• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.199-204
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• 2001

A Cryptate (221) having a short alcohol pendant (2) was metallated with europium(Ⅲ) in anhydrous condition, and its hydrolytic activity for phosphate esters at neutral pH was examined. While the activity for the phosphate diester and monoester is comparable to that of the parent metal complex [1Eu]3+, its hydrolytic activity towards a phosphate triester is significantly suppressed. Potentiometric titration and luminescence spectroscopic studies for the equilibrium behavior of the complex in solution suggest that a dimer formation through the metal hydroxides as well as the pendant alcohol is likely to happen. The low hydrolytic activity for the triester seems to be associated with the dimer formation.

• Elastomers and Composites
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• 제49권4호
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• pp.313-322
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• 2014

난연제 가운데 가장 많이 사용되는 할로겐 함유 난연제는 사용상 환경적인 제한을 받고 있어서 비할로겐타입인 인계에 기초한 난연제가 각광을 받고 있다. 난연제는 수지에 가해지는 경우에 흔히 열분해와 기계적 특성저하를 일으킨다. 물성의 열화를 최소화하고 충분한 난연성을 얻기 위한 시도로 새로운 난연제에 대한 연구를 수행하였다. 본 연구에 있어서는 diaryl alkyl phosphate esters, aromatic phosphate esters 및 phosphonium nitron 난연제 등 세가지 형태의 비할로겐 인계에 기초한 난연제를 합성하여 GC, IR 및 TGA 등으로 합성 및 열적 특성을 확인하였다.

• Tribology and Lubricants
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• 제11권5호
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• pp.177-183
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• 1995

Recent work with phosphate esters has shown that a lubricious polymeric film can formed from the vapor phase on interacting during and sliding. This lubrication technique has led to methods to reduce friction and wear to very low values at high temperatures up to 700$^{\circ}$C. Preliminary with synthetic tri aryl phosphates are very promising. The vaporized lubricant forms a polymeric film on the sliding and rolling surfaces reducing the coefficient of friction below 0.05. In-situ formation of the polymeric films shows that the polymer that is formed on the surface exists in different states depending on surface temperature.

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.491-493
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• 1999

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.2037-2039
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• 2012

• 공업화학
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• 제4권3호
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• pp.474-481
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• 1993

무극성, 극성 용매 중 무극성, 극성용질의 무한희석 활동도계수를 가스 크로마토그래피에 의하여 $60^{\circ}C$로부터 $100^{\circ}C$ 범위에서 측정하였다. 무극성용매(n-octadecane)와 극성용매(n-hexadecyl alcohol)에 있어서 무극성용질(alkanes, cyclohexane, benzene, toluene과 $CCl_4$)의 $ln{\gamma}{\infty}$는 1/T 따라 비례하여 증가하였으며, 일정온도에서 동족렬의 $ln{\gamma}{\infty}$는 용질의 탄소수 증가에 따라 비례하여 증가하였다. 극성용질(alcohols, esters and ketones)과 약극성용매(di-2-ethyl adiphate and di-2-ethylhexylsebacate)계에서, 용질의 $ln{\gamma}{\infty}$는 1/T 증가에 따라 변화율이 증가하였으며, 또 일정온도에서 동족렬 용질의 $ln{\gamma}{\infty}$는 탄소수 증가에 따라 반비례하여 감소하였다. 극성용질(alcohols, esters and ketones)은 극성이 큰 용매(triphenyl-phosphate and tricresyl phosphate)계에 있어서, $ln{\gamma}{\infty}$는 1/T 증가에 따라 변화율이 증가하였으며, 일정온도에서 동족렬의 $ln{\gamma}{\infty}$는 용질의 탄소수 증가에 따라 비례하여 증가하였다.

• Bulletin of the Korean Chemical Society
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• 제16권10호
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• pp.938-945
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• 1995

Hydrolysis of p-nitrophenyl acetate (PNPA) and p-nitrophenyldiphenyl phosphate (PNPDPP) by N-chloro compounds in micellar solution were studied. N,N'-dichloroisocyanuric acid sodium salt (DCI) in cetyltrimethylammonium chloride (CTACl) micellar solution gave pseudo first-order kinetics. But, DCI in cetyltrimethylammonium bromide (CTABr) micellar solution showed typical series first-order kinetics - fast hydrolysis of the esters and concomitant slow decay of the hydrolyzed product, p-nitrophenolate. The hydrolysis rate was decreased as the hydrophobicity of N-chloro compounds was increased, which is the opposite trend to the usual bimolecular micellar reaction. This curious behavior of the N-chloro compounds in the catalytic hydrolysis of PNPA and PNPDPP in a cationic micellar system can be best explained by participation of counter ions of the surfactants during hydrolysis.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.594-598
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• 2005

