• 펄프종이기술
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• 제40권3호
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• pp.36-41
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• 2008

It is known that ethanolamines play a critical role for deacidification of paper sized by alum-rosin. However, amines also are effective as a chelating agent of metal. The present work was focused on whether amines could scavenge metals and prevent from the aging of paper. Metals such as alum, copper(II) and iron(III) was added to paper, and the paper treated with amines was aged in a thermo-hygrostat for 3-6 days. In the case of paper added to alum, the amines efficiency against paper aging was good in the oder of triethanolamine, diethanolamine and monoethanolamine attributable to the intensity of basicity and steric effect. Even in the case of paper treated with copper(II) chloride, iron(III) chloride, and copper(II) chloride, the significant preservation efficiency was shown by ethanolamine during accelerated aging. This outcome pinpoints the fact that ethanolamine can prevent paper aging not only from acid by neutralizing acid contained in paper but also from metals by producing of complexes with metals. These consequences above convince that ethanolamine makes it possible for mass deacidification for paper which contains acid and metals. Future studies should be conducted concerning whether, in reality, the treatment of its gas mode, in a single or multiple applications, has significant effect on lessening paper aging.

• 폴리머
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• 제37권2호
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• pp.156-161
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• 2013

페놀계 산화방지제는 가공 및 사용 시 열분해를 방지함으로써 뛰어난 열 안정성을 제공하는 대표적인 1차 산화방지제이다. 그러나 NOx 가스를 포함한 특정 환경에 의해 황변이 일어나기 쉽기 때문에 2차 산화방지제를 추가로 도입하여 시너지효과를 기대하는 경우가 많다. 열에 취약한 비결정성 폴리알파올레핀 수지(APAO)에 여러 가지 페놀계 1차 및 2차 산화방지제를 도입하여 황변 여부를 조사한 결과 2차 산화방지제의 함량이 증가할수록 황변이 줄어들었으며 BHT와 같은 단순 구조의 폐놀계 산화방지제보다 긴 알킬 사슬을 도입시켜 입체장애효과를 증대시킨 산화방지제가 2차 산화방지제와의 시너지 효과가 더 큰 것으로 확인되었다.

• 한국환경과학회지
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• 제24권8호
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• pp.981-992
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• 2015

This study is mainly focused on micellar effect of tetradecyltrimethyl ammonium bromide(TTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). Dephosphorylation of DPNPIN is accelerated by $BI^{\Theta}$ ion in $10^2$ M Carbonate buffer(pH 10.7) of $4{\times}10^{-4}$ M TTABr solution up to 80 times as compared with the reaction in Carbonate buffer by no benzimidazole(BI) solution of TTABr. The value of pseudo first order rate constant($k_{\psi}$) of the reaction in TTABr solution reached a maximum rate constant increasing micelle concentration. The reaction mediated by $R-BI^{\Theta}$ in micellar solutions are obviously slower than those by $BI^{\Theta}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of $R-BI^{\Theta}$ in Stern layer of micellar solution. The surfactant reagent, TTABr, strongly catalyzes the reaction of DPNPIN with R-BI and its anion($R-BI^{\Theta}$) in Carbonate buffer(pH 10.7). For example, $4{\times}10^{-4}$ M TTABr in $1{\times}10^{-4}$ M BI solution increase the rate constant($k_{\psi}=99.7{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 28, when compared with reaction($k_{\psi}=3.5{\times}10^{-4}1/sec$) in BI solution(without TTABr). And no TTABr solution, in BI solution increase the rate constant($k_{\psi}=3.5{\times}10^{-4}1/sec$) of the dephosphorylation by a factor ca. 39, when compared with reaction ($k_{\psi}=1.0{\times}10^{-5}1/sec$) in water solution(without BI).

• 약학회지
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• 제36권6호
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• pp.518-528
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• 1992

