Vapor Pressure Data Research Articles

Extractive distillation of the benzene and acetonitrile mixture using an ionic liquid as the entrainer

The benzene and acetonitrile azeotropic mixture was proposed to be separated by extractive distillation using an ionic liquid (IL) as the entrainer. The suitable IL was selected by the COSMO-RS model, and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) was considered as the suitable entrainer mainly due to its high selectivity, low viscosity, and low price. The experimental vapor pressure data of the IL-containing systems (benzene + [EMIM][BF4] and acetonitrile + [EMIM][BF4]) were measured in the full concentration range. The results show that acetonitrile has a stronger interaction with IL than benzene, and the low deviations between the experimental and UNIFAC predicted values show the reliability of the UNFIAC model. The UNIFAC predicted vapor–liquid equilibrium data of the benzene + acetonitrile + dimethyl sulfoxide (DMSO)/[EMIM][BF4] system show that the relative volatility of benzene to acetonitrile is higher when the entrainer is [EMIM][BF4]. The process simulation results show that [EMIM][BF4] can reduce the material and energy consumptions compared with DMSO.

Thermodynamic optimization of the Cu–As–S system

A literature review, critical assessment and thermodynamic modeling of matte, metal (speiss) and solid phases in the Cu–As–S system are presented. The literature data include enthalpies and entropies of formation, activity measurements using vapor pressure, phase equilibrium and element distribution data. The model for the liquid phase was developed within the framework of the Modified Quasichemical Model (MQM) in pair approximation. Liquid metal and matte phases were described using the single solution with a miscibility gap. Previously published model parameters for the liquid phase in the Cu–S system were modified to achieve agreement with the data for the Cu–As–S system. The resulting set of model parameters was incorporated into a large multicomponent thermodynamic database intended for predictions of phase equilibria, heat balance and distribution of arsenic in the course of pyrometallurgical processing of copper- and lead-containing materials.

Methodology for constructing the equation of state and thermodynamic tables for a new generation refrigerant

A unified fundamental equation of state 2,3,3,3-tetrafluoropropene (R1234yf) has been developed, a fourth-generation ozone safe refrigerant, and a method for constructing the equation has been proposed. In the gas region, this equation transforms into the virial equation of state, and in the vicinity of the critical point it satisfies the requirements of the modern large-scale theory of critical phenomena and transforms into the Widom scale equation. On the basis of a single fundamental equation of state in accordance with GOST R 8.614-2018, standard reference data (GSSSD 380-2020) on the density, enthalpy, isobaric heat capacity, isochoric heat capacity, entropy and sound velocity of R1234yf in the temperature range from 230 K to 420 K and pressures from 0.1 MPa to 20 MPa. A comparison of the calculated values of equilibrium properties with the most reliable experimental data obtained in the famous of the world, and tabular data obtained on the basis of the known fundamental equations of state R1234yf. Uncertainties of tabulated data for saturated vapor pressure, density, enthalpy, isobaric heat capacity, isochoric heat capacity, entropy and speed of sound of 2,3,3,3-tetrafluoropropene are estimated – standard relative uncertainties by type A, B, total standard relative and expanded uncertainties. The results obtained in the work show that the proposed unified fundamental equation of state adequately describes the equilibrium properties of R1234yf in the range of state parameters stated above.

Study on Remote Sensing Inversion of Atmospheric Water Vapor Content Based on FY3B/MERSI Data

Atmospheric water vapor plays a vital role in global climate change. It not only affects local weather and climate but also influences the global water cycle and energy balance. Therefore, an accurate understanding of the atmospheric water vapor content and its changes are of great importance for forecasting climate, understanding global climate change, and studying the greenhouse effect. In this paper, the inversion of atmospheric water vapor content was conducted by FY3B/MERSI data, and verification was made by comparing with the sounding data, ground water vapor pressure data, and AQUA/MODIS water vapor content data. The results show that FY3B/MERSI atmospheric water vapor content has a significant positive correlation with the sounding water vapor content, ground water vapor pressure data, and AQUA/MODIS water vapor content data. Among them, the correlation with the sounding water vapor content is the most significant. An inversion correction model of MERSI atmospheric water vapor content can be established to improve the inversion accuracy.

