Amyl Acetate Research Articles

Modelling the Repair of Carbon-Centered Protein Radicals by Phenolic Antioxidants

Oxidative stress is a biological process that has been linked to many diseases, hence understanding how to prevent and repair it is essential to medicine. The thermodynamics and kinetics of the repair reactions of radically damaged leucine (a lateral chain in a simplified protein environment) by twenty phenolic antioxidants are studied at the M06-2X(SMD)/6-31++G(d,p) level of theory in water and pentyl ethanoate. The two repair mechanisms modelled are formal-hydrogen atom transfer (f-HAT) and single electron transfer (SET). Although all f-HAT reactions are thermodynamically favourable, only one of the phenols produced rate constants in the diffusion limit, exhibiting biological relevance. SET is not suspected to be an important repair pathway for the phenols studied. We show that the Bell–Evans–Polanyi principle, which relates thermodynamics and kinetics properties for a reaction, breaks down when comparing between the solvents, protein repair sites, and the phenolic antioxidants. While thermodynamic data can be used as valuable screening tools, the kinetic calculation of rate constants in solution is crucial for enhancing the biological relevance of theoretical studies.

Investigation of amyl acetate sorption impact on high‐density polyethylene bottle properties

AbstractThermoplastics based on polyolefins, including polypropylene, high‐density polyethylene and low‐density polyethylene, are extensively utilized across various packaging sectors. The selection of these materials for specific applications is influenced by multiple factors, such as the polymer's absorption characteristics and the impact on its mechanical properties when in contact with the packaged product. This study presents an experimental methodology designed to simulate the effects of absorption on the macroscopic and microscopic properties of high‐density polyethylene bottles in contact with amyl acetate. Macroscopic degradation was evaluated by modeling mechanical damage using unified theory and the energy method. Analytical techniques such as gravimetric analysis, scanning electron microscopy and Fourier transform infrared spectrometry were employed. The findings of this research provide valuable insights for suppliers and industries to experimentally determine the usability and safety intervals of plastic packaging through comprehensive macroscopic and microscopic analyses within relatively short timescales. © 2024 Society of Chemical Industry.

Vibrational Spectra and Computational Study of Amyl Acetate: MEP, AIM, RDG, NCI, ELF and LOL Analysis

This work is focused on biologically active neat amyl acetate and its solutions in ethanol/heptane. According to the experimental results, when the concentration of amyl acetate in the amyl acetate-ethanol solution decreases, the additional band appears on the low-frequency side. The primary reason for the formation of such additional band is the intermolecular hydrogen bonding between amyl acetate and ethanol. In the amyl acetate-heptane solution, as the concentration of amyl acetate in the solution decreases, the band corresponding to the C=O stretching vibrations shifted to a higher frequency. This is explained by the fact that heptane breaks intermolecular interactions in solution, resulting in a simpler spectral band corresponding to the C=O stretching vibrations. Calculations are also used to study interactions in amyl acetateethanol complexes and their spectral manifestations. When the complex formation energies are calculated, this energy increases with the number of molecules, but the average hydrogen bond energy per one bond remains unchanged. The density functional theory (DFT) method is used to analyze molecular structural parameters: Mulliken atomic charge distribution; thermodynamic parameters; molecular electrostatic potential (MEP) surface; atoms in molecules (AIM) analysis; quantum chemical parameters such as reduced density gradient (RDG) and noncovalent interaction (NCI) analysis; electron localization functions (ELF) analysis; and localized orbital locator (LOL) analysis.

Deciphering aroma complexity between melting flesh and stony hard peach (Prunus persica L.) fruit through integrative analysis of volatile contributions

Stony hard peach is favored in production for resistance to storage and transportation, but presents a challenge of lacking fragrance compared to traditional fragrant peach i.e., melting flesh peach. Addressing this concern necessitates material composition analysis from the perspective of volatile composition and aroma characteristics. However, the complex relationship between volatile compounds and aroma profiles in melting flesh and stony hard peach cultivars remains poorly understood. To address this gap, we examined contribution of volatiles to their aroma. The application of multiple analysis methods, including distribution, odor importance, and partial least squares discriminant analysis facilitated a comprehensive understanding of the contribution of 30 volatiles to aroma; and hierarchical clustering analysis revealed relationships among the compounds within the two types of peaches. The primary differential volatiles between them were cis-3-hexenol, pentyl acetate, prenyl acetate, trans-2-hexenal, cis-3-hexenyl acetate, dihydro-β-ionone, benzaldehyde, and a range of lactones (γ-decalactone, γ-hexalactone, γ-octalactone, δ-decalactone and γ-undecalactone). Overall, the melting flesh peach exhibited more pronounced aroma than the stony hard type. This study underscores the significance of understanding the intricate interplay between volatile compounds and aroma characteristics across cultivars with different textures, offering valuable insights into cultivar selection, flavor enhancement, and consumer preference assessment within the peach industry.

Temperature and Composition Dependence of the Densities, Speed of Sound, and Viscosities of Binary Liquid Mixtures of Tetrahydrofuran with Methyl Acetate, Propyl Acetate, and Pentyl Acetate

Temperature and Composition Dependence of the Densities, Speed of Sound, and Viscosities of Binary Liquid Mixtures of Tetrahydrofuran with Methyl Acetate, Propyl Acetate, and Pentyl Acetate

Abraham solvation parameter model: experiment-based solute descriptors for (2-nitrophenyl)acetic acid

ABSTRACT Mole fraction solubilities are reported for (2-nitrophenyl)acetic acid dissolved in 1-pentanol, 1-heptanol, 1-octanol, 2-butanol, 3-methyl-1-butanol, 2-pentanol, 4-methyl-2-pentanol, cyclopentanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 1,4-dioxane, methyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tert-butyl acetate, pentyl acetate, methyl butyrate, dimethyl adipate and propanenitrile at 298.15 K. Solubilities were determined using a spectrophotometric method of chemical analysis. Experiment-based Abraham model solute descriptors are calculated for the molecular, monomeric form of (2-nitrophenyl)acetic acid by combining our experimental values with the published solubility data obtained from the published paper by Zhou and co-workers. The calculated solute descriptors describe the observed solubility data to within an overall standard deviation of 0.10 log units.

Determination of Rhodamine 6G with direct immersion single-drop microextraction combined with an optical probe.

The combination of an optical probe and single-drop direct immersion microextraction (DI-SDME-OP) was used for the preconcentration and subsequent spectrophotometric determination of rhodamine 6G (Rh6G). The developed method is based on the formation of an ionic associate between Rh6G and picric acid at pH 3.0 and its extraction with amyl acetate. A microdrop of the organic phase was stably placed in the hole of an optical probe immersed in the sample solution. The absorbance of the extraction phase was monitored at 534 nm. The proposed method combines in a single step several stages of the analytical procedure, such as pre-concentration, phase separation, transfer of the extraction phase to the instrument and online measurement. The sensitivity of the proposed approach is not inferior to existing microextraction methods involving the combination of liquid-phase or solid-phase extraction with spectrophotometry or HPLC with a UV-Vis detector. The evaluation of the greenness of the developed method carried out by the AGREE method (0.58 points) showed that it outperforms other similar existing techniques using this parameter. The calibration plot for the determination of Rh6G by the DI-SDME-OP method was linear over the range of 10-500 nM with a correlation coefficient of 0.9956. The limit of detection was 3.4 nM. The accuracy and applicability of the method were evaluated by the determination of Rh6G in natural waters and lipstick.

Experimental and thermodynamic study of amyl acetate, amyl acetoacetate, and isoamyl acetoacetate in CO2 solvent

Acetate ester compounds find widespread use in various applications such as surface coatings, ink formulations, pharmaceuticals, and adhesives. It is essential to investigate the phase transition behavior of amyl acetate, amyl acetoacetate, and isoamyl acetoacetate in high-pressure supercritical CO2 (SC-CO2). The vapor-liquid equilibria (VLE) of the SC-CO2 + amyl acetate, SC-CO2 + amyl acetoacetate, and SC-CO2 + isoamyl acetoacetate systems were examined at different temperatures (313.2 ≤ T ≤ 393.2 K) and pressures (1.67 ≤ P ≤ 20.76 MPa). The solubility curve of these systems shows Type-I phase behavior, and the critical points of these binary mixtures were observed between the critical properties of the pure components involved in the systems. The solubility of amyl acetate, amyl acetoacetate, and isoamyl acetoacetate in the SC-CO2 + amyl acetate, SC-CO2 + amyl acetoacetate, and SC-CO2 + isoamyl acetoacetate systems increases with increasing temperature at constant pressure. The two-parameter model of Peng-Robinson equation of state along with a mixing rule, accurately correlated the phase transition behavior and critical mixtures curves for all three systems. The binary interaction parameters (BIPs) were adjusted, and the minimum root mean square deviation percentage was identified for all three systems. The calculated error% was found to be within reasonable limits, with values of 4.95 %, 3.93 %, and 4.18 % for SC-CO2 + amyl acetate, SC-CO2 + amyl acetoacetate, and SC-CO2 + isoamyl acetoacetate systems, respectively. Furthermore, the interaction parameters for the SC-CO2 + amyl acetoacetate mixture was found to be temperature-dependent, and the tested linear regression correlation coefficient for the BIPs parameters of (kij) and (ηij) are 0.98533 and 0.99083, respectively. This is the first research study on the phase behavior of acetate ester compounds in SC-CO2 solvents, and the results have a significant impact on industries at different operating conditions.

Computational assessment of the radical scavenging activity of cleomiscosin.

Coumarinolignans such as cleomiscosin A (CMA), cleomiscosin B (CMB), and cleomiscosin C (CMC) are secondary metabolites that were isolated from diverse plant species. Cleomiscosins (CMs) have numerous interesting biological activities, including noteworthy cytotoxicity of cancer cell lines along with hepatoprotective and assumed antioxidant activities. In this present study, the antioxidant properties of three cleomiscosins were investigated with a focus on the structure-activity relationship using thermodynamic and kinetic calculations with the M06-2X/6-311++G(d,p) method. The results show that CMs, including CMA, CMB, and CMC, are weak antioxidants in apolar environments, with k overall of 7.52 × 102 to 6.28 × 104 M-1 s-1 for the HOO˙ radical scavenging reaction in the gas phase and 3.47 × 102 to 6.44 × 104 M-1 s-1 in pentyl ethanoate. Remarkably, the difference in the fusion of phenylpropanoid structure with coumarin via two ortho-hydroxyl groups (CMA and CMB) does not cause any noticeable effect on their antioxidant activity, while the presence of a methoxy substitute on the aromatic ring of phenylpropanoid units (CMC) increases the reaction rate to about 61 to 84 times faster than that of CMA. In contrast, the studied CMs exhibit a good antioxidant capacity in polar environments, with a k overall range from 4.03 × 107 to 8.66 × 107 M-1 s-1, 102-103 times faster than that of Trolox, equal to that of ascorbic acid and resveratrol. The angular fusion of the phenylpropanoid and coumarin structures, as well as the methoxy substitution on the aromatic ring of the phenylpropanoid unit of the studied CMs, do not have any considerable effect on their antioxidant activity under the studied conditions.

Thermophysical properties of binary mixtures of pentyl acetate with butanol at 298.15 K to 318.15 K: PFP theory, FTB model, and Graph theoretical approach

The measured density (ρ) and refractive index (nD) of binary pentyl acetate (1) + isomers of butanol (2) mixtures were reported at T = 298.15 K to 318.15 K and at 0.1 MPa pressure. Using the experimental ρ, u and nD data, excess molar volume (VmE), excess ultrasonic speed (uE), excess isentropic compressibility (κSE), and excess refractive index (nDE) were calculated and correlated with the Redlich–Kister (RK) equation. The findings suggest that the behavior of a mixture is affected by intermolecular interactions (cohesive forces such as dipole–dipole, H–bonding, dispersive force) and structural aspects of the molecules. The Prigogine–Flory–Patterson (PFP) theory, Flory–Treszczanowicz–Benson (FTB) model, and Graph theoretical approach (GTA) accurately analyzed the VmE values. Both the FTB model and PFP theory predicted the VmE curves not only successfully but also accurately represented their shape and magnitude except GTA at a lower mole fraction of pentyl acetate (xA<0.2). The positive values of VmE values were observed for binary mixtures across all temperatures. The intermolecular interactions were also corroborated by uE, κSE and nDE.

Transport and acoustic properties of pentyl acetate with butanol at 298.15 K to 318.15 K: Singh model and ab-initio approach

ABSTRACT The viscosity ( η ) and speed of sound ( u ) of binary pentyl acetate (1) + isomers of butanol (2) mixtures were reported at T = 298.15 K to 318.15 K and at 0.1 MPa pressure. Using the experimental data, deviation in viscosity ( Δη ), deviation in speed of sound ( Δu ), and excess isentropic compressibility ( κ s E ) were determined and these were fitted with the RK equation. The findings suggest that the behaviour of a mixture is affected by intermolecular interactions (dipole – dipole, H – bonding, dispersive, and cohesive force) and structural aspects of the molecule. The Δη and κ s E curves were predicted well with the Singh model and ab – initio approach. At each temperature, the κ s E values were positive for binary mixtures, whereas the Δη and Δu values were negative. The numeric values of u were determined through numerous correlations. This study delves into the relative importance of these relations with the experimental values of u .

Efficient green synthesis of n-amyl acetate in liquid phase over metal-organic framework catalysts

This investigation describes, for the first time, the efficient and selective liquid-phase green synthesis of n-amyl acetate over UiO-66 and NH2-UiO-66 metal-organic framework catalysts. By employing UiO-66 and NH2-UiO-66 solid acid catalysts, n-amyl acetate can be produced without the corrosive impact and separation problems associated with homogeneous catalysis by mineral acids. Thermal, structural, textural, and morphological properties of the catalysts were evaluated by TG-DTA, XRD, FTIR, Raman spectroscopy, BET-surface area, SEM and HRTEM. Their surface acidities were characterized by the dehydration of isopropanol and the chemical adsorption of suitable probs. The effects of reflux time, acid: alcohol molar ratio, and catalyst load were extensively studied. Under the optimized conditions, UiO-66, and NH2-UiO-66 catalysts, respectively offered 85 and 67 % conversions, and 100 % selectivity into n-amyl acetate. Activity of catalysts was well correlated with the total number of acidic sites, SBET and the kinetic rate constants of the esterification reaction. Analysis of the pre-adsorption studies of the reactants on the catalyst surface demonstrated that the Langmuir-Hinshelwood mechanism was followed in this reaction. The UiO-66 catalyst was regenerated numerous times with nearly the same activity and 100 % selectivity.

A DFT study of the antioxidant potency of α-tocopherol and its derivatives: PMHC, Trolox, and α-CEHC

In this research, antioxidant potency (in terms of peroxyl radical scavenging and catalytic iron ions sequestration) of α-tocopherol and its analogues, has been theoretically investigated. A DFT based kinetic estimation of HOO• radical scavenging potency of PMHC (lipophilic α-TOH derivative) and Trolox (hydrophilic α-TOH derivative) was performed in eight solvents of different polarity. Calculations employing M06-2X functional, accompanied by 6-311++G(d,p) basis set and SMD solvation model, were found as more accurate in reproducing experimentally determined rate constants than M05-2X functional. Rate constant of Trolox in pentyl ethanoate also was estimated by using Snelgrove−Ingold equation and Abraham’s β2H solvent parameter. Scavenging of CH3OO• and HOO• radicals, which is influenced by location, orientation, and dynamics of α-TOH and its derivatives in the membrane lipid bilayer, was estimated by using M06-2X functional. Position of α-TOH phenolic OH group is opposite to that of its metabolite α-CEHC: α-TOH’s OH group is located at the membrane-water interface, and α-CEHC’s OH group is deeply buried into the bilayer. In the aqueous phase both fHAT and SET were investigated, and inside the bilayer only fHAT was considered as feasible. The spontaneous disproportionation of HOO•/O2•− in aqueous solutions should be taken into account to predict potency of antioxidant in scavenging of HOO• radicals. Iron chelating ability of α-TOH and α-CEHC was also investigated. Obtained results indicate α-CEHC, α-tocopherol final catabolite, as more potent scavenger of CH3OO• and HOO• radicals and iron ions chelator than the parent molecule.

