Blended Solvents Research Articles

Difenoconazole solubility in acetonitrile/N,N-dimethylformamide/acetone + water and quantum chemistry study into inter/intra-molecular interactions

The difenoconazole solubilities in acetonitrile/acetone/N,N-dimethylformamide (DMF) + water systems were acquired experimentally with the help of the isothermal shake-flask technique. Analysis of X-ray power diffraction revealed that difenoconazole did not exhibit any crystal transition as well as solvate formation. The solubility acquired here was accurately correlated, which yielded relative average deviations (RAD) of ≤4.99 % and a root-mean-square deviation of ≤20.59 × 10−5 through the Jouyban-Acree and modified van’t Hoff-Jouyban-Acree models Additionally, to explain the solubility behavior at a temperature of 298.15 K, this work examines the acetonitrile/acetone/DMF + water and the previously published methanol/ethanol/isopropanol/PG + water blends utilizing the extended Hildebrand solubility technique. The RAD levels remained below 6.88 %. The dipolarity-polarizability and the solubility parameter of blended solvents exert a substantial impact on the variability of difenoconazole solubility. The preferred solvation of difenoconazole at a temperature of 298.15 K was examined through the inverse Kirkwood-Buff integrals. The solvation parameters’ values of difenoconazole were positive in blends containing methanol, acetone, DMF, ethanol, isopropanol, and acetonitrile with moderate and rich compositions. This indicates that difenoconazole is preferentially solvated by them in above composition ranges. A shift from an enthalpy-driven mechanism to an entropy-driven one was revealed through an analysis of the thermodynamics of the entropy-enthalpy relationship in the dissolution of difenoconazole in blends. Furthermore, the mean local ionization energy, Hirshfeld surface as well as molecular surface electrostatic potential were employed to illustrate the microscopic electrostatic characteristics. The N and N groups in the five-membered ring of difenoconazole molecule are the primary sites for electrophilic attack. The weak contacts of difenoconazole-solvent were demonstrated with the help of a Hirshfeld partition analysis-based independent gradient model.

Synthesis, growth, and characterizations of bis-ethylene diammonium diphenolsulfonate monohydrate single crystal: Optoelectronic and antibacterial aspects

Bis-Ethylene Diammonium di-Phenolsulfonate monohydrate (EDDSM) single crystal was amalgamated by the process of slow evaporation solution with water and ethanol as blended solvents at room temperature. The synthesized crystal EDDSM structure was resolved by diffraction of X- rays using single crystal technique. The identification of different functional groups, various kinds of carbon atoms as well as protons in the EDDSM crystal were established by13Cand 1H NMR spectra respectively. The optical properties were studied, using optical absorption along with photoluminescence studies. The stability of EDDSM single crystal against temperature and mechanical stress was studied by examining TGA/DTA and Vickers micro hardness respectively. The nonlinear nature of the grown EDDSM was observed and established by ‘Second Harmonic Generation’ (SHG). The antibacterial and antifungal activities of EDDSM was evaluated using Staphylococcus aureus, Streptococcus mutans, Klebsiella pneumoniae, Pseudomonas aeruginosa whereas Aspergillus niger and Candida albicans. These reported features and characterizations establish the reported compound as a promising crystal.

Experimental Study on Electro-Dialysis Reclaiming of Degraded Blended Amine Solvents in Carbon Capture Process

Experimental Study on Electro-Dialysis Reclaiming of Degraded Blended Amine Solvents in Carbon Capture Process

Comprehensive solubility study and inter-molecular interactions on fenbendazole dissolved in some aqueous aprotic and protic co-solvent solutions