Total vapor pressure of hydrophobic deep eutectic solvents: Experiments and modelling

Headspace gas chromatography mass spectrometry (HS-GC–MS) was used to determine the volatility of six selected hydrophobic deep eutectic solvents (DESs). The partial pressure of each DES constituent (decanoic acid, thymol, 1-tetradecanol, menthol or lidocaine) was measured from 313.15 to 373.15 K. The activity coefficients of the hydrogen bond acceptor (HBA) and the hydrogen bond donor (HBD) were determined to quantify the interactions between the DES constituents, thereby deepening the understanding of the thermodynamic nature of the DESs. In addition, the activity coefficients for both components in each DES were predicted with the UNIFAC group contribution method. Similar trends and reasonably close values were obtained for the measured and predicted activity coefficients. It has been found that the interactions between the DES constituents tend to become weaker with increasing temperature. Strong interactions occur between thymol and lidocaine, and thymol interacts moderately with menthol. A weak force exists between decanoic acid and menthol. The mixtures of menthol with 1-tetradecanol or lidocaine are not strictly DESs since for each DES constituent both the measured and predicted activity value is close to unity. A viscosity study was also carried out to quantify the interactions and similar results were found. The ideal mixing rule was proven to correctly describe the viscosity for the mixture of menthol with 1-tetradecanol or lidocaine. While compared to the ideal mixture viscosity, an increase in viscosity was observed for other studied DESs indicating stronger interactions. Finally, the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was shown to accurately describe the thermodynamic properties, where the PC-SAFT pure-component parameters for the DESs were obtained by fitting to pure DES density and total vapor pressure data.

In the footsteps of August Michaelis: Syntheses and Thermodynamics of Extremely Low-Volatile Ionic Liquids.

A series of nine different known ionic liquids or low melting salts was synthesised and purified. They are composed of the [NTf2]– (bis(trifluoromethane)sulfonimide), [OTf]– (trifluoro‐methane‐sulfonate), or [B(CN)4]– (tetracyanidoborate) anion and [Ph4P]+ (tetraphenylphosphonium), [Ph3BzP]+ (triphenylbenzyl phosphonium), [nBu4P]+ (tetra‐nbutylphosphonium), [nBuPh3P]+ (tri‐phenyl‐nbutylphosphonium), [nBu4N]+ (tetra‐nbutylammonium), or the [PPN]+ (bis(triphenylphosphine)iminium) cation. Precise vapour pressure data and enthalpies of vaporisation were measured using the Quartz Crystal Microbalance (QCM) method and evaluated. Structure‐property relations are established using the obtained data as well as literature known data of ILs with alkyl‐substituted imidazolium cations. It turns out that ILs with the tetracyanidoborate anion have even higher values of the enthalpy of vaporisation than those with the common [NTf2]− or [OTf]− anion and therefore are even less volatile.

New modified PC-SAFT pure component parameters for accurate VLE and critical phenomena description

The theory of Perturbed Chain Statistical Associating Fluid (PC-SAFT) is largely applied in many industrial fields. It requires three parameters: the segment number (m), the hard-core segment diameter (σ), and the segment-segment interaction energy parameter (ε/k) for every pure non-associating fluid. By convention, they are determined by fitting vapor pressure and liquid density data. However, the shortage behind these parameters adopted by their respective authors is that they give excessive values of critical temperatures and critical pressures, which are crucial to forecasting vapor-liquid critical pressure and composition of the mixture at high pressures and temperatures.In this paper, a new approach is proposed to evaluate PC-SAFT parameters of different substances from diverse chemical families. Good fits of saturation pressure and vapor densities values of 94 pure substances are obtained, with an overall AARD of 0.89% and 1.50% respectively.The proposed method requires as input the critical pressure (Pc), the critical temperature (Tc), and the acentric factor (ω). By using these parameters, PC-SAFT estimates with accuracy the critical properties of pure compounds as well as the successful prediction of vapor-liquid equilibria for many non-associating binary systems at critical regions including mixtures containing ammonia, comparing with other literature values. But the limitation of this method is reflected in underestimated liquid densities.

