Aqueous Solutions Of 2-propanol Research Articles

Concentration Effects in the Hydrogenation of 4-Nitro-2′-Hydroxy-5′-Methylazobenzene over Skeletal Nickel in an Aqueous 2-Propanol Solution

The kinetics of hydrogenation of 4-nitro-2′-hydroxy-5′-methylazobenzene in aqueous 2-propanol solution over the skeletal nickel is investigated at different initial concentrations. It is established that the hydrogenation of 4-nitro-2′-hydroxy-5′-methylazobenzene over a skeletal nickel in azeotropic aqueous 2-propanol solution proceeds via two parallel pathways at both low and high initial concentrations. It is shown that increasing the initial concentration of the hydrogenated compound above its level of solubility raises the rate of azo group transformation in 4-nitro-2′-hydroxy-5′-methylazobenzene, while the content of 4-amino-2′- hydroxy-5′-methylazobenzene does not change in the hydrogenate and is not accumulated in the bulk of solution.

KINETIC OF HYDROGENATION OF 4-NITRO-2'-HYDROXY-5'-METHYLAZOBENZEN ON SKELETAL NICKEL IN AQUEOUS SOLUTION OF 2-PROPANOL

The article is devoted to the kinetics of hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene on skeletal nickel in an aqueous solution of 2-propanol with the azeotropic composition at various initial concentrations of the starting compound. According to the obtained dependences of hydrogen absorption during the process, the changes in the amounts of the initial 4-nitro-2'-hydroxy-5'-methylazobenzene, the processing of the kinetic curves in linear coordinates of different orders, the data on the material balance of reaction products, the conlusion is drawn that at low concentrations the hydrogen addition is carried out through the nitro and azo groups to the starting 4-nitro-2'-hydroxy-5'-methylazobenzene molecule. An increase in the initial amount of 4-nitro-2'-hydroxy-5'-methylazobenzene introduced into the reactor leads to a marked decrease in the content of 4-amino-2'-hydroxy-5'-methylazobenzene. It was experimentally established that at the low initial concentrations, hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene on skeletal nickel in aqueous solution of 2-propanol with the azeotropic composition proceeds on the first order and zero one for hydrogen. An increase in the initial concentration of hydrogenated compound above the solubility limit leads to a sharp increase in a value of excessive adsorption of 4-nitro-2'-hydroxy-5'-methylazobenzene, to an increase in diffusion inhibition on hydrogen and to a change in the order for reducing agent. At the initial amounts of 4-nitro-2'-hydroxy-5'-methylazobenzene studied the transformation proceeds in two parallel directions. One of the directions is due to the addition of hydrogen on nitro groups to form 4-amino-2'-hydroxy-5'-methylazobenzene, and the second one on azo groups to form 2-amino-4-cresol and 4-nitroaniline.Forcitation:Hoang Anh, Kalashnikova V.A., Lefedova O.V. Kinetic of hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzen on skeletal nickel in aqueous solution of 2-propanol. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 10-15

KINETICS OF 2-CHLORO-4-NITROANILINE HYDROGENATION OVER SUPPORTED PLATINUM AND PALLADIUM CATALYSTS IN WATER SOLUTION OF 2-PROPANOL

The kinetics of liquid-phase hydrogenation of 2-chloro-4-nitroaniline over supported platinum and palladium catalysts in the aqueous solution of 2-propanol (0.68 mole fraction) was studied. Dependences of changes in concentration of participants vs the reaction time was obtained. The orders of reaction with respect to hydrogen and initial reagent were zero and the first. The palladium catalysts in comparison with platinum catalysts absorbed more amount of hydrogen. The products of dehalogenation reaction are main by-products. The platinum catalysts, as rules, more active in the conversion of the nitro group and selective with respect to chloroamine. The chloroaniline hydrogenation over the studied catalysts proceeded on sequential scheme. So, the chloroamine was dehalogenated. The values of the rate constants for all catalyst samples were varied depending on the total metal content. It was found that low-percentage platinum catalysts allow to achieve high selectivity of hydrogenation of HNC with respect to CFDA while maintaining the values of the observed rates of hydrogen absorption the similar as palladium catalysts. It is known that the kinetic regularities of catalytic reactions are associated with the structural and physicochemical characteristics of the catalysts. In particular, palladium and platinum have different electronic structures and behave is different in the catalytic reaction. Structure characteristics have value for the reaction kinetics also. The obtained data are consistent with these facts. However, some assumption appeared, that when the nature of the solvent varies, the same catalyst can behave differently. So, determination the relationship between the structure and activity of the catalyst only is not sufficiently correct for liquid-phase systems, without including the effect of the nature of the solvent.Forcitation:Latypova A.R., Krasnov A.I., Sharonov N.Yu., Safarov I.M., Lefedova O.V. Kinetics of 2-chloro-4-nitroaniline hydrogenation over supported platinum and palladium catalysts in water solution of 2-propanol. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 42-48

