Azeotropic Composition Research Articles

Vapor-Liquid Equilibrium Data for The Binary Systems of Methacrylic Acid, Methyl Methacrylate, and Water at 26 kPa and 50 kPa

Methyl methacrylate (MMA) is a significant organic compound utilized across diverse industrial sectors. This research study aims to examine the separation of azeotropic systems containing MMA derived from the C4 route. The primary focus of this examination is on vapor-liquid equilibrium (VLE) data for binary systems of methacrylic acid (MAA) and water, as well as methacrylic acid and MMA. The study will be conducted under vacuum pressures of 26 kPa and 50 kPa. The objective of this study is to generate and analyze VLE data, thereby facilitating a comprehensive understanding of the azeotropic behavior and non-ideal interactions in these systems. The VLE data were obtained using a modified Rose-Williams type recirculation still. The azeotropic composition of the methacrylic acid and water system was confirmed, and the data were validated through Herrington and van Ness methods to ensure thermodynamic consistency. The findings indicate that the excess of the calculated Gibbs free energy and activity coefficient substantiates the non-ideal behavior. In conclusion, this study provides valuable insights into the design and optimization of the MMA by-product separation process. To further refine the model and enhance its predictive capabilities, additional research is recommended, focusing on exploring the impact of diverse experimental conditions and evaluating the efficacy of alternative predictive models.

Decreasing Electrical Resistivity of Ag Film by Low-Temperature Evaporation and Sintering through Azeotrope Application

In the temperature-sensitive components, such as perovskite solar cells, large-area electrical connections with high electrical conductivity are also required. To fulfill the requirements, low-temperature evaporation was realized by preparing binder-free pastes with Ag flakes and a solvent mixture, followed by sintering at 140 °C. The mixed solvent was based on viscous α-terpineol with the addition of an appropriate amount of dipropylene glycol methyl ether acetate or diethylene glycol diethyl ether to achieve an azeotrope composition, followed by the addition of a low-molecular-weight hydroxypropyl cellulose to increase the viscosity and thixotropy. During sintering at 140 °C in air for up to 30 min, the paste with 49.5 wt% α-terpineol, 49.5 wt% dipropylene glycol monomethyl ether acetate, and 1 wt% hydroxypropyl cellulose mixture exhibited an excellent electrical conductivity of 7.72 × 10−6 Ω·cm despite the implementation of low-temperature sintering. The excellent processability of the prepared Ag-based pastes at 140 °C demonstrated their potential for novel application areas.

Comparison of methods for calculating the enthalpy of vaporization of binary azeotropic mixtures

Objectives. To calculate the molar enthalpy of vaporization of binary homogeneous mixtures based on isothermal and isobaric vapor–liquid equilibrium data, and to compare the results of calculation of molar enthalpy of vaporization by different methods with experimental data.Methods. Simulation of the vapor–liquid equilibrium of binary systems according to the Non-Random Two Liquid “local compositions” equation and thermodynamic calculations of molar vaporization enthalpies of binary mixtures at different conditions of vapor–liquid equilibrium were used.Results. Arrays of calculated data were obtained with regard to molar enthalpies of vaporization for 25 compositions of binary azeotropes (isothermal, isobaric conditions of phase equilibrium), and the full range of compositions of the benzene–ethanol system at atmospheric pressure.Conclusions. The accuracy of thermodynamic methods for calculating the vaporization enthalpy of binary azeotropic mixtures according to vapor–liquid equilibrium data is higher in 85% of cases for isothermal, and in 75% of cases for isobaric conditions. By taking into account the influence of temperature on the activity coefficients of components in the liquid phase, the values of excess molar enthalpy both for azeotrope compositions and for the full concentration range of the benzene–ethanol system under isobaric conditions of liquid–vapor phase equilibrium can be accurately reproduced.

