Electrostriction in water and non-aqueous solvents

Top PDF Electrostriction in water and non-aqueous solvents:

Exploring electrochemical deposition in aqueous and non aqueous solvents using boron doped diamond electrodes

Exploring electrochemical deposition in aqueous and non aqueous solvents using boron doped diamond electrodes

Chapter 5 reports, ligands can slow down electrodeposition or inhibit it completely by adsorption of the ligands on the surface. 542 It is also important to note that for effective recovery of metals from aqueous solutions, acidic or basic media have been heavily used for sample digestion and electrochemical recovery enhancement. 543, 544 For example, Pd- acetate or PdCl 2 will dissolve in organic solvents but to dissolve in water, acid such as HCl should be added. For the industrial case, where electrodeposition has to be carried out from a solution containing diverse organic and inorganic molecules, addition of acids or bases may impact the structure of the APIs as an example. Hence, addition of acids or bases is not recommended. For our studies, we focus on Pd recovery, from Pd- acetate in MeCN, due the prevalence of this PGM, especially in the pharmaceutical industry. 368 Pd is described as a 4d-block transition metal, for more detailed properties data see Table 5.3, 535 which can form strong bonds because of its susceptibility to form hybridized orbitals along the direction of the d-orbitals by using ligand electrons. 545, 546 Because Pd is attached to oxygen containing ligands (in this case Pd is coordinated to the acetate groups), they form a strong coordination bond that can be described as a covalent bond because both Pd and O atoms are sharing their electrons. Pd phase transformation from the positively charged ion to Pd metal on the surface is then not possible. This is because it is difficult to extract electrons from the hybridised orbitals in this Pd-acetate structure and Pd is not solvated by the solvent molecules (i.e. we can think of it as the Pd ions being caged by their ligands and not free in the solution). 530 In contrast, if we were studying alkali and alkaline earth metals, then these metals have a tendency to lose electrons from the outermost shell (e.g. S orbital) and form ionic bonds and thus they are less susceptible to the ligand effects, which in many cases hinder metal deposition. 78
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EXPERIMENTAL EVALUATION OF TITRATIONS OF BENZIMIDAZOLES AND METAL BENZIMIDAZOLES IN NON-AQUEOUS SOLVENTS

EXPERIMENTAL EVALUATION OF TITRATIONS OF BENZIMIDAZOLES AND METAL BENZIMIDAZOLES IN NON-AQUEOUS SOLVENTS

The Arrhenius theory of electrolytic dissociation of acids and bases in water is reasonable to explain the titration in aqueous solutions only. This theory is clearly unsuited to explain the reactions in non-aqueous solvents which could conceivably contain hydrogen or hydroxylionGermann (1) considered that any substance that increases the solvent cation concentration is a corrosive, while any substance that increases the solvent anion concentration is a base. This theory appears satisfactory for ionisable solvent, yet is incapable of explaining corrosive base reaction in non-ionisable solvents, for example, dioxan, benzene.Bronsted considered an acid (A) as any compound or ions that can give up a proton and a base (B) as any compound or ion that can accept a proton.
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Acid Base Titrations in Aqueous Solvents

Acid Base Titrations in Aqueous Solvents

The very strong acids all completely dissociate in water, the differences in pKa value in this group are only noticeable in non-aqueous solvents such as acetone and alcohols. In water all the very strong act the same. The figure below presents titration curves of acids with different pK values using the degree of conversion λ versus pH.

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Kinetics of Acidic Mn(VII) Oxidation of Acetaldehyde in Aqueous and 5% Ethanol-Water Solvents

Kinetics of Acidic Mn(VII) Oxidation of Acetaldehyde in Aqueous and 5% Ethanol-Water Solvents

Which of course implies that the carbocation in the aldehyde is more susceptible to attack by MnO 4 - in non-aqueous solvent than in the aqueous solvent due to decrease in the dielectric constant of the reaction medium.The oxidation reaction studied in 5% Ethanol-Water mixture and aqueous solvents showed that reaction rate increases with decrease in dielectric constant of medium, suggesting that, polar solvents may require higher reaction time for oxidation reaction. Increase in the observed rate constant with decrease in dielectric constant of the medium implies an interaction between a dipole and a positive ion and also indicates the probable involvement of a protonated Mn 7+ specie in the presence of acid in the rate determining step. The rate of reaction increased with increase in temperature and the reaction were characterized by negative entropy of activation, which suggests the solvent molecules strongly surrounds the ions, which led to loss of entropy and the effect is more pronounced in non- aqueous solvents.
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Specific ion effects in non-aqueous solutions

