Aqueous Isopropanol Research Articles

Improved solution thermodynamics modeling in pervaporation

The current work features a system-level design of pervaporation processes (typically utilized to break azeotropes) that is solution thermodynamics-based (inclusive of validated excess thermodynamic properties). Unlike the standard pervaporation modeling methodology in the literature, the current method (referred to here as PervapS3) deconstructs the membrane module into its constituent units, and the material and energy flows were mathematically validated. These amendments to the previous methodology (i.e., leaf-wise modeling, mathematical validation, and inclusion of excess thermodynamic properties) revealed significant deviations in key parameter values. For a given large-scale pervaporation process dehydrating aqueous isopropanol, the total membrane area and energy requirement calculated were up to 22% and 19% less than the values calculated using the previous methodology. Moreover, due to the inclusion of excess thermodynamic properties in the PervapS3 method, the minimum separation work and the second law (thermodynamic) efficiency were up to 94% and 78% less. In other words, the previous pervaporation modeling methodology overestimated membrane area, energy requirement, minimum separation work, and second law efficiency. Considering a conventional azeotropic distillation process for comparison with pervaporation, it was observed that the simulation-based distillation models from the literature were inclusive of the system non-idealities. Per the previous method, the non-ideal second law efficiency of azeotropic distillation would be compared against the ideal second law efficiency of pervaporation, overestimating the latter. The non-ideal second law efficiency must be employed to facilitate a fairer and more accurate comparison of disparate separation technologies.

Preliminary Qualitative Analysis of Plant Samples by High-performance Thin-layer Chromatography for the Presence of Steroid Sapogenins of Some Representatives of the Dioscoreacae, Fabaceae, Ranunculaceae, Melanthiaceae, Scrophulariaceae

Introduction. Results of original research carried out by means of high performance thin layer chromatography (HPTLC) of various plant samples (air-dry raw material) of Dioscoreaceae, Ranunculaceae, Fabaceae, Melanthiaceae, Scrophulariaceae families are presented in this article.Aim. To carry out preliminary qualitative analysis by HPTLC method of steroidal sapogenins composition in hydrolyzed extracts, obtained from vegetative samples of above-ground and underground organs of some Dioscoreaceae, Ranunculaceae, Fabaceae, Melanthiaceae, Scrophulariaceae families.Materials and methods. Extraction from pre-dehydrated raw materials was carried out with 50 % aqueous isopropanol (c.p.) in an ultrasonic bath, followed by acidic hydrolysis of O-glycoside bonds, evaporation and redissolution of dry residue in 99 % methanol (c.p.); purification from suspended solids by filtering through filters with 20 µm perforation diameter. HPTLC was performed on apparatus complex CAMAG (Switzerland) using HPTLC Aluminium sheets Silica gel 60 F254 plates 20 × 20 cm, which were cut to the size 20 × 10 cm.Results and discussion. After scanning densitometry at 254 nm, we found that the separation of isopropanol extracts, followed by redissolution in strong methanol in this solvent system allows a fairly acceptable separation and identification of the compounds studied. Comparison of the tracks of plant extracts was performed with standard samples of steroid sapogenins, whose methanol solutions were applied to one stain-strobe of track 1, provided that they had different Rf indices and coloration after derivatization.Conclusion. Diosgenin was identified in plant extracts of rhizomes and roots of Dioscorea nipponica and Dioscorea caucasica and in seeds of Trigonella foenum-graecum preliminarily. Sarsasapogenin was verified in extracts of fruits of Sophora japonica, tigogenin in extracts of seeds of Trigonella foenum-graecum, herb of Pulsatilla patens and herb of Veronica officinalis. Yamogenin was detected in extracts of seeds of Trigonella foenum-graecum and herb of Veronica officinalis. This work is exploratory in nature, assessing the presence of certain saponins by their sapogenins in selected extracts. We will optimize the HPLC separation procedure and choose other detection methods to unambiguously assess the co-presence of the studied sapogenins with approximately the same staining shades after derivatization and matching retention indices: there are pairs of steroidal sapogenins that have the same retention, we decided to group them in mixtures so that there would be separation within the group and subsequent comparison with the original extracts would make it possible to identify those or other sapogenins in such extracts.

