Mixture Methyl Acetate Research Articles

Thermodynamic properties of binary mixtures of methyl acetate and some selected ketonesat varying compositions and temperatures

Density and viscosity measurements of binary mixtures of methyl acetate with propanone, butan-2-one and pentan-2-one were carried out at varying compositions (0 to 1) of methyl acetate and temperatures of 25, 30, 35 and 40◦C. The experimental data obtained were correlated with the Redlich-Kister polynomial equation from where excess molar volumes (VE ), excess viscosities (ηE), excess Gibbs free energies of activation for viscous flow (ΔG*E ), fitting coefficients and standard deviations of the mixtures were calculated. The ηE values were positive for mixtures of butan-2-one and pentan-2-one at all compositions and temperatures but gradually decrease with increasing composition and temperature. The mixtures of methyl acetate with propanone showed negative values of excess viscosity at all compositions of methyl acetate. The negative values are observed to be directly proportional to temperature. The values of VE for mixtures of methyl acetate + propanone system display positive deviations at lower compositions (0-0.4) and negative for higher mole fractions. The excess molar volumes of mixtures of butan-2-one and pentan-2-one are negative at the studied compositions and temperatures with a minimum at 0.3 composition and subsequent gradual decrease in negativity with increasing composition. The excess Gibbs free energy of activation for viscous flow (ΔG*E ) are positive at all compositions and temperatures and reaches a maximum at 0.3 composition above which it decreases. These results have been interpreted on the basis of the type and nature of interactions as well as differences in molecular architecture between the solvent mixtures.

Sustainable design and multi-objective optimization of heat pump assisted extractive distillation process for separating a ternary mixture of methyl acetate, tetrahydrofuran and methanol

The separation of a ternary mixture of methyl acetate (MeAc), tetrahydrofuran (THF), and methanol (MeOH) produced from chemical or pharmaceutical plants can not only recover the valuable chemicals but also reduce the environmental pollution caused by the emission of waste organics. In this study, a two-step extractive distillation process with four columns (FCED) with dimethyl sulfoxide and p-xylene serving as the entrainers was firstly proposed to separate the ternary mixture by using Aspen Plus simulation. The vapor recompression heat pump (VRHP) technology was introduced to improve the thermodynamic efficiency of the proposed FCED process. Subsequently, a multi-objective optimization using the non-dominated sorting genetic algorithm-II was employed to optimize the designed processes to accomplish a Pareto front trade-off in three crucial indicators, i.e., total annual cost (TAC), CO2 emission, and exergy efficiency. A Pareto ranking method, i.e., the technique for order of preference by similarity to ideal solutions combined with entropy weighting approach, was used to choose the best solution from the Pareto front. The results indicate that, compared to the FCED process, TAC (8-year payback period) and CO2 emissions of the VRHP-assisted FCED are reduced by 8.75% and 33.26%, respectively, while the exergy efficiency is increased by 8.06% from 3.67% to 3.96%, demonstrating that the introduction of VRHP can significantly improve the performance of the FCED process.

Digitally Printable Magnetic Liquid Metal Composite for Recyclable Soft‐Matter Electronics

AbstractThe increasing interest in epidermal patches for wearable monitoring makes it urgent to move toward “greener” and recyclable materials in printed electronics. However, combining scalable fabrication, stretchable function, and recyclable material architecture is challenging to achieve. Herein, this article introduces a printable biphasic liquid metal (LM)‐based composite that combines excellent electrical conductivity, high stretchability, low‐electromechanical gauge factor, printability, sinter‐free functionality, and compatibility with heat‐sensitive substrates, thanks to the sinter‐free formulation. The novel eutectic gallium indium LM‐nickel‐styrene‐isoprene (SIS) thermoplastic elastomer composite takes advantage of a “greener” solvent composed of a mixture of methyl acetate, cyclohexane, and 4‐chlorobenzotrifluoride compared to the toluene used in block copolymers (BCPs). Furthermore, it replaces the costly micron‐sized silver flake filler particles with nickel, a lower‐cost alternative that enables facile recyclability by using a magnetic force. The use of BCPs with non‐permanent physical cross‐links enables the possibility of recycling. A green route is shown for recycling the composite, using only bio‐friendly acids and daily used products such as sugar and Epsom salt. The application of these composites is shown through the digital printing of stretchable circuits and magnetic switches.