Specific ion effects in non-aqueous solutions

A first step in answering this question is taken with the examination of the volcano plots for non-aqueous solvents in Chapter 4. Starting with standard solvation energies, the volcano trends appear broadly in all solvents, sug- gesting that the same interactions are at play and determine the ion-solvent interaction. This is remarkable given the widely different properties of the range of solvents examined, and consolidates the thesis of Chapter 3, that the ions determine the fundamental ordering of sie. In addition, the data show that, whereas the cation and anion trends observed in water can be expected to hold for protic non-aqueous solvents, and the cation trends in water can be expected to hold also in aprotic solvents, this prediction does not apply to anion trends in aprotic solvents. In this last case, one could expect perturb- ations and reversal as a result of the solvent change from hydrogen-bonding to non-hydrogen bonding. The extension of the volcano plots to real con- centrations (by studying non-aqueous activity coefficients and the solubility of electrolytes) shows that the infinite dilution findings are generally con- firmed. This is important because the volcano plots at real-concentrations also take into account the cation-anion ‘matching’ effect. This study high- lights the limited ability of aprotic solvents to solvate anions, which reveals crucial for the appearance of solvent-related perturbations in volcano plots.
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Silicate-Promoted Phosphorylation of Glycerol in Non-Aqueous Solvents: A Prebiotically Plausible Route to Organophosphates

Silicate-Promoted Phosphorylation of Glycerol in Non-Aqueous Solvents: A Prebiotically Plausible Route to Organophosphates

Abstract: Phosphorylation reactions of glycerol were studied using different inorganic phosphates such as sodium phosphate, trimetaphosphate (a condensed phosphate), and struvite. The reactions were carried out in two non-aqueous solvents: formamide and a eutectic solvent consisting of choline chloride and glycerol in a ratio of 1:2.5. The glycerol reacted in formamide and in the eutectic solvent with phosphate to yield its phosphorylated derivatives in the presence of silicates such as quartz sand and kaolinite clay. The reactions were carried out by heating glycerol with a phosphate source at 85 °C for one week and were analyzed by 31 P nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The yield of the phosphorylated glycerol was improved by the presence of silicates, and reached 90% in some experiments. Our findings further support the proposal that non-aqueous solvents are advantageous for the prebiotic synthesis of biomolecules, and suggest that silicates may have aided in the formation of organophosphates on the prebiotic earth.
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FLASH POINTS OF AQUEOUS SOLUTIONS OF FLAMMABLE SOLVENTS

FLASH POINTS OF AQUEOUS SOLUTIONS OF FLAMMABLE SOLVENTS

1 Current address: Health & Safety Laboratory, Harpur Hill, Buxton, Derbyshire, SK17 9JN 2 Ecole des Mines d’Albi, Campus Jarlard, 81013 Albi, Cedex 09, France Many fine chemicals and pharmaceutical intermediates are processed using flammable solvents which are soluble in water. The disposal of such solutions of sol- vents as waste can be problematical, particularly as dilute aqueous solutions can be expensive to incinerate. Disposal to an effluent treatment plant can be hazardous if the solution is above its flash point. Hence the availability of the flash point of aqueous solutions of flammable solvents would be useful for selecting an appropriate disposal route. Whilst such data of actual measurements of aqueous solutions are valuable, a predictive method would also be useful, and the data of three solvents have been compared to simple theoretical models, to allow prediction to be under- taken using readily available spreadsheets or calculating tools, rather than using dedi- cated specialist software for physical property prediction. The decision to avoid proprietary prediction software was taken deliberately to make the method easily applicable to users in small and medium enterprises (SMEs) who may not have access to such specialised programmes. The correlations obtained were good, with actual flash points being within 5 K of the predicted values. Tables of measured values are presented for 18 common solvents.
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Measurement and Thermodynamic Modelling of Erythritol Solubility in Aqueous Solvents

Measurement and Thermodynamic Modelling of Erythritol Solubility in Aqueous Solvents

mixture was prepared in a screw-capped bottle using magnetic stirrer to provide continuous agitation. To generate the system of the solid–liquid equilibrium, the solid–liquid mixing was continuously stirred for 24 h at the set temperature, and then the solution was kept for 30 min. to allow the undissolved solids to settle down in the lower portion of the bottle. Then, each prepared mixture was statically placed for 24 h in controlled cooling water bath with a temperature stability of ±0.05 K (LAUDA Alpha RA 24, Germany).