A new air-stable Pd-PEPPSI N-heterocyclic carbene complex: Synthesis, structure, computational and catalytical studies

In this work, we have synthesized a new, air and moisture stable, Pd-PEPPSI (pyridine enhanced pre-catalyst preparation, stabilization and initiation) complex, [PdBr2(NHC)Py] (NHC is 3-benzyl-1-(4-methoxyphenyl)-1H-imidazolline-2-ylidiene) and successfully employed as catalyst under mild conditions (35 °C, 0.5 mol% Pd loading) Suzuki-Miyaura cross-coupling reactions of aryl halides with aryl boronic acids in aqueous isopropanol. A wide range of aryl bromides / iodides were effectively utilized as coupling partners with arylboronic acids to afford corresponding biaryls in moderate-to-excellent yields. The complex was characterized by ESI-MS, 1H and 13C NMR spectroscopy and the molecular structure was determined by X-ray single crystal analysis. In order to gain more insight about structure, bonding and electronic properties, density functional theory (DFT) studies were performed. Moreover, TDDFT calculations were also performed to interpret the observed electronic absorption bands in the UV-VIS spectra. A good agreement between experimental and theoretical data was observed.

Polyol grafted thin film nanocomposite membrane: Enhanced pervaporation performance for isopropanol dehydration

Isopropanol is used as a cleaning agents especially in the semiconductor industry. Thus, recycling, and purifying alcohol can reduce the overall cost of production. To improve the separation performance of the thin-film nanocomposite (TFN) membrane, nanozeolite (NZ) was embedded in polyamide layer followed by post-treatment of polyols. The polyamide layer was fabricated through interfacial polymerization of diethylenetriamine (DETA) and trimesoyl chloride (TMC). NZ was dispersed in TMC in order to be embedded on the separation layer. Afterwards, the membrane was simultaneously post-treated using polyols. Different types of polyols were introduced: d-sorbitol (DST), erythritol (ERT), and pentaerythritol (PET). A higher number of hydroxyl groups can provide a denser separation layer. Their chemical structures also affects the reaction rate, where more linear structures (DST and ERT) had better reaction and crosslinking with acyl chloride. High reaction rate of DST gives the roughest surface and high crosslinking degree. Compared to other polyols, Using DST in post-treatment exhibited the highest separation performance. It had a permeation flux of 3,098 g·m−2·h−1 and 99.9 wt% water concentration in permeate (feed = 70 wt% aqueous isopropanol solution at 25℃). Therefore, post-treatment using polyols can further enhance the separation efficiency of TFN membranes with a stable performance over a long period of time.

Effects of Dietary Supplementation of a Resin-Purified Aqueous-Isopropanol Olive Leaf Extract on Meat and Liver Antioxidant Parameters in Broilers.

Olive leaves are byproducts οf the agro-industrial sector and are rich in bioactive compounds with antioxidant properties. They could be supplemented in poultry diets powdered or less frequently as extracts to improve performance, health and product quality. The objective of this study was to investigate the possible beneficial effects of an aqueous isopropanol olive leaf extract-purified through filtration (250-25 µm) and a resin (XAD-4)-when supplemented in broiler chickens' diets, on meat quality parameters, focusing mainly on antioxidant parameters as there is limited published information. For this purpose, four-hundred-and-eighty-day-old broilers were randomly assigned to four dietary treatments: T1 (control: basal diet); T2 (1% olive leaf extract); T3 (2.5% olive leaf extract); T4 (positive control: 0.1% encapsulated oregano oil commercially used as feed additive). At the end of the experimental period (day 42), the birds were slaughtered, and samples from breast, thigh meat and liver were collected for antioxidant parameters evaluation. On day 1, after slaughter, in thigh meat, Malondialdehyde (MDA) was lower in T2 compared to T3, and total phenolic content (TPC) was higher in T2 compared to T3 and T4. Total antioxidant capacity (TAC) was increased in T2 and T4 breast meat compared to the control. In liver, T4 treatment resulted in higher TPC. The lack of dose-dependent effect for olive leaf extract may be attributed to the pro-oxidant effects of some bioactive compounds found in olive leaves, such as oleuropein, when supplemented at higher levels. In summary, it can be inferred that the inclusion of 1% olive leaf extract in the feed of broilers has the potential to mitigate oxidation in broiler meat and maybe enhance its quality.

