• Bulletin of the Korean Chemical Society
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• 제17권8호
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• pp.720-724
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• 1996

Catecholalane (1,3,2-Benzodioxaluminole, CA) prepared from catechol and aluminum hydride in tetrahydrofuran (THF) is found to be a selective reducing agent. The systematic study in order to characterize the reducing properties of the reagent under practical conditions (THF, 0 or 25 ℃, the quantitative amount of reagent to compound) has been done. The reagent reduces aldehydes, ketones, esters and acid chlorides to the corresponding alcohols, and primary amides to the corresponding amines. Especially noteworthy is that the reagent can convert both aromatic and aliphatic nitriles to the corresponding aldehydes in very high yields.

• 폴리머
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• 제29권6호
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• pp.571-574
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• 2005

[ $\AB_{2}$ ]형 단량체인 5-aminoisophthalic acid로부터 TPP를 촉매를 이용한 축중합 반응을 통하여 고차가지구조 방향족 폴리아미드를 합성하였다. 합성된 고차가지구조 고분자의 카복시 말단을 에탄올, 헥산올, 도데칸올로 에스테르화 하여 특성을 연구하였다. 카복시 말단의 고차가지구조 고분자에 비해 알킬기가 치환된 고차가지구조 고분자의 용해도가 증가하였다. 또한 말단의 알킬기의 길이가 길어짐에 따라 10wt$\%$ 무게 감소 온도가 감소하였다.

• Archives of Pharmacal Research
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• 제7권1호
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• pp.1-9
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• 1984

Polyethylene glycol 20, 000 and 6, 000 were found to have an upper consolute temperature, called "cloud point", and the effects of various additives on the polythylene glycols were investigated in this study. Electrolytes lowered the cloud point in proportion to their concentrations through dehydration and electrostriction. It was found that anions played a more important role than cations and the effects of both the cations and the anions clearly followed the classical Hofmeister series. However, the Schultze Hardy rule holds for the effect of anions, and fails for the effect of cations. Salts of large polarizable anions such as iodide and thiocynate rather raised the cloud point, and their effects were ascribed to the fact that they break the water structure and weaken hydrophobic bonding of the polyxyethylene moiety. Nitrates of polyvalent cations also raised the cloud point. This was ascribed to the complex formation between the polyvalent cations and ether oxygens of the polyoxyethylenes. This explained the failure 'of the Schultz-Hardy rule for cations. Uncharged aromatic compounds drastically lowered the clound point, while aliphatic alcohols slightly lowered the cloud point, This result suggests that there might be some interaction between ether oxygens and aromatic nucleus.c nucleus.

• 대한화학회지
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• 제45권1호
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• pp.51-60
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• 2001

치환된 하이드록시 방향족 화합물과 이차아민, paraformaldehyde를 비 양성자성 용매하에서 one-pot으로 반응시켜 기질에 따른 상대적인 반응성을 비교하였으며, Mannich반응이 일어난 자리도 조사하였다. 치환된 하이드록시 방향족 고리의 Mannich반응의 반응성과 위치선댁성은 기질의 친핵성도와 아민의 입체장애에 의존함을 알 수 있었다.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.125-132
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• 2022

There are many types of spring blossoms on the Daedeok campus of Chungnam National University (CNU) at the area of 1,600,000 square meters. As an assignment for the class of Analytical Chemistry I for second-year undergraduate students, 2021, flower petals collected from various floral groups (Korean azalea, Korean forsythia, Dilatata lilac, Lilytree, Lily magnolia, and Prunus yedoensis) were analyzed using headspace extraction coupled to gas chromatography-mass spectrometry (HS-GC-MS) to study the aromatic profiles and fragrance compounds of each sample group. Various types of compounds associated with the aroma profiles were detected, including saturated alcohols and aldehydes (ethanol, 1-hexanol, and nonanal), terpenes (limonene, pinene, and ocimene), and aromatic compounds (benzyl alcohol, benzaldehyde). The different contribution of these compounds for each floral type was visualized using statistical tools and classification models based on principal component analysis with high reliability (R² = 0.824, Q² = 0.616). These results showed that HS-GC-MS with statistical analysis is a powerful method to characterize the volatile aromatic profile of biological specimens.

