Neat Ethanol Research Articles

Solubility Behavior of Ethyl l-Thiazolidine-4-carboxylate Hydrochloride in 15 Neat Solvents and Ethanol + Methyl Acetate Binary Solvent from 283.15 to 323.15 K

The solubility (mole fraction) of ethyl l-thiazolidine-4-carboxylate hydrochloride in 15 individual solvents including water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-...

Solubility, dissolution thermodynamics and preferential solvation of 4-nitroaniline in (ethanol + water) mixtures

ABSTRACT In this research, the equilibrium mole fraction solubility of 4-nitroaniline (4-NA) in some aqueous-ethanolic mixtures was determined at seven temperatures from (293.15 to 323.15) K. The respective apparent thermodynamic functions (Gibbs energy, enthalpy, and entropy) of the dissolution processes were computed using the van’t Hoff and Gibbs equations. The enthalpy-entropy relationship for 4-NA was non-linear in the plot of enthalpy vs. Gibbs energy of solution with negative slopes from neat water to the mixture w 1 = 0.10 and from w 1 = 0.20 to neat ethanol but positive slope from w 1 = 0.10 to w 1 = 0.20. Therefore, the driving mechanism for 4-NA transfer processes is the entropy in water-rich mixtures. Additionally, by means of the inverse Kirkwood-Buff integrals is observed that 4-NA is preferentially solvated by water molecules in water-rich mixtures but preferentially solvated by ethanol molecules in the mixtures of 0.23 ≤ x 1 ≤ 1.00.

Uridine in twelve pure solvents: Equilibrium solubility, thermodynamic analysis and molecular simulation

in this work, the solubility of uridine in twelve neat solvents was investigated by using experimental laser monitoring method and molecular dynamic (MD) simulation analysis approach. The experimental solubility data of uridine in twelve neat solvents, including methanol, 2-methoxyethanol, ethanol, 2-ethoxyethanol, n-propanol, 2-propoxyethanol, isopropanol, n-butanol, 2-butoxyethanol, ethylene glycol, N, N-dimethylformamide (DMF) and water, was measured at temperature range of (278.15 K–323.15 K) under atmospheric pressure. The solubility of uridine was sensitive to temperature in tested solvents, namely, increased monotonously with rising temperature. The order of uridine solubility at 298.15 K in selected solvents is DMF (0.1780) > water (0.04061) > 2-methoxyethanol (0.01565) > ethylene glycol (0.01399) >2-ethoxyethanol (0.006413) > methanol (0.003195) > 2-propoxyethanol (0.003005) > 2-butoxyethanol (0.002241) > isopropanol (0.001238) > ethanol (0.001086) > n-propanol (0.001047) > n-butanol (0.0009806). the measurement solubility data was correlated by NRTL model, NRTL-SAC model, UNIQUAC model, λh equation and Apelblat equation, respectively. The derived apparent thermodynamic parameters (ΔdisGo, ΔdisHo, ΔdisSo, ζH, ζTS) shown an entropy-driven, endothermic and spontaneous process of dissolution of uridine in all chosen solvents, and the main contribution of ΔdisGo comes from the positive enthalpy. Hansen solubility parameters (HSPs) were employed to reveal the solubility phenomenon of uridine in selected solvents. Furthermore, the results of molecular dynamic simulation revealed using radial distribution function (RDF) analysis, which indicated that interactions of solvent-solute have well fitted with solubility order of uridine in selected solvents.

Effect of Waste Heat Recovery System on Performance and Emission Characteristics of Spark Ignition (SI) Engine Fuelled with Neat Ethanol (E100)

TheSI engine could not be operatedefficientlywith neat ethanol fuel due to its high selfignition temperature and latent heat of vaporizationcompared with petrol.The above issues of SI engine is turned to be an objective of this study, where the SI engine was operated with neat ethanol fuel under different inlet air temperatures.The result of this study is indicated that the neat ethanol fuel could be utilized efficiently in SI engine with waste heat recovery system.The specific fuel consumption (SFC) of SI engine has decreased with neat ethanol fuel compared with petrol fuelled engine. It is also found that theSI engine has registered almost same brake thermal efficiency (BTE) values with neat ethanol compared to petrol.The exhaust emissions such as carbon monoxide (CO) and Hydrocarbon (HC)were reduced in SI engine, at the same time there was an increase in oxide of nitrogen (NOx).

