Composition Of Solvent Mixture Research Articles

Solvatochromism in Solvent Mixtures: A Practical Solution for a Complex Problem

Many reactions are carried out in solvent mixtures, mainly because of practical reasons. For example, E2 eliminations are favored over SN2 substitutions in aqueous organic solvents because the bases are desolvated. This example raises the question: how do we chose binary solvents to favor reaction outcomes? This important question is deceptively simple because it requires that we understand the details of all interactions within the system. Solvatochromism (solvent-dependent color change of a substance) has contributed a great deal to answer this difficult question, because it gives information on the interactions between solvents, solute-solvent, and presumably transition state-solvent. This wealth of information is achieved by simple spectroscopic measurements of selected (solvatochromic) substances, or probes. An important outcome of solvatochromism is that the probe solvation layer composition is almost always different from that of bulk mixed solvent. In principle, this difference can be exploited to “tune” the composition of solvent mixture to favor the reaction outcome. This minireview addresses the use of solvatochromic probes to quantify solute-solvent interactions, leading to a better understanding of the complex effects of solvent mixtures on chemical phenomena. Because of their extensive use in chemistry, we focus on binary mixtures containing protic-, and protic-dipolar aprotic solvents.

Rapid investigation of the effect of binary and ternary solvent gradient mixtures on reaction outcomes using a continuous flow system

A flow technique for rapid investigation of the effects of solvents mixtures on organic transformations was developed. Reaction information against a full range of binary or ternary solvent mixture composition was obtained in a time efficient manner.

Utilization of red and yellow Coffea arabica var. Caturra pulp: macronutrient analysis, carotenoid extraction, and encapsulation for dairy product enrichment.

This study aimed to investigate the macronutrient and carotenoid content of red and yellow Coffea arabica var. Caturra pulp, a by-product of coffee processing in Colombia. The study employed ultra-sound-assisted extraction (UAE) to extract carotenoids, and a 23 factorial design was used to evaluate the effects of pulp color, biomass-solvent ratio, and solvent mixture composition on carotenoid content and extraction yield. The condition that provided the highest carotenoid extraction was further encapsulated by spray drying and added to a dairy product. The results showed that coffee pulp has significant dietary fiber content and high levels of carotenoids, with yellow pulp having a higher content than red pulp. Lutein isomers and lutein esters were the most abundant carotenoids found in both red and yellow coffee pulp. The highest carotenoid extraction was achieved using a 1:40 (g/mL) biomass:solvent ratio and a 20:80% v/v Ethanol:Ethyl Acetate solvent mixture for the yellow pulp. The carotenoid extract also demonstrated high encapsulation efficiency (46.57 ± 4.03%) and was found to be stable when added to a fermented milk product. This study presents an alternative solution for utilizing coffee by-products in Colombia, which could positively impact the families of over half a million Colombian coffee producers.

Extraction of Isoflavones, Alpha-Hydroxy Acids, and Allantoin from Soybean Leaves-Optimization by a Mixture Design of the Experimental Method.

Soybeans are commonly known as a valuable source of biologically active compounds including isoflavones as well as allantoin and alpha-hydroxy acids. Since these compounds exhibit skin therapeutic effects, they are widely used in the cosmetic and pharmaceutical industries. The presented paper shows the optimization of three solvent systems (ethanol, water, and 1,3-propanediol) to increase the extraction efficiency of isoflavones (daidzin, genistin, 6″-O-malonyldaidzin, 6″-O-malonylglycitin, 6″-O-malonylgenistin), allantoin, and alpha-hydroxy acids (citric acid, malic acid) from soybean leaves. A simplex centroid mixture design for three solvents with interior points was applied for the experimental plan creation. Based on the obtained results of metabolite extraction yield in relation to solvent composition, polynomial regression models were developed. All models were significant, with predicted R-squared values between 0.77 and 0.99, while in all cases the model's lack of fit was not significant. The optimal mixture composition enabling the maximization of extraction efficiency was as follows: 32.9% ethanol, 53.9% water, and 13.3% propanediol (v/v/v). Such a mixture composition provided the extraction of 99%, 91%, 100%, 92%, 99%, 70%, 92%, and 69% of daidzin, genistin, 6″-O-malonyldaidzin, 6″-O-malonylglycitin, 6″-O-malonylgenistin, allantoin, citric acid, and malic acid, respectively. The solvent mixture composition developed provides a good extraction efficiency of the metabolites from soybean leaves and high antioxidant properties.

