Month: January 2023

Contaminant occurrence, mobility and ecological risk assessment of phthalate esters in the sediment-water system of the Hangzhou Bay was written by Wang, Liu-Yong;Gu, Yan-Yu;Zhang, Ze-Ming;Sun, Ai-Li;Shi, Xi-Zhi;Chen, Jiong;Lu, Yin. And the article was included in Science of the Total Environment in 2021.Name: Dicyclohexyl phthalate This article mentions the following:

The pollution characteristics, spatiotemporal variation, sediment-water partitioning, and potential ecol. risk assessment of phthalate esters (PAEs) in the sediment-seawater system of the Hangzhou Bay (HZB) in summer and autumn were researched. The sum of the concentrations of the 10 PAEs in seawater ranges from 7305 ng/L to 22,861 ng/L in summer and from 8100 ng/L to 33,329 ng/L in autumn, with mean values of 15,567 ± 4390 and 17,884 ± 6850 ng/L, resp. The Σ16PAEs in the sediments are between 118 and 5888μg/kg and 145 and 4746μg/kg in summer and autumn, resp. The level of PAEs in seawater varies with the seasons, but it is relatively stable in the sediments. Di(2-ethylhexyl) phthalate (DEHP), di-Bu phthalate (DnBP), and diisobutyl phthalate (DiBP) are the predominant PAE congeners in the HZB. The DnBP and DiBP concentrations in seawater are greater than the DEHP concentration, which is the opposite in the sediments. The sediment-seawater equilibrium distribution study indicates that the PAEs with medium mol. weights, such as DiBP, Bu benzyl phthalate, and DnBP, are near dynamic equilibrium in the sediment-seawater system; PAEs with high mol. weights (e.g., di-n-octyl phthalate and DEHP) tend to transfer from water to the sediments; and PAEs with low mol. weights (e.g., di-Me phthalate, di-Et phthalate, and diamyl phthalate) tend to spread to seawater. The risk assessment results in seawater indicate that DEHP and DiBP might pose high potential risks to sensitive organisms, and DnBP might exhibit medium ecol. risks. In the sediment, DiBP might display a high potential risk to fish, and the potential risk of DEHP is high in several sites. In the experiment, the researchers used many compounds, for example, Dicyclohexyl phthalate (cas: 84-61-7Name: Dicyclohexyl phthalate).

Dicyclohexyl phthalate (cas: 84-61-7) 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. Name: Dicyclohexyl phthalate

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

Steady-State Based Model of Airborne Particle/Gas and Settled Dust/Gas Partitioning for Semivolatile Organic Compounds in the Indoor Environment was written by Li, Hai-Ling;Yang, Pu-Fei;Liu, Li-Yan;Gong, Bei-Bei;Zhang, Zi-Feng;Ma, Wan-Li;Macdonald, Robie W.;Nikolaev, Anatoly N.;Li, Yi-Fan. And the article was included in Environmental Science & Technology in 2022.Name: Dicyclohexyl phthalate This article mentions the following:

Indoor semivolatile organic compounds (SVOCs), present in the air, airborne particles, settled dust, and other indoor surfaces, can enter the human body through several pathways. Knowing the partitioning between gaseous and particulate phases is important in identifying specific pathway contributions and thereby accurately assessing human exposure. Numerous studies have developed equilibrium equations to predict airborne particle/gas (P/G) partitioning in air (K_P) and dust/gas (D/G) partitioning in settled dust (K_D). The assumption that P/G and D/G equilibrium are instantaneous for airborne and settled dust phases, commonly adopted by current indoor fate models, is not likely valid for compounds with high octanol-air partition coefficients (K_OA). Here, we develop steady-state based equations to predict K_P and K_D in the indoor environment. Results show that these equations perform well and are verified by worldwide monitoring data. It is suggested that instantaneous steady state could work for P/G and D/G partitioning of SVOCs in indoor environments, and the equilibrium is just a special case of the steady state when log K_OA < 11.38 for P/G partitioning and log K_OA < 10.38 for D/G partitioning. These newly developed equations and methods provide a tool for more accurate assessment for human exposure to SVOCs in the indoor environment. In the experiment, the researchers used many compounds, for example, Dicyclohexyl phthalate (cas: 84-61-7Name: Dicyclohexyl phthalate).