Thermodynamic optimization of the As–S system

Literature review, critical assessment and thermodynamic modeling of the liquid and solid phases in the As–S system are presented. A set of optimized model parameters was obtained to reproduce previously published experimental data. The literature data included enthalpies of formation, heat capacity, vapor pressure and phase equilibrium data. A significant discrepancy among different sets of literature data was revealed. The model for the liquid phase was developed within the framework of the Modified Quasichemical Model (MQM) in pair approximation. The resulting set of model parameters was merged and tested within a larger multicomponent thermodynamic database for pyrometallurgical copper, lead and recycling industrial operations.

Vapor Pressures and Thermophysical Properties of 1-Heptanol, 1-Octanol, 1-Nonanol, and 1-Decanol: Data Reconciliation and PC-SAFT Modeling

Vapor pressures for liquid 1-heptanol (CAS RN: 111-70-6), 1-octanol (CAS RN: 111-87-5), 1-nonanol (CAS RN: 143-08-8), and 1-decanol (CAS RN: 112-30-1) were measured by a static method near ambient temperatures over an operating pressure range from 0.5 to 1270 Pa, thus complementing literature vapor pressure data obtained by ebulliometry at higher temperatures. Liquid heat capacities of 1-octanol, 1-nonanol, and 1-decanol were determined by Tian–Calvet calorimetry. Ideal-gas thermodynamic properties of 1-alkanols up to 1-heptanol were obtained by a combination of quantum chemistry and statistical mechanics and validated against available experimental data. Ideal-gas heat capacities and entropies for longer homologues were obtained by deriving a methylene increment due to having a too complex conformational shape for analogical treatment. The thermodynamic consistency of available data was validated by simultaneous correlation of selected vapor pressures, literature enthalpies of vaporization, and heat capacity differences between the ideal gaseous and the liquid phase. The results are represented by the Cox equation and compared with available literature data. Moreover, the results were used to examine the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state for its performance in describing vapor pressures, enthalpies of vaporization, residual liquid heat capacities, and liquid densities of neat 1-alkanols from 1-hexanol to 1-decanol. A new PC-SAFT parameter set for each of them was also regressed that improves the PC-SAFT performance for the studied properties in comparison to existing parameters published in the literature.

Experimental and an electrolyte non-random two-liquid model to predict the vapor–liquid equilibrium of CO2 in aqueous solutions of diethylenetriamine

The absorption and desorption data of CO2 in aqueous solutions with a mass fraction of 10% and 20% of diethylenetriamine are measured at 313.15, 343.15, 373.15, and 393.15 K. The electrolyte non-random two-liquid theory is developed using Aspen V9.0 to correlate and predict the vapor–liquid equilibrium of CO2 in aqueous diethylenetriamine solutions. The model predicted the heat capacity and saturated vapor pressure data of diethylenetriamine, the mixed heat of a diethylenetriamine–H2O binary system, and the vapor–liquid equilibrium data of a diethylenetriamine–H2O–CO2 ternary system. The physical parameters and the interaction parameters of the model system are calculated. The model predicted CO2 solubility showing a 10% average absolute deviation from experimental data. The calculated values of the model are basically consistent with the experimental values.

Vapor Pressures of Phenolic Compounds Found in Pyrolysis Oil

Oil produced from pyrolysis of Kukersite oil shale and lignocellulosic biomass contains significant amounts of phenolic compounds. Here, we present new experimental vapor pressure data for two such...