Control of selective SiGe etching by enhanced formation of hydroxyl radicals and by surface passivation in peracetic acid solution

The selective etching of SiGe over Si is a crucial process in the fabrication of advanced 3D semiconductor devices. During the etching process, highly selective SiGe etching is required to obtain precise etch profiles. In this study, the enhancement of the selective SiGe etching in a peracetic acid (PAA) etchant solution by adding hydroxylamine and pentyl acetate was investigated. The addition of hydroxylamine increased the SiGe etching rate and SiGe/Si etching selectivity owing to the more vigorous oxidation of the SiGe surface produced by hydroxyl radicals. The SiGe/Si etching selectivity was also increased through the addition of pentyl acetate owing to the larger decrease in the Si etching rate when compared to that in SiGe. This is due to the stronger passivation effect of pentyl acetate on the Si surface, which suppresses its oxidation more effectively than on the SiGe surface. The SiGe etching rate and SiGe/Si etching selectivity were significantly increased from 223.3 nm/min and 125 to 310.8 nm/min and 557, respectively, through the simultaneous addition of hydroxylamine and pentyl acetate to the PAA etchant solution. Consequently, a mechanism for the selective etching of SiGe on vertically stacked SiGe/Si trench structures using the PAA etchant solution was proposed.

Dissolution dynamics of zirconia nanocluster resist

The metal oxide resists are promising materials for the high numerical aperture EUV lithography. In the metal oxide resists, the bridging ligands are generated upon exposure to radiations, which results in the formation of a pattern insoluble in developers. In this study, the dissolution dynamics of zirconia nanocluster resist was investigated using a quartz crystal microbalance method. The ligand was methacrylate. The developers used were ethyl, butyl, amyl, hexyl, 2-methylbutyl, and 3-methylbutyl acetates. The zirconia nanocluster resist showed characteristic dissolution dynamics. After the immersion into developers, the frequency slowly decreased with approximately constant impedance (no viscosity change of the film) for a while and then rapidly dissolved with the softening of resist film. The dependences of dissolution dynamics on the molecular structures of acetates and post exposure baking were clarified. The effect of branched structure at the third position of butyl was, in particular, remarkable.

Studies on thermodynamics properties of binary mixtures of amyl acetate with propanol at T = 298.15 K to 318.15 K

The thermophysical properties of amyl acetate and isomers of propanol are critical for a variety of industrial, scientific, and safety–related applications. The density (ρ), viscosity (η), speed of sound (u), and refractive index (nD) of binary amyl acetate (1) + propanol (2) mixtures were measured at T = 298.15 K–318.15 K and pressure of 0.1 MPa. The excess molar volume (VmE), deviation in viscosity (Δη), deviation in speed of sound (Δu), excess isentropic compressibility (κsE), and deviation in refractive index (ΔnD) were derived from measured data. The deviation parameters in binary mixtures are affected by H–bonding, interstitial accommodation, and dipole–dipole interactions. The VmE, Δη and κsE values were described with Graph theory, Prigogine-Flory-Patterson (PFP) theory, Singh model, and ab–initio approach. While the VmE and Δη rise with increment in temperature whereas Δu and ΔnD decrease with increase in temperature.

Changes in nutritional and antioxidant properties, structure, and flavor compounds of Tartary buckwheat (Fagopyrum tataricums) sprouts during domestic cooking

