• Bulletin of the Korean Chemical Society
• /
• 제35권6호
• /
• pp.1654-1658
• /
• 2014

High value-added aromatic aldehydes (e.g. vanillin and syringaldehyde) were produced from heavy fraction of bio-oil (HFBO) via catalytic oxidation. The concept is based on the use of metalloporphyin as catalyst and hydrogen peroxide ($H_2O_2$) as oxidant under alkaline condition. The biomimetic catalyst cobalt(II)-sulfonated tetraphenylporphyrin ($Co(TPPS_4)$) was prepared and characterized. It exhibited relative high activity in the catalytic oxidation of HFBO. 4.57 wt % vanillin and 1.58 wt % syringaldehyde were obtained from catalytic oxidation of HFBO, compared to 2.6 wt % vanillin and 0.86 wt % syringaldehyde without $Co(TPPS_4)$. Moreover, a possible mechanism of HFBO oxidation using $Co(TPPS_4)/H_2O_2$ was proposed by the research of model compounds. The results showed that this is a promising and environmentally friendly method for production of aromatic aldehydes from HFBO under $Co(TPPS_4)/H_2O_2$ system.

• Bulletin of the Korean Chemical Society
• /
• 제31권8호
• /
• pp.2289-2292
• /
• 2010

Long chain dicationic ammonium salts were used successfully as phase transfer catalyst in the condensation reactions of aromatic aldehydes in water under ultrasonic irradiation for the first time. The quaternary salt having longer distance between the cation centers was more effective than the mono- and dicationic ones having short chain.

• 대한화학회지
• /
• 제51권5호
• /
• pp.418-422
• /
• 2007

Sulphanilic Acid 촉매를 사용한 벤조인 또는 벤질, 초산암모늄 그리고 방향족 알데히드의 축합반응을 통한 간단하고 높은 수율의 2,4,5-Triarylimidazoles의 One-pot 합성에 대한 보고 값싼 가격의 촉매,높은 수율 그리고 짧은 반응 시간은 제시된 방법의 장점이다.

• Bulletin of the Korean Chemical Society
• /
• 제33권7호
• /
• pp.2129-2130
• /
• 2012

• Bulletin of the Korean Chemical Society
• /
• 제23권12호
• /
• pp.1697-1698
• /
• 2002

• Bulletin of the Korean Chemical Society
• /
• 제26권2호
• /
• pp.265-267
• /
• 2005

An efficient method of addition of trimethylsilyl cyanide to aldehydes by employing a zirconium complex as the catalyst has been described. A variety of aromatic, aliphatic, cyclic and heterocyclic aldehydes has been converted into corresponding trimethylsilyl ethers in excellent yield within short reaction time.

• Archives of Pharmacal Research
• /
• 제25권3호
• /
• pp.258-269
• /
• 2002

2-Thiouracil-5-sulfonylchloride 1 reacted with a series of aromatic and heterocyclic amines to give 2a-j. The same compound 1 was reacted with a series of sulphonamides giving different sulphonamides of type 3a-e. On the other hand compound 1 was allowed to react with p-aminoacetophenone givining compound 4 which in turn was allowed to react with derivatives of alkyl thiosemicarbazides to give thiosemicarbazones of type 5a-e, also compound 4 was monobrominated to give compound 6 which in turn was reacted thiosemicarbazones of some aldehydes to give the corresponding thiazole derivatives 7a-f. In the same time compound 4 was reacted with a series of aromatic and heterocyclic aldehydes givining chalcones 8a-g (Claisen-Schemidt reaction). Also compound 4 was allowed to react with a series of aromatic and heterocyclic aldehydes, ethyl cyano acetate and/or malononitrile, and ammonium acetate giving pyridine derivatives 9a-d and 10a-e respectively. The biological effects of some of the new synthesized compounds was also investigated.

• 한국식품영양학회지
• /
• 제30권1호
• /
• pp.120-128
• /
• 2017

This study aimed to provide volatile flavor compounds of three onion products through thermal process and alcohol fermentation, to meet the quality standard of onion products. The identified components of onion extracts (OE) included 49 (18 sulfur-containing compounds, 5 alcohols, 8 acids, 3 ketones, 4 esters, 4 aromatic compounds, 2 aldehydes, 1 pyrazines and 4 miscellaneous compounds), and 55 (17 sulfur-containing compounds, 15 alcohols, 5 acids, 11 ketones, 3 aromatic compounds, 2 aldehydes and 1 pyrazine) in autoclave-sterilized onion extracts (SOE); and 69 (10 sulfur-containing compounds, 27 alcohols, 11 acids, 11 ketones, 6 esters, 1 aromatic compound and 3 pyrazines) in onion wine (OW), respectively. Among the major flavor classes, sulfur-containing compounds (36.8%), acids (31.3%) and aldehydes (13.6%) in OE were changed to alcohols (46.5%) and ketones (27.3%) in SOE whereas, alcohols (56.3%) and acids (26.6%) in OW. Moreover, 1,3-butanediol, 2,3-butanediol, and 3-hydroxy-2-butanone were highly detected in SOE whereas, acetic acid, 3-methylbutanol, 2-phenylethanol and 1,2,3-propanetriol in OW.

• Bulletin of the Korean Chemical Society
• /
• 제27권8호
• /
• pp.1203-1205
• /
• 2006

During the synthesis of 4-fluorobenzaldehyde via the SNAr reaction of 4-nitrobenzaldehyde with TBAF, it was found that an equivalent amount of TBAF could oxidize benzaldehyde to benzoic acid. The reaction of 4-nitrobenzaldehyde with tetrabutylammonium fluoride (TBAF) gave 4-nitrobenzoic acid in high yield. Depending on the reaction conditions, other aromatic aldehydes produced acids with fewer amounts of alcohols. However, this type of oxidation has limited practical applications. Nevertheless, the mechanism is quite different from the Cannizzaro reaction because the amounts of the acid salt and alcohol formed were different.

• 한국식품영양과학회지
• /
• 제28권2호
• /
• pp.299-304
• /
• 1999

To compare the composition of volatile flavor components of two different types of rice, the volatile flavor concentrates isolated from brown rices Hyangnambyeo(aromatic cultivar) and Dongjinbyeo (normal cultivar) were analyzed by gas chromatography and gas chromatography mass spectrometry. A total of components, including 16 hydrocarbons, 16 aldehydes and ketones, 15 alcohols, 4 acids, and 10 miscellaneous components were identified positively or tentat ively. Among them, n pentanol was the most abundant component in both samples and Hyangnambyeo contained more aldehydes and alcohols than Dongjinbyeo. 2 Acetyl 1 pyrroline which is chiefly responsible for the character istic odor of aromatic type rice was high in Hyangnambyeo compare to Dongjinbyeo, but these were detected as minor component.