• 대한화학회지
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• 제17권3호
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• pp.174-181
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• 1973

이클로리도비스아세테이토 티탄(IV)은 알콜에 녹을 때 화학반응을 일으킨다. $TiCl_2(OAc)_2$의 이러한 가알콜분해 반응을 여러 형태의 알콜에 대하여 반응 용액의 핵자기 공명스펙트럼과 분리된 반응 생성물의 화학분석결과 등을 이용하여 완전히 구명하였다. $TiCl_2(OAc)_2$와 1급 알콜과의 반응은 다음과 같은 2단계의 리간드 치환반응이 정량적으로 일어남을 알았다. $TiCl_2(OAc)_2+ROH{\to}TiCl_2(OAc)_2(OR)+AcOH$, $TiCl_2(OAc)_2(OR)+ROH{\to}TiCl_2(OAc)_2+AcOH$ 또한 $TiCl_2(OAc)_2$가 알콜에 녹을 때 최초의 가용성 분자 형태는 $TiCl_2(OAc)(OR)$임을 알 수 있었다. 3급 알콜과의 가알콜분해 반응은 1급 알콜때와는 상당히 다름을 알 수 있었다. 즉 3급 부칠 알콜과 $TiCl_2(OAc)_2$의 몰비가 1:2이하인 경우에는 다음과 같은 치환 반응만 선택적으로 일어난다. $TiCl_2(OAc)_2+t-ButOH\toTiCl_2(OAc)_2+t-ButCl$그러나 위의 몰비가 1:2이상이 되면 이러한 반응과 병행하여 1급 알콜과의 첫단계 반응과 똑같은 형의 치환 반응이 경쟁적으로 일어남을 발견하였다. 3급 알콜과의 반응이 1급 알콜과의 반응과 또 다른 점은 $TiCl_2(OAc)_2$중의 두 개의 클로리도리간드 또는 두 개의 아세테이토리간드 중 하나만이 3급 부칠알콜의 OH또는 t-ButO기와 치환된다는 사실이다.

• 대한화학회지
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• 제16권2호
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• pp.80-83
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• 1972

The activity change of lysozyme resulted from its exposure to $Ti-H_2O_2$system in aqueous liquid at room temperature and to ${\gamma}$-irradiation in ice at $195^{\circ}K$ has been measured at room temperature with a Cary-14 spectrophotometer. The enzymatic activity of lysozyme which had been added to a previously flow-mixed solution of $TiCl_3$ and $H_2O_2$ (System I) was compared with the activity of a lysozyme-$H_2O_2$ solution after flow-mixing with $TiCl_3$ (System II), considering the differences between these two activity changes as the extent of the enzymatic inactivation by the involvement of OH radical reaction. The fraction of lysozyme inactivated by OH radical in the system containing 0.0025 M $TiCl_3-0.1M$ $H_2O_2$ (ph 3.5) was 13%, When the $TiCl_3$ concentration is double (pH 3.0), the fraction of enzyme inactivated increases to 36%. The activity of the system containing 0.025 M $TiCl_3-0.1$ M $H_2O_2$ (pH 1.5) was essentially zero. The results seem to support the previos view that the production of OH radical should be proportional to $TiCl_3$ concentration when $H_2O_2$ is present in excess. Increase in the extent of inactivation found in system I with increasing $TiCl_3$ concentration may be due to a pH effect. $H_2O_2$ seems to be less effective than $TiCl_3$ in the inactivation. 1% lysozyme solution, when ${\gamma}$-irradiated with a total dose of 3M rads, loses about 20% of its activity. Lowering of temperature also was found to yield a reduction in enzymatic activity.

• 대한화학회지
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• 제38권2호
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• pp.101-107
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• 1994

$MoCl_4(MeCN)_2$과 N, P, O주개 리간드를 반응시켜 새로운 몰리브덴(Ⅲ) 및 (Ⅳ)착물을 합성하였으며 원소분석과 적외선 및 전자 흡수스펙트럼 등을 이용하여 그 특성을 조사하였다. 사용한 리간드는 3,5-Lutidine, 1,2-phenylenediamine, 8-hydroxyquinoline, 9,10-phenanthrenequinone, triphenylphosphine 과 1,2-bis(diphenylphosphino)ethane이다. 합성된 몰리브덴(Ⅳ) 착물의 Mo-Cl 신축진동은 몰리브덴(Ⅲ)착물보다 증가한 영역에서 나타나므로, M-Cl 신축진동의 위치는 금속의 산화수에 비례한다는 사실과 잘 일치한다. 한자리 리간드의 착물에서는 Mo-Cl신축진동에 의해 강한 한 개의 흡수띠가 나타나는 반면, 두자리 리간드의 착물에서는 강한 네 개의 흡수띠가 나타나므로 이들 각각 trans($D_{4h}$)및 cis($C_{2v}$) 대칭임을 알 수 있다. 몰리브덴(Ⅲ)착물에서 acetonitrile의 C≡N 신축진동은 자유 리간드(2260 $cm^{-1}$)보다 약 30 $cm^{-1}$ 증가한 위치에서 나타나므로 이들 착물은 acetonitrile이 배위된 것을 알 수 있다. 이상의 분광학적 분석 결과를 종합해 보았을 때 $[MoCl_4(L)_2]$,[Mo$Cl_4$(L^L)], $[MoCl_3(L)_2MeCN]$ 및 [Mo$Cl_3$(L^L)MeCN]과 같은 팔면체 구조의 착물임을 알 수 있었다.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.295-300
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• 2012