Dicyclohexyl phthalate (cas: 84-61-7) 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. 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. Name: Dicyclohexyl phthalate

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

Electrochemical reduction of oxygen: an alternative method to prepare active CoN₄ catalysts was written by Bouwkamp-Wijnoltz, A. L.;Visscher, W.;Van Veen, J. A. R.;Tang, S. C.. And the article was included in Electrochimica Acta in 1999.SDS of cas: 2199-49-7 This article mentions the following:

An alternative method for preparing active catalysts for oxygen reduction with a similar performance as heat treated cobalt porphyrin on carbon is presented. The catalysts were prepared from cobalt acetate, carbon black and a nitrogen donor. Several nitrogen donors were studied. The best results were obtained with 2,5-dimethylpyrrole. In this case the activity of the heat treated cobalt porphyrin could be matched. EXAFS indicated that similar active sites were found on both types of catalyst, although in the alternative catalyst some metallic cobalt is also present. In the experiment, the researchers used many compounds, for example, Ethyl 4-methyl-1H-pyrrole-3-carboxylate (cas: 2199-49-7SDS of cas: 2199-49-7).

Ethyl 4-methyl-1H-pyrrole-3-carboxylate (cas: 2199-49-7) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. 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.SDS of cas: 2199-49-7

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

A new procedure for the synthesis of barbituric acid was written by Dick, J.;Drugarin, C.. And the article was included in Acad. Rep. Populare Romine, Baza Cercetari Stiint. Timisoara, Studii. Cercetari Stiinte Chim. in 1961.Related Products of 1190-39-2 This article mentions the following:

A mixture of 120 g. butanol, 50 g. malonic acid, and 3.7 g. H₂SO₄ is refluxed two hours to yield 72.5% pure dibutyl malonate (I), n²⁰_D 1.4255, d₂₀ 1.0005. I (15 g.) and 6 g. urea in 50 g. butanol is added to 50 g. butanol containing 2 g. Na; the mixture is refluxed two hrs., cooled to 70° 80 g. H₂O and 10 g. HCl added, and the mixture further cooled to 40° and filtered to yield 73% barbituric acid (II). In the experiment, the researchers used many compounds, for example, malonic acid dibutyl ester (cas: 1190-39-2Related Products of 1190-39-2).

malonic acid dibutyl ester (cas: 1190-39-2) 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.Related Products of 1190-39-2

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

The freezing temperature of organic substances was written by Serwy, H.. And the article was included in Bulletin des Societes Chimiques Belges in 1933.Application of 1190-39-2 This article mentions the following:

A tabulation of precise measurements of phys. properties of pure substances. Cl(CH₂)₃Cl, m. -99.5°, b. 120.4°; Cl(CH₂)₅Cl, m. -72.8°; b. 182.3°; d₄ 1.11622, d₄¹⁵ 1.10158, d₄³⁰ 1.08692; viscosity 1928 at 15°, 1481 at 30°; ns at 15° n He red 1.45858, n_α 1.45903, n He yellow 1.46161, n He green 1.46675, nβ 1.46801, n He blue 1.47189, n_γ 1.47681; Br(CH₂)₃Br, m. -34.2°, b. 167.34°; d₄ 2.01618, 1.98927 and 1.96238; viscosities 2241 and 1746; ns 1.52121, 1.52174, 1.52546, 1.53252, 1.53416, 1.53932 and 1.54464; Br(CH₂)₅Br, m. -39.5°, b. 222.3°, b₁₂ 99°; d₄ 1.72952, 1.70876 and 1.68788; viscosities 3888 and 2818; ns 1.50908, 1.50960, 1.51311, 1.51970, 1.52131, 1.52634 and 1.53072; NC(CH₂)₃CN, m. -29.45°, b₂₂ 160.4°, d₄ 1.00293, 0.99112 and 0.97930; viscosities 8104 and 5226; ns 1.43426, 1.43461, 1.43699, 1.44137, 1.44242, 1.44573 and 1.45048; NC(CH₂)₅CN, m. -31.4°, b_14.6 177.8°; d₄ 0.96181, 0.95070 and 0.93961; viscosities 9080 and 5501; ns 1.44010, 1.44044, 1.44278, 1.44721, 1.44816, 1.45167 and 1.45721; HO₂CCH₂CO₂H, m. 134.8-.9°; HO₂C(CH₂)₃CO₂H, m. 98.0-.1°; HO₂C(CH₂)₄CO₂H, m. 153.0.1°; HO₂C(CH₂)₅CO₂H, m. 105.7-.8°; EtO₂C(CH₂)₃CO₂Et, m. -23.80°, b. 233.68°, b₁₃ 117.6°; d₄ 1.04202, 1.02704 and 1.01210; viscosities 3260 and 2311; ns 1.42294, 1.42333, 1.42570, 1.42982, 1.43086, 1.43382 and 1.43820; EtO₂C(CH₂)₄CO₂Et m. -19.9°, b₁₃ 131°; d₄ 1.02589, 1.01165 and 0.99744; viscosities 3871 and 2648; ns 1.42673, 1.42708, 1.42924, 1.43362, 1.43463, 1.43783 and 1.44335; PrO₂CCH₂CO₂Pr, m. about -95°, b. 229.2°, b₁₃ 113°; d₄ 1.02929, 1.01453, 0.99977; viscosities 3161 and 2236; ns 1.41967, 1.42010, 1.42243, 1.42660, 1.42768, 1.43092 and 1.43569; PrO₂C(CH₂)₃CO₂Pr, m. -45.5°, b. 264.9°, b₁₃ 142.4°; d₄ 1.00766, 0.99385, 0.98001; viscosities 4437 and 3033; ns 1.42723, 1.42760, 1.42999, 1.43420, 1.43521, 1.43848 and 1.44144; PrO₂C(CH₂)₅CO₂Pr, m. -34°, b₁₃ 165.8°; d₄ 0.98676, 0.97371, 0.97074; viscosities 5017 and 4019; ns 1.43224, 1.43247, 1.43485, 1.43914, 1.44015, 1.44312 and 1.44890; BuO₂CCH₂CO₂Bu, m. -83°, b. 251.5°, b₁₃ 137.4°; d₄ 0.99930, 0.98560 and 0.97191; viscosities 3873 and 2682; ns, 1.42520, 1.42664, 1.42792, 1.43218, 1.43324, 1.43658 and 1.44133; BuO₂C(CH₂)₃CO₂Bu, m. -50.6°, b. 292.8°, b₁₃ 162.9°; d₄ 0.98534, 0.97227 and 0.95922; viscosities 5424 and 3659; ns 1.43147, 1.43189, 1.43426, 1.43845, 1.43955, 1.44279 and 1.44443; BuO₂C(CH₂)₅CO₂Bu, m. -30.5°, b_13.6 188.6°; d₄ 0.97509, 0.96295 and 0.95084; viscosities 8214 and 5262; ns 1.43460, 1.43673, 1.43910, 1.44344, 1.44445, 1.44771 and 1.45283; AmO₂CCO₂Am, m. -9°, b_14.8 154.1°; d₄ 0.98404, 0.97059 and 0.95718; viscosities 4983 and 3330; ns 1.42789, 1.42825, 1.43063, 1.43507, 1.43606, 1.43934 and 1.44496; AmO₂CCH₂CO₂Am, m. -60.0°, b_13.4 162.4°; d₄ 0.97853, 0.96550 and 0.95254; viscosities 5297 and 3562; ns 1.43041, 1.43080, 1.43316, 1.43748, 1.43847, 1.44180, 1.44293; AmO₂C(CH₂)₃CO₂Am, m. -35.1°, b_13.6 186.8°; d₄ 0.97607, 0.96367 and 0.95133; viscosities 8375 and 5308; ns 1.43597, 1.43631, 1.43868, 1.44313, 1.44411, 1.44740 and 1.45293; AmO₂C(CH₂)₅CO₂Am, m. -28.9°, b_17.4 213.4-3.5°; d₄ 0.95879, 0.94671 and 0.93471; viscosities 9428 and 5911. In the experiment, the researchers used many compounds, for example, malonic acid dibutyl ester (cas: 1190-39-2Application of 1190-39-2).

malonic acid dibutyl ester (cas: 1190-39-2) 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. Application of 1190-39-2

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

Small-molecule kinase inhibitors provide insight into Mps1 cell cycle function was written by Kwiatkowski, Nicholas;Jelluma, Nannette;Filippakopoulos, Panagis;Soundararajan, Meera;Manak, Michael S.;Kwon, Mijung;Choi, Hwan Geun;Sim, Taebo;Deveraux, Quinn L.;Rottmann, Sabine;Pellman, David;Shah, Jagesh V.;Kops, Geert J. P. L.;Knapp, Stefan;Gray, Nathanael S.. And the article was included in Nature Chemical Biology in 2010.Recommanded Product: Methyl 3-(cyclopentylamino)propanoate This article mentions the following:

Mps1, a dual-specificity kinase, is required for the proper functioning of the spindle assembly checkpoint and for the maintenance of chromosomal stability. As Mps1 function has been implicated in numerous phases of the cell cycle, the development of a potent, selective small-mol. inhibitor of Mps1 should facilitate dissection of Mps1-related biol. We describe the cellular effects and Mps1 cocrystal structures of new, selective small-mol. inhibitors of Mps1. Consistent with RNAi studies, chem. inhibition of Mps1 leads to defects in Mad1 and Mad2 establishment at unattached kinetochores, decreased Aurora B kinase activity, premature mitotic exit and gross aneuploidy, without any evidence of centrosome duplication defects. However, in U2OS cells having extra centrosomes (an abnormality found in some cancers), Mps1 inhibition increases the frequency of multipolar mitoses. Lastly, Mps1 inhibitor treatment resulted in a decrease in cancer cell viability. In the experiment, the researchers used many compounds, for example, Methyl 3-(cyclopentylamino)propanoate (cas: 754125-43-4Recommanded Product: Methyl 3-(cyclopentylamino)propanoate).

Methyl 3-(cyclopentylamino)propanoate (cas: 754125-43-4) 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. 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: Methyl 3-(cyclopentylamino)propanoate

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

Catalytic hydroconversion of Yiwu lignite over solid superacid and solid superbase was written by Liu, Zhong-Qiu;Wei, Xian-Yong;Liu, Fang-Jing;Liu, Guang-Hui;Zong, Zhi-Min. And the article was included in Fuel in 2019.Recommanded Product: Ethyl 2-hydroxybenzoate This article mentions the following:

Trifluoromethanesulfonic acid supported on attapulgite powder (TFMSA/AP) and Mg₂Si/γ-Al₂O₃ were facilely prepared by impregnating TFMSA onto AP and Mg₂Si onto γ-Al₂O₃. The extraction residue from Yiwu lignite (YL_ER) was subjected to non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) over TFMSA/AP and Mg₂Si/γ-Al₂O₃, resp. Detailed mol. compositions of the soluble portions from the NCHC (SP_NCHC) and CHC over TFMSA/AP (SP_CHC-A) and Mg₂Si/γ-Al₂O₃ (SP_CHC-B) were characterized with a gas chromatograph/mass spectrometer. As a result, the yields of SP_CHC-A and SP_CHC-B are 19.6% and 17.5%, resp., which are much higher than that of SP_NCHC (1.04%), suggesting that both TFMSA/AP and Mg₂Si/γ-Al₂O₃ show excellent activity for the CHC of YL_ER. Arenes and arenols are predominant in SP_CHC-A and SP_CHC-B, resp., while large amounts of alkanoates were detected in SP_NCHC. The results indicate that TFMSA/AP effectively catalyzes the cleavage of C_ar-C_alk and C_alk-O bridged bonds (BBs) in YL_ER, while Mg₂Si/γ-Al₂O₃ significantly promotes the cleavage of C-O BBs in YL_ER. Di(1-naphthyl)methane, 1-methylnaphthalene, oxydibenzene, and benzyloxybenzene were used as coal-related model compounds (CRMCs) for the CHC to further explore the catalysis of TFMSA/AP and Mg₂Si/γ-Al₂O₃. The results show that TFMSA/AP not only releases mobile H⁺ but also heterolytically splits H₂ to form an immobile H^– and a mobile H⁺, leading to the cleavage of C_alk-C_ar and C_alk-O BBs in the CRMCs. In contrast, Mg₂Si/γ-Al₂O₃ facilitates heterolytically splitting H₂ to an immobile H⁺ and a mobile H^–, resulting in the cleavage of C-O BBs in the CRMCs. In the experiment, the researchers used many compounds, for example, Ethyl 2-hydroxybenzoate (cas: 118-61-6Recommanded Product: Ethyl 2-hydroxybenzoate).

Ethyl 2-hydroxybenzoate (cas: 118-61-6) 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. Polyesters are important plastics, with monomers linked by ester moieties. 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.Recommanded Product: Ethyl 2-hydroxybenzoate

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

The synthesis and herbicidal activity of 1-alkyl-3-(α-hydroxybenzylidene)pyrrolidine-2,4-diones was written by Zhu, You-Quan;Yao, Chang-Sheng;Zou, Xiao-Mao;Hu, Fang-Zhong;Liu, Bin;Li, Yong-Hong;Yang, Hua-Zheng. And the article was included in Molecules in 2005.Product Details of 33166-79-9 This article mentions the following:

Title compounds I (R¹ = 3-NO₂, 4-NO₂, 2-Me, 3-Me, 4-Me, 2-MeO, 4-MeO, 2-Cl, 4-Cl; R² = Me, CHMe₂, CMe₃) were prepared by cyclocondensation of R¹C₆H₄COCH₂COOEt with R²NHCH₂COOEt. Preliminary bioassay results indicated that some of products have high herbicidal activity against annual dicotyledonous and monocotyledonous plants. In the experiment, the researchers used many compounds, for example, Ethyl 3-oxo-3-(m-tolyl)propanoate (cas: 33166-79-9Product Details of 33166-79-9).

Ethyl 3-oxo-3-(m-tolyl)propanoate (cas: 33166-79-9) 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, including apples, durians, pears, bananas, pineapples, and strawberries. 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.Product Details of 33166-79-9

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

Effect of Copper-Based Fungicide Treatments on the Quality of Hop Produced in the Northeastern United States was written by Chrisfield, Benjamin J.;Gugino, Beth K.;Hopfer, Helene;Elias, Ryan J.. And the article was included in Journal of the American Society of Brewing Chemists in 2022.Electric Literature of C12H20O2 This article mentions the following:

The quality of hops is dictated in large part by the content of flavor and aroma compounds These compounds vary in concentration and are affected by agricultural practises. Previous research has found that the application of Bordeaux Mixture may impact the aroma quality of hops by altering concentrations of varietal thiols. The impact of copper fungicides other than Bordeaux Mixture and in hop production areas outside of the Pacific Northwest in the United States has yet to be evaluated. Herein we study the effects of application frequency of a copper (II) hydroxide fungicide on markers of hop quality in hops grown in the Northeastern United States. Copper fungicide application was found to significantly increase the total copper content of hop cones, regardless of application frequency; however, traditional markers of hop quality, including yield, essential oil composition, and acid content, were not affected. Beer consumers were unable to discriminate between beers dry-hopped with conventional or copper-treated hops based on aroma but were able to discriminate based on in-mouth perception. These findings suggest that the use of copper (II) hydroxide for the mitigation of fungal pathogens in hops grown in the Northeastern United States is unlikely to adversely affect final hop yield, acid content, or thiol quality. In the experiment, the researchers used many compounds, for example, (E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3Electric Literature of C12H20O2).

(E)-3,7-Dimethylocta-2,6-dien-1-yl acetate (cas: 105-87-3) 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.Electric Literature of C12H20O2

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

Characterization of Key Aroma Compounds in Pellets of Different Hop Varieties (Humulus lupulus L.) by Means of the Sensomics Approach was written by Brendel, Sabrina;Hofmann, Thomas;Granvogl, Michael. And the article was included in Journal of Agricultural and Food Chemistry in 2019.Application of 868-57-5 This article mentions the following:

The use of hops in beer brewing is mainly based on its content of bitter acids and aroma compounds Due to the loss of volatile odorants during wort boiling, the so-called dry hopping is a possibility to intensify the hoppy aroma in the final beer. To clarify the potential of different hop varieties for aroma modulation of beer via dry hopping, key aroma compounds of three different hop varieties were characterized using the sensomics approach. Aroma extract dilution anal. revealed 41 aroma-active compounds, of which 39 were identified via gas chromatog.-olfactometry and gas chromatog.-mass spectrometry. The highest flavor dilution factor was determined for myrcene with a geranium-like odor. Fourteen substances were quantitated by stable isotope dilution anal. and further two odorants via the internal standard method; all of them revealed odor activity values (OAVs; ratio of concentration to odor threshold) �. Linalool, 3-methylbutanoic acid, myrcene, and di-Me trisulfide showed the highest OAVs (>1000) in all analyzed hop varieties. For validation of the anal. data, reconstitution models were prepared by adding all quantitated aroma compounds with OAVs �1 in their naturally occurring concentrations to cellulose as matrix. All three recombinates showed a very high similarity to the aroma profile of the resp. hop sample, confirming the correct identification and quantitation of all key aroma compounds In the experiment, the researchers used many compounds, for example, Methyl2-methylbutyrate (cas: 868-57-5Application of 868-57-5).

Methyl2-methylbutyrate (cas: 868-57-5) 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 868-57-5

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