Spatiotemporal variation of reference evapotranspiration in Shanxi Province, China

Based on data of daily precipitation, temperature, sunshine hours, relative humidity, wind speed and vapor pressure of 70 meteorological stations from 1960 to 2019 in Shanxi Province, the Penman-Monteith model was applied to calculate the reference evapotranspiration (ET0). The spatiotemporal variations of ET0 as well as the ET0 in different climatic zones and at different altitudes were quantitatively analyzed. The results showed that the mean annual ET0 decreased from west to east in 1960-2019. A jumping point was detected in 1982, with the mean annual ET0 increased both in 1960-1982 and 1983-2019. The monthly and ten-day changes of ET0 showed single peak curves. The variation of ET0 in different climatic zones was as follows: ET0 in temperate and semi-arid areas was higher than that in warm temperate and semi-humid areas and warm temperate and semi-arid areas in spring, summer, autumn and the whole year, while in winter, the highest ET0 was in warm temperate and semi-humid areas. ET0 varied with altitudes, with ET0 in <660 m altitude areas being higher than that in other altitudes in summer, autumn, winter and the whole year.

Vapor pressures and vaporization enthalpies of 1-nonadecanol. Isophytol, 2 Z- and 2 E-Phytol, and (2E,7R,11R) phytol by correlation gas chromatography

This work reports vapor pressures and vaporization enthalpies of 1-nonadecanol, isophytol, 2E- and 2Z-phytol, and the phytol found naturally, (2E,7R,11R)-phytol. Both phytol and isophytol are important commercial substances. 2E and 2Z-phytol exhibit a variety of useful pharmaceutical properties, are used in many fragrance formulations, and have been approved as a food flavor in the US. Isophytol also exhibits a similar fragrance and flavor profile and is an intermediate in the synthesis of vitamins E and F1. Vaporization enthalpies at T = 298.15 K are evaluated as are vapor pressures from T = (298.15 to 450) K for the phytols and from T = (298.15 to 550) K for 1-nonadecanol. Reasons for the variations in the temperature range studied are discussed. Vapor pressures are fit to a second order polynomial. Results for 1-nonadecanol at elevated temperatures are in good agreement with previous work. Vapor pressures for isophytol at elevated temperatures are in qualitative agreement with previous literature values but the calculated vaporization enthalpy at T = 454.1 K evaluated in this work differs significantly from the literature value calculated using previously reported vapor pressure data.

A Comparative Study for Application of Pitzer and ePC-SAFT Equations to Predict Volumetric and Saturation Properties in “Formation” Water

Predictions of salt solubility, brine vapor pressure and density are necessary to plan subsurface and surface operations. In this work, a comparative study was conducted to investigate prediction capabilities for salt solubility, equilibrium and volumetric properties of several minerals in “Formation” water by the Pitzer model (a commonly used industrial model) and by the ePC-SAFT equation of state (EOS). To achieve this, several validation and comparison steps were considered for reliable implementation of both models. Firstly, solubility, brine densities and vapor pressures for single-salt solutions were predicted. Afterward, the models’ applications were extended to several mixtures of two salts to predict solubility compared to experimental data from available literature. ePC-SAFT shows promising accuracy. The average relative deviation for prediction of liquid density (which cannot be estimated with the Pitzer model) for single-salt solutions of NaBr, KCl, NaCl and Na2SO4 are 1.13%, 0.70%, 1.02% and 0.36%, respectively. The average relative deviation from experimental data of vapor pressure for mixtures of NaCl and KBr is 0.75% and for mixtures of NaBr and KCl is 0.74% for systems with different concentrations. Moreover, a stochastic regression procedure is presented to evaluate the ePC-SAFT parameters. This technique is used for strontium in different salt solutions. The average relative deviation for mean ionic activity coefficients calculated by ePC-SAFT from experimental data using the ePC-SAFT parameters of strontium from the work of Held et al. [1] for single-salt solutions of strontium chloride, strontium bromide, strontium iodide, strontium nitrate and strontium perchlorate are 19.73%, 19.96%, 15.15%, 14.95% and 25.70%, respectively. These values using the ePC-SAFT parameters of strontium regressed in this work are 6.98%, 10.13%, 8.33%, 9.59% and 10.08%, respectively. Finally, the solubility of different salts was studied for mixing of formation water (FW) and injection water (SW).

