Propyl Acetate Research Articles

Identification of volatile organic compounds as markers to detect Monilinia fructicola infection in fresh peaches

Monilinia spp. are among the main fungal pathogen affecting peaches, and they can cause severe pre- and postharvest losses. Development of smart packaging technologies (e.g., volatile indicators), facilitating infection detection and preventing other fruit from being contaminated, is still limited. In this study, we compared for the first time the aroma profile of whole healthy fresh peaches to Monilinia fructicola-artificially inoculated peaches, identifying discriminant volatile organic compounds (VOCs). More than one hundred VOCs were detected by applying head space solid-phase microextraction followed by GC-MS analysis. The level of methyl esters, hydrocarbons, lactones, and acids decreased in infected peaches indicating fruit aroma deterioration, while the concentration of ethyl esters and alcohols increased. In particular, the amount of ethanol and derived ethyl acetate reached a maximum of 24- and 20-fold increase in the infected peaches, respectively. Isobutanol, propyl acetate, and ethyl isovalerate were specifically emitted by M. fructicola-infected peaches. These compounds might serve as markers for the development of smart sensors allowing the detection of fungal infection.

Adsorption Equilibria of Propyl Acetate on Activated Carbon Under Supercritical CO 2 Conditions

Adsorption Equilibria of Propyl Acetate on Activated Carbon Under Supercritical CO ₂ Conditions

Solubility measurement and data correlation of 3-ethoxysalicylaldehyde in twelve pure solvents at temperatures from 278.15 to 313.15 K

The solubility of 3-ethoxysalicylaldehyde in twelve pure solvents (water, methanol, ethanol, n-propanol, n-butanol, iso-propyl alcohol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, acetonitrile, and acetone) was determined by an isothermal saturation method over the temperatures ranging from 278.15 to 313.15 K at 101.6 ± 1.2 kPa. The solubility of 3-ethoxysalicylaldehyde in all studied solvents increases with the increase in temperature. The mole fraction solubility of 3-ethoxysalicylaldehyde is observed highest in acetone (0.6053 at 313.15 K), followed by methyl acetate, ethyl acetate (acetonitrile), propyl acetate, butyl acetate, methanol, ethanol, n-propanol, n-butanol, iso-propyl alcohol, and water. Three solubility fitting models were used to correlate the experimental mole solubility data, including the van’t Hoff model, modified Apelblat model, and λh model. The three models showed good fitting results, with the average RAD less than 5%. The thermodynamic properties of 3-ethoxysalicylaldehyde, including apparent standard dissolution enthalpy (ΔHsol), standard dissolution Gibbs energy (ΔGsol), and standard dissolution entropy change (ΔSsol), were calculated via the van’t Hoff equation. The positive values of ΔHsol and ΔGsol indicate that the dissolution process of 3-ethoxysalicylaldehyde is endothermic. The studied solubility data and the relevant thermodynamic analysis have an important guiding significance for the design and optimization of the crystallization process of 3-ethoxysalicylaldehyde.

Identification and biotransformation analysis of volatile markers during the early stage of Salmonella contamination in chicken

Salmonella is one of the most prevalent foodborne pathogens in poultry and its products. Its rapid detection based on volatile organic compounds (VOC) has been widely accepted. However, the variation in the VOCs of Salmonella-contaminated chicken during the early stage (48 h) remains uncertain. Headspace-SPME-gas chromatography-mass spectrometry (HS-SPME-GC–MS) and headspace-gas chromatography-ion migration spectroscopy (HS-GC-IMS) were used to identify VOCs and their variations after the chicken meat was contaminated with Salmonella. Chemometric and KEGG enrichment analyses were performed to identify VOC markers and their potential metabolic pathways. A total of 64 volatile compounds were detected using HS-GC-IMS, which showed a better differentiation than HS-SPME-GC–MS (45 volatile compounds) based on principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). Fatty acid degradation was the main cause of VOC variation. 2-Propanol, hexadecane, 3-methylbutanol, acetic acid, propyl acetate, acetic acid methyl ester, and 3-butenenitrile were identified as VOC markers in the middle stage of decomposition, and 1-octen-3-ol was recognized as a VOC marker of Salmonella-contaminated chicken during the first 48 h of contamination. This provides a theoretical basis for the study of Salmonella contamination VOC markers in poultry meat.

Identification on regional-markers based on the flavor molecular matrix analysis of sauce-aroma style Baijiu.

Baijiu is a very complex system and its flavor substances are endogenous influenced by raw materials, starter, production process, production region and other factors. The production region directly affects the composition of flavor substances and quality of Baijiu. However, identification of Baijiu region is challenging because the corresponding relationship between the production region and Baijiu quality is not clear, and the identification of regional-markers is indeterminate. In this study, the difference on volatile components of sauce-aroma style Baijiu from four representative regions were investigated. Consequently, a total of 94 volatile compounds were identified in samples tested. Additionally, it was verified that 35 potential flavor substances had important contributions to the aroma of sauce-aroma style Baijiu. Meanwhile, 9 potential regional-markers were screened through multivariate analysis. Further, based on distribution of volatile compounds and the results of sensory evaluation combined with multivariate analysis, molecular matrix and correlation network were established according to the result of addition experiments, which showed that 6 substances had a significant impact on the flavor of the tested samples. In this study, 6 key flavor substances (including ethyl octanoate, ethyl 2-methyl propanoate, propyl acetate, ethyl heptanoate, 2-nonanone and butyl hexanoate) were considered as important regional-markers to effectively identify the production region of sauce-aroma style Baijiu. This article is protected by copyright. All rights reserved.

Cinnamon essential oil vapor alleviates the reduction of aroma-related volatiles in cold-stored "Feicheng" peach using HS-GC-IMS.

"Feicheng" peach is popular for its unique aroma, but its defect of being highly sensitive to chilling injury (CI) often leads to aroma loss and internal browning. Essential oils (EOs) are often used to enhance the antioxidant capacity of plants and fruits, as well as to trigger their defense against biotic/abiotic stresses. This study aimed to examine the effect of cinnamon essential oil (CEO) vapor treatment on the aroma quality of peach fruit during cold storage using HS-GC-IMS. The results showed that 50 μL/L CEO vapor reduced the severity of internal browning (IB) in peaches at the stage of 7 ~ 21 d during refrigeration (Significantly, the L* value was higher and the IB index was lower than that of control, p < 0.05). Meanwhile, the evident reduction or loss of aroma content caused by CI was restored to a higher level than the control (p < 0.05). Furthermore, CEO treatment promoted the release of aroma-related volatiles as evidenced by more propyl acetate, and the dimer of amyl acetate, isoamyl acetate, butyl acetate detected than that on harvest day and no-treated group after 21 d of cold storage plus 2 d of shelf life. Genes of PpLOX1, PpLOX2, PpHPL1 and PpADH1 associated with aroma-related volatile biosynthesis revealed higher transcript abundance in peach fruits treated with CEO than the control (p < 0.05). Overall, our study demonstrated that CEO in vapor phase may be beneficial to alleviate the quality deterioration in aroma and flesh color of "Feicheng" peaches caused by CI, which lays a theoretical reference for maintaining postharvest quality of peach fruits.

Molecular interaction analysis and transport properties of binary liquid mixtures containing 1-Amino-2-propanol and alkyl acetates at T = 298.15–318.15 K: Application of Graph theory and DFT studies

The thermophysical properties of 1A2P (1-amino-2-propanol) (1) with AAc (methyl acetate (MAc) or ethyl acetate (EAc) or propyl acetate (PAc) or butyl acetate (BAc)) (2) were examined for understanding the molecular interactions between given binary liquid mixtures. Viscosity (η) was measured for 1A2P, AAc (alkyl acetate) and their binary mixture at five different temperatures (T = 298.15 to 318.15 K) and at 0.1 MPa pressure. From η data, the deviation in viscosity, Δη, and excess Gibbs free energy of activation, G∗E, were calculated. The Δη values were more positive for the 1A2P (1) + MAc (2) binary mixture at equimolar composition which indicate that there is strong intermolecular interaction between 1A2P and MAc molecules. Further, Δη values were also analyzed by Graph theoretical approach (GTA) and predicted that CO-----H-O interactions are stronger than OH----O-C interactions between 1A2P and AAc molecules in the liquid mixture which is also recognized by FTIR spectroscopic studies. Density functional theory (DFT) studies were employed to investigate the strength of molecular interactions.

Reactive extraction of protocatechuic acid by di-n-octylamine and optimisation with Box–Behnken design

ABSTRACT Protocatechuic acid (PCA) is typically produced by microbial fermentation. Its separation from fermentation broth or aqueous waste streams is of great importance. This study aimed to recover PCA by a secondary amine namely di-n-octylamine (DOA). Three organic solvents, namely isobutyl methyl ketone, propyl acetate and linalool, were used with DOA. Important extraction parameters were optimised by response surface methodology. DOA/isobutyl methyl ketone system showed 95.84% extraction efficiency under the optimum conditions. The maximum E% of the DOA/propyl acetate system was 86.73%. The maximum E% of the DOA/linalool system was 81.71%. Additionally, a thermodynamic study was carried out, and the reactions were endothermic. Highlights Protocatechuic extraction by di-n-octylamine has been done first in the literature. Different kinds of solvents have been used to solve di-n-octylamine. Useful information is obtained for the design of protocatechuic acid reactive extraction.

Comparative analysis of molecular interactions in quaternary fluid system performed by classical and ab initio molecular dynamics

Molecular interactions in the quaternary fluid system acetic acid–n-propanol–n-propyl acetate–water were analyzed by classical and ab initio molecular dynamics methods. It was shown that ab initio molecular dynamics simulation can reproduce the molecular mobility tendency and structural features of a multicomponent system without empirical parameters.

Solid-liquid phase equilibrium of adiphenine hydrochloride in twelve pure solvents

The solubility and apparent thermodynamic properties of Adiphenine hydrochloride (ADH) (Form I) in twelve mono-solvents including methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, n-amyl acetate, isopropyl acetate, isobutyl acetate, n-hexanol, n-heptanol, n-octanol, anisole and acetone were reported in this work. The solubility of ADH (Form I) was quantified by the laser monitoring method at atmospheric pressure and the selected temperature ranged from 278.15 K to 323.15 K. In the same solvent, the lower the temperature is, the less the solubility of ADH (Form I) is. A maximum mole fraction solubility of ADH (Form I) existed in n-hexanol (0.2241) at 323.15 K while the minimum mole fraction solubility (1.139 × 10−4) appeared in isopropyl acetate at 278.15 K. The experimental values of solubility were fitted by modified Apelblat model, NRTL model and UNIQUAC model, and it was found that the calculated values of the NRTL model and the modified Apelblat model were closer to the experimental values. The dipolarity/polarizability of the solvent and the acidity of the hydrogen bonds both play a positive role in increasing the solubility of ADH (Form I). The apparent thermodynamic properties of the dissolution process of ADH (Form I) were analyzed by the van't Hoff equation. It can be found that the dissolution process is an entropy-driven endothermic processes.

Viscosity, heat capacity and refractive index studies for binary liquid mixtures containing 1,3-diaminopropane and alkyl acetates: Experimental and theoretical interpretation

The viscosity (η), heat capacity (CP) and refractive index (nD) of 1,3-DAP (1,3-Diaminopropane) (1) + AAc (MAc(methyl acetate), EAc(ethyl acetate), PAc(propyl acetate) and BAc(butyl acetate)) (2) binary mixture were measured at standard ambient temperature i.e. 298.15 K under the atmospheric pressure 0.1 MPa. The data of η, CP and nD were further used to determine deviation in viscosity (Δη), excess molar heat capacity (CPE), excess Gibbs free energy of activation (G∗E), and deviation in refractive index (ΔnD). η were analyzed by Bloomfield and Dewan model (BFD). The η values were further correlated by various correlations like Kendall, Bingham, Kendall-Monroe, Arrhenius, Katti-Chaudhari, Tamura-Kurata, Grunberg-Nissan, Frenkel, Hind-McLaughlin-Ubbelohde, Heric, McAllister, Lulian, Krishnan-Laddha and Heric-Brewer. Further various correlations like Heller, Lorentz-Lorenz, Arago-Biot, Newton, Gladstone-Dale, Erying and Weiner were used to correlate nD data. The derived thermo-physical properties were also interpreted in terms of molecular interactions and correlated with Redlich- Kister polynomial equation (R.K.).

Liquid–Liquid Equilibrium Measurement and Thermodynamic Modeling for the Ternary System of Water + Epichlorohydrin + Solvents (n-Propyl Acetate, 2-Ethyl-1-hexanol) at Different Temperatures

To separate and purify epichlorohydrin from water, the liquid–liquid equilibrium (LLE) data of water + epichlorohydrin + solvents (n-propyl acetate, 2-ethyl-1-hexanol) at 303.2, 313.2, and 323.2 K were measured at 101.3 kPa. The extraction ability of an extractant was evaluated using the distribution coefficient (D) and selectivity factor (S). Simultaneously, the Bachmann and Hand equations were used to verify the accuracy of the liquid–liquid equilibrium data. The NRTL and UNIQUAC models successfully correlated the LLE data, and the root mean square deviation for each model was less than 0.50%. Finally, GUI-MATLAB tools were employed to confirm that the regression parameters of the thermodynamic model areconsistent.

Early transcriptional response of Saccharomyces cerevisiae in mixed culture with Torulaspora delbrueckii in cherry wine

Mixed culture by Saccharomyces cerevisiae and Torulaspora delbrueckii has been proposed for the production of wine with improved aroma, but the yeast-yeast interactive mechanism still needs in-depth elucidation. This study compared the transcriptome responses of S. cerevisiae in single and mixed fermentations with T. delbrueckii, in the initial stages of cherry wine fermentation, in order to disclose the possible relationship between aroma synthesis and gene expression. Transcriptome profiling showed a total of 446 and 186 differentially expressed genes were detected in S. cerevisiae and T. delbrueckii, respectively, and several metabolic pathways such as glucose, lipid and amino acid metabolisms were observed with variations. For aroma, a total of 35 volatile compounds were identified by HS-GC-IMS, and mixed fermentation prominently enhanced the syntheses of most esters including propyl acetate, 2-methylpropyl acetate, isoamyl acetate and 2-methylbutyl acetate. By integrating the transcriptomic and volatile results, we propose that ILV5, BATs, PDCs, ADHs, ALDs, ACS1, ACC1 and ARO10 genes are possibly the decisive genes in S. cerevisiae, which showed significant variations following S. cerevisiae's adaptive responses in mixed culture and associated with the formation of certain aldehydes, alcohols and esters in cherry wine.

Determination and Simulation of Menadiol Diacetate Solubility in 14 Solvents at Temperatures from 283.15 to 323.15 K

In this paper, the solubility of menadiol diacetate in nine alcohols (methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, n-amyl alcohol, i-amyl alcohol, and cyclohexanol) and five n-alkyl acetates (methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and amyl acetate) was experimentally measured with the aid of a laser dynamic device at temperatures from 283.15 to 323.15 K. The solubility of menadiol diacetate as a function of temperature was regressed in terms of three semiempirical solubility models (Apelblat, van’t Hoff, and λh), two activity coefficient solubility models (Wilson and NRTL), and the Jouyban model. The thermodynamic mixing properties (mixing Gibbs energy, entropy, and enthalpy) of the solutions were estimated in terms of the measured solubility data and the regressed parameters of the Wilson model.

Separation of butyl acetate and propyl acetate from wastewater by liquid-liquid extraction and molecular dynamics simulation

Pharmaceutical production processes produce ester-containing wastewater, and the concentration of esters must be reduced to a specific limit for wastewater discharge. Therefore, this study investigated a synthetic menthol eutectic solvent to separate the ester-water mixture and meet industrial discharge standards. A deep eutectic solvent (DES) composed of menthol as the hydrogen bond acceptor and lauric acid as the hydrogen bond donor in a molar ratio of 2:1 was synthesized to study the liquid–liquid extraction experiment by separating mixtures of water and propyl acetate (PA) and water and butyl acetate (BA) at 1 atm. In addition, a temperature range of 273.15–318.15 K was used to measure the influence of temperature on the experimental results within a 5 K interval. The experimental results indicated that the increase in temperature promoted the extraction efficiency of ester to some extent, but the fluctuation range was unclear. The DES had a high distribution coefficient (β) and selectivity (S) for ester, enabling a better separation of ester and water. Thereafter, molecular dynamics (MD) simulations were performed to ascertain the mechanism of the DES extraction of esters, and the molecular simulations were used to calculate the interaction energy, radial distribution function (RDF), spatial distribution function (SDF), and self-diffusion coefficient (D). The results of the MD simulations illustrated that menthol played an important role in the extraction process, and the hydrogen bond force between menthol and ester was the main force in the extraction process. Both BA and PA were effectively removed from the water by the DES. In general, the excellent extraction ability of the DES for esters was verified by experiments and simulation, which provides solid theoretical support for ester separations in other fields.

Experimental Determination and Modeling of Density, Viscosity, and Surface Tension for Sulfolane + Ethyl Acetate and + n-Propyl Acetate

The density, viscosity, and surface tension for the binary mixtures of sulfolane + ethyl acetate and + n-propyl acetate were measured at the atmospheric pressure and temperature ranging from 308.15 to 328.15 K. The linear equation and Andrade model were successfully used to correlate the experimental density and viscosity, respectively. On the basis of the experimental data, the viscosity energy barrier and the surface entropy/enthalpy were further obtained. The calculation of the molecular interaction energy using the Dmol3 module in Materials Studio software shows that the interaction energy in sulfolane + ethyl acetate is slightly greater than one in sulfolane + n-propyl acetate, which is consistent with the experimental observation. In addition, each experimental property of density, viscosity, and surface tension can well be reproduced by the square-well chain fluid with variable range (SWCF-VR) equation of state with one different binary adjustable parameter.

Liquid–Liquid Equilibrium Measurement for the Separation of n-Propanol + n-Propyl Acetate Using Imidazolium-Based Ionic Liquids with Different Anions at T = 303.15 K

Separating the mixture of the target product n-propyl acetate (NPAC) and the unreacted reactant n-propanol (NPA) is necessary during the production of NPAC. NPA and NPAC cannot be separated by simple distillation because the two could form an azeotrope under atmospheric pressure. Liquid–liquid extraction is an energy-saving and environment-friendly method for separating azeotropic mixtures. Ionic liquids (ILs) are promising alternatives to conventional extractants for separating azeotropes due to the advantages of designability and negligible vapor pressure. In this study, the liquid–liquid equilibrium (LLE) data for the ternary systems of NPAC + NPA + 1-butyl-3-methylimidazolium dihydrogen phosphate ([BMIM][H2PO4]) or 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) or 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) were determined at 303.15 K and 101.3 kPa. The accuracy of the experimental LLE data was checked by the Bachman, Hand, and Othmer–Tobias equations. The selectivity and partition coefficient were calculated to evaluate the extraction capability of the selected extractants. The experimental LLE data were correlated with the nonrandom two-liquid model, and the binary interaction parameters were regressed. Finally, the separation mechanism of the three ILs was explored through σ-profile analysis.

Ester Reduction with H2 on Bifunctional Metal‐Acid Catalysts: Implications of Metal Identity on Rates and Selectivities

AbstractEsters reduce to form ethers and alcohols on contact with metal nanoparticles supported on Brønsted acidic faujasite (M‐FAU) that cleave C−O bonds by hydrogenation and hydrogenolysis pathways. Rates and selectivities for each pathway depend on the metal identity (M=Co, Ni, Cu, Ru, Rh, Pd, and Pt). Pt‐FAU gives propyl acetate consumption rates up to 100 times greater than other M‐FAU catalysts and provides an ethyl propyl ether selectivity of 34 %. Measured formation rates, kinetic isotope effects, and site titrations suggest that ester reduction involves a bifunctional mechanism that implicates the stepwise addition of H* atoms to the carbonyl to form hemiacetals on the metal sites, followed by hemiacetal diffusion to a nearby Brønsted acid site to dehydrate to ethers or decompose to alcohol and aldehyde. The rates of reduction of propyl acetate appear to be determined by the H* addition to the carbonyl and by the C−O cleavage of hemiacetal.

Ester Reduction with H2 on Bifunctional Metal-Acid Catalysts: Implications of Metal Identity on Rates and Selectivities.

Esters reduce to form ethers and alcohols on contact with metal nanoparticles supported on Brønsted acidic faujasite (M-FAU) that cleave C-O bonds by hydrogenation and hydrogenolysis pathways. Rates and selectivities for each pathway depend on the metal identity (M=Co, Ni, Cu, Ru, Rh, Pd, and Pt). Pt-FAU gives propyl acetate consumption rates up to 100 times greater than other M-FAU catalysts and provides an ethyl propyl ether selectivity of 34 %. Measured formation rates, kinetic isotope effects, and site titrations suggest that ester reduction involves a bifunctional mechanism that implicates the stepwise addition of H* atoms to the carbonyl to form hemiacetals on the metal sites, followed by hemiacetal diffusion to a nearby Brønsted acid site to dehydrate to ethers or decompose to alcohol and aldehyde. The rates of reduction of propyl acetate appear to be determined by the H* addition to the carbonyl and by the C-O cleavage of hemiacetal.

Solid-liquid phase equilibrium and thermodynamic properties analysis of paliperidone palmitate in 21 kinds of mono-solvents

Solid-liquid equilibrium solubility paliperidone palmitate (PP) in 21 kinds of mono-solvents, including ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, 2-butanone, methyl isobutyl ketone, cyclohexanone, ethyl formate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, amyl acetate, N,N-dimethylformamide (DMF), tetrahydrofuran (THF), toluene, and 1,4‑dioxane were determined by a gravimetric method at a various temperature. The solubility of PP increases with the increase of temperature. In alcoholic solvents, the solubility order is: n-pentanol > i-pentanol > i-butanol > s-butanol > n-butanol > n-propanol > i-propanol > ethanol. In easter solvents, the solubility of PP ranking as: ethyl formate > amyl acetate > butyl acetate > propyl acetate > ethyl acetate > isopropyl acetate. For ketone solvent, the solubility order is: cyclohexanone > 2-butanone > methyl isobutyl ketone. In other solvents, the solubility order is: THF > toluene > 1,4‑dioxane > DMF. The maximum solubility of PP is 0.1922 mol·mol−1 (toluene, 353.15 K), and the minimum solubility is 0.0003788 mol·mol−1 (ethanol, 318.15 K). Four thermodynamic models, i.e., the modified Apelblat model, the Yaws model, the NRTL model and the Wilson model were selected to correlate the solubility data in this paper. NRTL model fits best among all the models with RAD no larger 4.84 × 10−2 (n-propanol) and RMSD value less than 12.55 × 10−4 (1,4-dioxane). Furthermore, dissolution thermodynamic properties of PP were evaluated based on the Wilson model. The dissolution process of PP is demonstrated to be spontaneous in the chosen organic solvents.