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.

Refractive Indices and Related Properties for Binary Mixtures of Methyl Acetate and Derivatives of Alkanolamines at Temperature Ranging from 293.15 to 313.15 K

Refractive indices, n D, of two binary liquid systems of methyl acetate (MAc) + methylethanolamine (MEA), and MAc + dimethylethanolamine (DMEA) each at twenty-one different compositions at T = 293.15, 303.15 and 313.15 K under ambient pressure are reported. The effect of temperature on the n D values is relatively small and the higher the temperature, the lower the refractive index. From the n D data, deviation in refractive indices, Δn D, molar refraction, R m, as well as deviation in molar refractions, ΔR m are estimated. The Δn D and ΔR m were correlated with the Redlich–Kister equation. For each system, as a function of composition of alkanolamines, x 2, the Δn D form a single positive lobe with a maximum between 0.5 and 0.65 mole fraction of alkanolamine. The ΔR m for both the systems are positive, the maxima lying within x 2 = 0.3 to 0.5.

Nafion modified with simple bases and amino acid derivatives: Survey of physical properties and search for effective pervaporation membranes

AbstractNafion, a solid perfluorinated polymeric sulfonic acid, reacts readily with bases and can thus be converted to a tremendous number of individual modifications. A survey of spectral, mechanical, thermal, and pervaporation characteristics of Nafion modified with simple inorganic and organic bases and with the derivatives of amino acids is thus reported. The spectral characteristics, thermal stability, and Tg changed pronouncedly for Nafion modified with the stronger bases, such as ammonium or tris(hydroxymethyl)aminomethane, while minor changes were observed for Nafion modified with the derivatives of amino acids. Permeability and selectivity of Nafion observed for the pervaporation of methanol–dimethyl carbonate and methanol–methyl acetate mixtures were mainly influenced by the modification with amines bearing hydroxyl and, most pronouncedly, sulfo groups. Importantly, the pervaporation membrane from Nafion modified with taurine appeared similarly permeable and hygroscopic but more methanol‐selective than that from pure Nafion.

Intercalation of multiply solvated hexafluorophospate anion into graphite electrode from mixtures of methyl acetate, ethyl methyl and ethylene carbonates

Multiply solvated PF 6 – intercalates into graphite positive electrode from ternary mixture of methyl acetate, ethyl methyl and ethylene carbonates.

Carbonyl stretch of CH⋯O hydrogen-bonded methyl acetate in supercritical trifluoromethane.

Infrared spectroscopy in the gas phase was used to study the formation reaction of the CH⋯O hydrogen bonding complex involving the CH group of trifluoromethane, as a hydrogen donor, and the carbonyl group of methyl acetate, as a hydrogen acceptor, under different (T, p) conditions. The hydrogen-bonded carbonyl stretch of the molecular pair was monitored in dilute mixtures of methyl acetate in trifluoromethane at near-critical temperatures, from gas- to liquid-like densities. In the gas region, it was possible to discriminate the carbonyl signal of the hydrogen-bonded complex from that of the free ester and have access to their relative concentration. The equilibrium constant of the hydrogen bonding reaction and the standard enthalpy and entropy changes in the process were determined using the spectroscopic data. CH⋯O bonding was favored by lowering temperature or pressurizing F3CH in the mixture, remaining essentially no free carbonyl groups about the critical density. The carbonyl band of the hydrogen-bonded pair appeared as a single symmetric peak up to liquid-like densities, suggesting that the 1:1 methyl acetate-trifluoromethane complex has the most abundant stoichiometry. Spectral features as frequency shift and bandwidth of the hydrogen-bonded carbonyl were studied as a function of temperature and solvent-density. A bathochromic (red) vibrational shift was registered for the bound carbonyl band against density, with a sudden change in behavior in the near-critical region, while the width of this band remains mostly unresponsive.

