids is studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

A thermostated reactor and UV–visible spectrophotometer analysis were used to determine the solubility of emodin and aloe-emodin, two naturally occurring compounds with pharmacological activity. At a pressure of 0.1 MPa under atmospheric conditions, and temperatures from 283.15 to 323.15 K with intervals of 5 K, the solubility in different water–ethanol combinations was the primary focus of the investigation. Under constant solvent composition, a positive correlation was observed between the solubility of emodin/ or aleo-emodin and the experimental temperature in all examined mixed solvent systems. To better understand the relationships between solutes and solvents and the interactions between several solvents, the KAT-LSER model was used to conduct multiple linear regression analysis on systems containing either pure solvents or a combination of solvents. In addition, several thermodynamic models were used to establish a connection with the empirical solubility data. These models included the Jouyban-Acree, Apelblat-Jouyban-Acree, van’t Hoff-Jouyban-Acree, and Ma models. The correlation findings demonstrate that all four thermodynamic models accurately predicted emodin and aleo-solubility emodin’s behavior under different solvent and temperature settings. Furthermore, the thermodynamic characteristics of emodin solubility in binary solvent combinations were determined using the van’t Hoff model. According to the findings, two compounds were found to undergo endothermic and non-spontaneous dissolution.

Nicotinic acid is a water-soluble compound recognized in the medical field for its ability to decrease low-density lipoprotein cholesterol levels. Additionally, nicotinic acid is used to alleviate the effects of heat stress in ruminant animals. The supercritical gas antisolvent technique was employed using carbon dioxide to encapsulate nicotinic acid in polyvinylpyrrolidone (PVP) using ethanol + acetone. Encapsulation efficiency, process yield and crystallite size data were evaluated using the Box-Behnken design. Gas chromatography-mass spectrometry quantified the encapsulation efficiency at (13.1 to 66.9)%, and the same technique was used to determine that the encapsulation of nicotinic acid increased the dissolution rate compared to the pure compound. A residual solvent level was quantified at least 33 times lower than the maximum permitted level. The encapsulation was shown to protect the active ingredient in thermal degradation tests in a climatic chamber. XRPD showed the stability of the crystalline structure of niacin after encapsulation, and the effects on its microstructure were evaluated using Rietveld analysis. Spectroscopic analysis showed evidence of intermolecular bonding between nicotinic acid particles and PVP. An average particle size of (80.4 to 238.9) µm was obtained by SEM analysis.

The utilization of Novel DESs can be greener alternative to traditional organic solvents. In present study, four polyols-based DESs are synthesized and characterized by several techniques. The prepared DESs are used for the efficient capture of hazardous iodine. In present study by simple combination of two readily accessible, economical, and biodegradable components four polyols-based DESs have been prepared. For the creation of these DESs, a hydrogen bond donors (HBDs) (polyols) and hydrogen bond acceptors (HBAs) (BTEAC) are used, which have melting points far lower than their respective melting points. The developed DESs were investigated for their physicochemical properties such as density, dynamic viscosity. Our results revealed distinct trends in these properties across different DES compositions, highlighting unique molecular interactions and solvation capabilities. The FTIR and NMR characterization study indicated considerable intermolecular interaction between the various component of the DES system. Further, Kamlet-Taft solvatochromic parameters were determined using Nile red dye, and other solvatochromic dyes. For synthesized DESs, the solvatochromic parameters E^N_T, normalized polarity parameter, π*, polarity / polarizability; β, hydrogen-bond acceptor basicity and α, hydrogen-bond donor acidity, have been determined. The E^N_T parameters demonstrate that both non-specific and specific interactions play a significant role in solute–solvent interactions. The synthesized DESs have been utilized for the efficient capture of the iodine. The removal efficiency of DES depends upon the mass of the DESs taken and time duration. These findings deepen our understanding of DES behavior and underscore their versatility in diverse industrial and scientific applications.

