Mass Fraction Of Ethanol Research Articles

Insight into Mocha Diffusion Occurring during Ethanol Droplet Spreading on Acrylic Paint.

Mocha diffusion, a significant interfacial phenomenon in pottery painting, remains insufficiently understood in the documented literature regarding its dynamics. This study experimentally investigates Mocha patterns by quantitatively dripping ethanol droplets onto an acrylic paint surface. Results indicate that the spreading radius increases with the ethanol mass fraction, while the fractal period decreases. The fractal dimension of all Mocha patterns approximates 1.4087. Marangoni flow, generated by the volatilization of ethanol, is crucial for the growth and fractal formation of the "dendrites" in this spreading. The scaling analysis is used to interpret the spreading dynamics. This work encourages the interface science community to develop a comprehensive theory for the dynamics of Mocha diffusion and highlights the potential of this intriguing decorative technique.

Study of celecoxib dissolution process in the mixtures of ethanol and propylene glycol at different temperatures

ABSTRACT Categorised as a nonsteroidal anti-inflammatory drug targeting the COX-2 enzyme over COX-1, celecoxib (CXB) demonstrates high membrane permeability and low aqueous solubility, placing it in class II of the biopharmaceutical classification system. Therefore, comprehension of its solubility behaviour under different configurations is desirable. The current study explores CXB solubility in propylene glycol and ethanol binary mixtures by varying temperature and cosolvent concentration, using the shake-flask method followed by spectroscopy analysis. The results show increased solubility of CXB in this mixture as ethanol mass fraction and temperature increase. Several cosolvency models were used to correlate data, including van't Hoff, Jouyban-Acree, Jouyban-Acree-van't Hoff, and mixture response surface/modified Wilson models. The mathematical models’ accuracy was investigated through mean relative deviation. The Gibbs and van't Hoff equations were employed to establish the thermodynamic features of CXB dissolution.

Bioprocess in-line monitoring and control using Raman spectroscopy and Indirect Hard Modeling (IHM).

Process in-line monitoring and control are crucial to optimize the productivity of bioprocesses. A frequently applied Process Analytical Technology (PAT) tool for bioprocess in-line monitoring is Raman spectroscopy. However, evaluating bioprocess Raman spectra is complex and calibrating state-of-the-art statistical evaluation models is effortful. To overcome this challenge, we developed an Indirect Hard Modeling (IHM) prediction model in a previous study. The combination of Raman spectroscopy and the IHM prediction model enables non-invasive in-line monitoring of glucose and ethanol mass fractions during yeast fermentations with significantly less calibration effort than comparable approaches based on statistical models. In this study, we advance this IHM-based approach and successfully demonstrate that the combination of Raman spectroscopy and IHM is capable of not only bioprocess monitoring but also bioprocess control. For this purpose, we used this combination's in-line information as input of a simple on-off glucose controller to control the glucose mass fraction in Saccharomyces cerevisiae fermentations. When we performed two of these fermentations with different predefined glucose set points, we achieved similar process control quality as approaches using statistical models, despite considerably smaller calibration effort. Therefore, this study reaffirms that the combination of Raman spectroscopy and IHM is a powerful PAT tool for bioprocesses.

Identification of maximal cyclic pressure with the non-motorized method based on specific refraction

ВACKGROUND: Russian scientists constantly deal with the issues of the engine performance evaluation with non-standard methods, as they are commonly called “express methods”. In many cases, if the initial components retain the relative constancy of their physicochemical properties, the determination of performance indicators can be carried out with simple classical methods of refractometry, magneto-optics, densimetry, interfacial tensiometry or their combination (aggregation).
 AIM: Identification of the maximal cycle pressure of an operating diesel engine with the non-motorized method based on the values of specific refraction for each type of biofuel.
 METHODS: The object of research was the D-245.5S2 turbocharged four-stroke engine with intercooler. Mixtures of DT with ethanol, rapeseed oil and surep oil were prepared for the study. The mass fraction of oils and ethanol in the mixture varied from 0% to 50%. Density d and refractive index were measured for each sample. The measurements were carried out at an ambient temperature of 20˚C. The refractive index of the samples was measured using the IRF – 454b refractometer. The density was determined using the PZh-2-25 pycnometer and the VIBRAAJH-620CE laboratory scales according to GOST 3900-85 “Oil and petroleum products. Methods for determining density”.
 RESULTS: Data analysis showed that there is a strong correlation between the specific refraction sR and the maximal pressure in a cylinder Pz (MPa). Linear regression models for various alternative fuel mixtures have been developed to determine the maximal cycle pressure during diesel operation.
 CONCLUSION: The application of the proposed dependencies makes it possible to identify the maximal cycle pressure of an operating a diesel engine with sufficient accuracy in a non-motorized way.

