• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2000년도 춘계총회 및 학술발표회
• /
• pp.36-36
• /
• 2000

• Archives of Pharmacal Research
• /
• 제15권4호
• /
• pp.304-308
• /
• 1992

The alkylation of resorcinol with cyclic allylic alcohol in non-aqueous acid medium gives intermolecular Friedel-Craft compounds. The products are primary alkylation products. The likage always occurs between carbon 3 of cyclic allylic alcohol and the position 2, 4, 5 or 6 of the resorcinol.

• Bulletin of the Korean Chemical Society
• /
• 제24권7호
• /
• pp.1032-1034
• /
• 2003

• Bulletin of the Korean Chemical Society
• /
• 제33권12호
• /
• pp.4188-4190
• /
• 2012

• 공업화학
• /
• 제16권5호
• /
• pp.684-688
• /
• 2005

산도가 각기 다른 양성자산(HF, HCI, HBr, HI, $H_2SO_4$)의 수용액내에서 아닐린을 중합하였다. 이때 산도(pH)와 상대이온(counter ion)의 반응성에 따른 반응속도에 관하여 조사하였다. 반응속도에 대한 양성자산의 영향을 조사하기 위하여, open-circuit potential을 측정하였다. 그 결과 HF 수용액내에서 중합속도가 가장 느리게 나타났고, HI 수용액내에서는 중합반응이 진행되지 않았으며, 이러한 결과들을 산도(pH)와 산화력과의 관계로 설명하였다. 양성자산의 종류에 따라 dimer들의 생성비율도 각기 다르게 나타났으며, 이러한 결과들을 상대이온(음이온)의 친핵성도 (nucleophilicity), 용매화효과 및 이동도의 영향으로 설명하였다.

• Bulletin of the Korean Chemical Society
• /
• 제23권1호
• /
• pp.123-131
• /
• 2002

Solvolyses rate constant of 1- and 2- naphthoyl chlorides (1 and 2) are reported for aqueous binary mixtures with methanol, ethanol, fluorinated alcohol, acetonitrile and dioxane. Kinetic solvent isotope effects (KISE) in methanol and product selectivities (S) of 2-naphthoyl chloride (2) in alcohol-water are also reported. Dispersions in Grunwald-Winstein correlations $(r{\leq}0.901)$ are discussed by multiple regression analysis incorporating ionizing power $(Y_{Cl})$ scale and rate-rate profiles. Major causes for these phenomena are investigated as an aromatic ring solvation effects, in conjunction with weakly nucleophilic solvation effects ($S_N2$ character), for solvolyses of 1 and for solvolyses of 2, as dual reaction channels, described as $S_N1$-$S_N2$ and $S_AN$-$S_N2$ processes. Distinct border lines between the two pathways are derived from solvolyses rates of 2 in 18 solvent using the results of $log(k/k_o)=mY_{Cl}+lN_T+hI$ plot with values of 1.13 for m, 0.37 for l and 0.15 for h value in 5 aqueous fluorinated alcohol mixtures. Using rate-product correlation, the validity of a third order model based on a general base catalyzed by solvent and contribution from these rate constants, $k_{aa},\;k_{aw}$ and $k_{aw}$, are investigated for $S_AN$-$S_N2$ solvolyses of 2 favored in more rich alcohol media and gradual addition of water to alcohol solvent shows a great shift away from stoichiometric solvation to predominantly medium effects. Rate-rate correlation between solvolyses of 2 and trimethyl acetylchloride (5) with alkyl group in the 29 aqueous solvent mixtures shows appreciable linearity (slope = 0.84, r = 0.987), caused by the same pathway ($S_N1$-$S_N2$ process), even if this correlation coincides with appreciable dispersion (different solvation effect).

• 분석과학
• /
• 제5권1호
• /
• pp.1-5
• /
• 1992

Amberlite XAD 고분자수지 및 고분자수지 대체흡착제인 rice bran, rice straw 그리고 sawdust에 대한 petroleum oil의 흡착량을 최저 흡착조건에서 뱃치법으로 측정하여 조사하였다. Rice bran과 rice straw에 대한 petroleum oil의 흡착량은 XAD계열수지의 흡착량의 약 50% 정도로 흡착성이 우수하였다. 또한 이들 대체흡착제의 흡착능을 증대시키기 위한 탄화시간은 $200^{\circ}C$, 30분이 최적 조건이었다. Sawdust의 경우에는 30% MeOH 매질에서는 흡착성이 매우 약한 반면 0.5M NaCl 매질에서는 XAD수지 흡착능이 약 1/2에 도달하였다. Rice bran과 rice straw는 외관상의 구조차이와는 관계없이 비슷한 흡착능력을 보였다. 따라서 rice bran과 rice straw들은 XAD계열 수지에 대한 대체흡착제로 충분한 흡착능력을 가지고 있는 것으로 보인다.