Dimethyl carbonate/methanol separation by azeotropic distillation with water: An alternative process driven by low-pressure steam

This study reported a conceptual design of dimethyl carbonate/methanol (DMC/MET) separation via an azeotropic distillation (AD) process with water as the entrainer. Water can form a minimum azeotrope with DMC, stripping DMC from MET via a distillation column. Meanwhile, the liquid–liquid equilibrium can lift the DMC fraction from the azeotropic composition to a much higher level with a decanter. It enables the subsequent distillation column to produce pure DMC. The techno-economic analysis after process optimization demonstrated that the total annualized cost (TAC) of the AD process is 13.8 % lower than the conventional extractive distillation (ED) process. Subsequently, heat integration and double-effect distillation were introduced to further increase the energy efficiency. The improved AD process is also superior to the improved ED process (31.7 % energy cost and 4.1 % TAC saved). Moreover, the moderate temperature of the reboilers of the AD process with water as the entrainer further elevates its superiority since industrial waste heat can be applied in this case.

Prediction of azeotropes position of refrigerant mixtures using the PHSC EoS

The work aims is predict the azeotropes' position in refrigerant mixtures using the Perturbed Hard Sphere Chain (PHSC) equation of state (EoS). The vapor-liquid equilibrium (VLE) of seventeen binary refrigerant mixtures has been correlated using two model-adjustable parameters. The results show that the proposed model can calculate the bubble and dew points of binary systems, accurately. The average ARD value of binary VLE calculations has been obtained 1.28 %. The azeotropes pressure and composition of binary mixtures have been predicted using the PHSC EoS with the average ARD values of 1.043 % and 2.23 %, respectively. The maximum relative deviation has been observed for R717+R125 systems with two azeotropes points; ARDx=12.2 %. The performance of the PHSC EoS has been evaluated by predicting the azeotropes position of ternary mixtures. The PHSC EoS results have been compared to three cubic-based EoSs containing the PR-vdW, PR-BM, and PR-MHV2-NRTL models. The results show that the PHSC EoS can predict the ternary VLE data and azeotropes position satisfactory. The relative absolute deviation does not exceed 1.7 % for the azeotropes pressure. The PHSC EoS can be used as a robust and efficient model for the prediction of the azeotropes' position in binary and ternary refrigerant mixtures. Prediction of azeotropic composition helps us to find promising refrigerant candidates in the pre-design stage of the desired apparatus.

Heat utilized pressure swing distillation (PSD) process for the separation of the maximum boiling azeotrope HCl and Water in the Cu-Cl Cycle

The four-step copper-chlorine cycle is utilized for hydrogen production from water. Intermediate copper and chlorine compounds facilitate the process, while all other reactants are regenerated and recycled, forming a closed-loop system. Hydrolysis of CuCl2, leading to the formation of Cu2OCl2 and dilute HCl, is a crucial step that uses a large excess of steam to ensure completion of reaction leading to the formation of dilute hydrochloric acid which needs to be recycled for the electrolysis reaction, requiring removal of the azeotrope between HCl and water. This study explores the utilization of pressure swing distillation (PSD) for concentrating HCl above azeotropic composition. Separation of the aqueous mixture of HCl and water using PSD is optimized using a sequential iterative optimization technique, focusing on process intensification. Integration of a simple heat-utilized FE-Process results in a reduction of TAC and energy cost (4.27% TAC and 7.20% energy cost) compared to the process without heat integration. A higher feed composition of HCl (8 mol %) leads to savings of ∼ 38.75% in TAC and a reduction of 53.06% in CO2 emissions compared to a lower feed composition (2.53 mol % HCl). The heat-utilized FE-Process with a higher feed composition is more economically viable for the separation of HCl and water.