The Exploration of Ink Formulations in Binder Jet 3D Printing Drugs.

The application of binder jet 3D printing technology in the pharmaceutical field is developing rapidly. The properties of the ink are very important, affecting the stability of the ejection and the precision of the finished product, but there is a great lack of research on pharmaceutical inks. This study used solvents and excipients commonly used in pharmaceuticals to quantify the printability of inks using printability Z value theory, while using an ink-jet printing and observation platform to analyze the droplet ejection state of different composition inks from microscopic level. Studies have shown that compared to ethanol, the ejection effect of droplets was better when isopropanol was added to the ink, and the proportion added should not be greater than 40%; as the molecular weight of polyvinylpyrrolidone (PVP) increased, the concentration of PVP tolerated by the ink decreased; glycerin has a high ejection efficiency when the proportion is within 10%. In summary, a superior ink formulation of 40% aqueous isopropanol plus 0.1% PVP K30 and 4% glycerin was obtained. With this ink, levetiracetam dispersible tablets were prepared with a smooth printing process and the tablets had good appearance, good mechanical properties, and rapid release. This study provides a mutual validation of the Z value theory and the results of droplet ejection and tablet printing, while providing good ideas.

KrF excimer laser for Pt–NPs synthesis by PLAL in isopropanol solution and their use in a SERS application

Pulsed laser ablation in aqueous isopropanol (IPA) solution (PLAL) using KrF excimer laser was employed for the first time to produce platinum nanoparticles (Pt–NPs). The dependence of their optical and morphological properties on the IPA concentration and ablation time at certain values of the laser fluence (LF) and repetition rates (RR), was investigated. The UV/Vis transmission (T) spectra of the Pt–NPs were measured to assess indirectly their type, relative mean size (MS) and standard deviation (SD). Peculiarities of this spectra, related to the presence of a volatile component in the solution are discussed. Morphological properties as shape, MS, SD, and microstructure were studied via High-Resolution Scanning Transmission Electron Microscopy (HR-STEM). The created Pt–NPs show spherical shape with smallest MS value of 1.7 nm using 2.3 Jcm−2 LF, 10 Hz RR and 10 min ablation time in 80% aqueous IPA solution and the narrowest SD of ±0.7 nm with the same technological parameters but using 30% IPA concentration. The Pt nature of the NPs was confirmed by Energy Dispersive X-Ray technique. The crystallographic structure was determined by HR-STEM and X-ray diffraction measurements. An application of the synthesized Pt–NPs is presented using their role as substrate in methylene blue through surface-enhanced Raman spectroscopy method.

Improved pervaporation dehydration performance of alginate composite membranes by embedding organo-montmorillonite

In this work, two different montmorillonite (MMT) nanoclays were incorporated in sodium alginate (Alg) solution for fabrication of hybrid membrane for pervaporative separation of aqueous isopropanol solution. Sodium-MMT (Na-MMT) was modified to organo-montmorillonite (O-MMT) using cationic surfactant dialkyldimethyl ammonium chloride (DDAC). The influence of incorporating MMTs on the membrane properties and separation performance was investigated. Intercalating of DDA+ on Na-MMT tailored the chemical structure and morphology of the MMTs. Integrating of MMTs modified the physicochemical properties of the membranes. The membrane morphology shows the homogeneous dispersion of MMTs in athe Alg matrix. Positron annihilation lifetime spectroscopy analysis revealed a tuned microstructure of the membranes. Swelling measurements showed better compatibility of O-MMT than the Na-MMT with the Alg matrix. As a result, AlgO-MMT had better separation performance than the AlgNa-MMT with permeation flux of 4764 g∙m−2∙h−1 and water concentration in permeate of 99.99 wt% on dehydrating 70 wt% IPA/water aqueous solution at 25 °C. Owing to the favorable compatibility between the polymer and filler, AlgO-MMT membrane demonstrated stability at different pervaporation operating conditions and long-term use. Our results demonstrated that the properties and separation performance of Alg membrane can be enhanced through incorporation of O-MMTs.