The Effect of Co-feeding Methyl Acetate on the H-ZSM5 Catalysed Methanol-to-Hydrocarbons Reaction

The reactivity of methanol and methyl acetate mixtures over a HZSM-5 catalyst is studied over a period of 6 h at 350 °C, with small molecular weight olefins and aromatic compounds observed as reaction products. Post-reaction analysis of the catalyst shows the coke content to increase with methyl acetate content. Vibrational spectra (DRIFTS and inelastic neutron scattering, INS) indicate the major hydrocarbon species present in the coked catalysts to be methylated aromatic molecules, with INS spectra indicating a greater degree of methylation in the catalysts used with higher methyl acetate content. The greater extent of deactivation at higher methyl acetate concentrations is tentatively attributed to a diminishment of water in the zeolite cavity, which would otherwise facilitate re-generation of the active sites.

Comparison of alternative methods for methyl acetate + methanol + acetic acid + acetic anhydride mixture separation

Objectives. The paper is a comparative analysis of methyl acetate + methanol + acetic acid + acetic anhydride industrial mixture separation flowsheets based on the use of special distillation methods (extractive distillation and pressure-swing distillation). The results obtained illustrate the variability of the structure of the technological separation flowsheet.Methods. Mathematical modeling using the software package Aspen Plus V. 10.0 was chosen as the research method. The simulation was based on the local composition equation NRTL and the Hayden–O’Connell equation of state. The relative uncertainties of phase equilibrium description do not exceed 3%.Results. The vapor–liquid diagram of the quaternary mixture of methyl acetate + methanol + acetic acid + acetic anhydride was studied using thermodynamic topological analysis. It was shown that the system contains one binary azeotrope and is characterized by one distillation region. Although the structure is not complex, there is a possibility of using several methods for mixture separation: pressure-swing distillation, and extractive distillation with different entrainers. Twelve flowsheets with different structure were proposed, and 29 variants of separation were compared.Conclusions. It was shown that the most perspective structure for the separation of a methyl acetate + methanol + acetic acid + acetic anhydride mixture is a combination of distributed sequence separation and extractive distillation.

Measurements by using an automatic pressure control and predictions of isobaric VLE at 1.5 MPa for binary mixtures of methyl acetate, ethyl acetate, 1–propanol and 1–butanol

The experimental data of vapor–liquid equilibrium for the binary systems methyl acetate+1–propanol, methyl acetate+1–butanol and ethyl acetate+1–propanol at 1.5MPa has been obtained, using an ebulliometer made of stainless steel. This equipment works through the Cottrell pump effect, so that the liquid and vapor phases are recirculated. The isobaric data T–x–y are informed and analyzed with respect to the literature data. The evolution of the azeotropic point with the pressure in the binary system of ethyl acetate+1–propanol is included. The thermodynamic consistency of the systems was verified by employing the Peng–Robinson equation of state in different forms and using the φ–φ approach.

Thermophysical Properties of p-Anisaldehyde–Methyl Acetate Mixtures

Densities, viscosities and ultrasonic velocities of p-anisaldehyde – methyl acetate mixtures have been measured over the entire mole fractions at 308.15, 318.15, and 328.15 K and at 0.1 MPa. The excess molar volume, viscosity deviations and ultrasonic velocity deviations have been calculated. The new equations have been developed for excess molar volume, viscosity deviations, and ultrasonic velocity calculations using statistical software Design Expert. The excess thermo physical properties were fitted to Redlich–Kister model, Hind model, and Grunberg–Nissan model to obtain their coefficients and standard deviations using DATAFIT software.