Treatment of a solution of $CuCl_2$ in dimethyl phosphate (DMP) with DMSO under nitrogen atmosphere afforded to a light blue fluorescence powder. Slow evaporation of $H_2O$-DMSO solution of this powder resulted in blue-sky crystals of a new polymeric Cu(II) complex, with a unit cell composed of $Cu_2(DMP)_4$(DMSO), (1). The crystal and molecular structure of the complex acquired crystallographically. Compound (1) crystallizes in the monoclinic space group $P2_1$/n with a = 12.8920(11) $\AA$, b = 13.1966(11) $\AA$, c = 14.7926(13) $\AA$, $\alpha$ = 90$^{\circ}$, $\beta$ = 98.943(2)$^{\circ}$, $\gamma$ = 90$^{\circ}$, V= 2486.1(4) ${\AA}^3$, and Z = 4. A square pyramidal environment for the metal center was established by coordination of oxygen atoms of four bridging DMP ligands in the basal positions and binding a tri-centered oxygen atom of DMSO in the apical disposition of Cu(II). The sixth position was also affected by a weak interaction with the sulfur atom of another DMSO. The phosphorous atom in the bridging DMP was arranged in a deformed tetrahedron with (gg) conformation for methyl esters with $C_{2v}$ symmetry.

• Asian-Australasian Journal of Animal Sciences
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• 제20권1호
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• pp.36-40
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• 2007

Proteins and lipids not only provide a source of energy to the cell, but also play vital roles in modifying the physical properties and function of the biological membranes. In the present study, we investigated the biochemical constituents, viz. proteins and lipids, in growing oocytes of goat antral follicles during summer and winter seasons. Goat genitalia in phosphate buffered saline (pH 7.4) were brought to the laboratory within one hour of slaughter under aseptic conditions at $37^{\circ}C$. Oocytes were aspirated from normal small (<3 mm in diameter) and large (>3 mm) follicles and pooled for biochemical estimations. A significant increase in the amount of protein and lipid was observed with the growth of the oocyte. The amount of protein varied non-significantly with the season, while the amount of lipid varied significantly. The amounts of phospholipid, cholesterol, free fatty acid, and triglyceride increased with the growth of the oocyte, but no significant effect of season in these constituents was observed. Lysolecithin, sphingomyelin, and sterols were the polar lipids identified in both oocytes prepared from small follicles (small oocytes) as well as large follicles (large oocytes). In addition, the small oocytes also contained phosphatidyl serine, while large oocytes contained phosphatidyl glycerol phosphate and phosphatidyl inositol. Among non-polar lipids, triglycerides and long chain alcohols appear only in small oocytes and not in large oocytes. Monoglycerides, 1,2-diglycerides, 1,3-diglycerides and o-dialkyl glycerol ethers, fatty acids, fatty acid methyl esters, and wax esters were identified in both small and large oocytes. Information on biochemical composition of growing oocytes is relevant to oocyte and embryo competence, culture and cryopreservation.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2003년도 제2차 연례학술대회 발표논문집
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• pp.5-5
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• 2003

The purple acid phosphatases comprise a family of binuclear metal-containing enzymes. The metal centre contains one ferric ion and one divalent metal ion. Spectroscopic studies of the monomeric, ${\sim}$36 kDa mammalian purple acid phosphatases reveal the presence of an Fe(III)Fe(II) centre in which the metals are weakly antiferromagnetically coupled, whereas the dimeric, ${\sim}$110 000 kDa plant enzymes contain either Fe(III)Zn(II) or Fe(III)Mn(II). The three dimensional structures of the red kidney bean and pig enzymes show very similar arrangements of the metal ligands but some significant differences beyond the immediate vicinity of the metals. In addition to the catalytic domain, the plant enzyme contains a second domain of unknown function. A search of sequence databases was undertaken using a sequence pattern which includes the conserved metal-binding residues in the plant and animal enzymes. The search revealed the presence in plants of a 'mammalian-type' low molecular weight purple acid phosphatase, a high molecular weight form in some fungi, and a homologue in some bacteria. The catalytic mechanism of the enzyme has been investigated with a view to understanding the marked difference in specificity between the Fe-Mn sweet potato enzyme, which exhibits highly efficient catalysis towards both activated and unactivated phosphate esters, and other PAPs, which hydrolyse only activated esters. Comparison of the active site structures of the enzymes reveal some interesting differences between them which may account for the difference. The implications fur understanding the physiological functions of the enzymes will be discussed.