To determine the optimal conformation of sulfonylureas, the correlation between conformation and hypoglycemic activity of the two sulfonylureas of tolbutamide and chlorpropamide as hypoglycemic agent was studied using an empirical potential function (ECEPP/2) and the hydration shell model in the unhydrated and hydrated states. The conformational energy was minimized from several starting conformations with possible torsion angles in each molecule. The conformational entropy change of each conformation was computed using a harmonic approximation. To understand the hydration effect on the conformation of the molecules in aqueous solution, the contribution of water-accessible volume of each group or atom in the lowest-free-energy conformation was calculated and compared each other. From comparison of the computed lowest-free-energy conformations of two sulfonylureas, it could be suggested that the hydration of sulfonylurea moiety is related to increase the hypoglycemic activity. From the calculation results, it was known that the conformational entropy is the major contribution to stabilize the low-free-energy conformations of two sulfonylureas in unhydrated state. Whereas, in hydrated state, the hydration free energy largely contributes to the total free energies of low-free-energy conformations of tolbutamide and conformational entropy contributes to stabilize the low-free-energy conformations of chlorpropamide. The torsion angles from phenyl ring to urea moiety of the low-free-energy conformations of the two sulfonylureas were shown the nearly regular trend. On the basis of these results, the conformation exhibiting the optimal hypoglycemic activity of sulfonylureas and the binding direction to pancreatic receptor site A could be predicted. Also, according to the side chain lengthening of urea moiety, tolbutamide showed various conformational change. Therefore, steric effect may be important factor in the interaction between sulfonylureas and the putative pancreatic receptor.

• 한국진공학회지
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• 제18권6호
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• pp.453-458
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• 2009

SiOC 박막을 BTMSM과 산소의 혼합가스를 사용하여 CVD 방법으로 증착하였다. 박막의 특성은 가스 유량비에 따라서 변하였다. 유전상수는 MIS 구조를 이용하여 C-V 측정법에 의하여 얻었다. 결합의 말단을 구성하는 Si-$CH_3$ 결합 사이의 공간효과에 의해서 기공이 만들어지며, 기공의 형성에 의해서 박막의 두께가 증가하였다. 그러나 분극의 감소에 의해서 만들어지는 SiOC 박막은 두께가 감소하면서 유전상수도 감소되었다. 열처리 후 유전상수는 수산기의 기화에 의해서 감소되었다. 박막의 두께는 분극의 감소에 의한 유전상수의 감소와 연관이 있었다. 굴절률은 박막의 두께에 반비례하는 경향성이 있으며, 박막의 두께와 굴절률의 경향성은 열처리 후에도 변하지 않았다.

• Applied Biological Chemistry
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• 제37권6호
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• pp.516-521
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• 1994

새로운 17종의 imazapyr 유도체인 3-(N-methyl-N(X)-치환-phenylaminooxoacetyl)-2-(4-isopropyl-5-oxo-2-imidazoline-2-yl)pyridine, 6을 합성하고 3-(N-methyl-N(X)-치환-phenylaminooxoacetyl group중의 X-치환기 변화에 따른 구조와 옥수수(Zea mays L.)와 참비듬(Amaranthus viridis L.)에 대한 발아 전의 제초활성에 미치는 관계(SAR)를 검토 한 바, 옥수수의 경우에는 MR상수의 적정값(optimal value)이 $5.56\;cm^3/mol$이었으므로 이 값보다 크거나 작을수록 제초활성이 작았다. 참비듬의 경우에는 $L_1$상수의 적정값이 3.34 A이므로 이 값에 가까울수록 제초활성이 클 것임을 알 수 있었다. 특히, 2,5-difluoro group 치환체, 6i는 참비듬에 가장 큰 제초활성을 나타내었으나 옥수수에는 가장 작은 제초활성을 미치므로써 현저하게 두 초종간에 선택성을 나타내는 화합물이었다.

• Applied Biological Chemistry
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• 제42권3호
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• pp.252-255
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• 1999

Chalcones 유도체들을 합성하고 farnesyl protein transferase(FPTase) 저해활성을 측정하여, 기질분자의 치환기 변화에 따른 구조와 활성과의관계(SAR)를 Free-Wilson법과 Hansch법으로 검토하였다. Benzoyl group 중 X-치환기가 styryl중 Y-치환기보다 활성에 더욱 큰 영향을 미쳤으며 meta- > ortho-, para-치환기의 순으로 활성을 나타내었다. 또한, X및 Y-치환기의 소수성이 적정값$(({\Sigma}logP)_{opt}\;=\;3.915)$에 근접할수록 활성이 증가 하였으며, X-치환기의 입체효과와(Es > O) 전자밀게 Y-치환기에 의한 공명효과(R < O)가 활성에 미치는 중요한 요소로 인식되었다. 다루어진 화합물중에서 비 치환체, 8은 가장 높은 FPTase저해활성$(pl_{50}\;=\;4.30)$을 나타내었다. 그리고 기질 수용체간의 상호작용을 가정하여 제안하였다.

• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1339-1343
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• 2005

The N-inversion energies and nucleophilic ring-opening reactions of N-substituted aziridine compounds are investigated using B3LYP/6-31+$G^*$ methods, where substituents (R) on the nitrogen atom has been H (1), Me (2), Ph (3), Bn (4), CHMePh (5), $CO_2Me$ (6), COPh (7) and $SO_2Ph$ (8). The N-inversion energy with X group are decreased as the following order: R = CHMePh (17.06 kcal/mol) $\gt$ Me (16.97) $\gt$ Bn (16.70) $\gt$ H (16.64) $\gt$ $SO_2Ph$ (12.18) $\gt$ Ph (8.91) $\gt$ COPh (5.75) $\gt$ $CO_2Me$ (5.48). For reactivity of the ring opening toward cyanide ion, the aziridine 6 (R=$CO_2Me$) is shown to be the most reactive one. During the ring opening of aziridine 6 by CN$^{\ominus}$, the torsional OCNC angle becomes near to $180^{\circ}$, where the geometry allows for the effective incorporation of electrons of the nitrogen atom to the C=O bond. It would be a possible driving force for nucleophilic ring opening reaction as well as decreasing the N-inversion energy barrier. Regarding to the regioselectivity, the orientation of nucleophile in ring opening reaction appears to be different in the case of 9 and 10. The results are discussed in terms of steric/electronic effect of the $C_2$-substituents.

• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1405-1408
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• 2001

Ca salt of soybean oil (PSO) and that of mustard oil plus mahua oil (PMOMO) (50:50) were prepared using double decomposition method, and further tested for their fatty acid composition and degree of saponification. Furthermore, the different levels of protected fat of PSO and PMOMO were evaluated in wheat straw based total mixed ration (TMR) in vitro. Results indicated that capric, lauric, myristic, palmitic, steric, oleic, linoleic, leinolenic acids were traces, traces, traces, 10.00, 2.00, 25.00, 58.50, 5.0% in PSO while the corresponding values in PMOMO were 1.08, 0.28, 0.45, 16.9, 12.95, 44.38, 17.46 and 6.50%, respectively. The degree of saponification of both protected fat supplements was more than 80%. Six treatment combinations were tested I.e., blank without feed and fat supplement (T1); control diet with out fat supplement (T2); control diet plus bypass fat supplement (PSO) so that diet contain 5% fat (T3); control diet plus bypass fat supplement (PSO) so that diet contain 7.5% fat (T4); two more diets viz. T5 and T6 were formulated using bypass fat supplement from PMOMO containing 5 and 7.5% fat respectively. TMR was prepared using 50% concentrate mixture and 50% wheat straw. Result indicated that TVFA, $NH_3-N$,TCA-N, total-N and total gas production were increased in treatment diets at 7.5% level of supplementation, however, fermentation pattern remain similar at 5.0% level of supplementation with respect to control diet. Nevertheless, IVDMD and IVOMD values remained unchanged, rather non-significant at both fat levels and with the both fat sources. On the basis of results it was concluded that Ca-salt of Soybean oil or Mustard plus Mahua oil did not show any negative effect either on digestibility or on microbial protein synthesis in rumen, hence the dietary fat upto 7.5% level in total mixed ration based on wheat straw, could be safely used without any adverse effect on rumen fermentation.

• 전기화학회지
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• 제16권4호
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• pp.198-203
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• 2013

본 실험에서는 MMA와 tBMA의 공중합체를 합성하고, tert-butyl 그룹의 가수분해를 선택적으로 유도하여 poly(MMA-co-MA)를 제조하였다. 또한 말단에 에폭시기를 함유한 다양한 분자량의 PEO와 MA와의 grafting-onto 커플링 반응을 통해 같은 주사슬을 가지지만 부사슬의 길이가 다른 poly(MMA-co-PEGMA)를 합성하여 조성이 이온전도도에 미치는 영향을 평가하였다. AC-impedance로 측정한 상온 이온전도도는 MMA의 몰분율이 82%에서 $5.11{\times}10^{-8}Scm^{-1}$의 값이 얻어진 반면, 48%에서는 $1.88{\times}10^{-6}Scm^{-1}$로서 많은 PEGMA에서 높게 관찰되었다. 또한 에폭시기를 함유한 PEO의 분자량에 따라 이온전도도의 차이가 발생하는데, grafting-onto 법의 입체적 장애가 원인으로 고려되었다. 한편, 합성된 poly(MMA-co-PEGMA) 고분자 전해질은 상온에서 6V까지 우수한 전기화학적 안정성을 보여주었다.