Impact of Endometallofullerene on P84 Copolyimide Transport and Thermomechanical Properties.

Novel polymer composite materials, including unique nanoparticles, contribute to the progress of modern technologies. In this work, the endohedral fullerene C60 with incapsulated iron atom (endometallofullerene Fe@C60) is used for modification of P84 copolyimide. The impact of 0.1, 0.5, and 1 wt % endometallofullerene on the structure and physicochemical properties of polymer films is studied through scanning electron microscopy, thermogravimetric analysis, and thermomechanical tests. Transport properties are estimated through sorption and pervaporation techniques toward methanol and methyl acetate mixture. The inclusion of endometallofullerene into the copolyimide matrix improves membrane permeability and selectivity in the separation of methanol—methyl acetate mixtures. The maximal effect is achieved with a composite containing 0.5 wt % Fe@C60. The developed composites are effective for energy and resource saving purification of methyl acetate by pervaporation.

Dielectric and FTIR studies on the hydrogen bonded binary system of ester and alcohol

ABSTRACTConcentration dependent dielectric constant, relaxation time, excess dielectric constant, excess inverse relaxation time and the effective Kirkwood correlation factor of the binary mixture of methyl acetate with butanol and pentanol, over the entire mixing range have been determined at room temperature. The values of these functions emphasize on the hydrogen bond interactions between the unlike molecules in ester-alcohols mixtures, the nature of which depends on the extent of substitution of the alcohols. The concentration depending values of excess dielectric constant and excess inverses relaxation time were used to analyze the hydrogen bonding complexes formed between unlike molecules and the strength of the molecular connectivities in the binary mixtures. Conformational analysis of the formation of hydrogen bond is also supported by the FTIR study.

Effect of feed temperature on economics and controllability of pressure-swing distillation for separating binary azeotrope

The mixture of methyl acetate and methanol created a minimum-boiling azeotrope which can be separated by pressure-swing distillation. The designs and optimizations of eight processes with eight different feed temperatures were studied to explore the effect of feed temperature on economics. Total annual cost (TAC) as the objective function reduced first and then increased with feed temperature increasing. Dynamic control of three typical temperature points was made. The designed process with feed temperature at 334.15K (vapor-liquid) had the minimum TAC, while the best dynamic control performance was found for the design process with feed temperature at 323.15K (cold). The choice of feed temperature should be considered from the perspectives of both TAC and the dynamic control performance.

Liquid–liquid equilibrium data and correlation for quaternary systems of acetic acid + water + methyl acetate + p-xylene at 313.2 K

The experimental liquid–liquid equilibrium (LLE) data of the quaternary (acetic acid+water+p-xylene+methyl acetate) system was investigated at 313.2K and atmospheric pressure. This research is aimed to examine the potential of the mixture of methyl acetate and p-xylene, which available as the remaining substances in terephthalic acid production, to be prospective extracting solvent for the acetic acid dehydration. LLE phase diagrams at different ratio of p-xylene to methyl acetate were presented for this quaternary system. The results showed that an enlargement of the LLE two-phase region occurred with increasing p-xylene to methyl acetate mass ratio in the initial solvent phase. The distribution coefficient and selectivity for the extraction of acetic acid were also obtained to evaluate the capability of solvent. LLE data were sufficiently correlated by Othmer-Tobias and Bachman equations. The experimental results were used to obtain binary interaction parameters as correlated by the non-random two liquid (NRTL) and universal quasi-chemical theory (UNIQUAC) equation models. The root mean square deviations (RMSD) values as low as 0.0119 and 0.0128 were calculated for NRTL and UNIQUAC, respectively; indicating excellent results for both models were suitable for the determination of LLE data of this quaternary system.