Slow photoionization via higher excited states of N,N-dimethylaniline in ethanol solution probed by femtosecond transient absorption spectroscopy under two-pulse two-photon excitation.

Photoionization dynamics of N,N-dimethylaniline (DMA) from highly electronically excited states in ethanol solution was investigated by means of femtosecond two-pulse two-photon excitation transient absorption (2PE-TA) spectroscopy. The first pump pulse prepares the lowest singlet excited state (S1 state) of DMA, and the second one excites the S1 state into higher excited states. In the case with the second pulse at 500 nm, the ionization took place via a rapid channel (<100 fs) and a slow one with the time constant of ∼10 ps. The excitation wavelength effect of the second pulse indicated that a specific electronic state produced directly from higher excited states was responsible for the slow ionization. By integrating these results with the time evolution of the transient absorption spectra of the solvated electron in neat ethanol detected by the simultaneous two-photon excitation, it was revealed that the slow ionization of DMA in ethanol was regulated by the formation of the anionic species just before the completion of the solvation of the electron, leading to the solvated electron in the relaxed state. From these results, it was strongly suggested that the capture of the electron of the Rydberg-like state by the solvent or solvent cluster regulates the appearance of the cation radical.

Solubility, Solution Thermodynamics, and Preferential Solvation of Amygdalin in Ethanol + Water Solvent Mixtures.

The equilibrium solubility of amygdalin in [ethanol (1) + water (2)] mixtures at 293.15 K to 328.15 K was reported. The thermodynamic properties (standard enthalpy ΔsolnH°, standard entropy ΔsolnS°, and standard Gibbs energy of solution ΔsolnG°) were computed using the generated solubility data via van’t Hoff and Gibbs equations. The dissolution process of amygdalin is endothermic and the driving mechanism in all mixtures is entropy. Maximal solubility was achieved in 0.4 mole fraction of ethanol at 328.15 K and the minimal one in neat ethanol at 293.15 K. Van’t Hoff, Jouyban–Acree–van’t Hoff, and Buchowski–Ksiazczak models were used to simulate the obtained solubility data. The calculated solubilities deviate reasonably from experimental data. Preferential solvation parameters of amygdalin in mixture solvents were analyzed using the inverse Kirkwood–Buff integrals (IKBI) method. Amygdalin is preferentially solvated by water in ethanol-rich mixtures, whereas in water-rich mixtures, there is no clear evidence that determines which of water or ethanol solvents would be most likely to solvate the molecule.

Solubility of 3-aminosalicylic acid in ethanol + water mixtures at different temperatures

Temperature-dependent solubility data of 3-aminosalicylic acid (3-ASA) are scarce in the literature and there is a particular need to explore cosolvency for this compound. Therefore, in the current study, the solubilization profile of 3-ASA along with density data in the mixtures of ethanol and water were measured at a temperature range of 293.2–313.2 K. The generated data were described by using some previously reported linear or non-linear mathematical models and their accuracies were investigated by calculating the mean relative deviations (MRD%). The apparent thermodynamic analysis for 3-ASA dissolution process was performed by the Gibbs and van't Hoff equations. Moreover, molecular insights in the local environment of the solute was obtained based on the inverse Kirkwood-Buff integrals, as it was observed that 3-ASA is preferentially solvated by water molecules from neat water to the mixture x1 = 0.24 and from x1 = 0.35 to neat ethanol. The experimental data and thermodynamic properties provide helpful information for the separation and purification of 3-ASA.

