• Title, Summary, Keyword: Chemistry

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Enhanced activity and stability of the monolithic Pt/SiO2-Al2O3 diesel oxidation catalyst promoted by suitable tungsten additive amount

  • Liang, Yanli;Zhao, Ming;Wang, Jianli;Sun, Mengmeng;Li, Shanshan;Huang, Yufen;Zhong, Lin;Gong, Maochu;Chen, Yaoqiang
    • Journal of Industrial and Engineering Chemistry
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    • v.54
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    • pp.359-368
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    • 2017
  • A series of the modified $Pt/SiO_2-Al_2O_3$ diesel oxidation catalysts with different $WO_3$ loading were prepared through co-impregnation method. With an optimum additive loading of 2 wt% $WO_3$, the catalyst significantly improved the performance and its stability. Compared to the free-tungsten sample, the catalyst increased the maximum conversion of NO by 5-10% and decreased the reaction temperature for 30% NO conversion by $7-28^{\circ}C$. It was found that there exist the electron and structure interaction between platinum and tungsten species. The interactions can generate and maintain more Pt sites in metallic state for the catalytic oxidation with enhanced activity and stability.

Preparation of a New Chiral Stationary Phase Based on (2S,3S)-O,O'-Bis-(10-undecenoyl)-N,N'-bis-(3,5-dinitrobenzoyl)-2,3-diamino-1,4-butandiol and Its Application

  • Hyun, Myung Ho;Boo, Chang-Jin;Choi, Hee-Jung;Kim, Yun-Kyoung;Kang, Bu-Sung;Ha, Hyun-Ju;Choi, Min-Ki;Tan, Guang-Hui
    • Bulletin of the Korean Chemical Society
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    • v.27 no.11
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    • pp.1769-1774
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    • 2006
  • A new liquid chromatographic chiral stationary phase based on (2S,3S)-O,O'-bis-(10-undecenoyl)-N,N'-bis-(3,5-dinitrobenzoyl)-2,3-diamino-1,4-butandiol was prepared starting from (2R,3R)-1,4-bis(benzyloxy)-2,3-butanediol. The new chiral stationary phase was applied to the resolution of racemic anilide derivatives of N-acetyl-a-amino acids, 1,1'-bi-2-naphthol and 3,3'-diaryl-1,1'-bi-2-naphthols. The CSP was also applied to the resolution of some chiral drugs including a diuretic, bendroflumethiazide, and non-steroidal anti-inflammatory agents such naproxen and alminoprofen. In every case, the chiral recognition efficiency of the new CSP was quite excellent.

Flavestin K, An Isoprenylated Stilbene from the Leaves of Macaranga recurvata Gage

  • Tjahjandarie, Tjitjik Srie;Tanjung, Mulyadi;Saputri, Ratih Dewi;Nadar, Puja Bintu;Aldin, Muhammad Fajar;Marliana, Eva;Permadi, Anton
    • Natural Product Sciences
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    • v.25 no.3
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    • pp.244-247
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    • 2019
  • A new isoprenylated stilbene, flavestinK (1) together with two known isoprenylated stilbenes, flavestin B (2), flavestin G (3), and two isoprenilated flavanones, 4-O-methyl-8-isoprenylnaringenin (4) and 8-isoprenyl-5,7-dihydroxyflavanone (5) were isolated from the leaves of Macaranga recurvata Gage. All of the structures have been determined based on HRESIMS, 1D and 2D NMR spectral data. All of the isolated compounds were evaluated for their cytotoxicity against three human cancer cells (HeLa, T47D and WiDr). Compound 1 showed higher activity than doxorubicin against HeLa cells with $IC_{50}$ value of $13.1{\mu}g/mL$.

Synthesis and Modification of Novel Iminecalix[4]arene Derivatives

  • Nimse, Satish Balasaheb;Kim, Jun-Bae;Lee, Jeong-Tae;Song, Keum-Soo;Kim, Jung-Hoon;Ta, Van-Thao;Nguyen, Van-Thuan;Kim, Tai-Sun
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1143-1145
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    • 2011
  • The synthesis of novel iminecalix[4]arenes and further modification thereafter is described using a synthetic strategy. The reaction of the benzaldehyde derivatives with tetraamine functions on the calix[4]arene easily afforded the pure compounds in 92.4-95.7% yields, regardless of the effect of the substituents on the benzaldehyde derivatives. These compounds were stable under the conditions to obtain their analogue dialkylated in the narrow rim, with 83.2-89.9% yields. Characterization of the newly synthesized iminecalix[4]arene derivatives by spectroscopic methods revealed that all compounds are in the cone conformations.