Kinetics of nitrobenzene hydrogenation on spongy nickel and catalyst with supported palladium in 2-propanol aqueous solutions with acid or base additives

The effect acetic acid and sodium hydroxide additives in a 2-propanol aqueous solution of azeotrope composition have on the rate of nitrobenzene (NB) hydrogenation over spongy nickel and supported palladium catalysts is studied. Analysis of the experimental data indicates that adding acid slows the rate more than adding a base during NB hydrogenation on spongy nickel. The observed rate for spongy nickel falls in a series of solvents: 2-propanol–water (0.68 mole fraction) > 2-propanol–water (0.68 mole fraction) + NaOH (0.01M) > 2-propanol–water (0.68 mole fraction) + CH3COOH (0.01 M). When a palladium catalyst is used, the addition of acid has less of an effect on slowing the rate of the reaction than that of the base: 2-propanol–water (0.68 mole fraction) > 2-propanol–water (0.68 mole fraction) + CH3COOH (0.01 M) > 2-propanol–water (0.68 mole fraction) + NaOH (0.01 M).

Kinetics of the hydrogenation of 2-chloro-4-nitroaniline over skeletal nickel and supported palladium catalysts in an aqueous solution of 2-propanol

The kinetics of the liquid-phase hydrogenation of 2-chloro-4-nitroaniline in an aqueous solution of 2-propanol over skeletal nickel and supported palladium catalysts is studied. The selectivity of the reaction with respect to 2-chloro-1,4-phenylenediamine is determined. It is found that samples of supported palladium catalysts differ with respect to the amount of the active component and the nature of the support. Some of their structural characteristics are provided.

Liquid Phase Hydrogenation of Maleic Acid Diethyl Ester and Its Mixture with 4-Nitrotoluene over Modified Skeletal Nickel

4-aminotoluene is known as a good octane additive, the mixture of maleic acid diethyl ester and Succinate acid diethyl ester has good lubricating characteristics. The process of hydrogenation of maleic acid diethyl ester at atmospheric pressure in aqueous solution of 2-propanol over skeletal nickel and modified skeletal one was investigated. It is established that the nickel surface modification by sulfur does not lead to the increase of the catalyst activity in the hydrogenation of maleic acid diethyl ester as opposed to 4-nitrotoluene. The principal possibility of selective hydrogenation of mixture of maleic acid diethyl ester with 4-nitrotoluene was demonstrated.

Effect of methanol in controlling defunctionalization of the propyl side chain of phenolics from catalytic upstream biorefining.

In recent years, lignin valorization has gained upward momentum owing to advances in both plant bioengineering and catalytic processing of lignin. In this new horizon, catalysis is now applied to the 'pulping process' itself, creating efficient methods for lignocellulose fractionation or deconstruction (here referred to as Catalytic Upstream Biorefining or 'CUB'). These processes render, together with delignified pulps, lignin streams of low molecular weight (Mw) and low molecular diversity. Recently, we introduced a CUB process based on Early-stage Catalytic Conversion of Lignin (ECCL) through H-transfer reactions catalyzed by RANEY® Ni. This approach renders a lignin stream obtained as a viscous oil, comprising up to 60 wt% monophenolic compounds (Mw < 250 Da). The remaining oil fraction (40 wt%) is mainly composed of lignin oligomers, and as minor products, holocellulose-derived polyols and lignin-derived species of high Mw (0.25-2 kDa). Simultaneously, the process yields a holocellulose pulp with a low content of residual lignin (<5 wt%). Despite the efficiency of aqueous solutions of 2-propanol as a solvent for lignin fragments and an H-donor, there is scant information regarding the CUB process carried out in the presence of primary alcohols, which often inhibit the catalytic activity of RANEY® Ni, as revealed in model compound studies performed at low temperature. Considering the composition of the lignin oils obtained from CUB based on ECCL, the processes commonly render ortho-(di)methoxy-4-propylphenol derivatives with a varied degree of defunctionalization of the propyl side chain. In this contribution, we present the role of the alcohol solvent (methanol or 2-propanol) and Ni catalyst (Ni/C or RANEY® Ni) in control over selectivity of phenolic products. The current results indicate that solvent effects on the catalytic processes could hold the key for improving control over the degree of functionalization of the propyl side-chain in the lignin oil obtained from CUB, offering new avenues for lignin valorization at the extraction step.