Manganese ($Mn^{2+}$) is a trace element that is essential for normal physiology, and is predominantly obtained from food. Several lines of evidence, however, demonstrated that overexposure to $MnCl_2$ exerts serious neurotoxicity, immunotoxicity and developmental toxicity, particularly in male. The present study aimed to evaluate the effect of 0, 1.0, 3.3, and 10 mg/kg/day doses of $MnCl_2$ on the reproductive organs in the immature female rats. Rats (PND 22; S.D. strain) were exposed to $MnCl_2$ ($MnCl_2{\cdot}4H_2O$) dissolved in drinking water for 2 weeks. The animals were sacrificed on PND 35, then the tissues were immediately removed and weighed. Histological studies were performed using the uteri tissue samples. Serum LH and FSH levels were measured with the specific ELISA kits. Body weights of the experimental group animals were not significantly different from those of control group animals. However, ovarian tissue weights in 1 mg and 3.3 mg $MnCl_2$ dose groups were significantly lower than those of control animals (p<0.05 and p<0.01, respectively). Uterine tissue weights of 3.3 mg dose $MnCl_2$ groups were significantly lower than those of control animals (p<0.01), while the 1 mg $MnCl_2$ dose and 10 mg $MnCl_2$ dose failed to induce any change in uterine weight. Similarly, only 3.3 mg $MnCl_2$ dose could induce the significant decrease in the oviduct weight compared to the control group (p<0.05). Non-reproductive tissues such as adrenal and kidney failed to respond to all doses of $MnCl_2$ exposure. The uterine histology revealed that the $MnCl_2$ exposure could affect the myometrial cell proliferation particularly in 3.3 mg dose and 10mg dose group. Serum FSH levels were significantly decreased in 1mg $MnCl_2$ dose and 10 $MnCl_2$ mg groups (p<0.05 and p<0.01, respectively). In contrast, treatment with 1 mg $MnCl_2$ dose induced a significant increment of serum LH level (p<0.05). The present study demonstrated that $MnCl_2$ exposure is capable of inducing abnormal development of reproductive tissues, at least to some extent, and altered gonadotropin secretions in immature female rats. Combined with the well-defined actions of this metal on GnRH and prolactin secretion, one can suggest the $Mn^{2+}$ might be a potential environmental mediator which is involved in the female pubertal process.

• 대한화학회지
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• 제63권3호
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• pp.160-165
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• 2019

A series of reactions between an amino alcoholic ligand, cis-2-((2-((2-hydroxyethyl)amino)ethyl)amino)cyclohexan-1-ol (HEAC), with the mixtures of group 12 metals including, $HgCl_2/CdCl_2$, $HgCl_2/CdI_2$, $ZnCl_2/CdCl_2$ and $ZnCl_2/CdCl_2/HgCl_2$ was experimentally and theoretically studied to determine the most stable product of these reactions. Furthermore, the Cambridge Structural Database (CSD) studies were done to evaluate the theoretical results. The products were characterized by elemental analysis, FT-IR, Raman, $^1H$ NMR spectroscopy and single-crystal X-ray diffraction. Based on these investigations a binuclear structure of cadmium, [$Cd_2(HEAC)_2({\mu}-Cl)_2Cl_2$] (1), is the most stable product that was formed in all studied reactions between HEAC and metals mixtures. In this structure, the cadmium atom has a $CdN_2O({\mu}-Cl)_2Cl$ environment and distorted octahedral geometry.