The isothermal shake-flask saturation method was used to experimentally determine the mole-fraction solubility of fenbendazole in three aqueous co-solvent blends of 1,4-dioxane/acetone/NMP encompassing the range of 283.15 to 328.15 K. The solubility of fenbendazole in various blended solvents ranks NMP + water (4.852 × 10−2) > 1,4-dioxane + water (14.81 × 10−4) > acetone + water (2.285 × 10−4) with composition of 1,4-dioxane (acetone or NMP) of 1 at 298.15 K. The solubility data rises monotonically with 1,4-dioxane/acetone/NMP concentration at the same temperature. X-ray power diffraction images show that no solvate production or crystal transition appeared throughout the studies. The solubility to solvent composition and temperature was satisfactorily associated by the modified van't Hoff-Jouyban-Acree, quantitative structure–property relationship, and Jouyban-Acree models with relative average deviations of no higher than 7.05 % and root-mean-square deviation of no higher than 1.225 × 10−3. In addition, the 1,4-dioxane/acetone/NMP + water blends studied in this paper and the methanol/ethanol/EG/DMF + water blends previously reported both used the extended Hildebrand solubility approach to quantitatively describe the solubility behavior at 298.15 K. The average relative deviations were kept under 4.06 % on both cases. As stated by the examination of the linear solvation energy relationship, the solubility parameter and dipolarity-polarizability of solutions have a significant influence on the solubility variation. The effective method of inverse Kirkwood-Buff integrals was used to investigate the preferred solvation of fenbendazole at 298.15 K. In blends with intermediate and rich ethanol/DMF/1,4-dioxane/acetone/NMP composition areas, the preferred solvation parameters of ethanol/DMF/1,4-dioxane/acetone/NMP displayed positive values, indicating the preferential solvation of fenbendazole by the co-solvents. Thermodynamic examination of the entropy-enthalpy compensation and dissolution parameters for fenbendazole dissolving in blends led to the identification of an enthalpy and/or entropy-driven mechanism as well as an endothermic process. Moreover, the average local ionization energy and electrostatic potential of molecular surface were utilized as effective instruments to demonstrate the microscopic electrostatic properties of acidity and basicity, respectively. The fenbendazole molecule's groups of –N in the five-membered ring and –NH in the straight chain serve as the main targets for electrophilic and nucleophilic assault. The weak interactions between fenbendazole and several solvents were shown using an independent gradient model based on Hirshfeld partition analysis.

Comprehensive kinetic study of carbon dioxide absorption in blended tertiary/secondary amine solutions: Experiments and simulations

This study investigated the kinetics of CO2 absorption by aqueous solutions of 2-(ethylamino)ethanol (EAE) and 2-(butylamino)ethanol (BAE) using a stopped-flow device under varying concentrations of amine (0.02 ∼ 0.05kmol/m3) and temperature (293 K to 313 K), and also explored the kinetic behavior of N,N-diethylethanolamine (DEEA) when combined with EAE and BAE. The model involving a combination of the zwitterion mechanism and base catalysis mechanism was proposed with the better prediction of the reactions than other models. The AARD% for the two blended systems was 7.52 % and 7.95 %, respectively. The absorption mechanism and free energy barrier of blended amine aqueous solution were calculated and validated by Density Functional Theory (DFT) calculations. The reaction mechanism obtained from the calculation results is in good agreement with the kinetic model used in the experiment. This study highlights that consistency of model and simulation results and revealed the interaction effects of the blended amines. The effect of secondary amine chain length on absorption was also discussed, which gave the good significance to the further investigations and developments of blended CO2 solvents.

Comparative techno-economic analysis of CO2 capture processes using blended amines

Blended amines synthesize the absorption characteristics of different amine solvents and show a great potential in carbon capture. However, a comprehensive techno-economic analysis (TEA) of the CO2 absorption process using blended amines is still lacking. In this study, we investigated three blended amine solvents: MEA/MDEA, PZ/MEA, and PZ/MDEA, with commercially available amine MEA used as the benchmark. Rigorous process simulation and techno-economic analysis were applied to evaluate the performance of the carbon capture process in a steel plant. CO2 molar loading in the lean solvent (αlean) and stripper pressure (P) were optimized to minimize the total annualized cost (TAC). The results demonstrated that PZ/MDEA-based process is most cost-effective (31.43$/tCO2) under the operating conditions of αlean = 0.15 and P = 1.25 bar. The cost breakdown analysis revealed that αlean and P significantly impact the TAC through the regeneration heat, equipment investment, and amines make-up cost. Furthermore, the energy analysis indicated that using a solvent with a low reaction enthalpy and heat capacity as well as high reactivity and absorption capacity could minimize the energy consumption of the process.