Understanding photochemical pathways of laser-induced metal ion reduction through byproduct analysis.

Laser-induced reduction of metal ions is attracting increasing attention as a sustainable route to ligand-free metal nanoparticles. In this work, we investigate the photochemical reactions involved in reduction of Ag+ and [AuCl4]- upon interaction with lasers with nanosecond and femtosecond pulse duration, using strong-field ionization mass spectrometry and spectroscopic assays to identify stable molecular byproducts. Whereas Ag+ in aqueous isopropyl alcohol (IPA) is reduced through plasma-mediated mechanisms upon femtosecond laser excitation, low-fluence nanosecond laser excitation induces electron transfer from IPA to Ag+. Both nanosecond and femtosecond laser excitation of aqueous [AuCl4]- produce reactive chlorine species by Au-Cl bond homolysis. Formation of numerous volatile products by IPA decomposition during both femtosecond and nanosecond laser excitation of [AuCl4]- is attributed to enhanced optical breakdown by the Au nanoparticle products of [AuCl4]- reduction. These mechanistic insights can inform the design of laser synthesis procedures to improve control over metal nanoparticle properties and enhance byproduct yields.

Synthesis of nanosize zinc oxide through aqueous sol–gel route in polyol medium

BackgroundThis study is aimed to synthesize nanosize zinc oxide by acid catalyzed sol–gel process using zinc nitrate hexahydrate as precursor, aqueous isopropanol as solvent and glycerin for making polyol system. The polyol mediated procedure was employed in combination with calcination induced synthesis of nanoparticles of numerous sizes obtained with the variation in calcination temperature from 500 to 900 ℃. The crystal structure of the prepared samples was characterized by X-ray diffraction analysis (XRD). Infrared spectroscopy (IR) was used to identify the surface hydroxyl groups. Thermal stability was confirmed by differential scanning calorimetry-thermogravimetric analysis (DSC-TGA) whereas field emission scanning electron microscopy (FESEM) was used to study the surface morphology of nanoparticles.ResultsResults revealed the formation of hexagonal wurtzite structure of irregular shaped nanoparticles having size ranging from 50–100 nm. However, the particles combined to form agglomerates of 200–400 nm with the rise in calcination temperature.ConclusionsThese results indicate that nanosize zinc oxide can be synthesized successfully by a simple process comprising of glycerin as a low-cost, non-toxic and eco-friendly polyol followed by calcination at ambient temperatures.

Energy-saving improvement of heat integration for separating dilute azeotropic components in extractive distillation

Three-column extractive distillation is often used to separate dilute azeotropic components. Although heat integration is not new, there are many new findings for it in the three-column extractive distillation process. For the first time, three kinds of multi-effect heat integration and five kinds of solvent sensible-heat recovery are compared. It is first found that the pre-concentrator distillate composition and the solvent feed temperature that are always ignored have unexpected effects on heat integration. It is first found that different forms of heat integration can all be fully thermally integrated by adjusting parameters especially the above two. Moreover, it is first found that splitting the fresh feed into two streams, one for the pre-concentrator and the other for the extractive column can improve some heat-integrated processes. Four improvement methods are proposed based on these findings. Separating dilute aqueous isopropanol is used to study these specific effects. Two other examples are used to illustrate the feasibility of the improvement methods. The results show that heat integration can be improved to be more energy efficient than the original heat integration, and even than some new methods.

Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes.