Room Temperature Evaporation Behavior of Homogeneous Azeotropes Used in Art Conservation Cleaning Treatments

Cleaning painted surfaces of their grime, aged varnishes, and discolored overpaint is one of the most common interventive treatments for art conservators. Carefully concocted solvent mixtures navigate the solubility differences between the material removed and the original paint underneath. However, these solutions may be altered by differential evaporation rates of the component solvents (zeotropic behavior), potentially leading to ineffectively weak cleaning or conversely overly strong residual liquid capable of damaging the underlying paint. Azeotropic solvent blends, which maintain a constant composition during evaporation, offer a promising solution. These blends consist of two or more solvents combined at precise concentrations to function as a single solvent. Additionally, pressure-maximum azeotropes feature higher vapor pressure compared to other mixtures, further minimizing contact time and sorption of the solvents into artworks. This study examines azeotropes of isopropanol with n-hexane and 2-butanone in cyclohexane, which have been used previously in art conservation. The evaporation behavior at room temperature of these boiling point azeotropes was assessed using vapor pressure measurements, refractive index determinations, gravimetric analysis, and gas chromatography. Results showed changes in composition during evaporation and found that the actual room temperature azeotropic composition can vary between 1 and 10% v/v in concentration with those commonly reported at their boiling points. Art conservators should be cautious when using azeotropic blends reported at boiling points significantly higher than room temperature. To ensure the safety and efficacy of these mixtures, it is recommended to determine individual azeotropic cleaning blends experimentally before their use.

Engineering organic solvent reverse osmosis in hybrid AlOxHy / polymer of intrinsic microporosity 1 (PIM-1) membranes using vapor phase infiltration

A solvent-free post-treatment process known as vapor phase infiltration (VPI) is used to engineer the organic solvent reverse osmosis (OSRO) performance of polymer of intrinsic microporosity 1 (PIM-1) membranes via infiltration of trimethylaluminum (TMA) metal-organic vapor. The infiltration of inorganic aluminum constituents hybridizes the pure polymer PIM-1 into an organic-inorganic material (AlOxHy/PIM-1) with enhanced chemical stability. A homogenous distribution of inorganic loading in PIM-1 is achieved due to the reaction-limited infiltration mechanism, and the OSRO performance is enhanced as a result. OSRO separations of ethanol/isooctane mixtures using these membranes are shown to be capable of breaking the azeotropic composition with a separation factor for ethanol over isooctane greater than 5 and an ethanol permeance of 0.1 Lm–2h–1bar–1. Thus, these organic-inorganic hybrid membranes created via VPI show promise as an alternative method for separating azeotropic liquid mixtures.

Formation of Films of Alloys of Cr–Ni, Cr–Ni–Si and Fe–Ni Systems by Sublimation and Evaporation Methods for Electronic Products

The processes of formation of films of alloys of the Cr–Ni, Cr–Ni–Si and Fe–Ni systems with a stab le elemental composition by evaporation methods are considered. It is shown that due to the large difference in the melting temperatures of Ni and Cr, nichrome films are obtained by sublimation. The design of the evaporator is proposed, which makes it possible to stabilize the composition of the films. Calculations of azeotropic compositions of alloys of the Cr–Ni–Si system have been carried out. The position of the isobars of the total pressure of iron and nickel on the state diagram was determined during evaporation in vacuum. The azeotropic composition of the alloy of the Fe–Ni system was calculated and experimentally verified.

Obtaining Multicomponent Coatings of a Stable Composition for Electromagnetic Radiation Screens

The formation processes of coatings of Cu–Ni and Ag–Cu systems with a stable elemental composition by the method of electron-beam evaporation are considered. It is shown that in the zone of action of the electron beam on the ingot placed in the crucible at the total vapor pressure of the alloy elements Σp above the pressure under the cap of the installation, the melt boils, and in the outer zone adjacent to the melt zone, the process of sublimation of the hard alloy occurs. The microrelief and elemental composition of the surface layer of the Cu–Ni alloy ingot in the zones of evaporation and sublimation, as well as the elemental composition of the coatings deposited in this case, have been studied. It is shown that the most acceptable way to obtain coatings of the Cu–Ni system with a stable elemental composition is the simultaneous electron-beam evaporation of copper and nickel from two crucibles. The azeotropic composition of the alloy of the Ag–Cu system was calculated and experimentally verified. The research results are used in the manufacture of multilayered screens of electromagnetic radiation.