Effect of deep eutectic solvents based on choline chloride on the thermodynamic and transport properties of D-fructose in aqueous solution

In this work, the effect of some deep eutectic solvents (DESs) based on choline chloride on the thermodynamic and transport properties of D-fructose in aqueous solutions was investigated. Using the vapor-liquid equilibrium (VLE) data, water activity (aw), osmotic coefficient and vapor pressure data were obtained. The performance of different local composition models such as Wilson, e-NRTL, and UNIQUAC for correlating of these data have been examined. The calculated negative values of Gibbs free energies of transfer (ΔGtri) indicate favorable interaction of DESs with D-fructose. Further, the standard partial molar volumes Vφ0, partial molar isentropic compressibility Kφ0, viscosity B-coefficient and molar refractions RD for the solutions have been calculated from the measured density and speed of sound, viscosity and refractive index data at T = (288.15 to 318.15) K. Interaction volume Vint and cavity volume Vcav have been computed from scaled particle theory (SPT) to probe solute-solvent interactions. The viscosity B-coefficients was used to discuss structure-making tendency of the solutions studied.

Experimental and modeling investigations of the interfacial tension of three different diesel + nitrogen mixtures at high pressures and temperatures

Interfacial tension (IFT) data are reported at temperatures up to 530 K and pressures up to 100 MPa for mixtures of N2 with a highly paraffinic diesel, an ultra-low sulfur diesel, and a highly aromatic diesel. The impact of composition on the IFT is determined by comparing data for each system at the same temperature and pressure calculated from a Tait-like relationship fit to the experimental data. The greatest differences in diesel + N2 IFT values are found near the normal boiling point (Tboil) of each diesel where lower molecular weight diesel components begin to dissolve in the N2-rich vapor phase. IFT data are modeled with density gradient theory (DGT) coupled with the perturbed-chain, statistical associating fluid theory equation of state (EoS). Diesel EoS parameters are calculated using three variations of a pseudo-component technique created from one group contribution (GC) method developed from high-pressure density data and from two other GC methods (S-GC and T-GC) developed from differing sets of pure component vapor pressure and saturated liquid density data. The IFT predictions significantly improve when the DGT influence parameter, cii, is allowed to vary with temperature. The DGT predictions with the B-GC method are in closest agreement with data at temperatures below Tboil, which is attributed to the more accurate representation of liquid phase densities. However, at temperatures above Tboil, where significant amounts of low molecular weight diesel components dissolve in the N2-rich vapor phase, DGT predictions with the S-GC and T-GC methods provide the closest agreement with IFT data.

Identification of Pesticide Residues and Prediction of Their Fate in Agricultural Soil

Fourteen pesticides were screened and determined through quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction process combined with GC-MS/MS in arid agriculture soil. The aims of the current investigation were to account the occurrence of organochlorine (OCP) and organophosphates (OPP) pesticide residues as well as other groups of pyrethroids (PYRs), carbamates, and biopesticides using a combined of QuEChERS and GC-MS/MS techniques in agriculture soils at Al-Kharj region, Saudi Arabia, and to investigate correlation between pesticide losses in soils and some physicochemical characteristics of pesticides including an octanol-water coefficient partition (Kow) and the vapor pressure (Vp). Prediction of pesticide fate by considering both pesticide and soil physio-chemical properties will facilitate the management of pesticide application and minimize the hazards of environmental pollution. The fate of pesticide residue in soils is generally controlled by soil/air exchange, water interaction, and biodegradation. The results indicated that 14 pesticide residues were measured in collected samples of various soils, spinosad, chlorpyrifos methyl, dimethoate, chlorpyrifos, lindane (γ-HCH), permethrin, and methomyl which were the most abundant sources of contamination in the studied region. p,p-DDT, o,p-DDT, bifenthion, β-cyfluthrin, and methidathion were less commonly detected. Single parameter least squares regression equations (sp-LSRE) for Vp and Kow against the loss of each pesticide residue showed a significant change in concentration levels (p < 0.05) between the two seasons. The results showed that vapor pressure and octanol-water partition coefficient data are not enough to model pesticide residue losses in arid low organic carbon soil. More soil-related data is needed to describe the dissipation mechanisms of these pesticide residues in the region.