Contact angle of ethanol, water, and their mixtures on stainless steel surfaces in dense carbon dioxide

HypothesisContact angle can be a key parameter in chemical engineering. However, the development and the optimization of numerous processes using supercritical CO2, considered as environmentally friendly, require new measurements under dense CO2 atmosphere. Besides, the influence of the roughness or the wetting regime on the contact angle is known at ambient conditions but remains to be discussed for systems under high pressure. ExperimentalContact angle measurements of ethanol, water, and their mixtures, with ethanol mass fractions ranging from 0.25 to 0.75, on two stainless steels in saturated CO2 at pressures ranging from 0.1 MPa to 15.1 MPa, and at313 K and 333 K were carried out in a set-up improving mass transfer between the studied liquid and the continuous fluid phase. Stainless steel surfaces have been characterized by atomic force and scanning electron microscopies allowing the application of the Wenzel equation. FindingsEthanol wetted totally both stainless steels while contact angles of all other liquids were increased by the rise of pressure, with contact angles up to 128° for water at 15.1 MPa. Trapped bubbles were observed at the solid/liquid interface and the bubble formation is discussed. Furthermore, the potential influence of bubble presence on the wetting regime is prospected through the question: could the pressure rise modify the wetting regime?

The dissolution mechanism, molecular dynamics simulation and thermodynamic analysis of nirmatrelvir (treatment of COVID-19) in aqueous ethanol mixtures

This research investigates the cosolvent effect of nirmatrelvir (treatment of COVID-19) in ethanol + water mixtures. The result shows that the maximum solubility in mole fraction is 8.313 × 10−2 at the ethanol mass fraction of 80%, which is greater than that in pure water. The solvent effect analysis indicates that the hydrogen bond acidity (HBA) of solvent has the greatest impact on the solubility of nirmatrelvir solubility. The negative preferential solvation values in water-rich regions indicate that nirmatrelvir molecules are preferentially solvated by water molecules. With the rising mass fraction of cosolvent, ethanol disrupts the ordered structure of water molecules in solution through hydrogen bonding, allowing nirmatrelvir molecules to be preferentially solvated by ethanol. Nonetheless, nirmatrelvir molecules are preferentially solvated by water again in ethanol-rich regions. Through molecular dynamics calculations (MD), it could be found that the dissolution behavior is consistent with its calculated by solvation free energy calculation. Furthermore, the tall and sharp peak of the RDF plots of O···H-O (ethanol/water) and N-H···O (ethanol/water) were attained at 1.50–2.50 Å, indicating that ethanol and water molecules form a regular and definite coordination sphere around the nirmatrelvir moiety at the distance of 1.50–2.50 Å through hydrogen bonding form. Additionally, the correlation fitting was performed for the solubility data through the Jouyban-Acree model and its derivative models. Moreover, “Apparent thermodynamic analysis” of nirmatrelvir dissolution process in aqueous ethanol mixtures including entropy, enthalpy and Gibbs free energy were completed.

Effect of raw material structural composition on the fermentation process of ethanol production

Ethanol is becoming the important renewable energy sources in the world which produces from carbohydrate resources. The raw material selection is the important procedure for real industrial production. The effect of biomass structural composition in feedstock on ethanol production is therefore needed to explore for feedstock selection. According to the previous research studies, the fermentation process includes pre-treatment and fermentation of sugar to ethanol. This study focuses on the simulation of raw material variation in ethanol production especially the structural composition of carbohydrate that contains three main components, cellulose, xylan, and lignin, in the fermentation section. The simulation model is validated by the data of previous study information with small deviation. The mixture design method is used for result interpretation and analysis. From the design of experiment, there are 14 scenarios and the selected response parameter is the mass fraction of ethanol in outlet stream of fermentation section. From the results, the maximum mass fraction of ethanol in outlet stream is in the scenario which has a large amount of cellulose and xylan fractions. This is because the conversion of reaction in the fermentation reactor mostly consumes cellulose and xylan to produce glucose and xylose, respectively, and converts them into ethanol product. From the overall result of this study, the important of raw material selection in ethanol production is illustrated.

