Benzyl Propionate Research Articles

Investigation of Excess Thermo‐Acoustic Behavior of Binary Liquid Mixture with Various Temperatures Using Ultrasonic Technique

AbstractUltrasonic methods have been very fruitful in studying the physical properties of binary liquid combinations. In this present study, the thermoacoustic behavior of benzyl propionate with dimethyl sulfoxide (DMSO) is observed using ultrasound, density, and viscosity at different temperatures between 308 and 328 K with a phase of 10 °C. Benzyl propionate is a sweet‐smelling liquid that is used in the botanical and fruit fragrance industries, as well as in the flavoring of organic products. DMSO is a dipolar aprotic, naturally soluble compound used for slow drug synthesis, device synthesis, and drug delivery to the body. Estimated values such as adiabatic compressibility, intermolecular free length, internal pressure, and free volume are determined from arbitrary ultrasonic velocity, density, and viscosity data. The same excess parameters of adiabatic compressibility, intermolecular free length, internal pressure, and free volume support finding the nature of the reaction. The sort of interactions has been accounted for utilizing these qualities. In the present work, benzyl propionate with dimethyl sulfoxide has been characterized by using ultrasonic waves and since this wave is a well‐known tool for NDT, so the mixture is properly characterized. These thermoacoustic parameters with different concentrations of DMSO at different temperatures have been used to study the complex formation and binding through intermolecular forces.

Changes of volatile substance composition during processing of nine-processed tangerine peel (Jiuzhi Chenpi) determined by gas chromatography-ion mobility spectrometry.

Nine-processed tangerine peel (Jiuzhi Chenpi in Chinese) is a famous Chinese traditional snack. The composition and contents of volatile substances during its processing is unclear. Gas chromatography combined with ion mobility spectrometry (GC-IMS) was applied to determine the characteristic changes of volatile components throughout the production process. Four stages such as untreated dry tangerine peel (raw material), debittered tangerine peel, pickled tangerine peel, and final product were examined. A total of 110 flavor compounds including terpenes, alcohols, aldehydes, ketones, esters, acids, and two others were successfully detected in tangerine peel samples across the various production stages. There were abundant amounts of terpenes contributing to the flavor, including limonene, gamma-terpinene, alpha-pinene, myrcene, beta-pinene, and alpha-thujene which were reduced at the later stage of production. Large amounts of esters and alcohols such as methyl acetate, furfuryl acetate, ethyl acetate, benzyl propionate, 2-hexanol, linalool, and isopulegol, were diminished at the early stage of processing, i.e., soaking for debittering. One the other hand, the final product contained increased amount of aldehydes and ketones including pentanal, hexanal, 2-hexenal, 2-heptenal (E), 2-pentenal (E), 1-penten-3-one, 6-methyl-5-hepten-2-one, 2-methyl-2-propenal, and 2-cyclohexen-1-one, and very high level of acetic acid. Present findings help to understand the formation of the unique flavor of nine-processed tangerine peel and provide a scientific basis for the optimization of processing methods and quality control.

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.

Benzyl propionate synthesis by fed-batch esterification using commercial immobilized and lyophilized Cal B lipase.

In this work, a fed-batch approach was adopted to overcome propionic acid lipase inactivation effects in the benzyl propionate direct esterification mediated by lipases. The ester synthesis was performed using commercial immobilized (Novozym 435) and lyophilized form Candida antarctica fraction B lipase (Cal B) as biocatalysts of the esterification between benzyl alcohol and propionic acid in a solvent-free system. The reaction involved the propionic acid-controlled addition during the first 5h ensuring an excess of alcohol to dilute the media. The biocatalyst Novozym 435 showed a good performance in the first cycle of the fed-batch esterification, ensuring 90 and 99% of conversion at substrates molar ratio of 1:1 and 1:5 (acid:alcohol), respectively. However, the enzyme lost the activity and the conversions were sharply reduced at the second cycle. A novel qualitative protein content analysis by optical microscopy showed that the lipase was desorbed from the support after the esterification, and this behavior was strongly related to the presence of propionic acid in the reaction medium. The lyophilized Cal B was also tested as biocatalyst of the benzyl propionate esterification and showed a similar performance (related to the Novozym 435) in ester conversion and initial reaction rates for all substrates molar ratios tested. Since the substrates affected the performance of the Novozym 435, the lyophilized Cal B is the most suitable catalyst to the benzyl propionate esterification with conversions above 90%, considering a the fed-batch approach in a solvent-free system.

