Benzyl Acetate Research Articles

Olfactory and behavioral responses to acetate esters in red imported fire ant, Solenopsis invicta.

The red imported fire ant, Solenopsis invicta Buren, is one of the most successful invasive ants in the world. Previous studies indicated that benzyl acetate and prenyl acetate elicited significant electroantennography (EAG) response in S. invicta and exhibited as attractants at certain concentrations. In addition, the easy commercial availability, low cost, and low mammalian toxicity make acetate esters ideal candidates to screen for potential use in S. invicta control. We examined the EAG and behavioral responses to 26 acetate esters in all castes of S. invicta. Our results demonstrated a large diversity of EAG tuning and behavioral responses to acetate esters in S. invicta. For linear alkyl acetate esters, EAG response was clearly affected by the carbon chain length of the alkyl group. Linear alkyl acetates with five to seven carbon chain length of the alkyl group elicited significant EAG response in S. invicta, whereas those with shorter (C1 to C4) or longer (C8 to C12) carbon chain lengths did not. Different substitutions also exhibited large variety of EAG and behavioral responses in S. invicta. Our works explored the olfactory and behavioral response of S. invicta to structurally different acetate esters, and identified two potential fire ant attractants, pentyl acetate and tran-2-hexenyl acetate, and two potential repellents, hexyl acetate and cis-3-hexenyl acetate. These compounds may be useful in developing new products for fire ant management. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Characterization of aroma‐active compounds in Jasminum sambac concrete by aroma extract dilution analysis and odour activity value

AbstractJasminum sambac is a flower and usually used in food, cosmetics or other chemical industries for its unique flavour characteristics in China. However, molecular sensory technologies have not applied to identify aroma‐active compounds in J sambac concrete. In this study, gas chromatography‐olfactometry (GC‐O), gas chromatography‐mass spectrometry and solvent‐assisted flavour evaporation were applied to isolate the odorants in three Chinese J sambac concrete (E1, E2 and E3) obtained from different companies. A total of forty‐nine, forty‐eight, thirty‐nine odorants were screened by GC‐O with aroma extract dilution analysis in E1, E2 and E3, respectively. The higher flavour dilution (FD) factors were linalool (19 683‐59 049, floral), methyl anthranilate (6561‐19 683, grape‐like) and benzyl acetate (2187‐19 683, floral). Twenty‐two aroma compounds were quantitated by gas chromatography‐flame ionization detection with internal standard, and then their odour activity values were obtained. Linalool, cis‐3‐hexenyl acetate, linalyl acetate, eugenol and methyl salicylate contributed greatly to the aroma of J sambac concretes. The aroma recombination model was established by mixing twenty‐two key odorants based on their measured concentrations, and the result revealed that the overall aroma profile was similar to that of the original sample. These results proved basic data for improvement of the national standard of jasmine concrete.

Metabolic, Enzymatic Activity, and Transcriptomic Analysis Reveals the Mechanism Underlying the Lack of Characteristic Floral Scent in Apricot Mei Varieties.

Apricot mei, a hybrid of Prunus mume and Prunus sibirica, usually has greater cold resistance than P. mume; however, most varieties of Apricot mei lack the characteristic floral scent of P. mume. The volatile and intracellular metabolites, activity levels of key enzymes, and transcriptomes of blooming flowers were comprehensively investigated in five varieties of P. mume. Benzyl acetate and eugenol were determined to be the main components of the P. mume floral scent. However, benzyl benzoate and benzyl alcohol benzoyltransferase activity was detected in only the low-fragrance varieties “Dan Fenghou” and “Yanxing.” No benzyl alcohol or benzaldehyde reductase (BAR) activity was detected in the non-fragrant variety “Fenghou.” PmBAR1 and PmBAR3 were identified as the key genes responsible for BAR activity. The lack of benzyl alcohol synthesis in the “Fenghou” variety was caused by low activity of PmBAR1-Fen and low expression of PmBAR3. The 60-aa segment at the N-terminus of PmBAR3 was found to play an important role in its enzymatic activity. Correlation tests between floral scent metabolites and the transcriptomes of the five different scented varieties showed that some transcripts associated with hormones, stresses, posttranslational modifications and transporters may also play important regulatory roles in floral scent metabolism in the different varieties.