Towards Developing an Unleaded High Octane Test Procedure (RON&gt;100) Using Toluene Standardization Fuels (TSF)

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;An increase in spark-ignition engine efficiency can be gained by increasing the engine compression ratio, which requires fuels with higher knock resistance. Oxygenated fuel components, such as methanol, ethanol, isopropanol, or iso-butanol, all have a Research Octane Number (RON) higher than 100. The octane numbers (ON) of fuels are rated on the CFR F1/F2 engine by comparing the knock intensity of a sample fuel relative to that of bracketing primary reference fuels (PRF). The PRFs are a binary blend of iso-octane, which is defined to an ON of 100, and n-heptane, which represents an ON of 0. Above 100 ON, the PRF scale continues by adding diluted tetraethyl lead (TEL) to iso-octane. However, TEL is banned from use in commercial gasoline because of its toxicity. The ASTM octane number test methods have a “Fit for Use” test that validate the CFR engine’s compliance with the octane testing method by verifying the defined ON of toluene standardization fuels (TSF). The RON test method defines TSFs in the range of 65.1 RON to 113.0 RON with blends of toluene, n-heptane, and iso-octane. Since TSFs do not contain TEL, they could potentially be used as bracketing reference fuels instead of leaded PRFs beyond RON 100. In this work, multiple CFR engines performed “Fit for Use” tests per the RON test method (ASTM D2699) and the TSF ratings closely correlated to their defined RON values without the need of intake air temperature tuning. In the next step, TSFs were used as non-leaded reference fuels to rate the RON of neat methanol, ethanol, iso-propanol, iso-butanol, ethyl acetate, and diisobutylene, all of which have a RON exceeding 100. These same fuels were tested on a separate CFR engine per the official ASTM D2699 RON test method with leaded PRFs. Their TSF-based RON ratings were found to be within the variations of RON values reported in the literature and closely matched with their standard RON rating using leaded reference fuels. Therefore, octane ratings of fuels beyond RON 100 with TSFs as reference fuels proved to be one viable pathway to rate fuels &amp;gt;100 RON without the need for leaded reference fuels.&lt;/div&gt;&lt;/div&gt;

Investigation of Dual-Fuel Combustion by Different Port Injection Fuels (Neat Ethanol and E85) in a DE95 Diesel/Ethanol Blend Fueled Compression Ignition Engine

Abstract This paper investigated the effect of different substitution ratios of neat ethanol (E100) and ethanol–gasoline blend E85 on in-cylinder combustion, engine efficiency, and exhaust emissions, in a dual-fuel diesel engine, using the ethanol–diesel blend (DE95). Experimental studies realized at 1400 rpm, 1600 rpm, and 1800 rpm engine speeds under constant engine load of 50% (20 Nm). For each engine speed, the injection timing of diesel and E95 fuels at 24 °CA bTDC kept constant while low-reactivity fuels (i.e., E100 and E85) substitution ratio changed in the range of 59–83%. The results showed that premixed fuels in different SRs have an impact on shaping engine emissions, ignition delay (ID), in-cylinder pressure, and heat-release rate. Also, at the dual-fuel experimental studies in all engine speeds, NOx about 47–67% decrease compared to single fuel conditions of reference diesel and DE95, and smoke opacity remained unchanged around 0.1 FSN, whereas HC and CO increased in the range of 20–50%. However, E85/DE95 and E100/DE95 dual-fuel combustion achieved lower brake thermal efficiency (BTE) and combustion efficiency compared to single diesel fuel combustion. On the other hand, in dual-fuel combustion conditions, despite the low combustion efficiency, premixed E85 fuel offered higher engine efficiency and lower exhaust emissions than E100.

Bezafibrate in several aqueous mixtures of low alcohols: Solubility, solvent effect and preferential solvation

By using the saturation shake-flask method, the saturated solubility of bezafibrate in neat water, methanol, ethanol, n-propanol and isopropanol and aqueous co-solvent mixtures of methanol (1) + water (2), ethanol (1) + water (2), isopropanol (1) + water (2) and n-propanol (1) + water (2) was experimentally acquired at temperatures from 283.15 Kto 323.15 K and local atmospheric pressure. The maximum solubility magnitudes in mole fraction were recorded in the neat solvents of methanol/ethanol/n-propanol/isopropanol for corresponding solutions. The mole fraction solubility was described mathematically by using the van’t Hoff-Jouyban-Acree and Jouyban-Acree models. The largest value of relative average deviations was 6.23%; and, root-mean-square deviations, 8.92 × 10−5. The local mole fractions of water and co-solvent (methanol, ethanol, n-propanol or isopropanol) around the drug bezafibrate were quantitatively investigated by the use of Inverse Kirkwood–Buff integrals method. Results indicated that the bezafibrate was preferentially solvated by methanol (ethanol, n-propanol or isopropanol) in alcohol-rich and intermediate compositions in the alcohol mixtures; while in water-rich compositions, bezafibrate was preferentially solvated by water. The main factors relating to solvent effect were inspected through Kamlet and Taft linear solvation energy relationships, demonstrating that the cavity formation energy and dipolarity-polarizability in methanol solutions, cavity formation energy and basicity in ethanol solutions, and cavity formation energy in n-propanol (isopropanol) solutions played the principal role upon the bezafibrate solubility variation.

Solubility Measurement and Various Solubility Parameters of Glipizide in Different Neat Solvents.

Glipizide (GLZ) is an oral hypoglycemic agent, which is a weakly aqueous soluble drug. The solubility values of GLZ in various neat solvents are scarce in the literature. Hence, the solubility of GLZ in 12 different neat solvents, namely, “water, methanol, ethanol, isopropanol (IPA), 1-butanol, 2-butanol, ethylene glycol (EG), propylene glycol (PG), poly(ethylene glycol)-400 (PEG-400), ethyl acetate (EA), dimethyl sulfoxide (DMSO), and Transcutol-HP (THP)”, at “T = 298.2–318.2 K” and “p = 0.1 MPa” was measured. The recorded solubilities of GLZ were correlated by “van’t Hoff and Apelblat models” using root-mean-square deviation (RMSD). The overall RMSD was obtained as 1.21 and 1.40% for “Apelblat and van’t Hoff models”, respectively. Different solubility parameters of all studied materials including drug and solvent were calculated to find the best solvent for GLZ. The solubilities of GLZ (expressed in mole fraction) have been found highest in DMSO (2.81 × 10–2), followed by THP, EA, 2-butanol, 1-butanol, IPA, PEG-400, ethanol, PG, methanol, EG, and water (1.98 × 10–4) at “T = 318.2 K”. All investigated solubility parameters of GLZ were recorded very close to the DMSO. “Apparent thermodynamic analysis” showed an “endothermic and entropy-driven dissolution” of GLZ in the 12 different neat solvents. The highest molecular interactions were recorded in GLZ–DMSO compared to other combinations. Overall, DMSO has been considered as the best solvent for the solubilization of GLZ.

Selective extraction of phospholipids from whey protein phospholipid concentrate using supercritical carbon dioxide and ethanol as a co-solvent

In recent years, using dairy phospholipids (PL) as functional ingredients has increased because PL have nutritional benefits and functional properties. In this study, a novel 2-step supercritical fluid extraction (SFE) process was used to extract whey protein phospholipid concentrate (WPPC), a dairy co-product obtained during the manufacture of whey protein isolate, for PL enrichment. In the first step, nonpolar lipids in WPPC were removed using neat supercritical carbon dioxide (S-CO2) at 41.4 MPa and 60°C. In the second stage, the feasibility of using the polar solvent ethanol as a co-solvent to increase the solubility of S-CO2 extraction solvent was explored. A 3 × 3 × 2 factorial design with extraction pressure (35.0, 41.4, and 55.0 MPa), temperature (40 and 60°C), and concentration of ethanol (10, 15, and 20%) as independent factors was used to evaluate the extraction efficiency providing the most total PL, and the best proportion of each individual PL from the spent solids collected during S-CO2 SFE. All lipid fractions were analyzed using thin-layer chromatography and high-performance lipid chromatography. The total amount of PL extracted from WPPC was significantly affected by ethanol concentration; the extraction pressure and temperature were nonsignificant. The optimal SFE condition for generating a concentrated PL lipid fraction was 35.0 MPa, 40°C, and 15% ethanol concentration; the highest amount of extracted PL averaged 26.26 g/100 g of fat. Moreover, adjusting SFE condition allowed successful recovery of a high concentration of sphingomyelin, phosphatidylcholine, and phosphatidylethanolamine, giving averages of 11.07, 10.07, and 7.2 g/100 g of fat, respectively, 2 to 3 times more than conventional solvent extraction. In addition, exhausted solids obtained after the SFE process were enriched with denatured proteins (72% on dry basis) with significantly more water-holding capacity and emulsifying capacity than untreated WPPC. Overall, this 2-stage SFE process using neat S-CO2 and ethanol has the greatest potential to produce a PL-rich lipid fraction from WPPC.