A green process for recovery of 1-propanol/2-propanol from their aqueous solutions: Experimental and MD simulation studies

In the present study, we have found that a common and relatively inexpensive biological buffer tris(hydroxymethyl)aminomethane (TRIS) is potentially applicable to shift the azeotrope compositions of aqueous solutions of 1-propanol and 2-propanol. By taking the advantage of our findings, we are proposing a green process for the recovery of these organics from their respective aqueous solutions. In order to confirm the effect of TRIS buffer on vapor–liquid equilibrium behavior of the aqueous propanol systems, we measured the isobaric vapor–liquid equilibrium (VLE) data at 101.3kPafor the 1-proponol+water+TRIS and 2-propanol+water+TRIS systems over the azeotropic range with various concentrations of TRIS (0.02, 0.04, 0.08, and 0.12 in mole fraction). The binary interaction parameters were obtained for TRIS with water, TRIS with 1-propanol, and TRIS with 2-propanol by correlating the new VLE data with the NRTL model. The isobaric VLE properties for the investigated propanol+water mixtures in the presence of various concentrations of TRIS were also predicted with the conductor-like screening model COSMO-RS. Based on the predicted excess molar enthalpies (HEm) from the COSMO-RS, the interactions between all constituent pairs of molecules were estimated. To explore the mechanism of TRIS-based separation of 1-propanol/2-propanol from their aqueous solutions, the interactions between different pairs of molecules were also investigated by using fluorescence analysis and Molecular Dynamic (MD) simulation. In comparison with the conventional corrosive inorganic salts and volatile organic entrainers, TRIS is non-corrosive, non-volatile, and almost totally recyclable. With the aid of TRIS, a cleaner separation process is proposed in the present study for recovery of 1-propanol and 2-propanol from their aqueous solutions based on buffer-swing distillation.

Electrochemical Measurement of Coenzyme Q10 Using Disposable Interdigitatad Array Electrode

Introduction Coenzyme Q10 (CoQ10) is an important component of the mitochondrial respiratory chain which exists as both oxidized form, CoQ10, and reduced form, CoQ10H2. CoQ10 is also known as an antioxidant in plasma, binding with lipoproteins during circulation. The antioxidative activity of CoQ10 depends on total CoQ10 concentration and percentage of CoQ10H2 in total CoQ10 in plasma. Since the ratio of CoQ10H2 is lower in patients with oxidative stress related diseases, it is considered to be an important marker for oxidative stress. At present, plasma CoQ10 and CoQ10H2 are usually determined by LC-electrochemical detector or LC-MS1,2) which are time-consuming, professional use and expensive analyzers. Considering the development of point of care (POCT) or on site sensor, simple, reliable, economical handy-type disposable test strip for CoQ10is favorable. Interdigitated array electrodes (IDAE) have excellent performances, such as high current density and high sensitivity, due to their hemisphere diffusion and array configuration. In this study, we will present electrochemical measurement of CoQ10using disposable IDAE for POCT or on site sensor. Methods Various concentrations of CoQ10 or CoQ10H2solution were prepared in mixture of 2-propanol and ammonium acetate aqueous solution . Amperometric measurements were performed by single mode or dual mode using IDAE. All solutions were bubbled with Ar before use. Results We first measured the dual mode redox current of working electrode 1 (collector electrode) and working electrode 2 (generator electrode), which were applied oxidizing potential and reducing potential, respectively. When CoQ10 solution was applied to sensor strip, faradaic signal from both generator and collector electrodes were soon reached to steady-state value. The response current on both generator and collector electrodes showed positive correlation with CoQ10 concentration. When CoQ10 oxidized form was applied to the strip, oxidation current was observed, indicating that CoQ10oxidized form was reduced onto the generator electrode and diffused and re-oxidized onto the collector electrode, thus redox cycle occurred successfully. Next, we measured the single mode redox current of working electrode 1 by applying reduction potential or oxidation potential. Reduction current was observed for CoQ10 and oxidation current was observed for CoQ10H2 and both of them exhibit steady- state currents soon after the potential application. The response current detected on working electrode 1 when reduction potential was applied to CoQ10 solution, oxidized form, showed positive correlation with CoQ10 concentration. When the oxidation potential was applied to CoQ10H2 solution, positive correlation with CoQ10H2concentration was observed. These results indicate that using IDAE, total CoQ10 concentration can be determined by dual mode amperometry and CoQ10 oxidized form or CoQ10H2can be determined by single mode amperometry (1) P. H. Tang et al., Clin. Chem. 2, 47 (2001) (2) J. Lagendijk, J. B. Ubbink, and W. J. H. Vermaak, J. Lipid Res. 1, 37 (1996) Figure 1

