January 2023 - Esters-buliding-blocks

Kiyooka, Shunichi et al. published their research in Bulletin of the Chemical Society of Japan in 1980 | CAS: 10203-58-4

Diethyl isobutylmalonate (cas: 10203-58-4) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Application In Synthesis of Diethyl isobutylmalonate

Enolate anions. III. Substituent effects of sodium diethyl alkylmalonates in DMSO was written by Kiyooka, Shunichi;Kodani, Tsukasa;Suzuki, Kojiro. And the article was included in Bulletin of the Chemical Society of Japan in 1980.Application In Synthesis of Diethyl isobutylmalonate This article mentions the following:

The conformations of Na enolate anions derived from RCH(CO₂Et)₂ (I; R = H, Me, Et, Pr, Me₂CH, Bu, Me₂CHCH₂, EtCHMe) were of the Z,Z type, according to their ¹H NMR spectra in Me₂SO. In the case of Me₃CCH(CO₂Et)₂ (II), such a Z,Z conformation contributes to a lesser extent to the conformations of the Na enolate anion because of repulsion between the tert-Bu substituent and the 2 EtO groups, which exist in 3 types of conformations (Z,Z, Z,E and E,E). All I (R = alkyl) except for II have 2 characteristic IR bands in the 1500-1700 cm^-1 region, the bands on the high-frequency side of which have nearly equal wavenos., while those on the low-frequency side correlate well with the substituent constant σ^*. In the experiment, the researchers used many compounds, for example, Diethyl isobutylmalonate (cas: 10203-58-4Application In Synthesis of Diethyl isobutylmalonate).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Utrilla-Vazquez, Marycarmen et al. published their research in Food Research International in 2020 | CAS: 659-70-1

Isopentyl 3-methylbutanoate (cas: 659-70-1) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone.HPLC of Formula: 659-70-1

Analysis of volatile compounds of five varieties of Maya cocoa during fermentation and drying processes by Venn diagram and PCA was written by Utrilla-Vazquez, Marycarmen;Rodriguez-Campos, Jacobo;Avendano-Arazate, Carlos Hugo;Gschaedler, Anne;Lugo-Cervantes, Eugenia. And the article was included in Food Research International in 2020.HPLC of Formula: 659-70-1 This article mentions the following:

Fermented cocoa beans can be described as a complex matrix that integrates the chem. history of beans, their processing, and environmental factors. This study presents an anal. that aims to identify volatile compounds of five varieties of fine-aroma cocoa types. The cocoa types studied were Carmelo, Rojo Samuel, Lagarto, Arcoiris, Regalo de Dios, that grow in the Maya lands of Chiapas, Mexico. Profile of volatile compounds was obtained from each cacao type during fermentation and drying process. This profile of volatile compounds also was compared with beans unfermented, using a statistical anal. of Venn diagram and a multivariate Anal. of Principal Components (PCA). One hundred nine different compounds were identified by SPME-HS GC-MS, these compounds mainly related to desirable aromatic notes generated by esters, aldehydes, ketones, and alcs. The differences in chem. composition of the volatile compounds were associated mainly with the process and not to cocoa varieties. Fermented dry cocoa beans showed a higher content of esters, aldehydes, pyrazines, alcs., some acids, and furans where Lagarto (CL), Rojo Samuel (CR), and Regalo de Dios (TRD) cocoas type showed a more interesting aromatic profile. On the other hand, as expected dry unfermented cocoas presented a few numbers of aroma compounds, in the five cacao types, where alcs., ketones and hydrocarbons predominated. In the experiment, the researchers used many compounds, for example, Isopentyl 3-methylbutanoate (cas: 659-70-1HPLC of Formula: 659-70-1).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Xiang, Wen-Liang et al. published their research in Food Research International in 2022 | CAS: 105-87-3

(E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3) belongs to esters. Esters perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Esterification is the general name for a chemical reaction in which two reactants (typically an alcohol and an acid) form an ester as the reaction product. Esters are common in organic chemistry and biological materials.Reference of 105-87-3

Tetracycline residue alters profile of lactic acid bacterial communities and metabolites of ginger pickle during spontaneous fermentation was written by Xiang, Wen-Liang;Zhao, Qiu-Huan;Lu, Yue;Tang, Jie;Cai, Ting;Rao, Yu;Liu, Lei;Zhang, Qing. And the article was included in Food Research International in 2022.Reference of 105-87-3 This article mentions the following:

Antibiotic residue, an emerging contaminant, has been an increasing concern worldwide in vegetables. However, the focus is still limited to its accumulation in vegetables and its adverse health effect on humans, with little mention of its impact on the vegetable process. Fermentation is an important method of the vegetable process. Tetracycline (TC) is the most widely used antibiotic, and its residue is often higher than other antibiotics in ginger. Therefore, current research was to characterize how the TC residue affected the lactic acid bacterial (LAB) communities and metabolites during the salted fermentation of ginger. The TC residue, organic acids, volatile compounds and LABs were analyzed during the fermentation, and the correlations between the LABs and compounds were also revealed. The results suggested that the hetero-lactic fermentation did not happen under the TC residue although the TC residue decreased from 4 mg/kg to 2.56 mg/kg in salt brine of ginger fermentation Meanwhile, TC residue affected the occurrence, propagation and succession of LABs. The LAB biomarkers shifted to Laboratory parafarraginis, Laboratory buchneri and Laboratory kisonensis under TC residue. Responded to LAB communities, the organic acids and volatile compounds were also markedly changed under the TC residue. And the important volatile compound variables shifted to citronellol, allylsenevol, geranyl acetate, vinylstearylether, isothiocyanic acid phenethyl, 3-octanol, geraniol, bingpian, citral and camphor. The transformation of LAB biomarkers induced by TC residue was the main cause of the change of important volatile compound variables, but interestingly, not all of them had significant pos. or neg. correlations. These results indicated that the antibiotic residue has an adverse ecol. effect on the vegetable fermentation process. Therefore, the antibiotic residue should be listed as a quality control index in fermented vegetable raw materials. In the experiment, the researchers used many compounds, for example, (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3Reference of 105-87-3).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Reddy, C. Ravindra et al. published their research in Catalysis Letters in 2005 | CAS: 1190-39-2

malonic acid dibutyl ester (cas: 1190-39-2) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Liquid esters of low volatility serve as softening agents for resins and plastics. Esters also include many industrially important polymers. Polymethyl methacrylate is a glass substitute sold under the names Lucite and Plexiglas; polyethylene terephthalate is used as a film (Mylar) and as textile fibres sold as Terylene, Fortrel, and Dacron.Product Details of 1190-39-2

Esterification of dicarboxylic acids to diesters over Mⁿ⁺-montmorillonite clay catalysts was written by Reddy, C. Ravindra;Iyengar, Pushpa;Nagendrappa, Gopalpur;Prakash, B. S. Jai. And the article was included in Catalysis Letters in 2005.Product Details of 1190-39-2 This article mentions the following:

Esterification of dicarboxylic acids with various alcs. and phenols in presence of metal exchanged montmorillonite clay catalyst (Mⁿ⁺-mont; Mⁿ⁺ = Al³⁺, Fe³⁺, Cr³⁺, Zn²⁺, Mn²⁺, and Ni²⁺) was studied. Among the catalysts used, Al³⁺-mont was found to be the most effective, as it gave good to excellent yields of esters under mild reaction conditions. The heterogeneous catalyst presented here can be regenerated and reused. All these features indicate the high potential of the reaction as “green chem.” process. In the experiment, the researchers used many compounds, for example, malonic acid dibutyl ester (cas: 1190-39-2Product Details of 1190-39-2).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

He, Hezhi et al. published their research in Journal of Applied Polymer Science in 2022 | CAS: 6683-19-8

2,2-Bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate) (cas: 6683-19-8) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits. Liquid esters of low volatility serve as softening agents for resins and plastics. Esters also include many industrially important polymers. Polymethyl methacrylate is a glass substitute sold under the names Lucite and Plexiglas; polyethylene terephthalate is used as a film (Mylar) and as textile fibres sold as Terylene, Fortrel, and Dacron.Product Details of 6683-19-8

Recycled polyethylene/polyethylene-ethylene-1-octene-maleic anhydride composite with improved mechanical properties was written by He, Hezhi;Wang, Yi;Gao, Jun;Huang, Zhaoxia;Liu, Yufan;Tian, Guidong;Xu, Li;Zhu, Zhiwen. And the article was included in Journal of Applied Polymer Science in 2022.Product Details of 6683-19-8 This article mentions the following:

In this work, we confirmed that the major sort of impurity in waste polyethylene (PE) packing films is calcium carbonate. Consequently, PE/poly(ethylene-co-1-octene)-maleic anhydride (rPE/POE-g-MAH) and poly(ethylene-co-1-octene) (rPE/POE) composites were recycled using a custom-made three-screw extruder, who can supply intensive shear flow during extrusion. The POE-g-MAH is detected to be filled between PE and inorganic impurities, and the compatibility is improved through chem. reactions. As mech. test manifested, the rPE/POE-g-MAH blends present higher tensile strength and elongation at break than the rPE/POE blends at the same composition The reason for such improved toughness of composite was explained in detail through the tensile fracture surface anal. Rheol. test further shows that POE-g-MAH improves the compatibility of matrix and impurities. In the experiment, the researchers used many compounds, for example, 2,2-Bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate) (cas: 6683-19-8Product Details of 6683-19-8).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Shahhoseini, Reza et al. published their research in Biochemical Systematics and Ecology in 2022 | CAS: 105-87-3