Experimental and Numerical Analysis for Improving CO2 Mass Transfer Performance of Blended Solvents in Hollow Fiber Membrane Contactors

Experimental and Numerical Analysis for Improving CO₂ Mass Transfer Performance of Blended Solvents in Hollow Fiber Membrane Contactors

Investigation on the performance of EDA-based blended solvents for electrochemically mediated CO2 capture

EDA-Cu based electrochemically mediated CO2 capture method was developed as a promising technology to substitute the conventional amine-based CO2 capture, especially in industries without available steam source. However, the highly corrosive and poor Cu cycling performance seriously obstruct its large-scale application. In this work, traditional primary amine, secondary amine and tertiary amine (MEA, DEA and TEA) are chosen to blend with EDA to alleviate the problems of EDA. Electrochemical measurements, corrosiveness comparison, CO2 absorption and desorption performance were conducted to investigate the advance performance of proposed blended solvents comprehensively. The corrosion potential in all the mixtures is significantly higher than that in sole EDA solution, which illustrates that the corrosiveness of proposed mixed solvents to Cu electrode is weaker. Besides, the Cu cycling performance is greatly improved and the energy consumption is significantly reduced by using blended solvents. Overall, 50/50 EDA/MEA mixed solution with high CO2 capacity and fast absorption rate is suggested to be a substitute for traditional EDA solvent. The CO2 desorption energy consumption of 50/50 EDA/MEA mixed solution decreases 14% than that of EDA solution at a current density of 0.01 A/cm2. Meanwhile, the copper cycling performance is also improved in 50/50 EDA/MEA mixed solution as the cathode Faraday efficiency (CFE) increased from 43% (EDA) to 53% (50/50 EDA/MEA). Results show that the proposed mixed amine solvents lead to the successful circumvention of highly corrosive and poor Cu cycling performance in the electrochemically mediated CO2 capture system, which will contribute to the exploration of efficient blended solvents for EMAR CO2 capture process and promote its industrial application.

Bench-scale CO2 capture using water-lean solvent of 2-(ethylamino) ethanol, 1-methyl-2-pyrrolidinone, and water

Water-lean amine are promising solvent for CO2 capture to significantly reduce regeneration energy. However, existing water-lean solvent hasn’t been put into commercial application due to high reaction heat, slow CO2 absorption rate, and high amine volatility of amine. In this paper, amines with one secondary amino (—NH), one hydroxyl (—OH), and carbon chain length between 3 and 6 (C3-C6) in structure were preferred for water-lean solvent in the light of amine structure–activity relationship. 2-(ethylamino) ethanol (EMEA) dissolving into 1-methyl-2-pyrrolidinone (NMP) and water were favorable water-lean solvent for CO2 capture, and EMEA/NMP was tested in a bench-scale platform. EMEA/NMP solvents have equivalent CO2 removal efficiencies, and 40–69% lower regeneration energy compared to blended amines and MEA solvents. The lower regeneration energy of EMEA/NMP results from lower water vapor ratio, lower reaction heat, and lower heat capacity. Viscosity of EMEA/NMP at rich loading is 6.92–11.11 mPa·s at 40℃. Increased stripper temperature increases CO2 removal efficiency by decreasing lean loading in EMEA/NMP solvents. CO2 desorption dominates mass transfer in stripper at low temperature while water evaporation dominates at high temperature. The lowest regeneration energy obtained with 5.0 M EMEA/NMP at liquid/gas ratio of 10.5 L/m3 and stripper temperature of 80℃ was 0.99 kWh/kg CO2 (equivalent to 3.6 GJ/tCO2), which is 69% lower than that of 5 M MEA. EMEA/NMP has an increasing amine emission from 109 to 1891 mg/m3 as absorber temperature increases from 34℃ to 54℃. Advanced processes would be employed for volatile amine emission control in future study.