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Structural Stability of Proteins in deep Eutectic Solvents and their Aqueous Solutions

Structural Stability of Proteins in deep Eutectic Solvents and their Aqueous Solutions

The results of protein stability were also confirmed by SASA analysis, represented on Figure 4.5. A low value of SASA shows that protein has low surface area accessible for solvent due to its compact shape. According to the results, in pure water, SASA of protein fluctuates from 73 nm 2 to 88 nm 2 , and becomes stable after 40 ns of the simulation. In addition, in pure reline and slightly diluted reline (10% ww water) there are smaller fluctuations in SASA values, with an average of 80 nm 2 and 75 nm 2 , respectively. As noted above, more compact structure of lysozyme is observed in the aqueous reline solution containing 10% water by weight. Furthermore, with addition of water, SASA values show high fluctuations reaching maximum 95 nm 2 in more diluted reline solutions.
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Solvation enthalpy of uranium tetrachloride in aqueous-alcohols mixed solvents

Solvation enthalpy of uranium tetrachloride in aqueous-alcohols mixed solvents

Introduction Article Research The process of interaction between ions of a solute and the molecules of the solvent through relatively weak covalent bonds is called solvation. It involves evening out a concentration gradient and evenly distributing the solute molecules within the solvent. Hydration is a special case of solvation when the solvent molecules are water. Solvation energy, generally, is the energy released when ions in crystal lattices associate with molecules in a solvent, how- ever it can be positive or negative, depending upon the combined effects of lattice and hy- dration energies in case of aqueous-ionic solid dissolution. Uranous chloride or uranium tet- rachloride (UCl 4 ) is a green crystalline solid which sublimes in vacuum at 500°C/10 -3 mm. It is a Lewis acid and hence dissolves in solvents which can act as non-protic Lewis bases. Al- though dissolution of uranium tetrachloride crystals in water is an exothermic process yield- ing a green solution which is fairly stable in the cold, yet is hydrolyzed to a considerable ex- tent to furnish an acidic reaction. Solvation enthalpies of quadrivalent uranium system have been scantly reported. The present communication deals with the calculation of enthalpy of solution of uranium tetrachloride in aqueous-non-aqueous solvent mixtures, particularly in 10 and 20 weight (wt) % methyl alcohol-water and ethyl alcohol-water systems at 25°C calo- rimetrically and thereby estimating the solvation enthalpy of UCl 4 in the said media.
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Prediction of solubility of practically insoluble drugs in water/ethanol solvents using non empirical methods

Prediction of solubility of practically insoluble drugs in water/ethanol solvents using non empirical methods

The solubilities of ibuprofen and diazepam in water/ethanol binary solutions were predicted using COSMO-RS and UNIFAC. In case of the ibuprofen system, RMSE was 0.183, and COSMO-RS reproduced the experimental values well. The RMSE of UNIFAC was 0.628, and the solubilities predicted by UNIFAC were smaller than experimental values. Polarizabilities of several drugs in vacuum, water, and ethanol were calculated. A linear correlation between polarizabilities and solubilities was observed to exist in water.

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Studying of two choline chloride’s deep eutectic solvents in their aqueous mixtures

Studying of two choline chloride’s deep eutectic solvents in their aqueous mixtures

Corresponding author: makbq6@mail.missouri.edu Abstract:- Deep Eutectic Solvents (DESs) are an interesting category of solvents that recently getting more attention due to their unique properties. DESs proved their reliability in many applications which made them overcoming the traditional solvents. In this work, two deep eutectic solvents choline chloride: urea and choline chloride: glycerol having molar ratio of 1:2 respectively were prepared and characterized. Different water content, 0, 3, 5, 10, 25, 50 and 75 wt. %, were added and the effect was studied. Cyclic voltammetry, viscosity, density and thermogravimetric analysis have been investigated and reported in this research. The viscosity was studied as a function of temperature at normal and high temperatures and as a function of shear rate at low temperature. For our best awareness, the non-Newtonian behavior of the above two DESs is first reported in this work. The shear rate effected the viscosity of the mixtures at low temperatures; thereby, by increasing the applied shear rate, the viscosity of the mixtures decreased at a fixed temperature.
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A Simple Theoretical Approach of Aqueous Solutions of Salts and Organic Solvents  in Paper Chromatography

A Simple Theoretical Approach of Aqueous Solutions of Salts and Organic Solvents in Paper Chromatography