• 통합자연과학논문집
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• 제4권3호
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• pp.177-181
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• 2011

The catalytic dehydrocoupling of bis(1-sila-3-butyl)benzene 1 and 2-phenyl-1,3-disilapropane 2 by $Cp_2ZrCl_2$/Red-Al and $Cp_2ZrCl_2$/n-BuLi was reported to compare their catalytic efficiency. The dehydrocoupling of monomeric silanes 1 with the $Cp_2ZrCl_2$/Red-Al and $Cp_2ZrCl_2$/n-BuLi combination catalysts produced two phases of polymers: one is a highly cross-linked insoluble solid, and the other is noncross-linked or slightly cross-linked soluble oil and could be a precursor for the solid polymer. The dehydrocoupling of 2 with the $Cp_2ZrCl_2$/n-BuLi combination catalyst similarly produced two phases of polymers. By contrast, the catalytic reaction of 2 with the $Cp_2ZrCl_2$/Red-Al combination catalyst produced a soluble polymer via redistribution/dehydrocoupling process.

• KSBB Journal
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• 제27권1호
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• pp.28-32
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• 2012

In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.395-406
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• 2014

This study provides a fundamental understanding of a cold finger melt crystallization technique by exploring the heat and mass transfer processes of cold finger separation. A series of experiments were performed using a simplified LiCl-CsCl system by varying initial CsCl concentrations (1, 3, 5, and 7.5 wt%), cold finger cooling rates (7.4, 9.8, 12.3, and 14.9 L/min), and separation times (5, 10, 15, and 30 min). Results showed a potential recycling rate of 0.36 g/min with a purity of 0.33 wt% CsCl in LiCl. A CsCl concentrated drip formation was found to decrease crystal purity especially for smaller crystal formations. Dimensionless heat and mass transfer correlations showed that separation production is primarily influenced by convective transfer controlled by cooling gas flow rate, where correlations are more accurate for slower cooling gas flow rates.

• 한국환경과학회지
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• 제11권4호
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• pp.347-353
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• 2002

본 연구의 시료는 현재 서울특별시와 수도권 도시들에서 상수원수로 이용하고 있는 한강수를 대상으로 수행되었다. 배ㆍ급수계통의 2차 소독을 위한 클로라민소독의 특성에 관하여 고찰하였으며 그 결과는 다음과 같다. 1) $25^{\circ}C$, Cl$_2$ / NH$_3$-N비 1:1 ~ 14:1에서 PH6, 7, 8의 불연속점은 각각 Cl$_2$ / NH$_3$-N비 11:1, 9:1, 10:1이었다. pH6의 경우, Cl$_2$ / NH$_3$-N비가 9:1일 때 총 잔류염소량이 최대인 반면, pH 7, 8의 경우 Cl$_2$ / NH$_3$-N비가 각각 6:1, 5:1 일 때 최대가 되었다. 2) pH가 6, 7, 8로 증가함에 따라 모노클로라민이 최대로 생성되는 Cl$_2$ / NH$_3$-N비는 7:1에서 5:1로 이동하였으며, pH6 ~ 8 범위에서 pH가 증가함에 따라 모노클로라민의 생성량이 많았다. 3) 클로라민의 분해는 Cl$_2$ / NH$_3$-N비가 증가하고 pH가 낮을수록 증가하였다. 클로라민의 잔류성은 유리염소보다 월등히 좋았다. pH6에서 모노클로라민과 디클로라민이 생성된 이후, 접촉시간이 경과함에 따라 디클로라민의 분포비가 증가하였다.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.191-199
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• 2019

We inoculated different combinations of three starter candidates, Bacillus licheniformis, Staphylococcus succinus, and Tetragenococcus halophilus, into sterilized soybeans to predict their contributions to volatile compound production through soybean fermentation. Simultaneously, we added NaCl to soybean cultures to evaluate its effect on the volatile compounds profile. Cells in soybean cultures (1.5% NaCl) nearly reached their maximum growth in a day of incubation, while cell growth was delayed by increasing NaCl concentrations in soybean cultures. The dominance of B. licheniformis and S. succinus in the mixed cultures of three starter candidates switched to T. halophilus as the NaCl concentration increased from 1.5% to 14% (w/w). Seventeen volatile compounds were detected from the control and starter candidate-inoculated soybean cultures with and without the addition of NaCl. Principal component analysis of these volatile compounds concluded that B. licheniformis and S. succinus made major contributions to producing a specific volatile compound profile from soybean cultures where both species exhibited good growth. 3-Hydroxybutan-2-one, butane-2,3-diol, and 2,3,5,6-tetramethylpyrazine are specific odor notes for B. licheniformis, and 3-methylbutyl acetate and 2-phenylethanol are specific for S. succinus. Octan-3-one and 3-methylbutan-1-ol were shown to be decisive volatile compounds for determining the involvement of S. succinus in the soybean culture containing 7% NaCl. 3-Methylbutyl acetate and 3-methylbutan-1-ol were also produced by T. halophilus during soybean fermentation at an appropriate level of NaCl. Although S. succinus and T. halophilus exhibited growth on the soybean cultures containing 14% NaCl, species-specific volatile compounds determining the directionality of the volatile compounds profile were not produced.