Assessment of the SM12, SM8, and SMD Solvation Models for Predicting Limiting Activity Coefficients at 298.15 K

The SMx (x = 12, 8, or D) universal solvent models are implicit solvent models which using electronic structure calculations can compute solvation free energies at 298.15 K. While solvation free energy is an important thermophysical property, within the thermodynamic modeling of phase equilibrium, limiting (or infinite dilution) activity coefficients are preferred since they may be used to parameterize excess Gibbs free energy models to model phase equilibrium. Conveniently, the two quantities are related. Therefore the present study was performed to assess the ability to use the SMx universal solvent models to predict limiting activity coefficients. Two methods of calculating the limiting activity coefficient where compared: (1) the solvation free energy and self-solvation free energy were both predicted and (2) the self-solvation free energy was computed using readily available vapor pressure data. Overall the first method is preferred as it results in a cancellation of errors, specifically for the case in which water is a solute. The SM12 model was compared to both the Universal Quasichemical Functional-group Activity Coefficients (UNIFAC) and modified separation of cohesive energy density (MOSCED) models. MOSCED was the highest performer, yet had the smallest available compound inventory. UNIFAC and SM12 exhibited comparable performance. Therefore further exploration and research should be conducted into the viability of using the SMx models for phase equilibrium calculations.

Hydrometeorological Study of Saturated Vapour Pressure (SVP) of Warri, Nigeria

The amount of water vapour present in the air is indirectly expressed through vapour pressure and for any given temperature there is a limit for water vapour that can be held by air. If the air is holding water vapour which is equal to the maximum that it can hold at a given temperature, then the air is said to be saturated. Hydrometeorological study was carried out using vapour pressure (VP) and maximum temperature data for Warri through 2009 – 2018 (10 years) Saturation Vapour Pressure (SVP) were estimated. A graph is established showing the relationship between the Saturation Vapour Pressure (SVP) and the temperature also the graphical representation showing variational trend of SVP and VP were plotted. The study shows the dew point (Td) ranging from 29.9°C to 31.5°C which explained the likely rainfall at any temperature below Td. The study also confirmed increase in SVP bringing increase in Temperature and the variational trend shows the same pattern all through.

Saturated vapor pressure and gaseous pvT property measurements for 3,3,3-trifluoroprop-1-ene (R1243zf)

Abstract 3,3,3-trifluoroprop-1-ene (R1243zf) is a potential alternative refrigerant with low global warming potential and 26 saturated vapor pressure data and 128 vapor phase pvT data are presented in this paper. The vapor pressure data were obtained in the temperature range from (253 to 376) K and pressure range from (0.13 to 3.46) MPa. The vapor phase pvT data were measured using a Burnett apparatus for the temperature range from (253 to 368) K, pressure range from (0.11 to 2.89) MPa and density range from (0.05 to 1.82) mol dm–3. The standard experimental uncertainties were estimated as 5 mK and 0.5 kPa for temperature and pressure, respectively. The relative uncertainty in density is better than 0.12%. In addition, the present pvT data were correlated by a truncated virial equation of state with the density average absolute relative deviation of 0.05%.