Kinetics and models of hydrogenation of phenylhydroxylamine and azobenzene on nickel catalysts in aqueous 2-propanol solutions

The kinetics of the hydrogenation of intermediates in the reduction of nitrobenzene in aqueous 2-propanol with acetic acid and sodium hydroxide additions on nickel catalysts was studied. A kinetic description of liquid-phase hydrogenation of azobenzene and phenylhydroxylamine was suggested. A kinetic model was developed. The dependences that characterize the variation of the amounts of the starting compound, reaction product, and absorbed hydrogen during the reaction were calculated. The calculated values were shown to be in satisfactory agreement with the experimental values under different reaction conditions.

Excess second-order thermodynamic derivatives of the {2-propanol + water} system from 313.15 K to 403.15 K up to 140 MPa. Experimental and Monte Carlo simulation study

In this work, the density of the aqueous solution of 2-propanol was measured from atmospheric pressure up to 140MPa in the 313.15–403.15K temperature interval throughout the composition range by using a vibrating tube densimeter. From these data, the volume, the isobaric thermal expansivity and the isothermal compressibility were derived using usual procedures, as well as their respective excess properties. Likewise, measurements of the isobaric heat capacity of the system were carried out by a Calvet calorimeter at p=0.1, 20, 40MPa from 313.15K to 393.15K at various concentrations of the alcohol. All this rich experimental information has been compared with Monte Carlo simulations, which were performed in coincident thermodynamic conditions by using a potential based on the OPLS for 2-propanol and the TIP4P/2005 for water, with the Lorentz–Berthelot mixture rules for determining crossing interactions. They were found to be in reasonable agreement with all observations. Likewise, the experimental results were compared with data previously reported in the field in order to further ensure the reliability of this work.

An Exceptional Artificial Photocatalyst, Nih‐CdSe/CdS Core/Shell Hybrid, Made In Situ from CdSe Quantum Dots and Nickel Salts for Efficient Hydrogen Evolution

A novel hybrid Nih -CdSe/CdS core/shell quantum dot is a simple and exceptional artificial photocatalyst for H2 production from 2-propanol aqueous solution. Studies on the nature of the artificial photocatalyst and mechanism for H2 production demonstrate that the synthetic strategy is general and the artificial photocatalyst holds promise for light capture, electron transfer, and catalysis at the surface of the Nih -CdSe/CdS core/shell quantum dots, leading to a self-healing system for H2 evolution in harmony.

Features of the kinetics of 4-nitroaniline and azoxybenzene hydrogenation in 2-propanol aqueous solutions

It is shown experimentally that the hydrogenation of 4-nitroaniline and azoxybenzene over a skeletal nickel catalyst in 2-propanol aqueous solutions proceeds selectively with the formation of the corresponding amines without the accumulation of side products in the bulk phase. It is concluded that during reduction, considerable participation of hydrogen bonded with active centers of a catalyst surface was observed. The competitive character of adsorption between the initial azoxybenzene and aniline formed as a result of reaction is established. It is ascertained that the character of changes in the rates of hydrogenation of nitro and azoxy groups is identical in the presence of additions of acid or base. It is demonstrated that a targeted change in the hydrogenation rates of these compounds is possible by introducing additions of acetic acid or sodium hydroxide into 2-propanol aqueous solution.