Thermophysical properties of 2-amino-2-methylpropan-1-ol + alkanol mixtures: Investigation of molecular interactions by insight of FT-IR spectroscopy

We report the experimental data of dynamic viscosity (η) and ultrasonic speed (u) for 2-amino-2-methylpropan-1-ol (AMP) (1) + alkanol (C1-C3) (2) at T = (298.15–318.15) K and 0.1 MPa pressure. The derived excess (or deviation in) properties like dynamic viscosity (Δη), speed of sound (Δu) and excess isentropic compressibility (κSE) were regressed through Redlich-Kister polynomial equation. The Δη values were analyzed in terms of an Ab-initio approach, to study the intermolecular interactions between the binary components. Our analysis indicated that compared to propanol, methanol and ethanol interact strongly with AMP and 2-propanol exhibited the weakest interactions with AMP owing to steric hindrance by branched propyl group. In addition, viscosity (η) values and ultrasonic speed (u) data were analyzed using the various thermodynamic models/correlations that agreed well with our experimental data. Furthermore, we analyzed the FT-IR spectra of pure components and their binaries and observed prevailing hydrogen bonding interactions between the N-atom and OH-group of AMP with the OH-group of alkanol. Our findings highlight the great bonding capability of AMP with lower alkanol due to its small size and linear shape and can provide information on designing effective binary mixtures (blended) solvents based on AMP for CO2 absorption.

Elucidation of Operating Parameters Influencing the Ultrasonic-Assisted Absorption of Bulk CO2 Using Unpromoted and Promoted Methyldiethanolamine

Various acid gas sweetening processes can be used to separate CO2 from natural gas. As one of the most matured and widely utilized gas sweetening processes, absorption has been continuously improved to meet the stringent separation requirement. Ultrasonic irradiation has recently been introduced as an alternative technique to intensify the absorption process. Nevertheless, further studies are still needed to mature this new technique, particularly using slow kinetic absorbents possessing high inherent CO2 absorption capacity. Moreover, performing experimental studies using blended solvents in the high-frequency ultrasonic-assisted absorption system has also introduced a new idea in this field. This experimental study presents the CO2 absorption into aqueous solutions of methyldiethanolamine (MDEA) and piperazine (PZ)-promoted MDEA in an ultrasonic-assisted batch reactor. The influences of various operating parameters on CO2 absorption performance were evaluated in both promoted and unpromoted conditions. The parameters of the experiments included ultrasonic power at a frequency of 1.7 MHz, absorbent concentration, temperature, and CO2 partial pressure. Based on the results, ultrasonic power was found to be the most critical factor influencing the CO2 absorption rate. Moreover, the potential of the high-frequency ultrasonic-assisted CO2 absorption reactor was further elucidated via comparison with the conventional stirring and silent conditions under identical operating conditions. The highest CO2 absorption rate was achieved at an ultrasonic power of 12.36 W, a temperature of 70 °C, a CO2 partial pressure of 10 bar, an absorbent concentration of 50 wt %, and a promoter concentration of 5 wt %. In addition, the CO2 absorption rate in the high-frequency ultrasonic-assisted reactor using the MDEA absorbent was 28 and 52 times higher compared to stirring and silent conditions, respectively. The CO2 absorption rate enhancement was approximately 17 and 54 times higher for the PZ-MDEA.

The Composition and Properties of Soluble Products from the Coal ThermoSolvolysis with Hydrocarbon Residues and Blends as Solvents

The dissolution of bituminous coal at mild temperature was studied using a variety of commercially available coal- and petroleum-derived hydrocarbon fractions, hydrorefined derivatives and blends as solvents. The chemical and molecular composition of the coal, solvents and extracts were characterized by chemical and group analyses, and by IRFT, 1H NMR, GC-MS and liquid chromatography. Low volatile solvents like highly aromatic coal tar (CT), its anthracene fraction (AFCT), petroleum-derived solvent (HGOCC) and binary blends were found to exhibit high performance for coal dissolution into quinoline solubles (to 79‒82%), and the yields of gases being no more than 0.5%. The extracts obtained using CT and AFCT solvents represented pitch-like matter consisting of rarely substituted aromatic molecules with 4‒5 condensed rings. HGOCC extract was much less aromatic, the aromatic rings being highly substituted with fairly large alkyl substituents. The blended solvents yielded more extracts, and their molecular indexes were average between those obtained with each solvent separately. A remarkable finding was that the extracts obtained were characterized by significantly lower content of benzo(a) pyrene (BaP) compared to solvents used, its content further decreased as the time of coal dissolution increased.