Encapsulation of Aromatic Compounds and a Non-Aromatic Herbicide into a Gadolinium-Based Metal–Organic Framework via the Crystalline Sponge Method

The crystalline sponge method (CSM) is a procedure that has the potential to remove the need to have good-quality single crystals of the target compound by soaking said compound into a crystalline metal–organic framework (MOF). To increase the range of compounds that can be employed with the CSM, a range of different MOFs must be investigated. In this study we have explored the use of a lanthanide-based MOF, RUM-2, recently shown to have potential as a CSM host. Specifically, we have successfully formed five novel inclusion complexes with the four aromatic guests: 2-phenylethanol, benzyl acetate, benzyl benzoate, and vanillin and the non-aromatic herbicide molinate. A detailed analysis of the effect of size on the positions guest molecules sit within the pores of the MOF was performed. The π···π, CH···π, hydrogen-bonding, and coordination host–guest and guest–guest interactions utilized in guest ordering were also investigated, and the disorder experienced by guest molecules was documented.

Measurement and Modeling of Liquid–Liquid Equilibria for Water–Phosphoric Acid–Aromatic Esters

Ternary liquid–liquid equilibrium (LLE) data were measured for the {water + phosphoric acid + aromatic esters (benzyl acetate, benzyl benzoate, dimethyl phthalate, and diethyl phthalate)} systems a...

Comparative Evaluation of the Liquid–Liquid Equilibria of the Extraction of Valeric or Caproic Acids from Water by Esters

Liquid–liquid equilibrium (LLE) values were determined for the six ternary mixtures composed of water, valeric acid or caproic acid, and esters (cyclohexyl acetate, benzyl acetate, and benzyl benzo...

Discrimination and Identification of Aroma Profiles and Characterized Odorants in Citrus Blend Black Tea with Different Citrus Species

Citrus blend black teas are popular worldwide, due to its unique flavor and remarkable health benefits. However, the aroma characteristics, aroma profiles and key odorants of it remain to be distinguished and cognized. In this study, the aroma profiles of 12 representative samples with three different cultivars including citrus (Citrus reticulata), bergamot (Citrus bergamia), and lemon (Citrus limon) were determined by a novel approach combined head space-solid phase microextraction (HS-SPME) with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS). A total of 348 volatile compounds, among which comprised esters (60), alkenes (55), aldehydes (45), ketones (45), alcohols (37), aromatic hydrocarbons (20), and some others were ultimately identified. The further partial least squares discrimination analysis (PLS-DA) certified obvious differences existed among the three groups with a screening result of 30 significant differential key volatile compounds. A total of 61 aroma-active compounds that mostly presented green, fresh, fruity, and sweet odors were determined in three groups with gas chromatography-olfactometry/mass spectrometry (GC-O/MS) assisted analysis. Heptanal, limonene, linalool, and trans-β-ionone were considered the fundamental odorants associated with the flavors of these teas. Comprehensive analysis showed that limonene, ethyl octanoate, copaene, ethyl butyrate (citrus), benzyl acetate, nerol (bergamot) and furfural (lemon) were determined as the characterized odorants for each type.

Encapsulation of fragrances and oils by core-shell structures from silica nanoparticles, surfactant and polymer: Effect of particle size

Oils and fragrances can be encapsulated by using composite shells of silica nanoparticles, polymer and surfactant (potassium oleate). The template for the creation of the core-shell structure is a particle stabilized (Pickering) emulsion. The surfactant adsorbs on the nanoparticles and leads to their reversible hydrophobization and adsorption on the oil/water interface. The outer layer of the self-assembled shell represents a layer from crosslinked polymer. The procedure of encapsulation is simple and includes single homogenization by ultrasound of the formulation that contains all ingredients together. The produced capsules have mean radius in the range between 2 and 11 microns. By order of magnitude and trend, the capsule size follows the law of limited coalescence with respect to the dependence on nanoparticle size and concentration. The composite structure of the shells leads also to dependence on the concentrations of added polymer and surfactant. The produced microcapsules are stable when rinsed with pure water of pH in the range 3 – 10. However, if dispersed in water of pH > 11, the microcapsules are destabilized and release their cargo, i.e., they are pH-responsive. Various fragrances and oils, such as limonene, citronellol, benzyl acetate, and sunflower seed oil were encapsulated. The developed methodology could find applications in any field, in which reversible encapsulation of oily substances is needed.

Characterization of Volatile Organic Compounds Emitted from Endophytic Burkholderia cenocepacia ETR-B22 by SPME-GC-MS and Their Inhibitory Activity against Various Plant Fungal Pathogens.