Application of Quantitative Proton Nuclear Magnetic Resonance Spectroscopy for the Compositional Analysis of Short Chain Fatty Acid Benzyl Ester Mixtures

Nuclear Magnetic Resonance (NMR) has become one of the cornerstones of instrumental analysis work done in chemistry laboratories. NMR is most powerful when used quantitatively, the technique of using NMR to quantify the concentration of an analyte is referred to as qNMR and proton NMR, in particular, is extremely useful in this pursuit to quantify organic compounds. In order to increase exposure to the quantitative and qualitative aspects of NMR in the undergraduate chemistry laboratory, we have created a qNMR experiment to be used in analytical chemistry and instrumental analysis courses. The objective of the experiment was to determine the % composition of a two-component mixture of benzyl acetate (BA), benzyl propionate (BP), and benzyl butyrate (BB). We report on the methodologies used to determine % BA, BP, and BB. Mixtures ranged from 100% to 20%. The results show a strong linear relationship relating known weight %’s with qNMR weight %’s and serves as confirmation of the quantitative utility of proton NMR as well as an educational tool for the undergraduate chemical laboratory.

Biocatalysis of aromatic benzyl-propionate ester by different immobilized lipases.

Benzyl propionate is an aromatic ester that possesses a fruity odor and is usually found in nature in the composition of some fruits such as plums and melons. This work aimed for the benzyl propionate synthesis by esterification using a new immobilized enzyme preparation with low-cost material from Candida antarctica (NS 88011) and three commercial immobilized lipases (Novozym 435, Lipozyme TL-IM and Lipozyme RM-IM). Novozym 435 had the best performance even when the solvent tert-butanol was absent of the reaction medium. Results from a 22 factorial design showed that an increase in the enzyme amount led to a higher conversion, even when the temperature was kept at the low value. Currently, no research had synthesized successfully benzyl propionate via esterification mediated by lipases; and we reached an ester conversion of ~ 44% after 24h indicating that it is a promising route for benzyl propionate biotechnological production.

Process optimization and kinetic modeling for esterification of propionic acid with benzyl alcohol on ion-exchange resin catalyst

Benzyl propionate, an ester with floral and fruity odor, has significant applications in perfumery and flavor industries. This paper describes the optimization of the synthesis of benzyl propionate catalyzed by Amberlyst-15. The effects of various process parameters such as catalyst loading, alcohol-to-acid molar ratio and reaction temperature on propionic acid conversion and yield of ester were assessed by response surface methodology (RSM). The external and internal mass transfer limitations were found to be absent. Analysis of variance (ANOVA) showed that the acquired quadratic model successfully interpreted the experimental data with the coefficient of determination values, (R2>0.98) and adjusted R2 values, (>0.97). The RSM model was validated by good agreement between the model predicted and experimental values for responses. Pseudohomogeneous (PH) kinetic model was used and validated (R2>0.95) with the experimental data. The activation energy and frequency factor were evaluated as 42.07 kJ mol−1 and 19,874.64 L mol−1 min−1, respectively.

Enhanced Biocatalytic Activity of Lipase Immobilized on Biodegradable Copolymer of Chitosan and Polyvinyl Alcohol Support for Synthesis of Propionate Ester: Kinetic Approach

The objective of this work was to investigate a kinetic and mechanistic analysis for the synthesis of benzyl propionate which has diverse applications. Furthermore this study illustrates the synthesis and beneficial uses of an ecofriendly support that is made up of chitosan (CHI) and polyvinyl alcohol (PVA) to immobilize lipase Pseudomonas cepacia (PCL), and it showed remarkable enhancement of biocatalytic activity over free lipase. Among various biocatalysts prepared, CHI:PVA:PCL (5:5:2) was found as a robust biocatalyst composition. The lower activation energy (Ea) of immobilized lipase (12.8 ± 0.11 kcal/mol) than that of free lipase (16.6 ± 0.65 kcal/mol) showed better catalytic activity of immobilized lipase. Kinetic parameters were determined which showed that benzyl propionate synthesis catalyzed by immobilized PCL followed the order bi–bi mechanism with benzyl alcohol inhibition. CHI/PVA immobilized lipase biocatalyst showed enhanced (3.5 fold) catalytic activity and efficient recyclability over th...

RAFT polymerization of N-vinylcaprolactam and effects of the end group on the thermal response of poly(N-vinylcaprolactam)

The reversible addition–fragmentation chain transfer (RAFT) radical polymerization of N-vinylcaprolactam (NVCL) was performed using either S-benzyl-S-(benzyl propionate) trithiocarbonate (CTA 1) or N, N-diethyl-S-(α,α′- dimethyl-α″-acetic acid) dithiocarbamate (CTA 2) as a chain transfer agent (CTA). The polymerizations were controlled processes that yielded polymers with high conversion (>60%), controlled molecular weights that were close to the theoretical values and a narrow molecular weight distribution (minimal value: 1.13). The cloud point temperatures of poly(N-vinylcaprolactam) (PNVCL) were measured by turbidimetry and shifted to lower temperature and concentrations as the hydrophobicity of the end groups and the molecular weights of the polymers increased.

Molecular Basis of Prodrug Activation by Human Valacyclovirase, an α-Amino Acid Ester Hydrolase

Chemical modification to improve biopharmaceutical properties, especially oral absorption and bioavailability, is a common strategy employed by pharmaceutical chemists. The approach often employs a simple structural modification and utilizes ubiquitous endogenous esterases as activation enzymes, although such enzymes are often unidentified. This report describes the crystal structure and specificity of a novel activating enzyme for valacyclovir and valganciclovir. Our structural insights show that human valacyclovirase has a unique binding mode and specificity for amino acid esters. Biochemical data demonstrate that the enzyme hydrolyzes esters of alpha-amino acids exclusively and displays a broad specificity spectrum for the aminoacyl moiety similar to tricorn-interacting aminopeptidase F1. Crystal structures of the enzyme, two mechanistic mutants, and a complex with a product analogue, when combined with biochemical analysis, reveal the key determinants for substrate recognition; that is, a flexible and mostly hydrophobic acyl pocket, a localized negative electrostatic potential, a large open leaving group-accommodating groove, and a pivotal acidic residue, Asp-123, after the nucleophile Ser-122. This is the first time that a residue immediately after the nucleophile has been found to have its side chain directed into the substrate binding pocket and play an essential role in substrate discrimination in serine hydrolases. These results as well as a phylogenetic analysis establish that the enzyme functions as a specific alpha-amino acid ester hydrolase. Valacyclovirase is a valuable target for amino acid ester prodrug-based oral drug delivery enhancement strategies.

Refractive Indices and Surface Tensions of Binary Mixtures of Ethyl Acetoacetate, Ethyl Isovalerate, Methyl Benzoate, Benzyl Acetate, Ethyl Salicylate, and Benzyl Propionate with Ethanol at (288.15, 298.15, 308.15, and 318.15) K

Refractive indices and surface tensions for binary mixtures of six flavor esters (ethyl acetoacetate, ethyl isovalerate, methyl benzoate, benzyl acetate, ethyl salicylate, and benzyl propionate) with ethanol over the whole composition range were measured at four different temperatures (288.15, 298.15, 308.15, and 318.15) K and atmospheric pressure. Refractive indices were measured using a digital Abbe-type refractometer. Surface tensions were determined using the Wilhelmy-plate method. Deviations in the refractive index ΔnD and deviations in the surface tension Δσ from volume fraction average for the binary mixtures were derived from experimental data. The binary data of ΔnD and Δσ were correlated as a function of mole fraction using the Redlich−Kister equation.

Densities and Viscosities of Binary Mixtures of Ethyl Acetoacetate, Ethyl Isovalerate, Methyl Benzoate, Benzyl Acetate, Ethyl Salicylate, and Benzyl Propionate with Ethanol at T = (288.15, 298.15, 308.15, and 318.15) K

Densities and viscosities for six binary mixtures formed by the flavor esters (ethyl acetoacetate, ethyl isovalerate, methyl benzoate, benzyl acetate, ethyl salicylate, and benzyl propionate) with ethanol over the whole composition range were measured at four different temperatures (288.15, 298.15, 308.15, and 318.15) K and atmospheric pressure. Densities were determined using a vibrating-tube density meter. Viscosities were measured with an automatic Ubbelohde capillary viscometer. Excess molar volumes (V E) and deviations in the viscosity from mole fraction average (Δη) for the binary mixtures were derived from experimental data. The binary data of V E and Δη were correlated as function of the mole fraction by using the Redlich−Kister equation. Furthermore, McAllister's multi-body interaction models are used to correlate the binary kinematic viscosities.