Composite Salting-out Agent for the Salting-out of Ethanol, Acetone and n-butanol in the Crude Alcohol

This paper introduces the salting-out technology of ethanol, acetone and n-butanol in the crude alcohol after the bio-butanol fermentation liquid is processed by the mash tower. Aiming at the problems of low total solvent concentration, difficult recovery and high energy consumption for the bio-butanol fermentation broth separation, this paper studied the effects of unsaturated composite salts, salting-out temperature, and the volume ratio of salting-out agent to crude alcohol on the water removal of bio-butanol system. According to the index of water content in the organic phase, the most beneficial salting-out agent for water removal was selected from various composite salts. A salting-out extractant composed of water and composite salts was developed. The results showed that the extraction effect of unsaturated salt was not good for n-butanol-acetone-ethanol-water system. The n-butanol-acetone-ethanol-water system is extracted with a composite salt and water extractant, which can increase the mass fraction of n-butanol, acetone and ethanol, and achieve the purpose of separating and concentrating n-butanol, acetone and ethanol. After the primary countercurrent extraction, the mass fraction of n-butanol in the organic phase increased from 26% to over 64%, the mass fraction of acetone increased from 10% to over 21%, and the mass fraction of ethanol increased from 4% to over 9%. The composite salting-out agent can achieve the purpose of efficient water removal.

A Study on the Dynamic Collision Behaviors of a Hydrous Ethanol Droplet on a Heated Surface

This study uses high-speed imaging to investigate the dynamic collision behavior of a single hydrous ethanol droplet in different water/ethanol ratios on a heated horizontal glass surface. The initial droplet diameter varied from 3.3 to 4.1 mm, and the impact velocity was 0.57 m/s. The study covers a range of surface temperatures (373 K to 553 K) and ethanol mass fractions (0% to 100%) to reveal four regimes of droplet-impinging behaviors, including quiescent surface evaporation, puffing or partial boiling, explosive nuclear boiling, and the Leidenfrost effect. The addition of volatile ethanol to less volatile water shifts the droplet collision behavior toward explosive boiling and the Leidenfrost phenomenon. As the ethanol mass fraction increased from 0% to 100%, the superheat limit temperature decreased by approximately 80 K, while the Leidenfrost temperature decreased by at least 100 K. The dimensionless droplet diameter in the regime of droplet spreading with quiescent surface evaporation is influenced by surface temperature, surface tension, and viscosity. Meanwhile, the dimensionless diameter and height of a droplet in the regime of the Leidenfrost phenomenon are mainly influenced by its surface tension. The study concludes that a single parameter, such as the superheat level, Weber number, or Reynolds number, is difficult to describe droplet collision behavior, and multiple factors would be required to best describe droplet collision behavior and establish empirical correlations. However, it is feasible to predict partial collision behaviors by using one of the single parameters under certain conditions.

Solubility Measurement of Cholesterol in Several Solvents from 283.2 to 323.2 K

The solubilities of cholesterol in methanol, anisole, acetic acid, ethyl acetate, heptane, methyl isobutyl ketone (MIBK), and mixed solvent (ethanol–MIBK) are determined in the temperature range of 283.2 to 318.2 K. The experimental solubilities of cholesterol in pure solvents and binary mixed solvents are found to increase with increasing temperature. In the binary mixed solvent (ethanol–MIBK), the cholesterol solubilities with increasing mass fraction of ethanol first increase and then decrease. The maximum cholesterol solubility can be obtained when the mass fraction of ethanol is approximately 10%. The solubilities of cholesterol in MIBK, ethyl acetate, and anisole are larger than those in methanol, heptane, and acetic acid. The experimental solubilities are correlated with the van′t Hoff, modified Apelblat, Yaws, van’t Hoff–Jouyban–Acree, and modified UNIQUAC models. The modified UNIQUAC model shows a better fitting result. The modified UNIQUAC model shows an average relative error (ARD) of less than 9%. The ARD values for the other models are all less than 12%.

Prediction of nitrogen oxide emissions from diesel exhaust gases when using composite fuel

BACKGROUND: The problem of using composite fuel (CF) in diesel engines consists in a wide variation of their physicochemical properties, which affect the emission of nitrogen oxides (NOx) with ex-haust gases (EG). Therefore, the predictive assessment of the formation of NOx with EG when using CF is very relevant.
 AIMS: Predictive assessment of quantitative NOx emission with diesel EG when using various types and compositions of CF. Scientific novelty lies in development of the method of prediction of NOx emission by a diesel engine when using CF.
 METHODS: The method of prediction of quantitative NOx emissions with diesel EG regarding the use of various CF kinds and compositions has been developed. Predictive indicators of NOx emissions have been defined. Multi-parameter characteristics of NOx emission with EG of the D-245.582 diesel engine of 4ChN 11.0/12.5 size have been obtained experimentally. Degree of convergence of the experimental data with the calculated values is assessed.
 RESULTS: As a result of the carried-out studies, it was theoretically established that the load (pe) increase from 0.2 to 1.0 MPa, the engine speed (n) decrease from 1800 to 1400 min-1 and decrease of mass fraction of rapeseed oil (RO) and ethanol (E) in CF from 40 to 20% lead to increased NOx emissions with diesel EG from 131 to 2225 ppm and from 75 to 1450 ppm respectively. The increase in NOx emissions with the EG from 152 to 2125 ppm for CF consisting of DF and RO and from 175 to 1550 ppm for CF consisting of DF and E in the above mentioned operating modes experimentally confirmed. The degree of convergence of the experimental data with the calculated values is 90.14%, which in turn indicates the possibility of using the developed methodology as a predictive indicator.
 CONCLUSIONS: As a result of the studies, it was established that the developed method of prediction of quantitative NOx emissions with diesel EG is highly likely to use for preliminary assessment when various CF kinds and compositions are considered, as the degree of convergence of the experimental data with the calculated values, assessed with a statistical processing method and experimental error calculation, is 90.14%.

Equilibrium solubility, computational modeling and thermodynamic behavior of relugolix (form I) in the mixtures of (ethanol + acetonitrile/methanol/ethyl acetate/isopropanol) at various temperatures

The solubility of relugolix (form I) in the four binary solvent mixtures of (ethanol + acetonitrile/methanol/ethyl acetate/isopropanol) was investigated at the temperature range from T = (298.15 to 323.15) K under 0.1 MPa. At the same mass fraction of ethanol and temperature, the maximum and minimum solubility appeared in (ethanol + acetonitrile) and (ethanol + isopropanol) mixtures, respectively. The solubility of relugolix (form I) in the four binary solvent mixtures was correlated by equations of van’t Hoff, modified Apelblat, Jouyban-Acree and Jouyban-Acree-van’t Hoff. In addition, the apparent thermodynamic parameters (ΔsolH0, ΔsolG0, ΔsolS0) of the dissolution process of relugolix (form I) were calculated. The plot of ΔsolH0 vs. ΔsolG0 was non-linear with a variant positive slope implied the main driving of the dissolution of relugolix (form I) solids into four solvent mixtures was the enthalpy.

Experiments and Numerical Simulation of N-decane/Ethanol Bi-Component Droplet Evaporation

The evaporation characteristics of n-decane-based bi-component or multi-component droplets have been veiled for application in advanced combustion. This paper proposes to experimentally investigate the evaporation of n-decane/ethanol bi-component droplets settled in the convective hot air, and numerically simulate the key parameters affecting the evaporation charactersitics. It was found that the evaporation behavior was interactively affected by the mass fraction of ethanol and the ambient temperature. For mono-component n-decane droplets, the evaporation process included the transient heating (non-isothermal) and steady evaporation (isothermal) stages. In the isothermal stage, the evaporation rate followed d2-law. The evaporation rate constant linearly increased as the ambient temperature enhanced (573~873 K). For n-decane/ethanol bi-component droplets, at low mass fractions (≤0.2), the isothermal evaporation processes were steady due to the good miscibility between n-decane and ethanol, like mono-component n-decane, whereas at high mass fractions (≥0.4), the evaporation process experienced ultrashort heating and fluctuating evaporation stages. During the fluctuating evaporation, the bubbles formed inside the bi-component droplets and expanded, resulting in the occurrence of the microspray (secondary atomization) and the microexplosion. The evaporation rate constant of bi-component droplets increased as the ambient temperature enhanced, and showed a "V-shaped" trend with the increase of the mass fraction, and the evaporation rate constant was the smallest at 0.4. The evaporation rate constants based on the numerical simulation by using the multiphase flow model and Lee model showed reasonable agreement with the experimental ones, suggesting a potential of application in practical engineering.

Prediction of ignition time delay in a diesel engine when using composite fuel

BACKGROUND: Analytical determination of ignition time delay (ITD) which would give a prediction of ignition in diesel engines of various types using composite fuel (CF) of various kinds and compositions depending on loading and speed operation modes is a relevant issue.
 AIMS: Determination of the ITD values for a diesel engine at all loading and speed operation modes with using various kinds and compositions of CF.
 METHODS: In order to determine ITD, theoretical and experimental studies of the D-245.582 tractor diesel engine of 4ChN 11.0/12.5 size with using compositions of CF including diesel oil (DO) and rapeseed oil (RO) or ethanol (E) were carried out. As a result of the studies, the diesel engine ITD predictive indicators determination method considering dependence on loading and speed operation modes and CF kind and composition has been developed.
 RESULTS: Calculated values of the ITD numerical relationships revealed that the load (pe) increase from 0.2 to 1.0 MPa, the engine speed (n) decrease from 1800 to 1400 min-1 and decrease of mass fraction of rapeseed oil (RO) and ethanol (E) in CF from 40 to 20% lead to diesel engine ITD decrease from 7.69 to 4.82 degrees of crankshaft rotation and from 11.70 to 7.92 degrees of crankshaft rotation respectively. It was experimentally found that the load (pe) increase from 0.2 to 1.0 MPa, the engine speed (n) decrease from 1800 to 1400 min-1 and decrease of mass fraction of rapeseed oil (RO) and ethanol (E) in CF from 40 to 20% lead to diesel engine ITD decrease from 7.59 to 4.22 degrees of crankshaft rotation and from 11.20 to 7.72 degrees of crankshaft rotation respectively. The degree of convergence of the experimental data with the calculated values, assessed with a statistical processing method and experimental error calculation, is 94.04%.
 CONCLUSIONS: Practical value of the study lies in prediction of diesel engine ITD with using composite fuels of various kinds and compositions at all loading and speed operation modes.

SIM.QM-S17 Ethanol in Aqueous Matrix: Supplement Key Comparison, Model 1

Main textTo establish international measurement capabilities for the determination of ethanol in aqueous matrices, the CCQM Organic Analysis Working Group (OAWG) has performed three ethanol Key comparisons (2002: CCQM-K27a for forensic aqueous ethanol and CCQM-K27b for ethanol in wine as a commodity; 2005: CCQM-K27 subsequent studies - four levels of ethanol in water; 2007: CCQM-K27.2 Subsequent 2 for forensic levels). To provide an opportunity for the NMIs and DIs within the RMOs, three Key comparisons has been conducted within SIM (SIM.QM-K1, SIM.QM-K27) and AFRIMETS (AFRIMETS.QM-K27). In addition, for the NMIs to support their ethanol in aqueous matrices measurements capabilities, a Track A Model 2 (formerly known as Track B) Key comparison CCQM-K79 (2010) has been completed to compare aqueous ethanol certified reference material (CRM) solutions certified by the participant NMIs and DIs. The current comparison is important to NMIs and DIs to maintain their ethanol in water measurement capabilities, to claim it as a new one as well as to complement their existing measurement capabilities, mainly within the range where the alcohol meter (breathalyzer) needs to be calibrated and verified.In 2017, several NMIs and DIs in SIM expressed their interest in a complementary SIM.QM-K27 comparison, therefore CENAM and INMETRO agreed to collaborate for the realization of a SIM supplement comparison, which was identified as SIM.QM-K27.2019 by the OAWG, and the final assigned name by SIM was SIM.QM-S17. The main purpose of this comparison was to offer to SIM countries and other regions an additional opportunity for the NMI and DIs to evaluate their measurements capabilities in determining mass fraction of ethanol in an aqueous matrix within the mass fraction range from 0.1 mg/g to 5 mg/g. Fourteen laboratories were registered to take part in this comparison, and thirteen sent their results. This report presents the results of the SIM Key comparison SIM.QM-S17.The measurements capabilities demonstrated by the participants in SIM.QM-S17, underpin their ability to assign reference values of ethanol content in aqueous samples for both forensic and commodities applications. Successful participation in SIM.QM-S17 demonstrates the laboratories measurement capabilities in determining mass fraction of ethanol in an aqueous matrix within the mass fraction range from 0.1 mg/g to 5 mg/g. The study material was two batches of solutions of ethanol in water prepared gravimetrically at concentrations between 0.1 mg/g - 5 mg/g by CENAM, dispensed in glass bottles of 50 mL sealed with tear off aluminum crimp seals, with rubber stoppers. In previous SIM.QM.K27 comparison, the purity-corrected gravimetric value of the aqueous ethanol solutions assigned by the coordinating NMI was used to link SIM.QM-K27 to the CCQM-K27 Key comparison reference value (KCRV), where 1 % uncertainty was assigned to the KCRV to have the same uncertainty from the CCQM-K27.2. For this comparison, SIM.QM-S17 two levels aqueous ethanol solutions, the purity assigned by CENAM was not used for KCRV as was informed initially in the protocol, instead in 5-June-2020 at the OAWG, CENAM gravimetric values were presented, as well as the participants results evaluated by four different statistical approaches to assess the candidate KCRV. For both levels of ethanol in aqueous matrix solutions, the DerSimonian-Laird Weighted mean and the Hierarchical Bayes mean methods seem to give a better estimation of the KCRV ± KCRU95 candidate and was agreed by OAWG to use the Hierarchical Bayesian mean, from where the KCRV for SIM.QM-S17 Level 1 (Low-level) and Level 2 (high-level) were (240.92 ± 1.28) mg/kg (k =2) and (389.87 ± 1.52) mg/kg (k =2), respectively. All the thirteen participants in the SIM.QM-S17, including both coordinators, demonstrated their capability to measure ethanol in aqueous matrix in the mass fraction range of 0.1 mg/g to 5 mg/g.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Solubility measurement, correlation, and dissolution thermodynamics of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane · 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (2HNIW·HMX) co-crystal in two binary solvent mixtures

The solubility of 2HNIW·HMX co-crystal in two binary solvent mixtures (ethanol + methyl acetate, and 1,2-dichloroethane + methyl acetate) was measured by gravimetric method at various temperatures (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15 K) under atmospheric pressure (0.1 MPa). The experimental results revealed that the solubility for co-crystal in binary solvent mixtures is a simple function of ethanol (or 1,2-dichloroethane) mass fraction and temperature, which decreased with increasing temperature and mass fraction of ethanol (or 1,2-dichloroethane) in the binary solvent mixtures. The solubility of 2HNIW·HMX co-crystal was correlated with the modified Apelblat equation, CNIBS/R-K model, Jouyban-Acree-van't Hoff model, and Jouyban-Acree-Apelblat model. The fitting results demonstrate that the modified Apelblat model and CNIBS/R-K model provided a better correlation with the experimental results than the other models. Furthermore, the van’t Hoff equation was used to study the thermodynamic properties of the 2HNIW·HMX co-crystal dissolution process, including the apparent molar enthalpy change (ΔdisH°), the apparent molar entropy change (ΔdisS°), and the apparent molar Gibbs free energy change (ΔdisG°). The results show that the dissolution of the co-crystal in the selected binary solvent mixture is an exothermic process. The experimental and calculated solubility data and thermodynamic properties of the 2HNIW·HMX co-crystal would be helpful for selecting the appropriate solvent system for the reaction, crystallization, and purification of the 2HNIW·HMX co-crystal.

ß-Damascenone Highly Diluted in Hydroalcoholic Mixtures: Phase Equilibrium Measurements, Thermodynamic Modeling, and Simulation of a Batch Distillation

ß-Damascenone is a carotenoid-derived compound that plays a key role in the characteristic aroma of wines and distilled spirits. Despite the valuable contribution of this compound to the flavor quality of alcoholic beverages, little is known about its volatility and its vapor–liquid equilibrium behavior in hydroalcoholic mixtures of different compositions. Such information is essential to be able to choose the right thermodynamic model for ß-damascenone when using a distillation process simulation software to gain a better understanding of the behavior of ß-damascenone during spirit distillation. In this context, this work presents new experimental VLE data for ß-damascenone highly diluted in ethanol + water mixtures. The measurements were carried out in a recirculation ebulliometer operating at 101.3 kPa for ethanol mass fractions between (0.10 and 0.79) g·g–1. Activity coefficient model NRTL was used to correlate the experimental data and binary interaction parameters. The parameters obtained for the NRTL model were employed to simulate a laboratory-scale batch distillation of a model solution of ß-damascenone, ethanol, and water. The simulation results were well fitted to experimental data. This approach can be further extended to other compounds that contribute to the aroma of distilled spirits, and the results can be transferred to simulate larger scale distillations.