Transfer Hydrogenation of Carbon Dioxide to Methanol Using a Molecular Ruthenium‐Phosphine Catalyst

AbstractTransfer hydrogenation using molecular catalysts has become a powerful tool in synthetic chemistry and a wide range of unsaturated substrates can be reduced with this protocol. Whereas reactions using iso‐propanol as hydrogen donor are already well established, recent examples demonstrate the possibility to use linear alcohols from renewable resources. Herein, the first effective transfer hydrogenation of the challenging substrate carbon dioxide (CO2) directly to methanol is described, applying a molecular ruthenium catalyst and linear alcohols as the hydrogen source. In neat ethanol, TONs up to 121 are achieved under moderate pressures of CO2. Moreover, systematic investigations enable to propose initial acceptorless dehydrogenation of the alcohol, followed by the reduction of CO2 to methanol via ethyl formate, as mechanistic basis.

Solubility modelling, solvent effect and preferential solvation of 6-chloropurine in several aqueous co-solvent mixtures between 283.15 K and 328.15 K

The mole fraction solubility of 6-chloropurine in aqueous mixtures of methanol, ethanol, N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) was measured by a saturation shake-flask method over the temperature range of (283.15–328.15) K at pressure of 101.2 kPa. The solubility of 6-chloropurine increased positively with increasing temperature at a given solvent composition and decreased with increasing mass fraction of water in each binary system. The maximum solubility was found in neat methanol, ethanol, DMF and DMA. Given the same temperature and mass fraction of the organic solvent, the solubility of 6-chloropurine was greater in (DMF + water) than in the other three solvent mixtures. The X-ray power diffraction (XPRD) analysis showed that no polymorphic transformation, solvate formation or crystal transition took place during the experiments. Linear solvation energy relationships concept was used to describe the variation in the solubility based on the solvent effect. The preferential solvation parameters were derived from their thermodynamic solution properties using inverse Kirkwood–Buff integrals. The preferential solvation parameters (δx1,3) for methanol, ethanol, DMF and DMA were negative in the four solvent mixtures with water-rich compositions, which indicated that 6-chloropurine was preferentially solvated by water. Temperature has little effect on the preferential solvation magnitudes. The higher solvation by water could be explained in terms of the higher acidic behavior of the solvents interacting with the Lewis basic groups of the 6-chloropurine. Furthermore, several mathematical cosolvency models were adopted to correlate the measured solubility values. The relative average deviation and root-mean-square deviation were no more than 2.36% and 1.026 × 10−3, respectively.

Tailoring the structure, pH sensitivity and catalytic performance in Suzuki–Miyaura cross-couplings of Ln/Pd MOFs based on the 1,1′-di(p-carboxybenzyl)-2,2′-diimidazole linker

An array of heterobimetallic Pd/Ln MOFs (1-4) with Sm, Eu, Tb, Dy as preferred metal nodes and 1,1'-di(p-carboxybenzyl)-2,2'-diimidazole (H2L) as a fairly suitable bifunctional organic linker have been synthesized, fully characterized and tested as catalysts in cross-coupling reactions. These robust MOFs, ensuring a uniform distribution of Pd, showed excellent stability in air and high catalytic activity in Suzuki-Miyaura reactions conducted in neat water, neat ethanol as well as water-ethanol mixture. Depending on the solvent, complex 1 could be effectively recycled 4-8 times without significant loss of catalytic activity. Importantly, this complex was found to be pH responsive in a reversible way, enabling convenient recovery from acidic aqueous solutions, indicating good recyclability as well as environment-friendly separation of the metal residues after the reaction.