Densities, Viscosities, Refractive Indices, and Surface Tensions for 12 Flavor Esters from T = 288.15 K to T = 358.15 K

Densities, viscosities, refractive indices, and surface tensions for 12 flavor esters were measured from 288.15 K to 358.15 K at atmospheric pressure. The esters studied were ethyl acetoacetate, isoamyl acetate, ethyl isovalerate, methyl benzoate, ethyl caproate, ethyl benzoate, benzyl acetate, isoamyl butyrate, ethyl salicylate, benzyl propionate, ethyl phenylacetate, and ethyl caprylate. Densities were determined using a vibrating-tube density meter, and viscosities were measured with an automatic Ubbelohde capillary viscometer. Refractive indices were measured using a digital Abbe-type refractometer, and surface tensions were measured using the Wilhelmy-plate method. The experimental data were correlated by temperature-dependent equations.

Full-scale chamber investigation and simulation of air freshener emissions in the presence of ozone.

Volatile organic compound (VOC) emissions from one electrical plug-in type of pine-scented air freshener and their reactions with O3 were investigated in the U.S. Environmental Protection Agency indoor air research large chamber facility. Ozone was generated from a device marketed as an ozone generator air cleaner. Ozone and oxides of nitrogen concentrations and chamber conditions such as temperature, relative humidity, pressure, and air exchange rate were controlled and/or monitored. VOC emissions and some of the reaction products were identified and quantified. Source emission models were developed to predict the time/concentration profiles of the major VOCs (limonene, alpha-pinene, beta-pinene, 3-carene, camphene, benzyl propionate, benzyl alcohol, bornyl acetate, isobornyl acetate, and benzaldehyde) emitted bythe air freshener. Gas-phase reactions of VOCs from the air freshener with O3 were simulated by a photochemical kinetics simulation system using VOC reaction mechanisms and rate constants adopted from the literature. The concentration-time predictions were in good agreement with the data for O3 and VOCs emitted from the air freshener and with some of the primary reaction products. Systematic differences between the predictions and the experimental results were found for some species. Poor understanding of secondary reactions and heterogeneous chemistry in the chamber is the likely cause of these differences. The method has the potential to provide data to predict the impact of O3/VOC interactions on indoor air quality.

AreCBA is an operon in Acinetobacter sp. strain ADP1 and Is controlled by AreR, a sigma(54)-dependent regulator.

The areCBA genes in Acinetobacter sp. strain ADP1, determining growth on benzyl alkanoates, are shown to be transcribed as a single operon and regulated by areR, which encodes a regulatory protein of the NtrC/XylR family. Assays of the Are enzymes and of two insertions of lacZ as a reporter gene have shown that the operon is induced by benzyl acetate, benzyl alcohol, and benzaldehyde, as well as 2- and 4-hydroxybenzyl acetates and benzyl propionate and butyrate. Two adjacent sites of transcriptional initiation were 97 and 96 bp upstream of the start codon for areC, near a sigma(54)-dependent -12, -24 promoter. Inactivation of areR and rpoN (for RNA polymerase sigma(54)) drastically reduced growth rates on the Are substrates and induction of the operon.

VOLATILITY AND SOLUBILIZATION OF SYNTHETIC FRAGRANCES BY PLURONIC P-85

ABSTRACT The volatility of synthetic fragrances (benzyl formate, benzyl acetate, benzyl propionate) from pluronic P-85 aqueous solution has been investigated by the dynamic headspace method The experimental results showed that the volatility of a more hydrophobic fragrance was strongly controlled by pluronic P-85. This volatile behavior was explained by the solubilization constants of fragrances between the micelle and bulk phase by semiequilibrium dialysis method.