Double Ternary Azeotropy in the Benzene + Perfluorobenzene + Water System at 26.66, 53.33, and 80.00 kPa

The existence of two ternary azeotropes in the pressure range of 26.66–80.00 kPa has been experimentally confirmed in the benzene + perfluorobenzene + water system. The compositions and the boiling points of azeotropes benzene + water, perfluorobenzene + water, benzene + perfluorobenzene, benzene + perfluorobenzene + water (unstable node), as well as the boiling point of internal saddle azeotrope at pressures of 26.66, 53.33, and 80.00 kPa were determined. The experimental data are in good agreement with the results of other authors. The evolution of the VLE diagrams of the system under pressure changes was studied. It was shown that when the pressure increases, the azeotrope benzene + perfluorobenzene first disappears (through an internal tangential azeotrope), which confirms the predictions of other authors, and then two ternary ones (also through an internal tangential azeotrope). The compositions of azeotropes in the bifurcation state were determined in the computational experiment.

Simulation Studies on Recovery of Acetonitrile from Aqueous Acetonitrile Waste from Pharmaceutical Processes

This paper presents simulation studies on the recovery of Acetonitrile from aqueous Acetonitrile waste from pharmaceutical processes. The focus is on atmospheric distillation in two sequential columns to understand the separation feasibility of the system; the first column produces a distillate of azeotropic composition, which is mixed with a fresh stream and fed to a second column, which produces a 99.9% pure Acetonitrile in the residue. The effect of reflux ratio, reboiler duty and the fresh stream flowrate on the purity of the product is analyzed. The study was performed using steady state simulator Aspen Plus, version 11.1. The simulation results indicate that it is possible to obtain a product of 99.9% w/w Acetonitrile from a 1:1 feed with a recovery of ~ 60%.

Cellulose nanofiber and halloysite nanotubes embedded polyvinyl alcohol membranes for pervaporation dehydration of epichlorohydrin–isopropanol–water ternary feed mixture

AbstractThe dehydration of epichlorohydrin (ECH)–isopropanol (IPA)–water mixtures was conducted by using pervaporation separation process. Two types of crosslinked polyvinyl alcohol (PVA) membranes, PVA‐Glu and PVA‐TEOS, were prepared using glutaraldehyde (Glu) and tetraethyl ortho silicate (TEOS), then mixed with cellulose nanofiber (CNF) and halloysite nanotube (HNT) fillers, respectively. They characterized using field emission scanning electron microscopy to observe surface morphology, Fourier‐transform infrared spectroscopy to study the filler–polymer interactions and chemistries of membranes, and X‐ray diffraction experiment for the analysis of membrane crystallinity. Finally, a pervaporation test was carried out to dehydrate the ECH–IPA–water feed solution at the azeotropic feed composition. From the result, the membrane of PVA‐Glu, including 4% w/w CNF filler, showed a flux of 0.17 kg (m2h)−1 and a separation factor of 456. However, the membrane of PVA‐TEOS with 5% w/w HNTs filler indicated a flux of 0.15 kg (m2h)−1 and a separation factor of 4158. The higher pervaporation performance of the HNTs‐added PVA‐TEOS membrane is attributed to the smaller size and more porous nature of HNTs than CNFs.

Conceptual design of sustainable extractive distillation processes combining preconcentration and extractive distillation functions for separating ternary multi-azeotropic mixture

Azeotropic mixtures with a large content of one component are often encountered. Several energy-efficient three-column extractive distillation processes with integrated distillation column (TCED-IDC) are conceptually designed for separating ternary multi-azeotropic mixtures with a large content of one component on the basis of the corresponding four-column extractive distillation (FCED) processes. The energy consumption and economic advantages of the TCED-IDC processes which realize the integration of extractive distillation function and preconcentration function are demonstrated by two cases, methanol/acetonitrile/benzene ternary azeotrope with chlorobenzene as solvent (Case1) and methyl acetate/ethyl acetate/methanol ternary azeotrope with dimethyl sulfoxide as solvent (Case2). The economic savings resulting from the integration of preconcentration function and extractive distillation function depend heavily on feed compositions and azeotropic compositions. In terms of assumed feed compositions, the TCED-IDC process can achieve 27.61%/21.64% economic costs reduction in Case1 and 49.66%/1.73% economic costs reduction in Case2 compared to the TCED process and the FCED process.

Effect of choline lactate ionic liquid as entrainer on the thermodynamic properties of alcohols + water azeotropic mixtures

Ionic liquids could be used as entrainer in the azeotropic mixture separation process efficiently. Accordingly, the thermodynamic properties of ionic liquid choline lactate ([Ch][Lac]) as a potential entrainer have been studied in different azeotropic mixtures. In this respect, the density and speed of sound for binary systems containing (water + [Ch][Lac]) (ethanol/ 1-propanol/ 2-propanol) + [Ch][Lac])] and also ternary systems with different mass percent from alcohol-containing (water + alcohol + [Ch][Lac]) have been measured under a pressure 871 hPa at different temperatures T = (288.15 to 318.15) K. These data are used to calculate standard partial molar volume (Vφ0), and the limiting apparent molar compressibility (κφ0) using the Redlich-Mayer model besides the intermolecular free length (Lf) and relative association (RA) to interpret the existing interaction in the azeotropic mixture of the studied alcohols. Also, the scaled particle theory is used as a microscopic approach. All of the properties have been analyzed to interpret the interactions between the components of the mixture and 2-propanol has stronger interactions with the [Ch][Lac] in the azeotrope composition. The results suggest that the [Ch][Lac] could be used as an entrainer to separate 2-propanol more efficiently rather than the other studied alcohols.

Azeotropic behavior of the 2-propanol + water + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide system

Vapor-liquid equilibrium data were measured isothermally in the vicinity of azeotropic points of the title system at 333.15, 343.15, and 353.15 K. Data were processed using a newly-developed method based on relatively small amounts of input data, which provides thermodynamic description of azeotropic behavior. The regular two-parameter Redlich-Kister equation was used for this purpose. The parameters obtained were correlated with ionic liquid concentrations to express the smooth analytical dependence of both the azeotropic composition and pressure.

Liquid-liquid extraction and mechanism analysis of extracting fuel additive isopropanol from mixture with choline-based deep eutectic solvents as efficient extractants

Deep eutectic solvents (DESs) have wide application prospects in azeotropic separation since of their advantages of good thermal stability, non harmfulness and low raw material price. As a green solvent, DESs has attracted more and more attention in recent years. As a high-quality fuel additive, isopropanol (IPA) has high chemical added value because of its high energy density, low volatile and small corrosive. Therefore, extracting high alcohols such as IPA from azeotropes can effectively improve the combustion efficiency of fossil fuels and reduce tail gas emissions. In this work, ethylene glycol and other hydrogen bond receptors were selected to synthesize three choline-based DESs to extract IPA from n-heptane. The selectivity of DESs to IPA was obtained by liquid–liquid equilibrium (LLE) experiment and the separate efficiency of diverse DESs was compared. To profoundly investigate the intrinsic principle of extracting IPA from DESs, molecular dynamics (MD) simulation method was utilized to acquire the interaction energy between DESs and IPA/n-heptane, as well as the radial distribution function between DESs and IPA and other kinetic analysis data. The data showed that the experiment is in great assertion with the simulation, DESs synthesized from choline chloride and ethylene glycol has the leading extraction impact of IPA among three kinds of DESs, and Cl- played an imperative part in LLE. In addition, the effect of azeotrope ratio on separation efficiency was explored by simulating LLE with different azeotrope composition.