Simultaneous determination of five alkaloids in Niuhuang Shangqing Tablets by micellar electrokinetic chromatography-mass spectrometry using laurel acyl malic acid ester

A micellar electrokinetic chromatography-mass spectrometric method based on laurel acyl malic acid ester (LMAE) for the separation and determination of coptisine, berberine, jatrorrhizine, phellodendrine and ligustrazine in Niuhuang Shangqing Tablets was established. The baseline separation of the five compounds was attained within 18 min by an uncoated capillary (88 cm x 50 microm) on the operating voltage of 25 kV using 7.5 mmol/L LMAE-15 mmol/L ammonia-50 mmol/L ammonium acetate mixture (pH = 7.0) containing 12.5% (v/v) acetonitrile as the electrophoretic medium and 50% 2-propanol aqueous solution (containing 3 mmol/L acetic acid) as the sheath liquid. The peak area of each component to its concentration showed a good linear relationship. The relative standard deviations of migration times and peak areas of the five components were less than 5% and the recoveries were between 96.0% and 105%. The developed method is simple, rapid, accurate and is suitable for the routine analysis of the five alkaloid components in Niuhuang Shangqing Tablets.

Preparation of poly(N-isopropylacrylamide) brush grafted silica particles via surface-initiated atom transfer radical polymerization used for aqueous chromatography

Thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) brushes were densely grafted onto silica surface via surface-initiated atom transfer radical polymerization (SI-ATRP). The grafting reaction started from the surfaces of 2-bromoisobutyratefunctionalized silica particles in 2-propanol aqueous solution at ambient temperature using CuCl/CuCl2/N,N,N′,N′,N″-pentamethyldiethylenetriamine (PMDETA) as the catalytic system. Based on thermogravimetric analysis (TGA) results, the grafting amount and grafting density of PNIPAM chains on the surface of silica were calculated to be 1.29 mg/ m2 and 0.0215 chains/nm2, respectively. The gel permeation chromatography (GPC) result showed the relatively narrow molecular weight distribution (Mw/Mn= 1.21) of the grafted PNIPAAm. The modified silica particles were applied as high-performance liquid chromatography (HPLC) packing materials to successfully separate three aromatic compounds using water as mobile phase by changing column temperature. Temperature-dependent hydrophilic/hydrophobic property alteration of PNIPAAm brushes grafted on silica particles was determined with chromatographic interaction between stationary phase and analytes. Retention time was prolonged and resolution was improved with increasing temperature. Baseline separation with high resolution at relatively low temperatures was observed, demonstrating dense PNIPAAm brushes were grafted on silica surfaces.

Peculiarities of azobenzene catalytic hydrogenation in 2-propanol aqueous solutions with acid or base additives

It is shown experimentally that the hydrogenation of azobenzenes over a nickel skeleton catalyst in 2-propanol aqueous solutions proceeds selectively with the formation of aniline. It is pointed out that during the reaction, considerable participation of hydrogen bonded with active centers of a catalyst surface was observed. The competitive character of adsorption between the initial azo compound and aniline formed as a result of reaction is established. It is concluded that purposeful change of the azo group hydrogenation rate is possible by introducing acid or base additives into 2-propanol aqueous solution.

Reaction Mechanisms and Structural Characterization of the Reactive Intermediates Observed after the Photolysis of 3-(Hydroxymethyl)benzophenone in Acetonitrile, 2-Propanol, and Neutral and Acidic Aqueous Solutions

Nanosecond time-resolved resonance Raman (ns-TR(3)) spectroscopy was employed to investigate the photoinduced reactions of 3-(hydroxymethyl)benzophenone (1) in acetonitrile, 2-propanol, and neutral and acidic aqueous solutions. Density functional theory calculations were utilized to help the interpretation of the experimental spectra. In acetonitrile, the neutral triplet state 1 [denoted here as (m-BPOH)(3)] was observed on the nanosecond to microsecond time scale. In 2-propanol this triplet state appeared to abstract a hydrogen atom from the solvent molecules to produce the aryphenyl ketyl radical of 1 (denoted here as ArPK of 1), and then this species underwent a cross-coupling reaction with the dimethylketyl radical (also formed from the hydrogen abstraction reaction) to form a long-lived light absorbing transient species that was tentatively identified to be mainly 2-(4-(hydroxy(3-(hydroxymethyl)phenyl)methylene)cyclohexa-2,5-dienyl)propan-2-ol. In 1:1 H(2)O:CH(3)CN aqueous solution at neutral pH, (m-BPOH)(3) reacted with water to produce the ArPK of 1 and then underwent further reaction to produce a long-lived light absorbing transient species. Three photochemical reactions appeared to take place after 266 nm photolysis of 1 in acidic aqueous solutions, a photoreduction reaction, an overall photohydration reaction, and a novel photoredox reaction. TR(3) experiments in 1:1 H(2)O:CH(3)CN aqueous solution at pH 2 detected a new triplet biradical species, which is associated with an unusual photoredox reaction. This reaction is observed to be the predominant reaction at pH 2 and seems to face competition from the overall photohydration reaction at pH 0.

The thermodynamic properties of solutions of sodium chloride, water, and 1-propanol

The temperature-concentration dependences of the activity coefficient of NaCl in aqueous solutions of 1-propanol at 298 and 318 K, solution ionic strength up to 3m, and alcohol contents of 10–40 wt % were determined by the method of electromotive forces with ion-selective electrodes. The results were used to estimate interaction parameters in the Pitzer model. The Darken method was used to calculate the integral Gibbs energy of solutions.

Measurement of Ternary Mutual Diffusion Coefficients from Ill-Conditioned Taylor Dispersion Profiles in Cases of Identical or Nearly Identical Eigenvalues of the Diffusion Coefficient Matrix

Taylor dispersion has gained popularity for the measurement of mutual diffusion coefficients (Dik) for multicomponent solutions. In practice, however, the analysis of dispersion profiles, like the analysis of free-diffusion boundaries measured by optical interferometry, becomes ill-conditioned for solutes of similar diffusivities if the eigenvalues of the Dik matrix differ by less than about (5 to 10) %. These numerical difficulties, well-known in studies of multiexponential decays with nearly identical decay constants, can produce large errors in measured Dik coefficients and even rule out studies of important systems, including solutions of isomers, oligomers, polydisperse polymers, strongly associated solutes, and mixed electrolytes composed of ions of similar mobility. To investigate diffusion in these systems, equations are derived for the Taylor dispersion profiles produced by ternary mutual diffusion with equal eigenvalues. Using these equations, a simple least-squares procedure is developed to evaluate Dik coefficients from equal-eigenvalue profiles. Dik coefficients are reported from the analysis of severely ill-conditioned refractive-index profiles measured for aqueous solutions of 1-propanol + 2-propanol, 1-propanol + glycine, and mannitol + tetra(ethyleneglycol). In cases where the eigenvalues are not identical, but differ by several percent, the resulting errors in the Dik coefficients are estimated to be small and similar in magnitude to the accuracy of the Taylor measurements.

Solubility, Density, Viscosity, Refractive Index, and Electrical Conductivity for Potassium Nitrate−Water−2-Propanol at (298.15 and 313.15) K

The solubility of potassium nitrate in aqueous 2-propanol solution has been determined at the temperatures of (298.15 and 313.15) K and atmospheric pressure. The densities, viscosities, refractive indices, and electrical conductivities of potassium nitrate in water and in the saturated solutions of aqueous 2-propanol were measured at these two temperatures. Solubilities were determined using the analytical gravimetric method. Densities were determined using a vibrating-tube densimeter. Viscosities were measured with an automatic microviscometer based on the rolling ball principle. Refractive indices were measured using a digital Abbe-type refractometer. Electrical conductivities were determined by measuring the electrical resistance between two electrodes facing each other in the solution. The experimental values of solubility, density, and electrical conductivity were found to decrease with an increase of the concentration of 2-propanol for the saturated solutions of potassium nitrate + water + 2-propanol, while different trends with a maximum and a minimum were observed for viscosity and refractive index, respectively. Equations are given for these properties as a function of concentration.