Solubility, solvent effect, preferential solvation and DFT computations of 5-nitrosalicylic acid in several aqueous blends

The purpose of this contribution was to investigate the solubility, computational techniques, solvent effect, and preferential solvation of 5-nitrosalicylic acid in blended solvents of acetonitrile/N,N-dimethylformamide(DMF)/methanol/n-propanol + water. Visualizing regions of weak contact between 5-nitrosalicylic acid and solvent using an independent gradient model based on Hirshfeld partitioning (IGMH), and providing a quantitative study for the molecule’s electrostatic characteristics using a molecular surface research and Hirshfeld surface analysis were carried out. All equilibrium solubility measurements were performed using a shake-flask technique at temperatures from 278.15 to 323.15 K and pressure of 101.2 kPa. For each blends studied, the lowest solubility was observed at 278.15 K in water and the highest at 323.15 K in pure organic solvent. Using linear solvation energy relationships, the effect of molecular interactions on solubility variation was studied, revealing that the solubility parameter and dipolarity-polarizability played a substantial impact in solubility variation. By correlating the derived equilibrium solubilities with the Jouyban-Acree, modified Apelblat-Jouyban-Acree, and van't Hoff–Jouyban–Acree models, a maximum relative average deviation of 4.01 percent was obtained. Quantitative investigation of the solvation behavior of 5-nitrosalicylic acid by solvent species was conducted using the method of inverse Kirkwood–Buff integrals. Positive values of the preferential solvation parameter in acetonitrile/DMF/methanol/n-propanol-middle and -rich blended systems indicated that acetonitrile/DMF/methanol/n-propanol solvated 5-nitrosalicylic acid preferentially. In the above composition ranges, it is hypothesized that 5-nitrosalicylic acid interacts with nearby methanol/DMF/n-propanol molecules as a Lewis acid, whereas solvation by acetonitrile is due to the polarization effect.

Experimental investigations of CO2 absorption and catalyst-aided CO2 desorption performance of several different amines blending with a promoter

This research presented the new experimental results of the absorption and desorption performance of various single and blended solvents in terms of initial CO2 absorption rate, initial desorption rate for blank solvents and solvents with the aid of HZSM-5 catalyst, and equilibrium CO2 solubility. MEA and PZ are two promoters used to facilitate several individual aqueous single solvents including BEA, AMP, BDEA, and MDEA. In order to check the altered performance of absorption and desorption, the solvents were specified at 2.5 M. The initial desorption rate was evaluated by varying the temperature, weight of the solid catalyst, and initial rich CO2 loading. The experimental results were then taken to compare with the obtained data of the benchmark solution (2.5 M MEA). The comparison results revealed that all the selected blank solvent blends can provide better absorption and desorption performance than the blank benchmark solution. The results also indicated that the performance of catalyst-aided CO2 desorption could be strongly affected by the rich loading and operating temperature. Meaning that the activation of proton donation by HZSM-5 was patently affected by the above two conditions, which eventually affect the CO2 separation from the rich solvent.

Rate-Based Modeling and Assessment of an Amine-Based Acid Gas Removal Process through a Comprehensive Solvent Selection Procedure

In this study, an industrial acid gas removal (AGR) process which uses amine-based solvents was designed and simulated. The selection of suitable absorbents is crucial for an effective AGR process. Therefore, various single and blended amine-based solvents for capturing acid gases were evaluated through a comprehensive procedure, including solvent screening and process design steps. First, various solvents were screened for their CO2 and H2S absorption efficiencies. Promising solvents were then selected for the process design step, in which all process alternatives were simulated and rigorously designed using Aspen Plus. The non-equilibrium rate-based method with an electrolyte non-random two-liquid thermodynamic model was employed for modeling the absorption column. All processes were evaluated in terms of energy requirements, costs, and carbon emissions. The results show that a blend of methyldiethanolamine and piperazine solutions are the most promising solvents for the AGR process, as they can save up to 29.1% and 30.3% of the total annual costs and carbon emissions, respectively, compared to the methyldiethanolamine + diethanolamine solvent process.

