• Title/Summary/Keyword: Microwave synthesis

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The Synthesis of Crystalline-Size Controlled Organic Pigment by Microwave Energy (마이크로파 에너지에 의해 결정 크기가 조절된 유기 안료의 합성)

  • 정기석;고진필;박상보;박찬영;민성기;권종호;오인환;박성수
    • Polymer(Korea)
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    • v.25 no.5
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    • pp.609-616
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    • 2001
  • The application of microwave technology to synthesis of polymer in solvent media has been shown by the synthesis of copper phthalocyanine (CUPc). The increase of synthetic yield-was demonstrated successfully in this study. A power variable microwave synthetic system has been developed with modifying cavity of domestic microwave oven and attaching microwave power controller. The properties of the specimen synthesized at various condition under the conventional thermal processing and microwave processing has been characterized by the means of chemical analysis, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA).

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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.

The Sialon Synthesis from Natural Silica and Al Powder Mixture by Using Home-style Microwave Oven (가정용 전자렌지를 사용한 천연규석분말과 Al분말 성형체로부터 사이알론상 합성에 관한 연구)

  • 안주삼
    • Journal of the Korean Ceramic Society
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    • v.34 no.1
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    • pp.1-6
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    • 1997
  • In home-style microwave oven, silica-Al powder mixture was ignited among pellets and combustion wave-front propagated to produce Si+AIN+Al2O3 as resultant phases under N2 atmosphere. Without cooling pro-cedure the resultant phases of Si+AIN+Al2O3 continously absorbed microwave and were heated to be syn-thesized into sialon phases. This synthesis rate of sialon phases from silica-Al powder mixture in home-style microwave oven was higher than that in conventional furnace, and total processing time was around 1 hour, which could save energy and cost.

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A Facile Synthesis of SAPO-34 Molecular Sieves with Microwave Irradiation in Wide Reaction Conditions

  • Jun, Jong-Won;Lee, Ji-Sun;Seok, Hwi-Young;Chang, Jong-San;Hwang, Jin-Soo;Jhung, Sung-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1957-1964
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    • 2011
  • Various reaction conditions uding temperature, time and type and concentration of templates have been changed in order to facilely synthesize, especially with microwave (MW) heating, SAPO-34 molecular sieves. SAPO-34 molecular sieve can be synthesized rapidly with microwave irradiation from a gel containing tetraethylammonium hydroxide (TEAOH) as a template. However, other several templating molecules lead to SAPO-5 molecular sieve under microwave irradiation even though SAPO-34 is obtained by conventional electric synthesis from the same reactant gels. Moreover, SAPO-34 can be obtained more easily by increasing the TEAOH or silica concentration or by increasing the reaction temperature. SAPO-34 can be obtained within 5 min in a selected condition (high temperature of 210 $^{\circ}C$) with microwave heating, which may lead to a continuous production of the important material. SAPO-34 synthesized by microwave irradiation is homogeneous and small in size and shows acidity and a stable performance in the dehydration of methanol and 2-butanol to olefins, suggesting potential applications in acid catalysis.

Effect of microwave irradiation on lipase-catalyzed reactions in ionic liquids

  • An, Gwangmin;Kim, Young Min;Koo, Yoon-Mo;Ha, Sung Ho
    • Analytical Science and Technology
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    • v.30 no.3
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    • pp.138-145
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    • 2017
  • Microwave-assisted organic synthesis has gained a remarkable interest over the past years because of its advantages - (i) rapid energy transfer and superheating, (ii) higher yield and rapid reaction, (iii) cleaner reactions. Ionic liquids are well known for their unique properties such as negligible vapor pressure and high thermal stability. With these properties, ionic liquids have gained increasing attention as green, multi-use reaction media. Recently, ionic liquids have been applied as reaction media for biocatalysis. Lipase-catalyzed reactions in ionic liquids provide high activity and yield compared to conventional organic solvents or solvent free system. Since polar molecules are generally good absorbent to microwave radiation, ionic liquids were investigated as reaction media to improve activity and productivity. In this study, therefore, the effect of microwave irradiation in ionic liquids was investigated on lipase catalyzed reactions such as benzyl acetate synthesis and caffeic acid phenethyl ester synthesis. Comparing to conventional heating, microwave heating showed almost the same final conversion but increased initial reaction rate (3.03 mM/min) compared to 2.11 mM/min in conventional heating at $50^{\circ}C$.

One Pot Synthesis of Novel Cyanopyridones as an Intermediate of Bioactive Pyrido[2,3-d]Pyrimidines

  • Khatri, Taslimahemad T.;Shah, Viresh H.
    • Journal of the Korean Chemical Society
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    • v.58 no.4
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    • pp.366-376
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    • 2014
  • Synthesis, structural characterization, and biological activity studies of novel pyrido[2,3-d]pyrimidines (10a-h, 11a-h) are described. Cyclization of cynoacetamides (4, 5) with malonitrile (7) and aldehyde (6a-h) via Hantzsch pyridine synthesis afforded cyanopyridones (8a-h, 9a-h), which on cyclization with formic acid under microwave conditions led to the final product. All the reactions are significantly faster and the isolated yields are remarkably higher in microwave conditions compared to the conventionally heated reactions. The compounds were tested in vitro for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtillus, Staphylococcus aureus, and Micrococcus luteus and antifungal activity against Trichphyton longifusus, Candida albicans, Microsporum canis, Fusarium solani. Compounds 10b, 10e, 11b and 11e exhibited good antibacterial and antifungal activities compared with standards.

A Facile Solvent and Catalyst Free Synthesis of New Dihydro Pyrimidinones as Antimicrobial Agents

  • Hegde, Hemant;Ahn, Chuljin;Gaonkar, Santosh L.;Shetty, Nitinkumar S.
    • Journal of the Korean Chemical Society
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    • v.63 no.6
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    • pp.435-439
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    • 2019
  • An efficient one pot multicomponent synthesis of pyrimidinone derivatives of Biginelli type is described. 4-amino-6-aryl-pyrimidine-5-carbonitrile molecules were synthesized efficiently via three-component Biginelli-type condensation of aldehyde, malononitrile, and semicarbazone as urea substituent in the presence of a catalytic amount of PEG-400 as green medium under microwave irradiation. The reactions proceeded efficiently in the presence of microwave radiation to afford the desired products in good to excellent yields. Products have been confirmed by IR, and NMR spectral analysis. All the molecules were tested for their antimicrobial activity against E. coli, S. aureus, P. aeruginosa and C. tropicalis. Some of the compounds have shown moderate to good inhibition efficiency against both gram-positive and gram-negative bacteria. The potent activity was observed against the fungal species with minimum inhibition concentration 12.5 ㎍/mL.