This study aimed to find an eco-friendly substitute method and chemical for conventional hydrogen peroxide (H₂O₂) bleaching of cotton fabric. We developed diverse functional groups containing titanium dioxide-doped single-wall carbon nanotubes (TiO₂-SWCNTs) particles, designed a photocatalytic system, and examined the effects of working conditions and functional group variations on the degree of fabric whitening. Throughout the many phases of the chemical development process, X-ray diffraction (XRD), Fourier transform infrared spectroscopy −Attenuated total reflectance (FTIR-ATR) and the scanning electron microscopy (SEM) tests were conducted. In addition, the color spectrum values, the whiteness indexes, the results of the tearing test, SEM and FTIR-ATR findings of 100% cotton textiles were presented that were treated with TiO₂-SWCNTs particles using the photocatalytic technique. The test results demonstrated the successful synthesis of various types of TiO₂-SWCNTs, leading to a significant enhancement in the whiteness of the cotton fabrics. This increase reached 21.79% using a small amount of nano-chemicals, surpassing the whiteness index value created by the conventional H₂O₂ bleaching process. Optimal results were achieved by using minimum quantities of substance and working at moderate temperatures. According to this information, it can be concluded that this approach may serve as a substitute for the conventional H₂O₂ whitening procedure in terms of both the substance utilized and the application method, specifically for treating cotton fabric. Moreover, the statistical analysis revealed that the fabric’s self-cleaning capacity is significantly influenced by the square of temperature and pH.

Sonocatalysis provides a green and sustainable strategy to remove industrial organic pollutants. Toward improving the sonocatalytic performance to remove the organic dyes, a new Cu-C@TiO₂ catalyst was prepared via doping the Cu(II) ions into the MIL-125(Ti) and then carbonizing the resultant Cu-MIL-125(Ti) in this study. By the SEM, EDS and BET, the obtained Cu-C@TiO₂ was a porous carbon-based hybrid with bimetallic centers, retaining a large amount of organic frameworks to supply adequate specific surface area for the adsorption; By the XPS and UV–vis DRS, the band gap of Cu-C@TiO₂ was reduced to significantly broaden the light absorption region and facilitate the separation of electron-hole pairs; By the fluorescence spectra, the graphite-like structure and Cu particles produced on the catalyst surface served as an electron trap to inhibit the recombination of charge carriers. The Cu-C@TiO₂ showed an excellent sonocatalytic performance to organic dyes, and under the ultrasound irradiation (35 KHz, 150 W), it could remove more than 95 % of rhodamine B (5.00 mg/L) and methylene blue (5.00 mg/L) within 10 min. By the kinetic analysis, it was found that the dye removal obeyed the first-order kinetic model, and the scavenging studies of free radicals (OH and O₂⁻) verified the Cu-C@TiO₂-mediated sonodynamic degradation was in the dye removal. In the end, a Cu-C@TiO₂-mediated adsorption/sonodynamic degradation mechanism was proposed to thermodynamically expound the removal process of organic dyes.

Drilling fluids play a pivotal role in well construction, serving as the key components that maintain the structural integrity of the well during drilling. The management of these fluids has seen swift advancements in technology recently, allowing for enhanced planning of well construction. These advancements have led to drilling fluids with improved properties, which greatly affect the efficiency and total cost of drilling activities. They are employed in drilling operations to cool and lubricate the drill bit, control formation pressure, transport cuttings to the surface, and fortify the stability of the wellbore. Recognizing their significance in the petroleum industry, the authors have conducted a comprehensive bibliometric analysis on drilling fluids. A thorough screening yielded 9,535 pertinent studies from Scopus over the past twenty years. Tools such as Office 365 VOS viewer and RStudio were used to analyse the metadata of these studies. The findings indicate a marked increase in drilling fluid research over this period. This study particularly identifies 150 noteworthy collaborations between China and the United States of America. These collaborations are probably a result of their respective large-scale oil and gas operations, sophisticated research facilities, and mutual dedication to the growth of petroleum industry technology. In addition, a comprehensive evaluation of the top 32 cited articles produced between 2018 and 2024 has been conducted, and their significance in the area has been rigorously examined and evaluated.

