System N-propanol Research Articles

Excess molar heat capacity for the binary system n-propyl alcohol + water in the temperature range 278.15–358.15 K: new data and application for excess enthalpy calculation

In this work, the new set of the data on the excess heat capacity (CPE ), density (ρ) and excess volumes (VE) for binary system n-propanol + water in the temperature range 278.15–358.15 K are presented. The concentration dependence of CPE was correlated using Redlich–Kister equation. Obtained experimental data of CPE were used to calculate excess enthalpies at various temperatures.

Heterogeneous azeotropic distillation for the separation of n-propanol + water mixture using n-propyl acetate as entrainer

Heterogeneous azeotropic distillation is a widely used process in the chemical process industries for the separation of binary azeotropic mixtures into their constituent pure components. It involves the addition of an entrainer which is partially miscible and forms a heterogeneous azeotrope preferably with one of the original components. For the design of heterogeneous azeotropic distillation columns, a detailed study of the heterogeneous region is crucial and this requires experimental vapor-liquid-liquid equilibrium (VLLE) data. The present study focuses on the study of n-propyl acetate as entrainer to effect the separation of industrially available azeotropic mixture n-propanol-water. A new and simple still was constructed to measure the VLLE data for the ternary system. The isobaric VLE data for the two binary systems n-propanol - water and n-propanol - n-propyl acetate and isobaric VLLE data for the ternary system n-propanol - water - n-propyl acetate were measured at atmospheric pressure. The experimental results have been compared with various thermodynamic models such as NRTL, UNIQUAC, UNIFAC (VLE) and UNIFAC (LLE). The set of parameters obtained from the above models has been used to construct the residue curve map (RCM) for the ternary system and the effect of n-propyl acetate to accomplish the separation of the azeotropic mixture has been discussed.

Chemical equilibrium and liquid-phase splitting in acetic acid + n-propanol + n-propyl acetate + water system at 293.15 and 353.15 K

The paper presents new experimental data on the chemical equilibrium in the system n-propanol + acetic acid + n-propyl acetate + water at 293.15 and 353.15 K, and the data on liquid–liquid equilibrium at 353.15 K. Based on the experimental and literature data, the possibilities that chemical equilibrium exists in a homogeneous or heterogeneous region of compositions has been analyzed. The temperature shift of chemical and phase equilibria and the values of the thermodynamic constants of chemical equilibrium are discussed.

Hydrate formation in the system n-propanol–water

The phase diagram of the binary system n-propanol alcohol–water was investigated with use of differential thermal analysis and powder X-ray diffraction. The phase diagram has three groups of thermal effects, which can be considered as peritectic melting of three different hydrates (−60.0, −53.5, and −41.5 °C). At the same time, powder X-ray diffraction data indicate the existence of only one compound in this system (cubic unit cell, a = 12.09 ± 0.01 A and 12.15 ± 0.01 A at −109 to −66 °C, respectively). The most probable explanation of this contradiction seems to be the existence of several hydrates belonging to the same structural type but different in composition.

2-D Model for the Description of Thermal Diffusion Cloud Chambers: Description and First Results

In thermal diffusion cloud chambers (TDCCs), a decrease of nucleation rate with increasing total pressure was observed repeatedly, both near atmospheric pressures and at elevated pressures. Because this pressure effect was observed almost only using TDCCs, there have been some concerns inside the nucleation community whether it is not an experimental artifact. One questionable point in this context is that, to calculate the profiles of temperature and saturation ratio in TDCCs it is assumed that if the chamber is sufficiently “flat”, a 1-d model can be used for the description of the transport processes in the central part of the chamber. The major concern in this context is that the heated chamber wall may cause a buoyancy driven convection that can propagate toward the center of the chamber and cause a slow motion of the gas mixture. To investigate this effect, a 2-d model of coupled mass, heat, and momentum transport in TDCCs has been developed. In the paper this model is described, and its predictive force is shown in comparison with a state-of-the-art 1-d model and with experimental data from the system n-propanol−He. Furthermore, results concerning the effects of wall heating, total chamber pressure, carrier gas, and chamber geometry on nucleation rates are presented. The influence of wall heating on the nucleation rate was found to be significant when transport processes inside TDCC are dominated by buoyant convection. Using the 2-d model made it possible to partly (but not completely) explain the pressure effect observed in TDDCs. It was also shown that including the process of thermal diffusion in the model may have a significant influence on the resulting profiles of nucleation rate. It was confirmed that the choice of the carrier gas in the chamber can strongly influence stability of chamber operation. With respect to the optimal chamber geometry it was shown that TDCCs should have a diameter as small and a diameter-to-height ratio as large as possible to minimize the 2-d effects. All in all, it was proven that application of 1-d models to describe the heat and mass transfer in TDCC may lead to an erroneous determination of temperature, saturation ratio, and nucleation rate profiles.