(E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Esters are more polar than ethers but less polar than alcohols. They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility.SDS of cas: 105-87-3

Evaluation of phytochemical profiles and relationships of compounds in Lippia citriodora during multiple growth-exploitation phases was written by Shahhoseini, Reza. And the article was included in Biochemical Systematics and Ecology in 2022.SDS of cas: 105-87-3 This article mentions the following:

In the present study the variations of biomass, essential oil content and composition of lemon verbena (Lippia citriodora) during different growth-exploitation phases from 27^th May 2020 to 8^th June 2021 were investigated. The uniform rooted cuttings were planted in the greenhouse under natural light. The aerial parts of lemon verbena at flowering stage were harvested at six times included 27th May (H₁), 29th August (H₂), 4th Nov. (H₃), 17th Jan. (H₄), 27th March (H₅), and 8th June (H₆). Hydro distillated essential oils were analyzed by using GC-FID and GC/MS techniques to determine the essential oil profile. Results showed a considerable variation in plant biomass, essential oil quantity and quality at different harvesting times. Plant biomass increased by 66.83% up to fourth harvesting time (H₄) then decreased. During the studied harvesting frequencies the essential oil content of L. citriodora showed a sinusoidal trend. The highest essential oil content (0.858% v/w) and yield (17.95 L ha^-1) were obtained at third harvesting time (H₃) and in the followed harvesting times their contents were decreased. The observed changes in the essential oil composition of L. citriodora during different harvesting times were due to the relative proportions of constituents and the presence of new constituents. In the all essential oil samples, oxygenated monoterpenes represented by geranial (25.42-30.11%) and neral (19.81-24.19%) were the predominant compounds The highest ratio of monoterpenes to sesquiterpenes compounds (≈5:1) was recorded in collected plants at third harvesting time. In the experiment, the researchers used many compounds, for example, (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3SDS of cas: 105-87-3).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Gauthier, Raphael et al. published their research in Organic Letters in 2019 | CAS: 17920-23-9

Diethyl 2-(prop-2-yn-1-yl)malonate (cas: 17920-23-9) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits. Many esters have the potential for conformational isomerism, but they tend to adopt an s-cis (or Z) conformation rather than the s-trans (or E) alternative, due to a combination of hyperconjugation and dipole minimization effects. The preference for the Z conformation is influenced by the nature of the substituents and solvent, if present. Lactones with small rings are restricted to the s-trans (i.e. E) conformation due to their cyclic structure.COA of Formula: C10H14O4

Gold-Catalyzed Hydrofluorination of Internal Alkynes Using Aqueous HF was written by Gauthier, Raphael;Mamone, Marius;Paquin, Jean-Francois. And the article was included in Organic Letters in 2019.COA of Formula: C10H14O4 This article mentions the following:

The gold-catalyzed hydrofluorination reaction of internal alkynes using hydrofluoric acid is reported. Notably, these conditions use one of the most economical sources of HF and are free of addnl. additives. Both sym. and unsym. internal alkynes can be utilized, and the use of alkynes bearing a fluorinated group at the propargylic position as substrates allowed for a regioselective hydrofluorination reaction. In the experiment, the researchers used many compounds, for example, Diethyl 2-(prop-2-yn-1-yl)malonate (cas: 17920-23-9COA of Formula: C10H14O4).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Ribeiro, Rita et al. published their research in Industrial Crops and Products in 2022 | CAS: 105-87-3

(E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Recommanded Product: (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate

Comparing the effect of Thymus spp. essential oils on Candida auris was written by Ribeiro, Rita;Fernandes, Liliana;Costa, Raquel;Cavaleiro, Carlos;Salgueiro, Ligia;Henriques, Mariana;Rodrigues, Maria Elisa. And the article was included in Industrial Crops and Products in 2022.Recommanded Product: (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate This article mentions the following:

Candida auris is an emergent yeast pathogen responsible for many invasive fungal infections due to its multidrug-resistant character and its huge transmission ability. Essential oils (EOs) obtained from several aromatic plants have been regarded as an alternative treatment upon to fungal infections. For example, Thymus spp. are known by their antifungal effect due to the presence of some volatile compounds in their EOs, such as carvacrol, thymol, linalool and gamma-terpinene. So, the main goal of this work was to compare the effect of several EOs from Thymus spp. on C. auris biofilm. The antifungal activity of Thymus vulgaris, Thymus zygis, Thymus satureioides and Thymus mastichina against planktonic cells of C. auris NCPF 8971 was assessed by agar disk diffusion method. The effect of these EOs with direct or vapor phases on preformed biofilms was evaluated by colony-forming unitsprime enumeration. Importantly it was noticed a completely different range of action between the EOs from the same genus. While T. vulgaris showed the biggest antifungal effect with a halo of 59.75 plusmn 15.75 mm, T. mastichina for the other side, presented a halo of 13.13 plusmn 1.36 mm, showing a very low activity. In addition, the direct application of T. vulgaris and T. zygis EOs demonstrated higher antifungal activity against C. auris biofilms than vapor phase application. However, T. vulgaris also showed significant action in the vapor phase mode. The chem. composition of Thymus EOs was analyzed by GC and GC-MS, and was demonstrated that they have different chem. profiles, namely in the amount of phenolic compounds, which justify the different antifungal actions.In conclusion, T. vulgaris and T. zygis oils, can be pointed out as a great contribution to the treatment of C. auris infections, being promising alternatives to conventional therapy. However, the efficiency of the EOs differs substantially between the four species of Thymus. Therefore, the selection of natural therapies should always have in account EOs composition In the experiment, the researchers used many compounds, for example, (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3Recommanded Product: (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate).

(E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Recommanded Product: (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Zhang, Hong et al. published their research in Food Packaging and Shelf Life in 2022 | CAS: 6683-19-8

2,2-Bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate) (cas: 6683-19-8) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.Application of 6683-19-8

Migration testing of metallized polypropylene films treated with ionizing radiation was written by Zhang, Hong;Wang, Yini;Wu, Jingjie;Zhu, Lei;Xia, Yining. And the article was included in Food Packaging and Shelf Life in 2022.Application of 6683-19-8 This article mentions the following:

An UHPLC-QTOF/MS method was employed to identify chems. migrating from metalized polypropylene (met PP) films. The migration test was conducted by converting met PP films into pouches filled with 95% ethanol as a fatty food simulant and treating the pouch samples with gamma and electron beam irradiation at a dose of 10 kGy. A temperature of 22°C and a duration time of 21 days were used for the migration test. Over 10 chems. were identified, 3 of them were intentionally added substances (IAS), while the rest were considered as non-intentionally added substances (NIAS) including radiolysis products (RPs) derived from antioxidants. Based on the identification results, 5 chems. (3 hindered phenolic compounds, 1 phosphate compound and 1 phosphonate compound) were selected and their migration behaviors were evaluated under the effect of irradiation It was found that irradiation treatment significantly reduced the migration level of all substances. The extent of decrease was dependent on their stability under irradiation The phosphate/phosphonate compounds recorded higher stability resulting in less decrease (3-25%) in migration level. The hindered phenolic compounds were susceptible to irradiation and a large drop (45-88%) of migration level was observed Potential risks of met PP films were evaluated by comparing the migration levels of selected chems. with their migration limits either listed in Regulation (EU) Number 10/2011 or established with Cramer classification. The results showed that the migration level of the phosphonate compound was above the recommended migration limit, which may present a safety concern. In the experiment, the researchers used many compounds, for example, 2,2-Bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate) (cas: 6683-19-8Application of 6683-19-8).

2,2-Bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate) (cas: 6683-19-8) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.Application of 6683-19-8

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Haag, Franziska et al. published their research in Food Chemistry in 2022 | CAS: 706-14-9

5-Hexyldihydrofuran-2(3H)-one (cas: 706-14-9) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone.Reference of 706-14-9

The key food odorant receptive range of broadly tuned receptor OR2W1 was written by Haag, Franziska;Di Pizio, Antonella;Krautwurst, Dietmar. And the article was included in Food Chemistry in 2022.Reference of 706-14-9 This article mentions the following:

Mammals perceive a multitude of odorants by their chem. sense of olfaction, a high-dimensional stimulus-detection system, with hundreds of narrowly or broadly tuned receptors, enabling pattern recognition by the brain. Cognate receptor-agonist information, however, is sparse, and the role of broadly tuned odorant receptors for encoding odor quality remains elusive. Here, we screened IL-6-HaloTag-OR2W1 and haplotypes against 187 out of 230 defined key food odorants using the GloSensor system in HEK-293 cells, yielding 48 new agonists. Altogether, key food odorants represent about two-thirds of now 153 reported agonists of OR2W1, the highest number of agonists known for a mammalian odorant receptor. In summary, we characterized OR2W1 as a human odorant receptor, with a chem. diverse but exclusive receptive range, complementary to chem. subgroups covered by evolutionary younger, highly selective receptors. Our data suggest OR2W1 to be suited for participating in the detection of many foodborne odorants. In the experiment, the researchers used many compounds, for example, 5-Hexyldihydrofuran-2(3H)-one (cas: 706-14-9Reference of 706-14-9).

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics