• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1272-1287
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• 2002

Sonochemical Reformatsky reaction of aldehydes or ketones with ethyl bromoacetate in the presence of indium afforded $\beta-hydroxyesters$ in good to excellent yields under mild conditions. 2- or 3-Hydroxybenzaldehyde that contains an acidic hydrogen r eacted with ethyl bromoacetate to provide the desired compounds with the same efficiency. In the case of ethyl 2-bromopropanoate and ethyl 2-bromo-2-methylpropanoate, the desired products were obtained in good yields. Reaction of aldehyde with indium reagent in the presence of ketone group proceeded chemoselectively.

• Journal of Industrial Technology
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• v.19
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• pp.409-413
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• 1999

Chemical oxidation of humic acid by ozonation process was investigated in the batch reactor. Aldehydes and ketone were identified as PFBOA derivatives in ozonated humic acid solutions using gas chromatography with PDECD. The formaldehyde was as a main by-product of ozonation. The characteristics of the formaldehyde production were discussed with respect to concentration at different experimental conditions.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3559-3564
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• 2012

An efficient one-pot synthesis of ${\beta}$-acetamido ketones was accomplished by AgOTf-catalyzed multicomponent reactions of substituted acetophenones with aromatic aldehydes and acid chloride in acetonitrile in high yields. The methods offer several significant advantages of easy handling, mild reaction conditions, and use of effective and non-toxic catalyst.

• Journal of the Korean Society of Food Culture
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• v.22 no.2
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• pp.246-253
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• 2007

Mineral and volatile flavor compounds of Pimpinella brochycarpa N., a perennial Korean medicinal plant of the Umbelliferae family, were analyzed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and simultaneous steam distillation extract (SDE)-gas chromatography mass spectrometry (GC/MS), head space solid phase micro-extraction (HS-SPME)-GC/MS. Mineral contents of the stalks and leaves were compared and the flavor patterns of the fresh and the shady air-dried samples were obtained by the electronic nose (EN) with 6 metal oxide sensors. Principal component analysis (PCA) was carried out using the data obtained from EN. The 1st principal values of the fresh samples have + values and the shady air-dried have - values. The essential oil extracted from the fresh and the shady air-dried by SDE method contain 58 and 31 flavor compounds. When HS-SPME method with CAR/PDMS fiber and PDMS fiber were used, 34 and 21 flavor compounds. The principal volatile components of Pimpinella brachycarpa N. were ${\alpha}$-selinene, germacrene D, and myrcene.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.153-156
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• 2001

Traditional static headspace and headspace solid-phase microextraction(SPME) techniques were compared for their effectiveness in the extraction of volatile flavor compounds from the headspace of persimmon vinegar. The adsorption condition of SPME fiber for equilibrated headspace vapor was selected as $80^{\circ}C$ and 20 min. Total FID response for volatiles of persimmon vinegar was exactly higher such as total peak area $18.18{\times}10^6$ in SPMEGC technique than total peak area $1.35{\times}10^6$ in static headspace-GC. The major volatiles in persimmon vinegar were acetic acid, ethyl acetate, 3-hydroxy-2-butanone, ethanol, phenethyl alcohol. From static headspace-GC technique, 3 acids, 3 aldehydes, 5 alcohols, 9 esters and 1 ketone were identified. From SPME-GC technique, total 34 compounds including 6 acids, 7 aldehydes, 6 alcohols, 9 esters, 2 hydrocarbones, 1 ketone, 3 others were detected. Also the ratio for benzaldehyde, phenethylacetate and phenethylalcohol were higher in SPME-GC.

• Elastomers and Composites
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• v.54 no.2
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• pp.110-117
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• 2019

The characterization of the ozone oxidation for raw natural rubber (NR) was investigated under controlled conditions through image and fourier transform infrared (FT-IR) analysis. The ozone oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at $40^{\circ}C$ under low humidity conditions to completely exclude thermal, moisture, or light oxidation. The ozone concentration was set at 40 parts per hundred million (pphm). Before or after exposure to ozone, the image of the thin film for raw NR was observed at a right or tilted angle. FT-IR absorption spectra were measured in the transmission mode according to ozone exposure time. The ozone oxidation of NR was determined by the changes in the absorption peaks at 1736, 1715, 1697, and $833cm^{-1}$, which were assigned to an aldehyde group (-CHO), a ketone group (-COR), an inter-hydrogen bond between carbonyl group (-C=O) from an aldehyde or a ketone and an amide group (-CONH-) of protein, and a cis-methine group ($is-CCH_3=CH-$, respectively. During ozone exposure period, the results indicated that the formation of the carbonyl group of aldehyde or ketone was directly related to the decrement of the double bond of cis-1,4-polyisoprene. Only carbonyl compounds such as aldehydes or ketones seemed to be formed through chain scission by ozone. Long thin cracks with one orientation at regular intervals, which resulted in consecutive chain scission, were observed by image analysis. Therefore, one possible two-step mechanism for the formation of aldehyde and ketone was suggested.

• Analytical Science and Technology
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• v.9 no.4
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• pp.399-405
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• 1996

The flavor compounds of the oil from roasted sesame seeds were collected by simultaneous steam distillation/ extraction(SDE) and dynamic headspace sampling(DHS) and were analyzed using a gas chromatograph equipped with a flame ionization detector and connected into a mass spectrometer. Among the flavor compounds collected by the SDE method, 46 compounds were identified. They consisted of 6 alcohols, 6 aldehydes, 5 ketones or acids, 4 furans or phenols, 12 pyrazines, 4 pyridines or thiazoles, and others. Thirty six compounds were identified by DHS and many of them were the same as those identified by the SDE method. However, some compounds such as 1-hexanol, pentanal, and dimethylsulfide were identified only by the DHS method.

• Bulletin of the Korean Chemical Society
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• v.16 no.5
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• pp.416-421
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• 1995

The approximate rates and stoichiometry of the reaction of excess lithium gallium hydride with selected organic compounds containing representative functional groups were examined under the standard conditions (diethyl ether, 0 $^{\circ}C)$ in order to compare its reducing characteristics with lithium aluminum hydride and lithium borohydride previously reported, and enlarge the scope of its applicability as a reducing agent. Alcohols, phenol, and amines evolve hydrogen rapidly and quantitatively. However lithium gallium hydride reacts with only one active hydrogen of primary amine. Aldehydes and ketones of diverse structure are rapidly reduced to the corresponding alcohols. Conjugated aldehyde and ketone such as cinnamaldehyde and methyl vinyl ketone are rapidly reduced to the corresponding saturated alcohols. p-Benzoquinone is mainly reduces to hydroquinone. Caproic acid and benzoic acid liberate hydrogen rapidly and quantitatively, but reduction proceeds slowly. The acid chlorides and esters tested are all rapidly reduced to the corresponding alcohols. Alkyl halides and epoxides are reduced rapidly with an uptake of 1 equiv of hydride. Styrene oxide is reduced to give 1-phenylethanol quantitatively. Primary amides are reduced slowly. Benzonitrile consumes 2.0 equiv of hydride rapidly, whereas capronitrile is reduced slowly. Nitro compounds consumed 2.9 equiv of hydride, of which 1.9 equiv is for reduction, whereas azobenzene, and azoxybenzene are inert toward this reagent. Cyclohexanone oxime is reduced consuming 2.0 equiv of hydride for reduction at a moderate rate. Pyridine is inert toward this reagent. Disulfides and sulfoxides are reduced slowly, whereas sulfide, sulfone, and sulfonate are inert under these reaction conditions. Sulfonic acid evolves 1 equiv of hydrogen instantly, but reduction is not proceeded.

• Food Science of Animal Resources
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• v.44 no.5
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• pp.1096-1107
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• 2024

This study investigated the changes in volatile compounds in chicken flesh after boiling at various pHs (6.0-9.0) and after chilling storage (4.0±1.0℃) for 7 d. The volatile compounds were assessed qualitatively and quantitatively by using a headspace gas chromatography-mass spectrometry analysis. Twenty-one volatile compounds were discovered and categorized as amine, aldehyde, alcohol, ketone, acid, and furan. One type of amine, (2-aziridinylethyl) amine, was the most prevalent volatile component, followed by aldehyde, ketone, aldehyde, acid, ester, and furan. The results showed that the quantity and quality of the volatile compounds were influenced by a pH of the boiling medium. Additionally, the types and volatile profiles of the chicken were altered during chilling. In particular, in the chicken that was boiled at a pH of 8.0, the hexanal (an aldehyde) content increased the most after 7 d of chilling. Moreover, various alcohols formed after the 7 d of chilling of the chicken that was boiled at pHs of 8.0 and 9.0. Because of the oxidation and degradation of fat and proteins, the most altering volatile compounds were the reducing amines and the increasing aldehydes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.3
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• pp.481-489
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• 1994

Volatile flavor compounds in low salt-fermented anchovy pastes by adding koji(Koji), compared with Control, were analyzed by simultaneous steam distillation -solvent extraction /gas chromatography/mass spectrometry. Volatile compounds (106) were detected inboth samples during fermentation. Among these, 79 compounds were positively identified and were composed mainly of aldehydes, esters, alcohols, ketones, nitrogen-containing compounds, aromatic hydrocarbons, and furans. Aldehydes and esters were found higher amounts that other compounds in both samples. Alkylpyrazine, such as 2, 6-dimethylpyrzine, 2-ethyl-6-methylpyrazine, trimethylpyrazie, 2-ethyl-3, 5-dimethylpyrazine and tetramethylpyrazine, and also 2-phenylethanol were identified only in Koji.