In this work, thin-film composite polyamide membranes were fabricated using triethylenetetramine (TETA) and trimesoyl chloride (TMC) following the vacuum-assisted interfacial polymerization (VAIP) method for the pervaporation (PV) dehydration of aqueous isopropanol (IPA) solution. The physical and chemical properties as well as separation performance of the TFCVAIP membranes were compared with the membrane prepared using the traditional interfacial polymerization (TIP) technique (TFCTIP). Characterization results showed that the TFCVAIP membrane had a higher crosslinking degree, higher surface roughness, and denser structure than the TFCTIP membrane. As a result, the TFCVAIP membrane exhibited a higher separation performance in 70 wt.% aqueous IPA solution at 25 °C with permeation flux of 1504 ± 169 g∙m−2∙h−1, water concentration in permeate of 99.26 ± 0.53 wt%, and separation factor of 314 (five times higher than TFCTIP). Moreover, the optimization of IP parameters, such as variation of TETA and TMC concentrations as well as polymerization time for the TFCVAIP membrane, was carried out. The optimum condition in fabricating the TFCVAIP membrane was 0.05 wt.% TETA, 0.1 wt% TMC, and 60 s polymerization time.

Microporosity engineered printable silk/graphene hydrogels and their cytocompatibility evaluations

In this work, regenerated silk fibroin (RSF)/reduced graphene oxide (rGO) hybrid ink system was fabricated in aqueous phase, extrusion printed and photocrosslinked to hydrogels with tunable physicochemical properties and cell-gel interactions. Aqueous isopropyl alcohol was used to disperse the rGO into RSF matrix, where the RSF molecules showed relatively increased radius of gyration with IPA resulting in increased pore size and water uptake capacity of the photocrosslinked hydrogels. Incorporation of IPA along with increase in rGO content systematically decreased the viscosity, contact angle and printing accuracy of RSF/rGO hybrid inks, where the ink with highest rGO content exhibited relatively loose network structure at printing shear rate. However, no secondary structural change and fibrillogenesis was observed under printing shear stress, making it a suitable system for bioprinting silk hydrogel scaffolds. In addition, increase in rGO content systematically increased the crosslink density, β-sheet content, and mechanical properties of RSF/rGO hybrid hydrogels, whereas decreased the micropore size and water uptake capacity. Moreover, with increase in rGO content, the hybrid and bioprinted hydrogels showed good biocompatibility with marginal difference in cell viability on hybrid and bioprinted gels. The developed hydrogel systems could be potentially applied for tissue engineering and other functional applications.

Efficacy of Bottle Gourd Seeds' Extracts in Chemical Hazard Reduction Secreted as Toxigenic Fungi Metabolites.

Bottle gourd seeds are surrounded by innumerable bioactive components of phytochemicals. This work aimed to evaluate the effectiveness of bottle gourd extracts as antimicrobial and an-ti-mycotoxigenic against toxigenic fungi and mycotoxins. Polar and nonpolar extracts were made from the seeds. The polar eco-friendly extract was prepared by an ultrasonication-assisted technique utilizing aqueous isopropanol (80%), whereas the non-polar extract was obtained using petroleum ether (40–60). The antioxidant efficacy, total phenolic content, and flavonoid content of the extracts were all measured. The fatty acid profile was measured using GC equipment, and the influence on toxigenic fungus and mycotoxin release was also investigated. The antioxidant efficacy of the polar extract is reflected. The total phenolic values of the oil and polar extract were 15.5 and 267 mg of GAE/g, respectively. The total flavonoid content of the oil was 2.95 mg catechol/g, whereas the isopropyl extract of seeds contained 14.86 mg catechol/g. The polar extract inhibited the DPPH more effectively than oil. When compared to other seed oils, the fatty acid composition differed. The pathogens were distinguished by the MIC and MFC for the polar extract. Three sterols were found in the oil, with a high concentration of B-sitosterols. The oil’s valuable -carotene content and tocopherol content were recorded. When compared to traditional antibiotics, the polar extract has shown promising antimicrobial activity against infections and toxigenic fungi. Bottle gourd extracts, as a non-traditional bioactive source, are viewed as a potentially promising alternative that might contribute to increased food safety, shelf-life, and security.

Significant improving H+/VO2+ permselectivity of Nafion membrane by modification with PDDA in aqueous isopropanol

The modification of Nafion® membranes with poly(diallyldimethylammonium chloride) (PDDA) in aqueous solutions of isopropanol has been investigated. A remarkable decrease in vanadyl ion permeability (by 3.5 orders of magnitude), accompanied by a decrease in proton conductivity sixfold at most, was found for Nafion membranes modified in 30–35 wt% isopropanol solutions providing a high swelling of the membranes. The Bradford reagent has been used for the detection of PDDA on the membrane surface.

Thermal effect of carbohydrate dissolution in aqueous-organic media

This work is devoted to the theoretical substantiation of connection of temperature dependence of the solubility of carbohydrates with thermal effect of their dissolution in the water-containing organic solvents that is of great importance for optimization of the technology of their extraction from plant raw materials and further purification and separation by recrystallization. The dependence of the solubility of fructose, glucose, sucrose, and maltose in aqueous isopropanol and acetone at temperatures of 298 К (25 оС) and 275 К (2 оС) from water content in a solvent was studied. The constancy of the mechanism of solubility of carbohydrates in these environments in the given temperature interval is experimentally proved. For the first time based on the equation of Vant-Goff the logical connection of temperature dependence of solubility and thermal effect of solubility of carbohydrates is strictly grounded. The values of the thermal effect that are determined by the experimental data allow calculating the solubility of the studied carbohydrates in the aqueous–organic solvent of different concentration in the temperature range from 2оС to 25 оС. It has been established that the main contribution to the thermal effect of dissolving carbohydrates is the hydration process. Solvation by molecules of organic solvent practically does not change the value of the specified thermal effect. The significance of determined temperature dependences of the solubility of fructose, glucose and maltose is shown to optimize the technological conditions for the separation of glucose-fructose and glucose-maltose syrups by selective crystallization.

Bifonazole dissolved in numerous aqueous alcohol mixtures: Solvent effect, enthalpy–entropy compensation, extended Hildebrand solubility parameter approach and preferential solvation

The accessible mole fraction solubility of bifonazole in n-propanol/methanol/isopropanol/propylene glycol (PG) (1) + water (2) mixtures at 298.15 K was investigated in the light of molecular interactions between solvent and solute via extended Hildebrand solubility approach (EHSA). For aqueous methanol/PG systems within entire mole fraction range of methanol/PG, aqueous n-propanol system within mole fraction range of n-propanol from 0 to 0.8 and aqueous isopropanol system within mole fraction range of isopropanol from 0 to 0.7, the solute–solvent interaction energies are larger than the ones of geometric mean for regular solution, asserting that there exists some association between bifonazole and mixtures; whereas within the other composition regions for the aqueous isopropanol/n-propanol systems, the solutions consisting of bifonazole present regular behavior at several solubility points. The inverse Kirkwood–Buff integrals tool was utilized to investigate the local mole fractions of bifonazole in the solutions of alcohol (1) + water (2) in the light of the solubility. For the aqueous solutions of isopropanol/n-propanol with middle and isopropanol/n-propanol-rich mole fractions, preferential solvation of bifonazole was observed for isopropanol/n-propanol. Bifonazole was not solvated preferentially by PG/methanol in the above composition regions for aqueous PG/methanol mixtures. The solvent effect was quantitatively described by modeling the solubility change by means of the linear solvation energy relationships. The solubility parameter and dipolarity-polarizability of system descriptors presented the dominant contributions to variation of solubility values. The transfer and dissolution properties, e.g. entropy, Gibbs free energy change and enthalpy were calculated. In addition, the analysis of enthalpy–entropy compensation was performed, specifying that the variation of bifonazole solubility in the four aqueous alcohol solutions was controlled by two different mechanisms, enthalpy-driven and entropy-driven.

SYNTHESIS, CHARACTERIZATION OF SOME SUBSTITUTED BIPHENYL-2- AMINOTHIAZOL DERIVATIVES

The synthesis explored to serve novel functional group extended Anti-microbial bio-active molecules of substituted Aminothiazoles. It reveals from overall available up to date literature feedback of Aminothiazoles, it is difcult to synthesis of substituted biphenyl-2-aminothiazoles from Suzuki coupling reaction of 5-(4-bromophenyl) thiazol-2-amine with substituted Boronic acids in presence of Palladium (II) acetate catalyst and in 5% aqueous Isopropyl alcohol used as a solvent. This is a shortest pathway to synthesis of biphenyl derivatives of Aminothaizoles by Suzuki coupling method.

Equilibrium solubility of edaravone in some binary aqueous and non-aqueous solutions reconsidered: Extended Hildebrand solubility approach, transfer property and preferential solvation

The accessible equilibrium solubility data of edaravone in methanol/ethanol/isopropanol (1) + water (2) and ethyl acetate/acetonitrile (1) + methanol/ethanol/n-propanol (2) mixtures was investigated in terms of solvent–solute molecule interactions based on extended Hildebrand solubility method. For methanol (1) + water (2) with x1 (mole fraction) from 0 to 0.8, ethanol (1) + water (2) with x1 from 0 to 0.5 and isopropanol (1) + water (2) with x1 from 0 to 0.3, the interaction energies of solute-solvent molecules were greater than the geometric average values of regular solution, specifying some association between edaravone and mixed solvents. While in the other regions for the three aqueous solutions and ethyl acetate/acetonitrile + methanol/ethanol/n-propanol mixtures, edaravone solutions acted as regular ones at several points. A quartic expression of energy term W in terms of solvent solubility parameter of these mixtures could be successfully used to predict the equilibrium solubility of edaravone in the studied blended mixtures. The preferential solvation of edaravone by means of inverse Kirkwood–Buff integrals tool for the isopropanol/ethanol/methanol + water and ethyl acetate + n-propanol/methanol/ethanol mixtures was analyzed. For the isopropanol/ethanol/methanol + water blended solvents, the drug edaravone was surrounded preferentially by water in water-rich ranges, and by alcohols in other composition regions of binary blended solvents except for isopropanol solutions with isopropanol-rich compositions, where edaravone was preferentially solvated by water. As well, edaravone was preferentially solvated by ethanol for ethyl acetate + ethanol mixture with rich ethyl acetate compositions. The highest degree of preferential solvation was observed in aqueous isopropanol solutions. Selective solvation of the edaravone by water (isopropanol/ethanol/methanol + water mixtures) or ethanol (ethyl acetate + ethanol mixture) was attributable to greater acidity of water or ethanol that enabled interactions with Lewis basic groups of edaravone. In addition, the apparent dissolution enthalpy and transfer Gibbs free energy (ΔtrGo), transfer enthalpy (ΔtrHo) and transfer entropy (ΔtrSo) were derived and deeply discussed.

Boosting the Antimicrobial Activity of Highly Diluted Aqueous Alcoholic Sanitizers by Fortification with Essential Oil Components: I- Carvacrol

The current study aims at developing alcoholic-based sanitizing formula against some pathogenic bacteria based on highly diluted (< 70.0%) aqueous isopropanol solution which is fortified with small amount of an essential oil component like carvacrol. This phenolic compound can act as antimicrobial booster for the compensation of alcohol reduction in the sanitizer. The solubility behavior of carvacrol in the aqueous alcoholic solution containing different ratios of isopropanol and water was investigated using the Gibbs’ phase diagram. Based on that, a selected formula containing 1.0% carvacrol dissolved in the highest possible dilution of isopropanol (45.0%) was chosen for testing its antimicrobial activity against some gram positive and negative pathogenic bacteria in comparison to the standard 70.0% alcohol formula without carvacrol. Results indicated that a 45.0% aqueous isopropanol solution can hold up to 5.0% carvacrol at maximum in a physically stable and homogenous sanitizing formula. Antimicrobial evaluation of the developed diluted aqueous isopropanol fortified with 1.0% carvacrol showed the same inhibition against the tested pathogenic bacteria as the standard 70.0% alcohol sanitizer without carvacrol. In conclusion, 45.0% diluted isopropanol fortified with a minimum of 1.0% up to 5.0% carvacrol (in case of intensive sanitization) can possibly be used as sanitizer for protection against some pathogenic bacteria. The practical significance of this study is the production of diluted alcoholic sanitizing formula for decontamination of surfaces against some pathogenic bacteria with the advantage of increasing alcohol dilution in order to spare the absolute alcohol reserve for more quantitative production of the sanitizer.