• Bulletin of the Korean Chemical Society
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• 제15권10호
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• pp.873-881
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• 1994

The approximate rate and stoichiometry of the reaction of excess diisobutylaluminum hydride-dimethyl sulfide complex($DIBAH-SMe_2$) with organic compounds containing representative functional group under standardized conditions (toluene, $0{\circ}C$) were examined in order to define the reducing characterstics of the reagent and to compare the reducing power with DIBAH itself. In general, the reducing action of the complex is similar to that of DIBAH. However, the reducing power of the complex is weaker than that of DIBAH. All of the active hydrogen compounds including alcohols, amines, and thiols evolve hydrogen slowly. Aldehydes and ketones are reduced readily and quantitatively to give the corresponding alcohols. However, $DIBAH-SMe_2$ reduces carboxylic acids at a faster rate than DIBAH alone to the corresponding alcohols with a partial evolution of hydrogen. Similarly, acid chlorides, esters, and epoxides are readily reduced to the corresponding alcohols, but the reduction rate is much slower than that of DIBAH alone. Both primary aliphatic and aromatic amides examined evolve 1 equiv of hydrogen rapidly and are reduced slowly to the amines. Tertiary amides readily utilize 2 equiv of hydride for reduction. Nitriles consume 1 equiv of hydride rapidly but further hydride uptake is quite slow. Nitro compounds, azobenzene, and azoxybenzene are reduced moderately. Cyclohexanone oxime liberates ca. 0.8 equiv of hydrogen rapidly and is reduced to the N-hydroxylamine stage. Phenyl isocyanate is rapidly reduced to the imine stage, but further hydride uptake is quite sluggish. Pyridine reacts at a moderate rate with an uptake of one hydride in 48 h, while pyridine N-oxide reacts rapidly with consumption of 2 equiv of hydride for reduction in 6h. Similarly, disulfides and sulfoxide are readily reduced, whereas sulfide, sulfone, and sulfonic acid are inert to this reagent under these reaction conditions.

• 생명과학회지
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• 제21권2호
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• pp.292-299
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• 2011

식초는 동서양의 대표적인 발효식품으로 조미용뿐만 아니라 건강기능식품 음료로써 잠재력을 가진 식품으로, 다양한 종류의 식초음료가 요구되고 있다. 따라서 본 연구는 시판 수입산 식초음료 3종(이탈리아산 발사믹식초음료-IVB, 일본산 포도블루베리식초음료-JVB, 일본산 유자폰즈-JYP) 및 국내산 1종(백포도식초음료-KWVB)의 휘발성 향기성분을 비교하여 다양한 식초음료개발에 대한 기초자료를 제시하고자 하였다. 분석결과 IVB 경우 총 62종의 화합물(산류 11종, 에스테르류 17종, 알콜류 10종, 알데히드류 8종, 테르펜류 3종, 방향족화합물 4종 및 케톤류 9종)이 검출되었다. 휘발성 화합물의 조성비율을 본다면 산류(61.3%), 에스테르류(11.7%) 및 케톤류(10.7%)가 대부분의 함량을 차지하였다. JVB는 총 55종 화합물(산류 7종, 에스테르류 8종, 알콜류 9종, 알데히드류 7종, 테르펜류 13종, 방향족화합물 7종, 케톤류 1종 및 기타 3종)로 산류 56.3%, 케톤류 15.7% 및 에스테르 8.97%로 IVB에 비해 전반적인 함량은 낮으나 유사한 조성비율 나타내었다. JYP의 경우 총 106종 화합물(산류 3종, 에스테르류 12종, 알콜류 8종, 알데히드류 7종, 테르펜류 63종, 방향족화합물 6종, 케톤류 2종 및 기타 5종)이 검출되었다. 휘발성 화합물의 조성비율을 본다면 유자로부터 기인되는 테르펜류화합물(79.6%)이 대부분의 함량을 나타내었다. KWV의 경우는 총 50종의 화합물(산류 10종, 에스테르류 10종, 알콜류 9, 알데히드류 8종, 테르펜류 2종, 방향족화합물 5종, 케톤류 4종 및 기타 2종)으로 산류 81% 및 케톤류 9.0%가 대부분의 함량을 나타내었다. KWVB 경우 다른 식초음료에 비해 산류의 함량이 높으나 다른 화합물의 함량은 낮고 조성비율도 낮게 나타났다. 와인을 원료하여 제조된 basamic식초음료에는 5가지 휘발성 향기성분인, 2-phenylethyl acetate (꽃향, 과일향), 2-phenylethanol (장미향), vitispirane (과일향), geranylacetone (fragrant향) 및 acetic acid가 주된 휘발성 향기성분으로 검출되었다.