Methyl acetate production by coupled esterification-reaction process using synthesized cross-linked PVA/silica nanocomposite membranes

Cross-linked PVA/silica nanocomposite membranes were synthesized via the solution casting technique and used to dehydrate the reaction mixture of methyl acetate through the coupled pervaporation-reaction in a batch mode using fumaric acid as the cross-linking agent. The membranes thus prepared were initially characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The SEM micrographs established the nano-scale distribution of silica nanoparticles in the polymer matrix. Moreover, the XRD results showed that the crystalline regions of the polymer reduced slightly with increasing silica content of the membranes. Investigation of the effects of different experimental variables revealed that acid conversion was increased and water permeance through the membranes was correspondingly enhanced with increasing silica content of the membranes. The optimum acid conversion was found to be 94%, which was achieved with 20wt.% silica in the hybrid membrane over a period of 240min. Maximum conversion rate was obtained under the following operational conditions: catalyst loading at a weight fraction of 15wt.% relative to acetic acid, an initial alcohol/acid molar ratio of 4:1, and a temperature of 70°C.

Pervaporative Separation of Methanol–Methyl Acetate Mixtures with Commercial PVA Membranes

Pervaporation may successfully be implemented for the separation of azeotropic mixtures which generally requires energy intensive separation procedures. Separation of methanol from methyl acetate by pervaporation is a representative application. In this study the commercial polyvinyl alcohol (PVA)-based membranes PERVAPTM 4155-30, PERVAPTM 4155-70, and PERVAPTM 4155-80 were used to recover methanol from binary methanol–methyl acetate mixtures. The separation performance was investigated for various operating parameters such as feed composition, feed temperature, and permeate pressure and discussed in terms of permeance and selectivity. An empirical model was developed to quantify the effect of membrane swelling on the permeate flux.

Separation of methyl acetate + methanol azeotropic mixture using ionic liquids as entrainers

Three ionic liquids (ILs), namely 1-butyl-3-methylimidazolium chloride ([C4MIM][Cl]), 1-(2-chloroethyl)-3-methylimidazolium chloride ([ClC2MIM][Cl]) and 1-butyl-3-methylimidazolium bromide ([C4MIM][Br]), were investigated as entrainers for the separation of azeotropic mixture of methyl acetate and methanol. Isobaric vapor–liquid equilibrium (VLE) data for the ternary systems containing ILs were measured in a recirculating still at 101.3kPa. It was found that all the three ILs produced a salting-out effect on methyl acetate, thus enhancing the relative volatility of methyl acetate to methanol. The salting-out effect of the ILs employed in this study follows the order: [C4MIM][Cl]>[ClC2MIM][Cl]>[C4MIM][Br]. Moreover, [C4MIM][Cl] could eliminate the azeotropic point at a mole fraction of 0.134. The experimental data were well correlated with the nonrandom two-liquid (NRTL) model.

Application of <SUP>1</SUP>H-NMR for the Quantitative Analysis of Short Chain Fatty Acid Methyl Ester Mixtures: An Undergraduate Instrumental Analysis Experiment

Nuclear magnetic resonance spectroscopy (NMR) is one of the most important instrumental techniques used to elucidate the molecular structure of organic compounds. However, there are not many good simple applications of using NMR for the quantitative assay of impure or mixtures of organic substances. The current experiment was developed as part of an ongoing effort to increase exposure to quantitative proton NMR methodology in the undergraduate chemistry laboratory curriculum. The objective of the experiment is to determine the percent composition of a two component mixture of short chain fatty acid methyl esters using chemical shift and integration values obtained from running solvent-less samples both with and without an internal reference standard. We report on the experimental methods and results obtained from examining the quantitative NMR properties of a series of mixtures of methyl acetate (M.A.) and methyl propionate (M.P.) solutions ranging from 100% MA to 100% MP. Also similar data was obtained for the MA - methyl butyrate (MB) pair. The results exhibit a linear relationship of the percent composition of the methyl acetate binary mixtures found by proton NMR with the theoretical (i.e. samples prepared based on measured weights) percent compositions. The experiment confirms the quantitative usage of 1H NMR and serves as an educational tool for the undergraduate chemical laboratory.