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M. Rekha,N. Nagaraju,H.R. Manjunath 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.1
Mn/Al2O3 and Mn/ZrO2 were prepared by precipitation method. Their catalytic activity was investigated in the synthesis of biologically important bis(indolyl)methanes via, a condensation reaction between an indole and different aldehydes. The materials exhibited excellent catalytic activity (TOF in the range 180–380 h1) and produced the expected product in good yield and selectivity. Isolation of product from the reaction mixture was simple and neat. The catalysts were found to be recyclable and used up to five cycles without any loss in their catalytic activity. Mn/ZrO2 was also found to be a better catalyst than Mn/Al2O3 in terms of isolated yield of the product and recyclability. Mn/ZrO2 catalyst was found to be selective for aldehydes and not for ketones. In order to investigate the relationship between the catalytic activity and physico-chemical properties, Mn/Al2O3 and Mn/ZrO2 were characterized for their surface and bulk properties by PXRD, BET, TPD-NH3 and SEM techniques. A good correlation between the catalytic activity of the materials and the concentration of the acid sites with intermediate strength was observed. Mn/ZrO2 exhibited rod like structure. This material was found to be a general catalyst for the synthesis of a number of bis(indolyl)methane derivatives with good yield and selectivity.
Preparation of polypyrrole by chemical oxidation: applications for sensor studies
S. Pavithra,R. Thejas,H. N. Anil Rao,B. S. Krishna,G. Nagaraju 한국고분자학회 2024 Macromolecular Research Vol.32 No.1
Polypyrrole has gained more attention in conducting polymer science due to its ease of preparation and many advantages. In this article, by chemical oxidation method, three different polypyrroles were prepared using ferric chloride as an oxidant, including surfactant and natural directing agent, and named the samples PPY-1, PPY-2, and PPY-3. XRD, XPS, EDX, FT-IR, SEM, and electrical conductivity was used to characterize the synthesized polypyrrole. XRD confirms that the prepared samples were polypyrrole by showing peaks in the range of 20°–23°. SEM analysis shows that the sizes are between 120 and 180 nm. The present research work is a modest attempt to demonstrate for the first-time detection of hazardous gas using natural directing agent during polypyrrole synthesis. The prepared samples were used for the sensing of butane. PPY-2 shows a high electrical conductivity of 14 × 10– 3 S cm− 1 and gas sensing with a sensitivity value of 42.03 with lesser response and recovery time. This study reveals the fabrication of low-cost materials for butane sensors.
Vijayasankar, A.V.,Aniz, C.U.,Nagaraju, N. Korean Chemical Society 2010 대한화학회지 Vol.54 No.1
다양한 철 원소의 조성을 갖는 인산알루미늄 철을 합성하여 표면 성질과 벌크 성질을 조사하였다. 벤질 알코올과 디에틸 말론산의 transesterification반응에 의해 촉매 특성을 결정 하였다. 에틸 벤질 말론산과 디벤질 말론산을 유일한 생성물로 얻었다. 철 성분이 0.025 몰 퍼센트인 FeAlP의 경우에 특이한 촉매 특성과 조직상의 특성이 나타난다. 디에스터의 형성은 중간 정도 크기의 산성 자리에서 이루어진다. 물질 안에 수화된 알루미나와 polycondensed인산이 존재할 경우에는 에스터교환 반응에서 인산 알루미늄 철의 촉매 특성이 감소하게 된다. Iron aluminophosphates (FeAlP) with different percentage of iron were synthesized and characterized for their surface and bulk properties. The catalytic activity was determined in the transesterification of diethyl malonate with benzyl alcohol. Benzyl ethylmalonate and dibenzyl malonate were obtained as the only products. FeAlP with 0.025 mole % of iron was found to be distinctly different in its textural and catalytic properties. Formation of diester was found to be favored by the acid sites of intermediate strength. The presence of hydrated alumina and the polycondensed phosphates in the materials reduced the catalytic activity of iron aluminophosphates in transesterification reaction.