Synthesis of substructures of soraphen A: formation of the enolate of benzyl propionate

During the preparation of substructures of the fungicidal natural product soraphen A 1, it was observed that the β-keto ester 12 was formed as the major product upon deprotonation of benzyl propionate with LDA. Studies of the stability of the enolate 13 showed that two mechanisms previously described for the decomposition of ester enolates cannot be operating in this example. A competition between deprotonation and condensation is proposed, which is in accord with the results described here and in the literature. The use of a reactive base is shown to provide good yields of the enolate 13. In addition, temperature is shown to be another factor influencing the yield of 13.

Dabbing and shooting of benzo- and naphthoquinone secretions: Defensive strategies of bark-inhabiting aleocharine (col.: Staphylinidae) and tenebrionid (col.: Tenebrionidae) beetle larvae

The abdominal glands of three bark-inhabiting larvae of generaBolitochara, Leptusa (Staphylinidae), andHypophloeus (Tenebrionidae) were studied chemically and morphologically. Behavior of the larvae indicated that secretion is emitted only after severe disturbance of the larvae. These mechanical contacts may also occur incidentally with coinhabiting nonpredatory arthropods when the beetle larvae move within small interstices under bark. Depending on the species, the secretions contained 1,4-benzoquinone derivatives and three 6-alkyl-naphthoquinones dissolved within various alkanes, alkenes, ethyl-, isopropyl-, and isoamylesters. More erratically distributed gland constituents also detected were acetophenone, benzyl propionate, and methyl hydroxybenzoate. In the laboratory, synthetic quinone-containing solutions simulating those found inLeptusa andBolitochara larvae acted as strong topical irritants and caused further damage to last-stageCalliphora vomitoria larvae if hydrocarbons or esters were used as solvents. The natural secretions ofHypophloeus versipellis elicited considerable mortality in two subcortical sciarid larvae cooccurring with tenebrionid larvae. Bioassay and secretion chemistry of the Staphylinidae/Tenebrionidae larval secretions indicated that they are typical defensive secretions that act topically. Morphological data characterized Bolitocharini larvae as possessing protuberant abdominal tergites supplied with an interiorly situated gland reservoir. After mechanical contact, the defensive secretion is topically applied to other arthropods by dabbing this tergal protuberance on targets. The defensive gland ofHypophloeus versipellis is unusual in possessing a movable reservoir opening situated at the anterior border of tergite IX. By this peculiar gland morphologyHypophloeus larvae are capable of shooting secretion droplets frontally from their slightly depressed dorsal abdominal surface without bending their abdominal tips dorsally. This seems an adaptation to the interstitial habitat of the larvae. The types of defensive glands and their phylogenetic value in Aleocharinae/Tenebrionidae larvae are discussed.

Identification of Additional Volatile Compounds from Cbntaloupe

ABSTRACTThe volatile components of cantaloupe pericarp were analyzed during ripening by gas‐liquid chromatography‐mass spectrometry. Thirty‐two compounds were identified from concentrates prepared by steam distillation‐solvent extraction of the volatiles. Eight of the constituents including ethyl (methylthio) acetate, (Z)‐6‐nonenyl acetate, (Z, Z)‐3,6‐nonadienyl acetate, benzyl propionate, benzyl alcohol, a sesquiterpene hydrocarbon, cinnamyl acetate and an isomer of 3,4‐dimethoxyacetophenone have not been identified previously. Headspace analysis of cantaloupe samples at six stages of maturity showed increases in total ethyl and acetate esters, acetaldehyde, ethyl acetate, and ethanol with maturation. Levels of these compounds remained low and relatively constant until the breaker stage and thereafter increased rapidly until the fruit was fully mature.

Determination of volatile carboxylic acids in animal wastes by (GC)2 of their benzyl esters

AbstractThe C1 ‐C6 fatty acids present in various types of heterogeneous animal wastes were isolated by steam distillation and determined as benzyl esters by high resolution gas chromatography. Glass capillary columns, deactivated with barium carbonate and coated with UCON HB 5100, allowed the analysis of benzyl formate, acetate, propionate, isobutyrate, butyrate, isovalerate, valerate, and caproate in less than 20 minutes. Recovery tests, performed on more than 50 different samples, indicated a benzylation yield and an overall efficiency higher than 99%, with a standard deviation of 2.6% (C5) to 6.0% (C1). The absolute detection limit ranged from 0.3 picomole (caproic acid) to 1.0 picomole (formic acid).