Thermal energy storage is gaining much attention and experiencing a renascence in last years. In this sense, storing thermal energy in form of latent heat is of special interest due higher energy density, lower energy losses and higher energy efficiency. To store thermal energy as latent heat the presence of a phase change material (PCM) is needed and its performance the key for its implementation in a thermal energy storage (TES) system and the temperature at which the phase change takes place, low (<150 °C) or high (>150 °C) temperature, will condition the application of a given PCM. In this context, the development of PCM materials to store latent heat at mid-to-high temperature in between 150 °C and 350 °C is of special interest e.g., in the field of concentrated solar power or heat recovery. There are already some solid–liquid phase change materials working in this range of temperature e.g., sugar alcohols, aromatic organic compound, inorganic salts, or blend of inorganic salts but all of them present different drawbacks, such as vapor pressure, degradation, low thermal conductivity, corrosion, etc. In consequence, there is a need to explore new PCM materials in this range of temperature applications. In this context, ionic liquids could play a key role in the development of novel PCMs due to their intrinsic properties. Indeed, ILs are gaining increased attention in the field of thermal energy storage in the last years but mainly in the low temperature range (<150 °C) remaining their application in the mid-to-high temperature range in between 150 °C and 350 °C underestimated. In this work, we prepared six different alkali alkanoate ionic liquids, namely [Na][MeOC₂], [K][MeOC₂], [Na][MeOC₃], [K][MeOC₃], [Na][MeOC₄] and, [K][MeOC₄] by direct reaction between the desired methyl methoxycarboxylate ester with NaOH or KOH. The prepared ionic liquids were structurally characterized, and their thermal–physical properties evaluated. Five of them but [K][MeOC₃] showed good enthalpy values ranging from 119 J/g to 197 J/g and four of them [Na][MeOC₂], [K][MeOC₂], [Na][MeOC₄] and, [K][MeOC₄] have showed excellent thermal stability above 380 °C. In addition, these four ionic liquids have successfully passed the cyclability test showing no significant enthalpy losses (between 0 % minimum and 7 % maximum) after 50 heating/cooling cycles compiling with the cycling category F of the RAL-GZ 896 (Quality Association PCM). All in all, these prepared ionic liquids surpass sugar alcohols in terms of cyclability and thermal stability and are comparable with the inorganic salts e.g. NaNO₃ employed in the studied range of mid-to-high temperature (150–350 °C).

Soy protein isolate (SPI) can interact with volatile compounds, which affect flavor perception and limit its application in liquid foods. This study aimed to elucidate the interaction mechanism between SPI and six main flavors of bean (aldehyde flavor compounds with different carbon chain length and unsaturation). The results showed that carbon chain length and unsaturation of compounds influenced the combining ability with SPI. (E, E)-2,4-decadienal and (E, E)-2,4-nonadienal with longer carbon chain length and higher unsaturation showed higher affinity with SPI. Multi-spectroscopy showed that aldehyde flavor compounds could induce the unfolding of SPI structure and expose hydrophobic groups. The presence of CC enhanced the hydrogen bonding between the carbonyl group and SPI. Thermodynamic analysis revealed that complexes mainly relied on hydrophobic interaction and hydrogen bonding-driven interactions. Molecular simulations further confirmed that aldehyde flavor compounds maintained binding stability with SPI the high-flexibility key amino acid residues (Leu⁷⁹, Pro⁸², Lys¹¹³, Glu³⁵⁸, etc.). This study improves the understanding of interactions between SPI and volatile compounds at the molecular level and provides a theoretical basis for SPI flavor improvement.