4.1.3. Phosphates of Monovalent Salts The chromatograms of the phosphates confirm those obtained previously. An- hydrous potassium phosphates behave like anhydrous potassium halides. So- dium tri-phosphate gives seemingly unusable results but explains the phenome- non of mercerizing by the modification of the cellulose of the paper under the action of the soda liberated by this very alkaline salt. It was possible to calculate the molecular volume of di potassium phosphate hence his density. The study of the ratio between the molecular weight Mw and the slope Rf x 0 C x 0 reveals a new family of the graphical representation developing only in the positive zone of the graph. The slopes of the lines of potassium and sodium phosphates meet at point 95, corresponding to the molecular weight of the anion PO 3 4 − = 94.97 while the straight lines joining the potassium and sodium phosphates meet on the left ordinate of the Rf.
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Separation of Acetic Acid from Aqueous Solution using Various Organic Solvents

Separation of Acetic Acid from Aqueous Solution using Various Organic Solvents

In the study a model has been developed to separate the acetic acid from aqueous solution by liquid-liquid extraction and find out the proper solvent for this separation. Various solvents such as n-butanol, iso butanol, amyl alcohol and ethyl acetate are used for separation of acetic acid from water. The binodal curves (mutual solubility curves) for acetic acid distributed between water and an organic solvent were obtained by titrating known mixtures of two components (water and solvents) with the third component acetic acid to the point of first appearance of permanent turbidity. In order to determine the tie-lines, the absorbance of the coexisting phases, obtained by the separation of ternary mixtures within the binodal curve are needed to be determined. The absorbance of each point had been determined by a UV spectrophotometer. Distribution diagrams are obtained by plotting weight percent of acetic acid in solvent phase against the weight percent of acetic acid in water phase. Selectivity diagrams are also obtained by plotting (wt. % of acetic acid) / (percent of acetic acid + percent of water) in solvent phase against the same quantity in the diluent phase. The separation factor is determined numerically from the tie-line data.
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Carbon dioxide removal by alkanolamines in aqueous organic solvents. A method for enhancing the desorption process

Carbon dioxide removal by alkanolamines in aqueous organic solvents. A method for enhancing the desorption process

Figure 4 shows the increased normalized values of the mass transfer coefficient and the physical solubility of CO 2 into 3.0 kmol m -3 MDEA as a function of methanol or ethanol mole fractions relative to water at 25 °C. [4] The plot shows a steep increase of the mass transfer coefficient at alcohol mole fractions lower than 0.1. Figure 5 shows the effect of methanol or ethanol mole fraction relative to water on m k l E of CO 2 when absorbed into 3.0 kmol m -3 MDEA at 25 °C, which was assumed to take place in the pseudo-first order regime. m k l E is proportional to the square root of the overall kinetic rate constant multiplied with the diffusivity of CO 2 . Because of the complexity of the current chemical system, the kinetic rate constants were, however, not determined. The values in Figure 4 do however give an indication of the initial mass transfer rate performance of MDEA in aqueous organic solvents. The initial mass transfer rate is seen to increase with increasing fraction of methanol or ethanol, and increases the most in the case of methanol to a factor of about seven at a methanol fraction of unity.
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Extraction of Phenol from Industrial Water Using Different Solvents

Extraction of Phenol from Industrial Water Using Different Solvents

The analysis and efficiency of phenol extraction from the industrial water using different solvents, were investigated. To our knowledge, the experimental information available in the literature for liquid-liquid equilibria of ternary mixtures containing the pair phenol-water is limited. Therefore the purpose of the present investigation is to generate the data for the water-phenol with different solvents to aid the correlation of liquid-liquid equilibria, including phase diagrams, distribution coefficients of phenol, tie-lines data and selectivity of the solvents for the aqueous phenol system. The ternary equilibrium diagrams and tie- lines data for systems containing Water-Phenol-Benzene, Water-Phenol-Chloroform, Water-Phenol-iso-Butyl Acetate, Water- Phenol-Butanol, Water-Phenol-Ethyl Methyl Keton and Water-Phenol-Toluene, were determined at 303 K and atmospheric pressure. The capacity and selectivity of these organic solvents in each of these systems were determined from the tie-lines data. The capacity of the isobutyle acetate was found to be the highest among the other solvents, and its selectivity was also the highest. Similar results also were obtained for the ethyl methyl keton but gave less capacity and selectivity as compared to the isobutyle acetate. It can be concluded that both isobutyle acetate and ethyl methyl keton are good solvents for extraction of phenol from industrial water. The liquid-liquid equilibrium data of ternary systems were correlated to the NRTL, UNIQUAC and UNIFAC models of activity coefficient to determine their adjustable parameters. The standard deviations from experimental compositions were calculated. Results show that the correlation may be greatly improved by applying the NRTL model with the regression criteria based on minimizing the experimental and calculating distribution coefficients S K to give an
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Non - Aqueous Acid - Base Titration

Non - Aqueous Acid - Base Titration

 Neutralization is an interaction between an Acid and a Base to produce Salt and Water. Arrhenius’s Acid – Base Theory does not explain the acidity or basicity of com[r]

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Membrane separation for non-aqueous solution

Membrane separation for non-aqueous solution

Subramanian et al. [87] reported that the color compounds and oxidation products could be effectively reduced by using hydrophobic nonporous membranes while the beneficial compounds could be retained. In the vegetable oil processing, the recovery of solvent from oil extraction (micelle) is the most critical steps regarding the economic, environmental, and safety reasons [70]. The controlling parameters of the permeation rate through membranes were solvent solubility parameter, dielectric constant (polarity), surface tension, and solvent viscosity [88]. The membranes processes like UF and RO have been used to recover the solvent from the micelle [89]. The important characteristics of membrane for solvent recovery are their solvents-resistance and the rejection performance [90]. The flux of permeate depends on the applied TMP, temperature, feed concentration, and cross-flow velocity. Higher pressures, temperatures, and cross-flow velocities yielded better permeate flux.
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Structure Evolution of Ordered Mesoporous Carbons Induced by Water Content of Mixed Solvents Water/Ethanol

Structure Evolution of Ordered Mesoporous Carbons Induced by Water Content of Mixed Solvents Water/Ethanol

Experimental Typically, 1.0 g of copolymer was dissolved in (20 − X) ml ethanol and X water mixed solvents under magnetic stir- ring at 30 °C. The volume of water, X, was in a certain range (X = 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 ml) to study the influence of water on the final mesostructures. Then, low-molecular-weight phenolic resol precursors were pre- pared as previously reported with some modifications [17]. The typical process was as follows: 1.0 g of phenol was melted at 45 °C before 0.31 g NaOH aqueous (20 wt%) was added into with stirring. 2.1 g of formalin (37–40 wt%) was added dropwise, and the mixture was stirred at 75 °C for 60 min. After cooling the mixture to room temperature, the pH of the reaction was adjusted to neutral (7.0) using 2.0 M HCl solution. Water was then re- moved under vacuum below 50 °C for 2 h. The final prod- uct was redissolved in ethanol and was added dropwise to the above solution containing copolymer, further stirred for 10 min. The solution was transferred to a dish, and the mixed solvents evaporated at room temperature over 8 h to produce a transparent membrane. The membrane was cured at 100 °C for 24 h in air for further thermopolymeri- zation. The product was carbonized at 800 °C for 2 h, with a heating rate of 1 °C min −1 under nitrogen atmosphere;
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The future of polar organometallic chemistry written in bio-based solvents and water

The future of polar organometallic chemistry written in bio-based solvents and water

While most of these DES studies use solvent systems based on the non-toxic quaternary ammonium salt ChCl, recent studies on the addition of aryllitium reagents to nitriles 26 to access aromatic ketones 27, under air and at room temperature, have shown that glycerol can also be used as an environmentally responsible reaction medium, showing similar conversions to those observed using the eutectic mixture ChCl/2Gly or water (Scheme 12). [49] Interestingly, these reactions occur heterogeneously ("on glycerol" conditions) where the lack of solubility of nitriles in glycerol and the ability of this solvent to form strong intermolecular H-bonds seem to be key factors to allow the smooth nucleophilic addition of the ArLi reagents to these carboxylic acid derivatives. Indeed, when glycerol-soluble MeCN was employed, no reaction was observed. Consistent with the proposed “on glycerol” conditions, with the reactions being thought to occur at the organic/liquid glycerol interface with glycerol-insoluble reactants, the yields are greatly influenced by stirring/agitation effects, which can affect the volume and surface area of the organic droplets (Scheme 12). This reactivity contrasts with that observed using water as the reaction medium, where even water-soluble nitriles could be successfully elaborated to tertiary carbinamines by a double nucleophilic addition jointly promoted by ArLi and (allyl)MgCl (Scheme 5). [29] Thus, although sharing some physico-chemical properties with water, glycerol is on a different ground, and a comparison of the outcome of the reaction using these two solvent systems is always recommended.
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