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金屬킬레이트化合物의 觸媒作用에 依한 Aminophenol 類의 酸化的 重縮合反應 (Ⅰ) 溶媒의 效果와 生成重合體의 特性
최규석,Choi, Kyu-Suck 대한화학회 1968 대한화학회지 Vol.12 No.3
Fe-EDTA complex, which is easily formed when Fe salt and EDTA.2Na are mixed in the aqueous medium, is found to be a very effective catalyst in the dehydropolycondensation of aminophenols. In the dehydropolycondensation of aminophenols, the catalyst, Fe(Ⅲ)-EDTA complex (higher oxidation state) is reduced to less stable Fe(Ⅱ)-EDTA complex (lower oxidation state), and the latter is easily oxidized by air to the original higher oxidation state complex, therefore the catalytic action of Fe-EDTA complex is found to be recycled effectively. Under the catalytic action of the above mentioned complex, p-aminophenol is polymerized in the aqueous medium to form the oligomers of p-aminophenol, which the degree of polymerization to be 5 or more. The oligomers formed contain partly quinone nucleus as well as amino and hydroxyl groups. In this study, the effects of the solvents and characteristics of the oligomers are discussed. These types of polymerizations catalyzed by the metallic chelate compounds are considered to be very closely related to the reactions in the living matters.
金屬킬레이트 化合物의 觸媒作用에 依한 Aminophenol 類의 酸化的 重縮合反應 (Ⅱ) Ligands 種의 效果, 混合錯物의 構造및 副反應
최규석,Choi, Kyu-Suck 대한화학회 1968 대한화학회지 Vol.12 No.3
In the oligomerization of p-aminophenol under the catalytic action of the metallic complexes, the effects of the ligands are studied. When the initial velocity of $O_2$ uptake at pH 8 using Fe(Ⅲ) as the central metal and N-hydroxylethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), 1,2-cyclohexanediaminetetraacetic acid(CyDTA) as the ligands respectively are compared, the velocities are as the following order: HEDTA > EDTA > DTPA > CyDTA. Further when the effect of the ligands, nitrilotriacetic acid (NTA), HEDTA, EDTA, and DTPA, on the yields of oligomers are compared, the result shows as the following order: NTA > HEDTA > EDTA > DTPA. These are nearly reverse order of the stability constants of the complexes. In order to determine the composition of the mixed complexes at the initial step, the method of continuous variation is used, and it is found that the composition ratio of Fe-EDTA complex to monomer in the mixed complexes is one at pH 5-8 range. It is also found that at pH 9 or in the more alkaline range, side reactions occur to form water soluble dimer of quinone type and the catalytic action of the metallic complex markedly decreases on account of the hydrolysis of the central metal by the $OH^-$ ion.
최규석,박종진,임종수 한국인터넷방송통신학회 2011 한국인터넷방송통신학회 논문지 Vol.11 No.2
본 논문에서는 기존 지상파 이동멀티미디어 방송시스템인 Terrestrial-DMB(T-DMB) 시스템의 성능개선을 위하여 이동환경에서 고전송 효율, 고품질 서비스를 제공할 수 있는 새로운 휴대 이동 멀티미디어 방송 시스템인 Advanced T-DMB 시스템의 시험시스템 구현 및 현장 시험결과를 기술한다. 기존 방식보다 멀티미디어 방송성능이 한층 개선된 Advanced T-DMB 시스템은 계층변조 및 터보 코드 방식을 이용하여 기존 T-DMB와 역호환성을 유지하면서 동일한 주파수 대역폭에서 전송률을 최대 2배로 높이기 위해 연구개발되었다. 제안된 시스템의 성능검증을 위해 현장 시험을 하였으며, 그 결과 이동서비스를 목표로 하는 B-모드와 고정 서비스를 목표로 하는 Q-모드에 대해 각각 0.576Mbps, 1.152Mbps의 전송용량이 증가된 것을 확인할 수 있었다. In this paper, we describes about implementations of Advanced Terrestrial DMB prototype system which can provide high higher efficiency of transmission and better quality of service than Terrestrial DMB(T-DMB) system for performance improvement of conventional mobile multimedia broadcasting system. And also we analyze field test results of the system. Advanced T-DMB system has been developed to increase data rate up to double of conventional T-DMB in same bandwidth while maintaining backward compatibility, using hierarchical modulation and turbo code. We conducted field tests to verify the performance of the proposed system through implementing of test system. As a result, we confirmed 0.576Mbps and 1.152Mbps were added to mode B and mode Q of Advanced T-DMB respectively than T-DMB system.