Economic effect of an efficient and environmentally friendly extractive distillation/pervaporation process on the separation of ternary azeotropes with different compositions

Exploring the process of cost-effective and efficient technology to separate ternary aqueous azeotropic systems has become essential research in chemistry and materials science. Traditional distillation technology and promising membrane technology occupy an irreplaceable position in wastewater treatment. However, single separation technology for the separation of azeotropic systems has disadvantages. To better meet the industrial practical needs of different azeotropic compositions in each process of rapeseed oil production, the separation performance and economic cost of single extractive distillation and an extractive distillation coupled pervaporation process for ternary azeotropic systems with different feed compositions were studied. Environmentally friendly and effective solvents were selected as extractants in the extractive distillation process from two aspects: selectivity and biological toxicity. Sequential iterative optimization algorithms were used to optimize the process with the ratio of water to the total amount of cyclohexane and isopropanol ranging from 1:9 to 9:1, considering cost as the evaluation index. The results showed that the cost of the processes increases significantly with increasing water content in the feed composition. Because the flux and selectivity of the membrane module were considerably affected by temperature when the water content was less than 0.4, the integrated process was more economical; otherwise, the extractive distillation process was more economical when the water content was greater than 0.4.

ВЛИЯНИЕ СОСТАВА РАСТВОРИТЕЛЯ НА КИНЕТИКУ ГИДРОГЕНИЗАЦИИ 4-НИТРО-2'-ГИДРОКСИ-5'-МЕТИЛАЗОБЕНЗОЛА НА СКЕЛЕТНОМ НИКЕЛЕ В ВОДНЫХ РАСТВОРАХ 2-ПРОПАНОЛА

The article is devoted to the analysis of the kinetics of hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene on skeletal nickel in aqueous solutions of 2-propanol without additives and with additions of acetic acid and hydroxide. Elucidation of the effect of the solvent composition on the kinetics of transformations of compounds containing several reactive groups is a theoretical and practically significant problem. According to the data obtained, during the hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene on skeletal nickel, the introduction of an acid or base into an aqueous solution of 2-propanol of azeotropic composition leads to a change in the ratio of directions in the parallel-sequential scheme of transformations of the starting compound. With the introduction of acetic acid, the contribution of the direction due to the transformation of the azo group noticeably increases, while the introduction of sodium hydroxide completely suppresses this process and the addition of hydrogen in the first phase of the reaction is carried out exclusively at the nitro group in the starting 4-nitro-2'-hydroxy -5'-methylazobenzene. The change in the contributions of the directions associated with the transformation of the azo or nitro group in 4-nitro-2′-hydroxy-5′-methylazobenzene cannot be caused by a change in the excess adsorption values of the hydrogenated compound. When the adsorption values of 4-nitro-2'-hydroxy-5'-methylazobenzene change within 30%, the rate constants of hydrogenation of the starting compound under the influence of the solvent change more than 8 times. One of the reasons for such a change in the observed rate constants for the hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene may be a change in the ratio of forms of hydrogen adsorbed on the catalyst surface under the influence of a solvent.

Study on energy saving of heat integrated distillation process for methyl acetate–methanol–tetrahydrofuran–water

ABSTRACT Based on the characteristics of binary azeotropic composition in the mixture of methyl acetate–methanol–tetrahydrofuran–water sensitive to pressure, pressure swing distillation (PSD) and double-solvent extraction distillation (DSED) were proposed to study the separation of the quaternary system. Numerical simulations were performed by ASPEN PLUS software (version 10.0) environment under the WILSON thermodynamic model. The economy of PSD and DSED process was performed, and the heat integration of two distillation processes was compared based on total annual cost (TAC). Research results of PSD indicated that compared with conventional PSD (CPSD), heat-integrated PSD (HIPSD) can save energy consumption and TAC by 33.87% and 30.70%, respectively, and moreover increase thermodynamic efficiency by 1.77%, so it had obvious energy-saving effect and economic advantage. Simulation results of DSED showed that water (H2O) and ethylene glycol (EG) were most suitable extractants for the system, and the suitable solvent ratios for H2O and EG were 0.28 and 0.38, respectively. Compared with conventional double-solvent ED (CDSED), heat-integrated double-solvent ED (HIDSED) can save energy consumption and TAC by 43.29% and 28.12%, respectively, and moreover increase thermodynamic efficiency by 3.25%, so it was superior to CDSED. The results indicated that the energy consumption and TAC of HIDSED are respectively 63.56% and 44.01% less than the HIPSD process, and the thermodynamic efficiency of the former is 3.9% larger than the latter, so the HIDSED process shows better economic and energy-saving effect.