Synthesis and Characterization of Some Quinazoline Derivatives as Potential Antimicrobial Agents under Microwave Irradiation

  • Mehta, Sarika;Swarnkar, Neelam;Vyas, Madhuri;Vardia, Jitendra;Punjabi, Pinki B.;Ameta, Suresh C.
    • Bulletin of the Korean Chemical Society
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    • v.28 no.12
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    • pp.2338-2343
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    • 2007
  • Under the framework of green chemistry, an efficient and extremely fast procedure for the synthesis of 5a-h through four-step procedure starting from 2-arylidenetetralin-1-one 1a-d under microwave irradiation is described. A considerable increase in the reaction rate has been observed with better yield. The structures of the synthesized compounds have been characterized on the basis of their elemental analysis and spectral data. Synthesized compounds 5a-h was evaluated for their antimicrobial activity. Some of the compounds exhibited appreciable activity.

Selective Synthesis of N-(Cyclohexylmethyl)-N-alkylamines from Primary Amines and Pimelaldehyde using Tetracarbonylhydridoferrate, $HFe(CO)_4^\;-$, as a Reducing Agent

  • Sang Chul Shim;Young Gil Kwon;Chil Hoon Doh;Byung Won Woo;Jin Ook Baeg;Hong Seok Kim;Tae Jeong Kim;Dong Ho Lee;Young Woo Kwak;Jin Soon Cha;Hyung Soo Lee;Jae Kook Uhm;Young Bae Park
    • Bulletin of the Korean Chemical Society
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    • v.11 no.2
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    • pp.140-143
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    • 1990
  • Ethanolic tetra carbonylhydridoferrate solution combined with dialdehyde (no of carbon; 4,5,6) is very efficient for the selective transformation of amino group into N-heterocyclic compound. However, a large variety of both aliphatic and aromatic amines react with the ferrate-pimelaldehyde at room temperature under an atmospheric pressure of carbon monoxide to give the corresponding N-(cyclohexylmethyl)-N-alkyiamine derivatives in moderate yields instead of the corresponding N-substituted perhydroazocine derivatives.

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Improved photoelectric performance via fabricated heterojunction g-C3N4/TiO2/HNTs loaded photocatalysts for photodegradation of ciprofloxacin

  • Wu, Dongyao;Li, Jinze;Guan, Jingru;Liu, Chongyang;Zhao, Xiaoxu;Zhu, Zhi;Ma, Changchang;Huo, Pengwei;Li, Chunxiang;Yan, Yongsheng
    • Journal of Industrial and Engineering Chemistry
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    • v.64
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    • pp.206-218
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    • 2018
  • An Intercalated heterostructural $g-C_3N_4/TiO_2/HNTs$ supported photocatalyst was successfully prepared via sol-gel and calcination methods. The introduction of HNTs and the $g-C_3N_4-TiO_2$ heterojunction effectively enhanced the charge transfer and separation efficiency of photogenerated electron-hole pairs, which endued the $g-C_3N_4/TiO_2/HNTs$ hybrid material with an outstanding photoelectric performance and good stability. And an obviously enhanced photocatalytic activity was exhibited by photodegrading ciprofloxacin compared with pure $TiO_2$. Furthermore, the main active species were detected through trapping experiment and ESR spin-trap technique with DMPO, which confirmed that the $^{\bullet}O_2{^-}$ and the $h^+$ were the main active species in the photocatalytic system.

Synchrotron Grazing Incidence X-ray Scattering and Its Applications in Polymer Nanotechnology

  • Ree, Moon-Hor;Lee, Byeong-Du;Yoon, Jin-Hwan;Heo, Kyu-Young;Jin, Kyeong-Sik;Jin, Sang-Woo;Kim, Hyun-Chul;Kim, Gha-Hee;Choi, Seung-Chul;Oh, Weon-Tae;Park, Young-Hee;Hwang, Yong-Taek;Kim, Jong-Seong
    • Proceedings of the Polymer Society of Korea Conference
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    • pp.120-120
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    • 2006
  • In our study grazing incidence X-ray scattering (GIXS) measurements with synchrotron radiation sources were conducted statically and in-situ for a series of nanoscale thin films prepared from nanoporous dielectrics, block copolymers, brush polymers, and molecular assemblies. All GIXS measurements were performed at the Pohang Accelerator Laboratory. The measured scattering data were analyzed in detail by using newly developed GIXS scattering theory. All GIXS results will be discussed in details with considering the materials chemistry and nanostructure formation process parameters.

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