Diesel and Spark Ignition Engines Emissions and After-Treatment Control: Research and Advancements

One of the major risks mankind has encountered during recent years is, without a doubt, the anthropogenic contribution to environmental pollution [...]

Solvent exchange in a metal-organic framework single crystal monitored by dynamic in situ X-ray diffraction.

Understanding the processes by which porous solid-state materials adsorb and release guest molecules would represent a significant step towards developing rational design principles for functional porous materials. To elucidate the process of liquid exchange in these materials, dynamic in situ X-ray diffraction techniques have been developed which utilize liquid-phase chemical stimuli. Using these time-resolved diffraction techniques, the ethanol solvation process in a flexible metal-organic framework [Co(AIP)(bpy)0.5(H2O)]·2H2O was examined. The measurements provide important insight into the nature of the chemical transformation in this system including the presence of a previously unreported neat ethanol solvate structure.

Acceptorless Dehydrogenative Coupling of Neat Alcohols Using Group VI Sulfide Catalysts

Group VI sulfides were synthesized via coprecipitation of elemental sulfur and metal hexacarbonyl and characterized with XRD, XPS, and TEM. These materials were then demonstrated as active catalysts for the acceptorless dehydrogenative coupling of neat ethanol to ethyl acetate, rapidly reaching equilibrium conversion and up to 90% selectivity. Other primary alcohols form the corresponding esters, while diols formed the corresponding cyclic ethers and oligomers.

Solubility, solution thermodynamics and preferential solvation for 4-bromopyrazole in mixed solvents of (methanol/ethanol + water) from T = (283.15 to 318.15) K

The solubility of 4-bromopyrazole in binary (methanol+water) and (ethanol+water) solvent mixtures were investigated by using the isothermal dissolution equilibrium method under atmosphere pressure. The maximum solubility was observed in neat methanol or ethanol. At the same mass fraction of methanol or ethanol and temperature, the solubility of 4-bromopyrazole was greater in (ethanol+water) than in (methanol+water) mixed solvents. The obtained solubility data were correlated with Jouyban-Acree model, modified Apelblat-Jouyban-Acree model and van’t Hoff-Jouyban-Acree model. The largest values of relative average deviation and the root-mean-square deviation were 3.59×10−2 and 6.60×10−3, respectively. Positive apparent enthalpies showed that dissolution of 4-bromopyrazole in these mixed solvents was an endothermic process. Preferential solvation parameters of 4-bromopyrazole were also derived by means of the inverse Kirkwood-Buff integrals method. The preferential solvation parameter was negative in water-rich mixtures but positive in intermediate composition and alcohol-rich mixtures. In the latter case, it is conjecturable that 4-bromopyrazole is acting as a Lewis acid with alcohol molecules. The co-solvent action may be related to the breaking of the ordered structure of water around the polar moieties of 4-bromopyrazole which increases the solvation of this solute. The solubility data and thermodynamic study expanded the physicochemical information about 4-bromopyrazole in binary solvent mixtures.

A site-holding effect of TiO2 surface hydroxyl in the photocatalytic direct synthesis of 1,1-diethoxyethane from ethanol.

To understand the mechanism of the photocatalytic direct synthesis of 1,1-diethoxyethane (DEE) from ethanol is vital for enhancing the reaction efficiency. Based on photocatalytic data of different phase TiO2 and F-TiO2 catalysts, radical trapping data, and GC-MS data, we proposed a photocatalytic mechanism for the preparation of both DEE in neat ethanol and 2,3-butanediol (2,3-BD) in ethanol-H2O using photocatalytic methods. In neat ethanol, hydroxyl isn't involved in the catalytic cyclic process but hydroxyl has an indirect site-holding effect, thus leading to more hydroxyl groups with higher activity. In ethanol-H2O, although the strong oxidant ˙OH radical is involved, fewer OH groups lead to higher selectivity of 2,3-BD. The interaction of the reactant/solvent with the surface group of the catalyst is important in the activity and selectivity of photocatalytic reactions. This finding gives fundamental insight into the role of TiO2 surface hydroxyl in the photocatalytic dehydrogenation process of alcohols and opens a promising path to obtaining both high selectivity and high conversion in TiO2-based photocatalytic activity.