Experimental investigations and the modeling approach for CO2 solubility in aqueous blended amine systems of monoethanolamine, 2-amino-2-methyl-1-propanol, and 2-(butylamino)ethanol.

In this work, new CO2 solubility data on three types of aqueous amine blends were reported to complement existing databases. The experiments were conducted at temperatures of 313K (absorption condition) and 363K (desorption condition). The effect of the MEA concentration on the CO2 solubility in several amine blends at low CO2 partial pressure (8 to 50.65kPa) were studied in this work, including 0.1, 0.3, 0.5mol/L MEA + 2mol/L AMP; 0.1, 0.3, 0.5mol/L MEA + 2mol/L BEA; and 0.1, 0.3, 0.5mol/L MEA + 1, 2mol/L AMP + 1, 2mol/L BEA. Besides, an additional group of equilibrium CO2 solubility data were conducted at 298K in order to estimate the heat of CO2 absorption of the blended solvents at a temperature range from 298 to 313K. A new simplified Kent-Eisenberg model was developed for the predictions of blended solvents, and a multilayer neural network model with Levenberg-Marquardt backpropagation algorithm was developed upon five hundred reliable published experimental data. The predictions from two methods are both in good agreement with the experimental CO2 solubility data.

Extended Hildebrand Solubility Approach and Inverse Kirkwood–Buff Integrals Method Applied to Chloroxine Solubility in Several Blended Solvents

ABSTRACT Extended Hildebrand solubility approach (EHSA) was used in this work to analyse the chloroxine solubility in mixtures at temperature of 298.15 K. A good prediction results of EHSA were observed to correlate the interaction parameter (W) and solubility parameter of blends in the absence of chloroxine (δ 1+2). Nonetheless, the forecasting outcomes of EHSA were similar with that attained when natural logarithm of solubility (lnx 3) was associated with δ 1+2. Additionally, the local mole fraction of ethyl acetate and n-propanol/methanol/isopropanol/ethanol in the vicinity of chloroxine were quantitatively derived by the inverse Kirkwood–Buff integrals method. It could be conjectured that in the alcohol-rich solutions, the interactions of acidic sites of alcohols on basic sites of chloroxine have crucial responsibility for the solvation. It is remarkable the present work does expand the preferential solvation analysis of chloroxine by the particular solvent species in the ethyl acetate + alcohol mixtures.

Solubility, solvent effect, enthalpy–entropy compensation and solvation thermodynamics of 4-(bromomethyl)-2(1H)-quinolinone in several aqueous blends

The current study was mainly devoted to solubility for the systems formed by 4-(bromomethyl)-2(1H)-quinolinone (BMQ) and blended solvents of isopropanol, N-methyl-2-pyrrolidinone (NMP), ethanol and n-propanol with water. Experiments for solubility determination were conducted by employing the shake-flask equilibration method from 278.15 to 318.15 K under 101.2 kPa. For each aqueous cosolvent mixture, the minimum solubility was recorded in water at 278.15 K; and the maximum value, in neat organic solvents at 318.15 K. The solubility performance was illustrated by Hansen solubility parameters of water, BMQ and co-solvents. No occurrence of polymorphic transformation or solvation was observed after experiments based on the XRD spectra of raw BMQ and excess solids analyzed. The satisfactory correlation results for solubility data was obtained by modified Wilson model, mixture response surface model, modified van’t Hoff-Jouyban–Acree model and Jouyban–Acree model. The relative average deviations were calculated to be no more than 8.72 %. Investigation on the relative contributions from inter- and intra-molecular interactions to the solubility variation of BMQ at temperature of 298.15 K was quantitatively performed via the linear solvation energy relationships (LSER). The descriptors of solvent blends including solubility parameter, dipolarity-polarizability and hydrogen-bond basicity were primarily responsible for the solubility variation. As well, the preferential solvation of BMQ was researched quantitatively via the inverse Kirkwood–Buff integrals method on the basis of some obtainable properties of solvent blends. The positive preferential solvation parameters for BMQ in middle and cosolvent-rich blends strongly suggest that the crystalline solute of BMQ is preferentially solvated by cosolvents of isopropanol, NMP, ethanol and n-propanol. The transfer and apparent dissolution properties including apparent Gibbs energy change (298.15 K), dissolution enthalpy and dissolution entropy (298.15 K) were derived and discussed. Analysis of enthalpy–entropy compensation indicates the entropy-driven mechanism of BMQ dissolved in all blend solvents.

Solubility, solvation thermodynamics and solvent effect of thiabendazole in several cosolvent blends

Equilibrium solubility determination and model correlation were performed in the present research for the systems formed by solid solute of thiabendazole and binary aqueous blends of acetonitrile, methanol, n-propanol and isopropanol. Experiments at temperatures ranging from 283.15 to 323.15 K were conducted by the use of the shake-flask saturation technique at 101.2 kPa. For the given binary solvent blends, the minimum mole fraction solubility was recorded in water at 283.15 K; and the maximum one, in neat organic solvent at 323.15 K. The generated equilibrium solubility was satisfactorily described by two models, modified van’t Hoff-Jouyban–Acree and Jouyban–Acree, with the relative average deviations (%) of no more than 6.08. Good prediction results of extend Hildebrand solubility approach (relative average deviations < 4.10%) were observed in terms of quartic polynomial for the four solution systems to correlate the interaction parameter (W) and solubility parameters of the solvents’ blends in the absence of thiabendazole (δ1+2). Analysis of the relative contributions from intra- and inter-molecular interactions to solubility variation of solid solute of thiabendazole (298.15 K) was quantitatively carried out via the linear solvation energy relationships (LSER). The descriptors of blended solvents comprising solubility parameter and hydrogen-bond basicity were principally responsible for the variation of determined solubility. Besides, the preferential solvation of thiabendazole was quantitatively researched via the inverse Kirkwood–Buff integrals method on the basis of some accessible properties for blended solvent systems. The positive preferential solvation parameters for thiabendazole in the middle and cosolvent-rich blends powerfully suggested that thiabendazole was preferentially solvated by cosolvents of isopropanol, acetonitrile, n-propanol, ethanol and methanol. The conjecture was reasonable that in above compositions, thiabendazole mainly served as Lewis acidic in terms of its interactions with alcohol molecules; while for the acetonitrile mixtures, this behavior was contributed by polarization effect. Besides, thiabendazole was preferentially solvated by ethanol (2) in ethyl acetate (1) + ethanol (2) solutions with ethyl acetate-rich compositions, and by water (2) solvent in aqueous blends with rich water compositions.

Reclaiming degraded mixed monoethanolamine and N-methyldiethanolamine solvent in carbon dioxide capture process

In this work, the effect of thermosiphon on vacuum distillation of degraded amine solutions was investigated for the amine reclamation process. A detailed analysis of the feed, the recovered solvent, and the waste streams showed that this novel reclamation process modified with thermosiphon was able to remove most of the undesirable impurities and degradation products and to restore the single degraded solvent to almost its original purity at a high recovery efficiency compared with the original process. Therefore, the thermosiphon was found to increase the recovery efficiency of degraded single amine reclamation at a steady-state. The average rate of products obtained from the enhanced unit was 2.64 mL/min, 6.28 times higher than the rate of product collected from the original unit (0.42 mL/min) at a temperature of 140 °C and vacuum pressure of 20 kPa. However, due to heavy amine in formulated mixed amines, the phenomenon of hindered circulation in thermosiphon occurred to make reclamation efficiency decline considerably. In order to maintain the original recovery efficiency in case of mixed solvents, after eliminating the thermosiphon part, the vacuum distillation temperatures were increased to a maximum of 170 °C close to heavy amine boiling point, by our new feeding mode of opening and closing feed valve intermittently in equal interval of 10 min to increase the evaporation rate of heavy amine at unsteady state. The analysis results showed that most of the undesired degradation products and impurities were removed, and the recovered product had a high weight ratio of MDEA/MEA in the range of 0.45–0.6. The total solvent concentration of the product was close to the feeding solvent concentration. These data will benefit for commercial reclaiming system design for blended amine solvents.