The dissolution behavior and thermodynamic properties analysis of pentoxyverine citrate in aqueous solutions of alcohols

The objective of this work is to study the dissolution behavior and thermodynamic properties of pentoxyverine citrate in aqueous solutions of alcohols. The results of solubility data at temperature range from 278.15 K to 318.15 K were obtained by the isothermal equilibrium method under atmospheric condition. In pure solvents, the largest solubility data in mole fraction is found in water at 318.15 K (2.756 × 10−2), followed by ethanol (1.156 × 10−2), n-propanol (8.129 × 10−3), isobutanol (5.233 × 10−3), isopropanol (4.340 × 10−3) and 1-butanol (3.435 × 10−3). The order of solubility from large to small is consistent with the order of solvent polarity. The solubility profile in mixtures of (ethanol + water), (n-propanol + water) and (isopropanol + water) increases firstly and then decreases with the increasing mass fraction of alcohols at all studied temperatures, and it reaches a maximum at w = 0.60 (the mass fraction of ethanol) in mixtures of (ethanol + water) at all investigated temperatures, for two other binary mixtures, the mass fraction of n-propanol and isopropanol is 0.40. The analysis of extended Hildebrand solubility approach indicate the solvent–solvent interactions and specific interactions are unfavorable for the dissolution process. The values of relative average deviation (RAD) for crystalline pentoverine citrate demonstrated well correlation of solubility values with Apelblat equation and Jouyban-Acree model. The positive values of ΔHsolo and ΔSsolo for dissolution behavior indicate the dissolution process was not only endothermic but also entropic-favouring. Moreover, the enthalpy is the main contributing force to the Gibbs free energy during the dissolution of pentoverine citrate.

Insight into the Nucleation Mechanism of p-Methoxybenzoic Acid in Ethanol-Water System from Metastable Zone Width.

The metastable zone width (MSZW) of p-methoxybenzoic acid (PMBA) in an ethanol-water system was measured using the polythermal method. The nucleation order m obtained by the Nývlt’s model indicates the nucleation of PMBA following a progressive nucleation mechanism at low saturation temperature (m = 3.18–7.50) and an instantaneous nucleation mechanism at high saturation temperature (m = 1.46–2.55). Then, combined with the metastable zone experiment and the Sangwal model, we found that the MSZW and the interfacial energy reached the maximum when the mass fraction of ethanol was 0.8, which resulted in the smallest crystal product size. Meanwhile, the maximum and obtained based on the modified Sangwal model indicating the PMBA needs to overcome a higher nucleation barrier in the ethanol mass fraction of 0.8. Finally, we proposed a preferential strategy for adjusting MSZW by correlating the interfacial energy with the change in ethanol mass fraction, saturation temperature, and cooling rate, respectively.

The effect of solvents on the morphology of NTO crystal by molecular dynamics

In this paper, a molecular model for adsorption of NTO surface-solvent was constructed, and the effects of different solvents on the morphology of NTO crystal were simulated by molecular dynamics. The selected solvents included ethanol, water, acetone, N-methylpyrrolidone (NMP), ethyl acetate and N,N-dimethylformamide. Pure solvents and two co-solvents including NMP/water and ethanol/water were studied to provide theoretical guidance for the selection of solvent systems for NTO recrystallization. In pure solvents, the results show that the crystal morphology of NTO can be effected by all solvent and in NMP solvent is the best. In co-solvents, when the mass ratio of ethanol to water is 9:1, the best morphology of NTO crystals is found . In ethanol/water system, the morphology of NTO crystals changes from near-cube to cuboid with the decrease of ethanol mass fraction, and the aspect ratios of NTO crystals increase. In NMP/water system, the decrease of the mass fraction of NMP makes the crystal morphology deteriorate. This is manifested as the crystal develops towards a narrow needle shape, and the value of the aspect ratio increases.