Separation of vitamin B complex and folic acid using TLC plates impregnated with some transition metal ions.

The separation of Vitamin B complex and folic acid was achieved on silica gel layers impregnated with Mn++, Fe++, Co++, Ni++, Cu++, Cd++, Zn++, or Mg++ (0.1%, 0.2%, 0.3%, 0.4% of each ion). Three new solvent systems n-propanol: n-butanol:water:ammonia (7:5:1:2, by vol), n-propanol:n-butanol:water:ammonia (7:5:1:1.5, by vol), n-propanol:n-butanol:water:ammonia (7:5:0.75:2, by vol) were developed. The spots of vitamins were located by exposing the chromatoplate to iodine vapours.

A Chromatographic Study of the Anthraquinones ofRhamnus alaternusL. III. Extraction, Isolation and Chromatographic Characterization of the Anthraglycosides of the Stem Bark

AbstractSeveral anthraglycosides were isolated from the bark of Rhamnus alaternus L. These had the following Rf values when chromatographed on Whatman no. 1 paper in the solvent system n-propanol, ethyl acetate, water (40:30:30 v/v): G1, 0.98; G2, 0.92; G3, -; G4, 0.79; G5, 0.72; G6, 0.65; G7, 0.61. However, in the TLC system chloroform, ethanol-95%, water (60:30:2 v/v) on silica gel G, G5 was found to be a mixture of G5a and G5b, the latter with the lower Rf value; while G7 separated into G7a, G7b and G7c in descending order of their Rf values. G2, highest in yield, is an emodin glucoside; G4 is an alaternin glucoside; G1 occurs in least amount. G1, G5b, and G6 are diglycosides of emodin, each yielding glucose and rhamnose. G6 hydrolyzes into G2 on TLC in the solvent system methanol, ethyl acetate, water (17:100:13 v/v) on silica gel G. G5a yields physcion, glucose and rhamnose. The total yield of G5 is close to but lower than that of G2. G7 may be a mixture of dianthrone glycosides, yielding on total hy...

Excess enthalpy, volume, and Gibbs free energy of n-propanol – isopropanol mixtures at 25 °C

The results of calorimetric, dilatometric, and circulation still studies of the system n-propanol – isopropanol at 25 °C are reported. Examination of the behavior of the excess properties indicates that deviations from ideality can be attributed mainly to the formation of mixed association complexes.

Identifizierung organischer verbindungen : LV. Paierchromatographische trennung und identifizierung von nitro- und nitrosophenolen

The chromatographic behaviour of nitro- and nitrosophenols in various solvent systems was studied. The best results were obtained in the solvent systems I-bromonaphthalene/80 % acetic acid and on papers impreganted with formamide, hexane, benzene, chloroform or their mixtures with acetic acid being the mobile phase. For nitro derivatives of dihydroxybenzenes the solvent system n-propanol—ammonia (2:1) is most suitable. The relations between chromatographic behaviour and structure of nitrophenols is discussed.

Liquid-Vapour Equilibria. IX. The Systems n-Propanol + Benzene and n-Butanol + Benzene at 45°C

Liquid-vapour equilibrium data are given for the systems n-propanol+benzene and n-butanol+benzene at 45.00 OC. The data are used to calculate the excess free energy of mixing for these systems.