This study aims to investigate the impact of domestic cooking methods, such as microwave, steaming, and boiling, on the color, sensory quality nutritional content, antioxidant capacity, structure, and flavor of Tartary buckwheat (Fagopyrum tataricum) sprouts. According to research, the highest cooking loss in 90 s of microwave was 28.89%. Steaming had been found to have the most significant impact on color loss. Microwaving for 30 s had been observed to increase reducing sugar levels by 4.65%, while boiling for 60 s increased chlorophyll levels by 14.52%. The highest retention rates of total flavonoids, total phenols, and vitamin C were 87.25%, 97.25%, and 92.80% respectively when the food was microwaved for 30 s. Moreover, the microwave treatment exhibited the highest antioxidant capacity. Further analysis using FTIR and SEM techniques revealed an increase in carbonyl content under microwave treatment and the presence of a small amount of ungelatinized starch granules. Different cooking methods had similar effects on flavor, reducing eucalyptol and ethylbenzene content, increasing amyl acetate, hexanal, and limonene content, and the emergence of oily and fruity aromas. This study found that microwaves are the best way to retain the nutritional value of Tartary buckwheat sprouts, providing data reference for the development of future cooking technology.

Influence of the Use of a Mixed Solution of Equal Amounts of Amyl Acetate, Acetone, and Ethanol on the Cleaning of Endodontic Sealer Residues on the Bond Strength of the Fiber Post Cementation System: A Laboratory Investigation

Influence of the Use of a Mixed Solution of Equal Amounts of Amyl Acetate, Acetone, and Ethanol on the Cleaning of Endodontic Sealer Residues on the Bond Strength of the Fiber Post Cementation System: A Laboratory Investigation

A combination of vortex-assisted liquid–liquid microextraction with fluorescence detection: An innovative approach for a green and highly sensitive determination of sodium dodecyl sulfate in water samples and pharmaceuticals

A new green, highly sensitive, and selective method based on a combination of vortex-assisted liquid–liquid microextraction with fluorescence detection (VALLME-FLD) was developed for the determination of sodium dodecyl sulfate (SDS). The method is based on the reaction of SDS with the fluorophore 3,3′-diethyloxadicarbocyanine iodide (DODC) at pH 3, followed by VALLME of the formed ion associate (IA) into a microvolume of the organic phase (n-amyl acetate). Fluorescence measurements were made at 668 nm, with excitation at 635 nm. During the optimization, the influence of various chemical and physical factors on the relative fluorescence intensity was studied. The linearity of the calibration curve was observed in two concentration ranges of SDS, from 0.30 to 3.0 µg L-1, R2 = 0.9980 (microextraction into 70 µL n-amyl acetate), and 3.0 to 14.0 µg L-1, R2 = 0.9960 (microextraction into 500 µL n-amyl acetate). The limits of detection (LOD) were 0.10 µg L-1 and 0.90 µg L-1, respectively. The accuracy and precision of the proposed method were verified during two consecutive days with a relative standard derivation of 2.2–4.9 % and recovery of 93.3–106.7 %. The system showed high selectivity towards SDS in the presence of at least 200-times higher concentrations of NO3–; 500-times higher concentrations of F-, Br-, HPO42-, and Fe2+, and 1000-times higher concentrations of CO32–, SO42-, Cl-, Mg2+, and Ca2+. The method was developed and applied to the determination of SDS/anionic surfactants in real water samples and pharmaceutical tablets.

Synthesis and computational evaluation of the antioxidant activity of pyrrolo[2,3-b]quinoxaline derivatives.

Pyrrolo[2,3-b]quinoxaline derivatives are known to possess antioxidant, anticancer, and antibacterial properties. Here we report the successful synthesis of five derivatives of 3-hydroxy-3-pyrroline-2-one through substitution. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was employed to evaluate the antioxidant activity of the compounds. Out of these, ethyl 1,2-diphenyl-1H-pyrrolo[2,3-b]quinoxaline-3-carboxylate (3a) demonstrated the greatest potential as a radical scavenger. Thermodynamic and kinetic calculations of the radical scavenging activity indicated that 3a exhibited HO˙ radical scavenging activity with the overall rate constant of 8.56 × 108 M-1 s-1 in pentyl ethanoate; however, it was incapable of scavenging hydroperoxyl radicals in nonpolar media. In non-polar environments, the hydroxyl radical scavenging capability of 3a is fairly similar to that of reference antioxidants such as Trolox, melatonin, indole-3-carbinol, and gallic acid. Hence, in the physiological lipid environment, 3a holds promise as a scavenger of HO˙ radicals.