• Membrane and Water Treatment
• /
• 제8권3호
• /
• pp.259-277
• /
• 2017

Adsorption is a widely used technique for the removal of dyes from wastewaters by variety of adsorbents. In this work, the main focus is on the potential assessment of anion exchange membrane for the removal of different dyes using batch system and investigation of experimental data by applying various kinetic and thermodynamic models. The removal of anionic dyes i.e., Eosin-B, Eriochrome Black-T and Congo Red by anion exchange membrane BII from aqueous solution was carried out and effect of various parameters such as contact time, membrane dosage, temperature and ionic strength on the percentage removal of anionic dyes was studied. The experimental data was assessed by kinetic models namely pseudo-first-order, pseudo-second-order, Elovich liquid film diffusion, Bangham and the modified Freundlich models equation have been used to analyze the experimental data. These results indicate that the adsorption of these anionic dyes on BII follows pseudo-second-order kinetics with maximum values of regression coefficient (0.992-0.998) for all the systems. The adsorption of dyes was more suitable to be controlled by a liquid film diffusion mechanism. The adsorptive removal of dye Eosin-B and Eriochrome Black-T were decreased with temperature and thermodynamic parameters such as free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$) and entropy (${\Delta}S^o$) for adsorption of dyes on membrane BII were calculated at 298 K, 308 K and 318 K. The values of enthalpy and entropy were negative for EB and EBT representing that the adsorption of these dyes on BII is physiosorptive and exothermic in nature. Whereas the positive values of enthalpy and entropy for CR adsorption on BII, indicating that its adsorption is endothermic and spontaneous in nature. It is evident from this study that anion exchange membrane has shown good potential for the removal of dyes from aqueous solution and it can be used as adsorbent for dues removal on commercial levels.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.421-421
• /
• 2008

Generally, the polymer thick-film resistors for embedded organic or hybrid substrate are patterned by screen printing so that the accuracy of resistor pattern is not good and the tolerance of resistance is too high(${\pm}$20~30%). To reform these demerits, a method using Fodel$^{(R)}$ technology, which is the patterning method using a photosensitive resin to be developable by aqueous alkali-solution as a base polymer for thick-film pastes, was recently incorporated for the patterning of thermosetting thick-film resistor paste. Alkali-solution developable photosensitive resin system has a merit that the precise patterns can be obtained by UV exposure and aqueous development, so the essential point is to get the composition similar to PSR(photo solder resist) used for PCB process. In present research, we made the photopatternable resistor pastes using 8 kinds of epoxy acrylates and a conductive carbonblack (CDX-7055 Ultra), evaluated their developing performance, and then measured the resistance after final curing. To become developable by alkali-solution, epoxy acrylate oligomers with carboxyl group were prepared. Test coupons were fabricated by patterning copper foil on FR-4 CCL board, plating Ni/Au on the patterned copper electrode, applying the resistor paste on the board, exposing the applied paste to UV through Cr mask with resistor patterns, developing the exposed paste with aqueous alkali-solution (1wt% $Na_2CO_3$), drying the patterned paste at $80^{\circ}C$ oven, and then curing it at $200^{\circ}C$ during 1 hour. As a result, some test compositions couldn't be developed according to the kind of oligomer and, in the developed compositions, the measured resistance showed different results depending on the paste compositions though they had the same amount of carbonblack.

• 대한화학회지
• /
• 제36권6호
• /
• pp.824-831
• /
• 1992

수용액에서 Ho(III) 이온과 간단한 리간드 사이의 착물 형성에 대한 온도와 리간드 농도의 영향을 흡수 스펙트럼을 이용하여 연구하였다. Hypersensitive 전이$(^5I_8\;\to\;^5G_6)$의 전이세기 변화는 온도와 리간드의 영향을 크게 받고, 이 변화는 Ho(Ⅲ) 이온의 배위 환경 변화로 해석될 수 있다. 이 스펙트럼에서 관찰된 전이세기를 분석하여 Judd-Ofelt 전이세기 파라미터($\Omega_\lambda$, $\lambda$ = 2, 4, 6)를 구했다. 이 파라미터들 중 $\Omega_2$ 파라미터가 온도와 리간드에 의해 가장 큰 변화를 보이고, 이 변화로부터 $Cl^-$와 ${NO_3}^-$가 수용액에서 내부권 착물을 형성함을 보였다