Rotational dynamics study of structurally similar (medium sized) coumarin dyes in aqueous mixtures of DMSO and DMA

The rotational diffusion dynamics of four medium sized, structurally similar, polar Coumarin dyes namely, Coumarin-478 (C478), Coumarin-480 (C480), Coumarin-519 (C519), and Coumarin-523 (C523) has been studied at room temperature in aqueous DMSO and aqueous DMA by using steady state and time resolved fluorescence depolarization techniques. All the probes exhibited faster rotation in organic solvent rich zone than in water rich zone that resulted in a downward bent “hook profile” of rotational reorientation time as a function of viscosity. A faster rotational diffusion is observed for C523 in contrast to the other three solutes in both the aqueous solvent mixtures. The difference between τr values at iso-viscous points is smaller in case of aqueous DMA than in aqueous DMSO which reveals the importance of dielectric friction. Since both solutes and solvents are polar in nature, the Nee-Zwanzig (NZ) and van der Zwan and Hynes (ZH) dielectric friction theories have been used along with Stokes-Einstein-Debye (SED) hydrodynamic theory to assess the experimental results and understand the microfriction experienced by the solute. An important aspect of this work is to establish a relation between viscosity and hydrogen bond strengths at varying compositions of solvent mixtures as well as hydrogen bond strength between solute and solvents with the help of Gaussian 09 software. The H-bond strength thus calculated is found to be higher at a composition where the viscosity is the maximum. It provides an additional support to the experimental results.

Оценка параметра растворимости Гильдебранда смеси растворителей нефтяного происхождения по их структурным элементам

The work is devoted to the methodological aspects of estimating the Hildebrand solubility parameter of a mixture of organic solvents using the characteristics of their structural elements. A method is proposed for calculating the solubility parameter for mixtures of solvents that differ in composition and structure depending on the ratio of components. The results of calculations make it possible to predict the optimal composition of solvent mixtures for polymers with a known Hildebrand solubility parameter. The proposed method makes it possible to estimate the solubility parameter of complex mixtures of hydrocarbons of petroleum origin, for example, the vacuum residue of oil distillation - goudron, when it is used as a polymer solvent. Based on the results of 1H NMR analysis,the structural elements of goudron were determined and its Hildebrand solubility parameter was calculatedn.

Extraction of H3PO4 from low-grade phosphate rocks leachate of HCl-route by the mixture of TBP and IPE: Optimization, mass transfer and mechanism

The mixed solvent of tributylphosphate and isopropyl ether was used to extract H3PO4 and separate Ca2+ and Cl− from low concentration wet process phosphoric acid prepared by low-grade collophane and 30 wt% hydrochloric acid solution. Then, the effects of extraction temperature, composition of solvent mixture, aqueous/organic phase ratio, extraction time and extraction stage were investigated, respectively. The result shows that the extraction process of H3PO4 is an exothermic process and the enthalpy changes (ΔH) is −12.50 kJ mol−1. The McCabe–Thiele diagram shows two counter-current stages achieves about 76.9 wt% H3PO4 extraction at 293 K. Based on the mass transfer theory of liquid–liquid extraction, extraction yields for all tested component were summarized as an exponential function of cross-flow extraction stages. Meanwhie, extraction mechanism studies show that the comlex of αH3PO4 βTBP was formed in extraction process and higher Ca2+ concentration was beneficial for H3PO4 extraction. Meanwhile, the effects of stripping temperature, aqueous/organic phase ratio and stripping time on the re-extraction performance of H3PO4, Ca2+ and Cl− were studied, respectively. The result of experiment will provide some theoretical support for the industrial application of HCl-route wet process phosphoric acid on low-grade phosphate rock and phosphate tailings.

Combined experimental and molecular dynamic simulation study on low pressure solubility of CO2 in Thymol - Decanol based hydrophobic deep eutectic solvent and its binary mixtures with ethylene glycol

Deep eutectic solvents (DESs) as new classes of green solvents have been widely applied in many chemical and physical processes. Carbon dioxide (CO2) capturing by solvent is one of the interested issue which have been recently studied in DESs. This work includes the experimental results as well as the molecular dynamics (MD) simulation data of the solubility of CO2 in Thymol - Decanol as a hydrophobic DES and its binary mixtures with ethylene glycol (EG). The solubility of CO2 was measured at different compositions of binary solvent mixture under pressures 0.1–0.6 MPa at temperature range of 298–318 K. Experimental results showed that the CO2 solubility increased with increasing of DES molar fraction. The dependence of Henry's constant on solvent composition was investigated using preferential solvation model. Results showed that CO2 was preferentially solvated by DES molecules in binary solvent mixtures. In addition, MD simulations confirmed result of the experimental finding and preferential solvation model.

A drug delivery system based on poly-L-lysine grafted mesoporous silica nanoparticles for quercetin release

This work focuses on the preparation of a pH-sensitive antimicrobial drug delivery system based on Mesoporous silica nanoparticles (MSN), functionalized with aminopropyl-triethoxysilane (MSN-NH2), triethylenetetramine (MSN-TETA) and poly-L-lysine (MSN-NH2-PLL, MSN-TETA-PLL), and loaded with the flavonoid quercetin. The systems were fully characterized by means of several techniques. Besides the role of the different functionalization of MSNs, this work aimed to optimize both loading and release processes of quercetin, using two different ethanol-water mixtures as solvent, namely EtOH:H2O mixtures at the ratios 80:20 and 50:50. Whereas loading was higher using the 80:20 solvent mixture, a more efficient release was ascertained using the solvent mixture 50:50 as demonstrated by the release kinetics, and also by the amount of the released drug. It was suggested that in the presence of less ethanol, quercetin solubility decreases, and a physical adsorption of quercetin at the functional groups of MSNs can be favoured with respect to a random distribution over many surface sites with which only weak interactions can occur. This means that in the presence of high amount of ethanol, used very often when dealing with poorly water-soluble drugs, the impregnation process becomes dominant, loading increases significantly, but subsequently burst release of high amounts of drug occurs. In this work, using the specific case of quercetin, we found a more sustained release as the result of a predominant adsorption mechanism due to the careful choice of the solvent mixture composition during the loading step. Moreover, the new drug delivery system allowed for a significant improvement in quercetin stability and the optimal release concentration attainment.

Tuning structural-response of PLA/PCL based electrospun nanofibrous mats: Role of dielectric-constant and electrical-conductivity of the solvent system

The role of optimum solvent systems on the fabrication of uniform, bead-free electrospun-nanofibrous-mats (ENMs) of polylactic acid (PLA), poly(ε-caprolactone) (PCL), and their blends, is investigated. The solvent systems influenced the fiber-diameters, morphology, crystallinity, thermal stability, hydrophobicity, quasi-static mechanical, and solid-state visco-elastic responses of the ENMs. Defect-free ENMs were obtained by using CF/DMF (80:20 v/v) binary solvent system while showing a relatively higher extent of crystallinity (PLA/PCL blend ∼34%), lower hydrophobicity (PLA ∼1170), higher strength (PLA ∼6 MPa), and moduli (PLA ∼305 MPa) for PLA and PLA/PCL blend systems whereas a higher strain-at-break (∼ 82%) was shown by PCL based ENMs. PLA/PCL blend based ENMs fabricated using DCM/DMF (80:20 v/v) solvent-mixture exhibited comparatively lower crystallinity (∼ 25%) but higher fiber diameter (1.03 ± 0.21 µm), strain-at-break (∼ 155%), and hydrophobicity (∼ 130 0) compared to CF/DMF (80:20 v/v) system. Dynamic mechanical analysis (DMA) revealed the structural relaxation behaviors indicating the intrinsic structural deformability and flexibility of the mats. The study demonstrated the systematic role of solvent characteristics in terms of their volatility, dielectric constant, and solvent-mixture composition on the electro-spinnability and fabrication of high-strength, deformable, hydrophobic, bead-free ENMs with near monodisperse fibrous assemblies for biomedical applications.

Understanding the physical and thermodynamic properties of monoethanolamine‐ionic liquids for solvent screening in CO2 capture process

AbstractThe physical properties such as density, surface tension, and viscosity of monoethanolamine (MEA)‐ionic liquids (ILs) solvent mixtures were studied experimentally in this work. The ILs namely, tetrabutylammonium acetate TBAAc, tetrabutylammonium bromide TBABr, and tetrabutylammonium hydroxide TBAOH were used. All the above parameters were measured at atmospheric pressure and various temperatures from 283 to 313 K with a 10 K interval. From the measured experimental data, thermodynamic properties such as thermal expansion, excess molar volume, viscosity deviation, and excess Gibbs free energy were also calculated. The physical and thermodynamic properties are more important to understand the solvent behavior during solvent screening in solvent‐based CO2 capture process. The 30 wt% solvent mixture composition was prepared as 28, 25, and 20 wt% MEA mixed with 2, 5, and 10 wt% ILs. Furthermore, a single empirical model was developed from the measured experimental data and the results are correlated. A good agreement was obtained between correlated and experimental data.

Hydroalcoholic extraction of bioactive compounds from expeller soybean meal under subcritical conditions

The extraction of bioactive compounds from expeller soybean meal (ESM) was performed using different ethanol + water mixtures under subcritical conditions in a dynamic mode. The influence of temperature, solvent mass flow rate, solvent mixture composition, ionic strength, and particle size of the matrix on the extraction yield and the extract characteristics (total phenol and total flavonoid content and antioxidant activity) was evaluated using a screening design. Extracts that showed better results were analyzed by ORAC and TEAC tests. Finally, to predict the extraction kinetics of the bioactive compounds, the one-site desorption model and the thermodynamic partition model were compared. The results show that it was possible to obtain extracts with a high phenols and flavonoids content (23.04 mg GAE/g ESM and 7.34 mg QCE/g ESM, respectively) with good antioxidant capacity compared to extracts obtained from other vegetable matrices.

Regeneration of CO2‐rich aqueous amine‐ionic liquid blends in CO2 capture process

AbstractIn this present work, solvent regeneration of CO2‐rich aqueous solvent blends containing Monoethanolamine (MEA) and Ionic liquids was studied experimentally. The ionic liquids (ILs) used are tetrabutylammonium acetate [TBA][OAC] and tetrabutylammonium bromide [TBA][Br]. The solvent mixture composition of ILs are 2, 5, 10 wt% and their respective MEA as 28, 25, 20 wt%. CO2 absorption and desorption process were performed using solvent blends. The recovery of solvent was performed for three different temperatures 358, 368 and 373 K. The findings reveal that solvent blends of MEA with [TBA][Br] exhibit higher regeneration efficiency and lower regeneration energy than MEA with [TBA][OAC] blends with a minimum composition of 2 wt% [TBA][Br]. Energy consumption for recovery of 2 wt% [TBA][Br] blend with 28 wt% MEA was found to be 65.66 KJ mole−1 of CO2 which is 41.97% less than 30 wt% MEA. Furthermore, physicochemical properties such as pH, density, viscosity, carbon loading and surface tension have been measured before and after CO2 absorption and desorption process. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.

Preferential Solvation of 4-Carboxyl-2, 6-Dinitrophenylazohydroxynaphthalenes in Mixed Hydroxylic Solvents

Background: The applications of a group of 4-carboxyl-2,6-dintrophenylazohydroxynaphathalenes, AZ-01 to 04, as colourants, chemosensors or synthetic intermediates have been limited by their solubility.Aim: To investigate the effect of solvent mixture composition on the solubility, solution thermodynamics and position of equilibrium processes of the dyes.Method: The UV-visible spectral patterns of the dyes in binary mixtures including Methanol:Water, Ethanol:Water, Methanol:Ethanol, Methanol:Propan-1-ol, Methanol:Propan-2-ol, Propan-1-ol:Water and Propan-2-ol:Water were acquired. The type and quantitative estimation of solute-solvent interactions at play were determined by fitting spectral patterns to solvent parameters using multilinear regression.Results: Preferential solvation was detected by the non-ideality of the plots of E12 as against the mole fractions of co-solvent in all binary mixtures. In pure solvents, the spectral shifts of AZ-01, 03 and 04, which exist predominantly in the hydrazone form, were affected by polarity of solvent milieu while solvent basicity and acidity, in that order, were the significant parameters for AZ-02. In aqueous alcoholic mixtures, solvent polarity was contributory, although to different degrees, to the observed spectral data of the four dyes. However, solvent acidity and basicity were the primary determinants of spectral shifts observed with AZ-04 and AZ-03 respectively. Spectra-structure relationships identified the formation of the charged hydrazone tautomer which requires stabilisation by polar solvent milieu as responsible for the observed trend. In addition, interactions between new aggregated solvent-solvent species and the propionic acid substituent present in AZ-03 contributed to its spectral shifts.Conclusion: The solvatochromic properties of the phenylazonaphthalene series in binary mixtures have been successfully studied.

Solvatochromic Study of Two Carbanion Monosubstituted 4-Tolyl-1,2,4-triazol-1-ium Phenacylids in Binary Hydroxyl Solvent Mixtures

Two 4-tolyl-1,2,4-triazol-1-ium methylids, namely 4-tolyl-1,2,4-triazol-1-ium-phenacylid and 4-tolyl-1,2,4-triazol-1-ium-4′-nitro-phenacylid, are studied from solvatochromic point of view in binary solvent mixtures of water with ethanol and water with methanol. The contributions (expressed in percent) of the universal and specific interactions are separated from the spectral shifts recorded in the visible range for each composition of the binary solvent mixture. The essential role of the orientation and induction interactions in the studied solutions was demonstrated. Based on the statistic cell model of the binary solvent mixture solutions, the difference between the formation energies of ylid-water and ylid-alcohol complexes is estimated. The composition of the ylid’s first solvation shell was also established using the model of the binary solvent mixture solutions. The results obtained from the statistical cell model were compared with those obtained by using the Suppan’s model, resulting a good agreement.

Computer Aided Design of Solvent Blends for Hybrid Cooling and Antisolvent Crystallization of Active Pharmaceutical Ingredients.

Choosing a solvent and an antisolvent for a new crystallization process is challenging due to the sheer number of possible solvent mixtures and the impact of solvent composition and crystallization temperature on process performance. To facilitate this choice, we present a general computer aided mixture/blend design (CAMbD) formulation for the design of optimal solvent mixtures for the crystallization of pharmaceutical products. The proposed methodology enables the simultaneous identification of the optimal process temperature, solvent, antisolvent, and composition of solvent mixture. The SAFT-γ Mie group-contribution approach is used in the design of crystallization solvents; based on an equilibrium model, both the crystal yield and solvent consumption are considered. The design formulation is implemented in gPROMS and applied to the crystallization of lovastatin and ibuprofen, where a hybrid approach combining cooling and antisolvent crystallization is compared to each method alone. For lovastatin, the use of a hybrid approach leads to an increase in crystal yield compared to antisolvent crystallization or cooling crystallization. Furthermore, it is seen that using less volatile but powerful crystallization solvents at lower temperatures can lead to better performance. When considering ibuprofen, the hybrid and antisolvent crystallization techniques provide a similar performance, but the use of solvent mixtures throughout the crystallization is critical in maximizing crystal yields and minimizing solvent consumption. We show that our more general approach to rational design of solvent blends brings significant benefits for the design of crystallization processes in pharmaceutical and chemical manufacturing.

Hierarchical multi-layered scaffolds based on electrofluidodynamic processes for tissue engineering

The aim of this study was to obtain hierarchical scaffolds combining 3D printing and two electrofluidodynamic methods. The multi-layered scaffold is composed by 3D printed struts, electrospun fibers obtained from poly(ϵ-caprolactone) and electrosprayed spheres produced from hydrophobically modified chitosan, namely chitosan grafted with linoleic acid (CHLA). Since CHLA has been used for the first time in the electrospraying (electro dynamic spraying, EDS) process, the formation of spheres needed an optimization process. The EDS process was strongly affected by the solvent mixture composition, concentration of acid used for CHLA dissolution and solution flow rate. By using the optimized electrospraying conditions, uniformly distributed spheres have been obtained, decorating struts and nanofibers. Preliminary biological tests with mouse preosteoblasts (MC3T3-E1) were performed to investigate the effect of the hierarchical scaffold on cell seeding efficacy. Results showed that the hierarchical structure enhances cell seeding efficacy, respect to the 3D printed struts alone, preventing that the cells passed through the struts during the seeding. Moreover, the addition of the electrosprayed nanoparticles does not affect the cell seeding efficiency. The versatility of the proposed structure, with the added value of CHLA nanoparticles decoration could be suitable for several applications in tissue engineering, mainly related to drug delivery systems.

Replacing DMF in solid-phase peptide synthesis: varying the composition of green binary solvent mixtures as a tool to mitigate common side-reactions

The composition of green binary solvent mixtures is used as a tool to mitigate side-reactions in SPPS.

Protein Extraction from <i>Spirulina platensis </i>by Using Ultrasound Assisted Extraction: Effect of Solvent Types and Extraction Time

Protein is a substantial nutrition that essentially required by human. Spirulina platensis (Spp), well known as protein source could be a significant source to be used for many industrial applications. This study was investigated the effectiveness of ultrasound assisted extraction (UAE) method for protein extraction from Spp at various composition of solvent mixture and extraction time. Ethanol and mixture of methanol-ethanol were used as solvent. Extraction was conducted by varying ratios of solvent to biomass at 10:1, 12.5:1, and 15:1 (v/w), and extraction time (20, 35, and 50 min). Optimum protein recovery from dry Spp was 42.55 ± 0.43% obtained by using 20 ml of the mixture of methanol and ethanol at 50 min of extraction time. This study also conducted that mixture of methanol and ethanol was a better solvent on improving the ultrasound assisted extraction, as indicated by high protein recovery with less amount of solvent volume used.

Conductance behavior of material onium dichromates in aqueous-Methyl acetate mixtures

The paper explores conductance behaviour of material hetero cyclic Benzimidazolium, Indolenium and Imidazolium dichromates at 278–308 K in Methyl acetate, water and water-Methyl acetate mixtures of different compositions (v/v). The Kraus-Bray and Shedlovsky equations are used to calculate conductance data in this present work. The limiting molar, Ʌo, varies depending on the solvent mixture's composition. The preferential/selective conductance of cations by ethanol is interpreted using this method. In line with composition reliance of the Walden product, the effect of diverse solvent composition onion conductance is studied. With the help of the ‘R’-factor, the influence of the diverse solvent composition on the conductance of ions have been discuss.