• 한국수산과학회지
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• 제39권6호
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• pp.437-440
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• 2006

To develop natural crab-like flavorants from red snow crab Chionoecetes japonicus cooker effluent (RSCCE), the flavor was analyzed during the concentration of RSCCE up to $40^{\circ}Brix$. Using solid phase microextraction (SPME)/gas chromatography (GC)/mass selective detection (MSD), 30 volatile flavor compounds were detected in four RSCCE samples (10, 20, 30, and $40^{\circ}Brix$). These comprised 12 aromatic compounds, 5 N-containing compounds, 2 5-containing compounds, 2 alcohols, 2 aldehydes, and 7 miscellaneous compounds. The amounts of all volatiles except alcohols and aldehydes increased significantly with the concentration (p<0.05). Of the volatiles detected, the most abundant was a dimethyl trisulfide with an odor like onion/cooked cabbage. Of the N-containing compounds (nutty, roasted peanut-like odor), 2-ethyl-5-methylpyrazine was the most abundant, followed by 2,5-dimethylpyrazine and 2-methyl-5-isopropylpyrazine in that order (p<0.05). The N- and S-containing compounds with characteristic odors detected in this experiment are thought to play a positive role in RSCCE during concentration.

• 한국축산식품학회지
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• 제37권4호
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• pp.606-616
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• 2017

The objective of this research was to investigate the effects microbial transglutaminase (mTGs) on the physicochemical, microbial and sensory properties of kefir produced by using mix cow and soymilk. Kefir batches were prepared using 0, 0.5, 1 and 1.5 Units m-TGs for per g of milk protein. Adding m-TGs to milk caused an increase in the pH and viscosity and caused a decrease in titratable acidity and syneresis in the kefir samples. Total bacteria, lactobacilli and streptococci counts decreased, while yeast counts increased in all the samples during storage. Alcohols and acids compounds have increased in all the samples except in the control samples, while carbonyl compounds have decreased in all the samples during storage (1-30 d). The differences in the percentage of alcohols, carbonyl compounds and acids in total volatiles on the 1st and the 30th d of storage were observed at 8.47-23.52%, 6.94-25.46% and 59.64-63.69%, respectively. The consumer evaluation of the kefir samples showed that greater levels of acceptability were found for samples which had been added 1.5 U m-TGs for per g of milk protein.

• 한국식품영양과학회지
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• 제26권2호
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• pp.222-228
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• 1997

전라남도 지방의 전통수산발효식품인 토하젓을 현대기호에 맞는 지역특산품으로 발전시킴과 동시에 품질표준화 및 고급화를 유도하기 위해 현재, 유통되고 있는 2종류의 시료, 즉 담금직후 및 90일간 저온$(5{\pm}2^{\circ}C)$에서 숙성발효시킨 토하젓을 구입하여 휘발성 향기성분을 분석한 결과, 2시료에서 총 104종의 화합물이 동정되었으며, 이중에서 담금직후의 토하젓에서 70종, 숙성된 토하젓에서는 68종이 검출되었다. 내부표준물질(TMP)에 대한 각 화합물의 상대적 면적비로 환산하였을 경우, 담금직후의 토하젓에는 함황화합물, terpene류, alcohol류 및 ester류 화합물 순으로 그 양이 많았으며, 숙성된 토하젓은 alcohol류, 함황화합물, terpene류 및 ester류 화합물 순으로 많이 함유되어 있었다. 또한 숙성된 토하젓은 담금직후의 토하젓에 비해 alcohol류, ketone류 (및 방향족 화합물의 양이 많았고, aldehyde류, terpene류, 함황화합물 및 ester류 화합물은 적었다. 특히 alcohol류의 경우, 숙성된 토하젓이 당금직후의 토하젓에 비해 약 21배 정도 많았는데, 이는 발효과정 중 당의 분해로 인해 생성된 ethanol의 양이 증가한데서 기인되었다. 한편 토하젓의 특이한 제조방법에 따라 첨가된 부원료의 영향으로 인해 2종류의 시료 모두 생강의 향기성분인 terpene류, 마늘의 향기성분인 함황화합물, ester류의 양이 많았는데, 이들 휘발성 성분들과 발효 중 증가한 ethanol이 어우러져 시판 토하젓에 독특한 풍미를 부여하는 것으로 확인되었다.