The use of antagonistic microorganisms and their volatile organic compounds (VOCs) to control plant fungal pathogens is an eco-friendly and promising substitute for chemical fungicides. In this work, endophytic bacterium ETR-B22, isolated from the root of Sophora tonkinensis Gagnep., was found to exhibit strong antagonistic activity against 12 fungal pathogens found in agriculture. Strain ETR-B22 was identified as Burkholderia cenocepacia based on 16S rRNA and recA sequences. We evaluated the antifungal activity of VOCs emitted by ETR-B22. The VOCs from strain ETR-B22 also showed broad-spectrum antifungal activity against 12 fungal pathogens. The composition of the volatile profiles was analyzed based on headspace solid phase microextraction (HS-SPME) gas chromatography coupled to mass spectrometry (GC-MS). Different extraction strategies for the SPME process significantly affected the extraction efficiency of the VOCs. Thirty-two different VOCs were identified. Among the VOC of ETR-B22, dimethyl trisulfide, indole, methyl anthranilate, methyl salicylate, methyl benzoate, benzyl propionate, benzyl acetate, 3,5-di-tert-butylphenol, allyl benzyl ether and nonanoic acid showed broad-spectrum antifungal activity, and are key inhibitory compounds produced by strain ETR-B22 against various fungal pathogens. Our results suggest that the endophytic strain ETR-B22 and its VOCs have high potential for use as biological controls of plant fungal pathogens.

Biosynthesis of benzyl acetate: Optimization of experimental conditions, kinetic modelling and application of alternative methods for parameters determination

Abstract In this work, the enzymatic synthesis of benzyl acetate by transesterification between the benzyl alcohol and an acyl donor, has been studied. As first objective the selection of the biocatalyst, acyl donor, stirring, solvent and the enzyme amount, was done and, to do this, three immobilized derivatives of commercial lipases, Lipozyme®TLIM, Novozym®40086 and Novozym®435 were tested, being Novozym®435 the immobilized derivative chosen. Vinyl acetate, 300 rpm and n-heptane were selected as acyl donor, stirring and solvent, respectively. As the main objective, the kinetics of the bioprocess was analysed and a bisubstrate Ping-Pong kinetics was proposed. By using two different procedures, the values of the kinetic parameters: Michaelis constants of both substrates and the specific activity of enzyme have been determined. A good level of agreement between the experimental data and the ones calculated with the kinetic model was obtained.

Experimental verification of conservatively perturbed equilibrium for a complex non-linear chemical reaction

Abstract The phenomenon of ‘‘conservatively perturbed equilibrium’’ (CPE) for a complex non-linear chemical system was experimentally verified in a batch reactor in which ethanol and benzyl alcohol react with acetic acid producing two different esters and water. Three possible CPE cases, i.e., acetic acid and water unperturbed, ethanol and ethyl acetate unperturbed, benzyl alcohol and benzyl acetate unperturbed, were systematically investigated. For unperturbed substances with initial concentrations of their corresponding equilibrium concentrations, unavoidable extreme values were observed in relaxation to the equilibrium. If the unperturbed substances were involved in two reactions, a proper momentary partial equilibrium was not observed at the transient extremum. However, the transient extremum could be an approximate momentary partial equilibrium for the reaction of the unperturbed substance if the rate of some step is insignificant. This fact provides essential information about the detailed mechanism of the complex reaction.

Thermophysical Properties of Binary Mixtures of Diisopropyl Ether with Methyl Benzoate, Ethyl Benzoate, and Benzyl Acetate at Various Temperatures

Densities and viscosities of binary mixtures of diisopropyl ether (DIPE) with methyl benzoate (MB), ethyl benzoate (EB) and benzyl acetate (BA) were measured experimentally at T = (298.15, 303.15, 308.15, and 313.15) K and P = 0.1 MPa for the entire composition range. The estimated values of the pure liquids and mixtures were subsequently used to determine the properties such as excess molar volume (VE), deviation in viscosity (∆η), and excess Gibbs free energy (∆G*E). These results were fitted into Redlich–Kister polynomial equation to calculate the coefficients and standard errors.

Deep analysis of the solubility behaviour mechanism of alpha-(trichloromethyl) benzyl acetate in three binary aqueous solvents

Abstract The solubility of alpha-(Trichloromethyl) benzyl acetate (ATMBA) in three water-organic binary solvent mixtures at atmospheric pressure from 288.15 K to 328.15 K was investigated by the gravimetric method and molecular simulations. The experimental solubility data were well correlated by the modified Apelblat model Van’t Hoff equation and the NRTL model. In addition calculations of the mixed thermodynamic properties indicate that the mixing process of ATMBA in the solvent systems studied is exothermic and spontaneous. Further to reveal the solubility behaviour of ATMBA thermodynamic analysis crystallographic structure analysis and σ-profile analysis were applied. After comprehensive analysis we found that the reason of the abnormal solubility of ATMBA in acetic acid is that in the binary solvent of acetic acid and water the solute (ATMBA) forms a strong halogen bond with the ionized acetic acid (acetate ion). Finally we validate the rationality of the above analysis process by dynamics simulation (MS). And the Radial distribution function (RDF) shows that it is indeed possible to form a halogen bond between the solute and the acetate ion. Subsequently under the guidance of this theory the binary mixed solvents of formic acid and water were used for experimental verification and the results showed an excellent solubility tendency which proved that the theory is indeed credible. The experimental data can be used as basic data in the industrial production and scientific research of ATMBA a high value-added product. Thermodynamic analysis crystallographic structure analysis σ-profile analysis MD simulations and correlation models herein are helpful to a further understanding of solid-liquid equilibrium of compounds in binary solvent systems.

Layered δ-MnO2 as an active catalyst for toluene catalytic combustion

• Layered δ-MnO 2 was synthesized by an optimized redox precipitation. • Layered δ-MnO 2 showed high performance for toluene catalytic combustion. • The high catalytic performance was related to high surface area, strong redox capacity and rich oxygen vacancy of layered δ-MnO 2 . Layered δ-MnO 2 was successfully synthesized by redox reaction precipitation between KMnO 4 and n-butanol. Then, the as-synthesized layered δ-MnO 2 was used as catalyst for toluene catalytic combustion and showed excellent catalytic performance. The T 10 and T 90 (the temperatures corresponded to the toluene conversion of 10 % and 90 %) were just 160 °C and 199 °C, respectively (1000 ppm toluene, GHSV = 60,000 mL/(g h, 20 vol.%O 2 /N 2 ). In addition, the layered δ-MnO 2 showed well catalytic stability and humid resistance. The as-prepared catalysts were characterized by XRD, N 2 sorption, SEM, TEM, XPS, H 2 -TPR, O 2 -TPD and so on. Compared with the referenced ε-MnO 2 and γ-MnO 2 , the higher catalytic activity of layered δ-MnO 2 was ascribed to its higher specific surface area, stronger low-temperature reducibility and richer oxygen vacancy. Finally, the toluene catalytic oxidation mechanism over δ-MnO 2 was also proposed based on the results of in-situ DRIFTs. And the key successively intermediate species for toluene oxidation over δ-MnO 2 were benzyl alcohol, benzoic acid, maleic anhydride and acetate.

Selection and application of antifungal VOCs-producing yeasts as biocontrol agents of grey mould in fruits

Rotting caused by grey mould (Botrytis cinerea) is a concerning disease for numerous crops both pre- and postharvest stages. Application of antagonistic yeasts is a promising strategy for controlling grey mould incidence which could mitigate undesirable consequences of using synthetic fungicides. In this work, a screening for detection of yeasts isolated from figs producers of antifungal volatile organic compounds (VOCs) were performed by confrontation in double dishes systems. Eleven out of 34 yeasts confronted reduced B. cinerea growth parameter in vitro. This reduction was correlated (p≤0.050) with the production of 10 volatile compounds: two acids (acetic acid and octanoic acid), 7 esters (Ethyl propionate, n-Propyl acetate, Isobutyl acetate, 2-methylbutyl acetate, furfuryl acetate, phenylmethyl acetate, 2-phenylethyl acetate) and one ketone (Heptan-2-one). In bases on in vitro assay, Hanseniaspora uvarum 793 was applied to in vivo assays with strawberries and cherries. The reduction of incidence of B. cinerea in strawberries at 7°C and 25°C was 54.9 and 72.1% after 6 and 3 days, respectively. The reduction of incidence of B. cinerea in cherries at 7°C and 25°C was 48.9 and 45.6% after 5 and 4 days, respectively. These results showed that VOCs produced by Hanseniaspora uvarum 793 are effective in the control of incidence of Botrytis cinerea in fruits, being a potential alternative to chemical fungicide.

Oenological Characteristics of Fermented Apple Musts and Volatile Profile of Brandies Obtained from Different Apple Cultivars.

Volatile profile of spirits is the most important factor, because it can contribute to pleasant flavor. The aim of the study was to determine the impact of dessert apple cultivar used for fermentation on the concentration of volatile compounds in apple spirits. SPME-GC-MS (solid-phase microextraction- gas chromatography- mass spectrometry) method enables the detection of 69 substances and GC-FID (gas chromatography - flame ionization detector) 31 compounds. Characteristic volatiles for brandies obtained from Topaz were limonene, myrcene, methyl valerate and 1,1-diethoxy-propane, from Rubin—β-citronellol and isopropyl acetate, Elise—limonene, myrcene benzyl acetate and isopropyl acetate, Szampion—β-citronellol, Idared—1,1-diethoxy-propane and Jonagored—ethyl trans-4-decanoate. Of the ten analyzed apple spirits, those obtained from Topaz, Rubin and Elise cultivars demonstrated the most diverse profile of volatile compounds. Moreover, their oenological parameters that are the most important in the production of alcoholic beverages were the most favorable. On the other hand, the content of sugars was relatively low in Elise must, while it was highest in Topaz must, which later on translated into differences in alcohol content. Brandies obtained from Gloster contained the smallest concentrations of esters and terpenes. Results of the sensory analysis showed that highest rated brandies were obtained from Topaz, Rubin, Elise and Florina.

Enhanced emission of linalool from floral scent volatile bouquet in Jasminum auriculatum variants developed via gamma irradiation

Gamma irradiation is utilized in floriculture for generating variants with improved traits. In the present study, stem cuttings of Jasminum auriculatum Vahl. were irradiated with different levels of gamma rays viz. 0, 10, 20, 30, 40 and 50 Gray (Gy) to examine any alterations on the profile of floral volatile compounds (FVOCs). It was demonstrated that low dose (10 Gy) could enhance the contents of desired FVOCs as compared to non-irradiated plants, indicating a hormetic effect. The concentration of linalool (a monoterpene volatile) in the floral scent bouquet was found to be increased by two-fold in 10 Gy gamma-irradiated variants as compared with control. A concurrent decrease in benzyl acetate concentration was also noticed. Principal component analysis (PCA) of major FVOCs could cluster the plants developed from high and low irradiation doses. Expression analysis of acetyl-CoA-benzylalcohol acetyltransferase (JaBEAT), monoterpene synthase (JaMTS) and MYB transcription factor (JaMYB) genes correlated well with the concentrations of the corresponding FVOCs. Inter simple sequence repeat (ISSR) profiling of 10 Gy gamma-irradiated variants revealed the presence of significant DNA polymorphism (36.67%), as compared with control.

Colletotrichum gloesporioides inhibition using chitosan-Ruta graveolens L essential oil coatings: Studies in vitro and in situ on Carica papaya fruit

In this study we assessed the efficacy of chitosan (CHI) (2%) emulsion added with Ruta graveolens L. essential oil (REO) at different concentrations (0.5%, 1.0% and 1.5%) to control C. gloesporioides grows both "in situ" and "in vitro" in papaya Maradol (Carica papaya L.). In vitro studies showed a decrease on fungal growth (mycelia diameter) with the increase of REO concentration, while 0.5% of REO induce a reduction of 56.42%, REO at 1.0% and 1.5% induced a reduction of 97%. Microscopic analysis showed irreversible deleterious morphological and ultrastructural alterations as well as changes in conidia morphology, and conidia germination inhibition up to 90%. Among the most abundant REO constituents, 2-Nonanol showed strong antifungal activity followed by 2-Undecanone, Benzyl acetate, 2-Nonanone, 2-Tridecanone and 2-Dodecanone. Studies "in situ" on papaya fruit during 12days at 20°C, showed a reduction of the C. gloesporioides lesion expansion by 50% using CHI-REO 0.5% emulsions and by 100% with treatments of CHI-REO 1.0 and 1.5%, in addition the emulsions were efficacious to reduce the fruit surface microbiota. On the other hand, physicochemical analysis of the papaya fruits demonstrated that CHI-REO emulsions treatment delayed papaya ripening without affecting the organoleptic characteristics. All these results demonstrated for the first time the application of coatings CHI-REO as a postharvest treatment for the control of anthracnose on papaya fruit.

Selective Conversion of Benzylic Phosphates into Diarylmethanes Through Al(OTf)3‐Catalyzed Friedel–Crafts‐Type Benzylation

Al(OTf)3 was identified as a high‐performance catalyst for Friedel–Crafts‐type benzylation using benzylic phosphates as electrophiles. The reaction proceeded even with 0.2 mol‐% of the catalyst. A series of diarylmethanes (21 examples) was obtained in moderate to high yield. The catalyst showed unique chemoselectivity, preferentially converting the benzylic phosphate motif, even with a benzylic acetate group existed in the same molecule.

Synthesis of 2,4,5-Triaryl- 1H-imidazole derivatives using SiO2-NaHSO4

A mixture of benzyl, aromatic aldehyde and ammonium acetate in presence of SiO2-NaHSO4 under solvent-free condition converted to 2,4,5-Triaryl-1H-Imidazoles. The short reaction time, cleaner reaction, and easy workup make this protocol practical and economically attractive.