• 제목/요약/키워드: Catalyst-free

검색결과 269건 처리시간 0.02초

Tin-Free Three-Component Coupling Reaction of Aryl Halides, Norbornadiene (or Norbornene), and Alkynols Using a Palladium Catalyst

  • Choi, Cheol-Kyu;Hong, Jin-Who;Tomita, Ikuyoshi;Endo, Takeshi
    • Bulletin of the Korean Chemical Society
    • /
    • 제23권1호
    • /
    • pp.112-118
    • /
    • 2002
  • Good-to-excellent yields of 2,3-Disubstituted norbornenes (or norbornanes) were obtained using a Pd/Cu catalyzed three-component ternary coupling reaction of aryl halides, norbornadiene (or norbornene), and alkynols in toluene at $100{\circ}C$ in the presence of 5.5 M NaOH as a base and benzyltriethylammonium chloride as a phase transfer catalyst. The results of experiments using various aromatic halides suggest that the ternary coupling reaction is promoted by bromide.

Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Using HClO4-SiO2 as a Heterogeneous and Recyclable Catalyst

  • Maheswara, Muchchintala;Oh, Sang-Hyun;Kim, Ke-Tack;Do, Jung-Yun
    • Bulletin of the Korean Chemical Society
    • /
    • 제29권9호
    • /
    • pp.1752-1754
    • /
    • 2008
  • A simple and efficient synthesis of 3,4-dihydropyrimidinones or thiones is described, using silica-supported perchloric acid ($HClO_4-SiO_2$) as a heterogeneous catalyst from an aldehyde, $\beta$-dicarbonyl compound, and urea or thiourea under solvent-free conditions. Compared to the classical Biginelli reactions, this method consistently has the advantage of high yields, short reaction time, easy separation, and tolerance towards various functional groups.

유동층반응기에서 촉매를 이용한 메탄 열분해 (Thermal Decompostion of Methane Using Catalyst in a Fluidized Bed Reactor)

  • 장현태;이지윤;차왕석
    • 한국산학기술학회논문지
    • /
    • 제9권2호
    • /
    • pp.487-492
    • /
    • 2008
  • 본 논문은 유동층반응기에서 메탄 열분해에 의한 수소 생산과 탄소 생성에 대한 연구를 수행하였다. 환경에 대한 영향을 최소화한 상태에서 one-step에 의한 메탄의 전환반응을 메탄 분해촉매활성에 영향을 미치는 인자에 대하여 연구하였다. 측정된 압력요동특성치의 해석을 통하여 유동층 열분해촉매의 유동화현상을 측정하였으며, 유동화특성에 따른 메탄열분해능을 측정하였다. 메탄의 분해능는 생성되는 수소의 농도로부터 측정하였다. 유동층의 특성인 층내 입자 이동성, U-Umf, 마모, 비산유출, 유동화가스의 효율밀도에 따른 분해효율에 미치는 영향을 고찰하였다.

Solid-Phase Synthesis of 2-Arylbenzothiazole Using Silica Sulfuric Acid under Microwave Irradiation

  • Niralwad, Kirti S.;Shingate, Bapurao B.;Shingare, Murlidhar S.
    • Bulletin of the Korean Chemical Society
    • /
    • 제31권4호
    • /
    • pp.981-983
    • /
    • 2010
  • The condensation of several aromatic/heteroaromatic aldehydes with 2-aminothiophenol catalyzed by silica sulfuric acid under microwave irradiation afforded 2-arylbenzothiazoles in high yields and short reaction times under solvent-free conditions. The major advantages of the present method are good yields, ecofriendly, reusable catalyst, mild and solvent-free reaction conditions.

Styryl-6-Methoxy-2-Naphthyl Ketone 유도체의 합성 및 특성 분석 (Synthesis, Characterization and Correlation Analysis in Styryl 6-Methoxy-2-Naphthyl Ketones)

  • Thirunarayanan, G.
    • 대한화학회지
    • /
    • 제51권2호
    • /
    • pp.115-124
    • /
    • 2007
  • α, β-불포화 케톤 유도체를 실리카-황산 촉매 하에서 비용매 교차 알돌 응축 반응법을 이용하여 합성하였다. 합성 수율은 90% 이상이었으며, 사용된 촉매는 회수 가능하였다. 합성돤 화합물들의 물리화학적인 특성은 IR, NMR, Mass 등의 분광학적 분석 방법을 이용하여 결정하였다. 케톤 생성물에 미치는 치환기 효과는 측정된 분광 데이터와 Hammet 치환기 상수간의 상관관계로 표현되는 다중 상관계수 방정식에 의하여 잘 설명될 수 있었다.

10 kW 급 암모니아-수소 혼소엔진을 위한 암모니아 개질 촉매 및 반응기 설계에 관한 연구 (A Study on Ammonia Reforming Catalyst and Reactor Design for 10 kW Class Ammonia-Hydrogen Dual-Fuel Engine)

  • 이상호;최영;박철웅;김홍석;이영덕;김영상
    • 한국수소및신에너지학회논문집
    • /
    • 제31권4호
    • /
    • pp.372-379
    • /
    • 2020
  • Ammonia-hydrogen dual-fuel engine is a way to reduce greenhouse gas emission because ammonia and hydrogen are carbon-free fuels. In ammonia-hydrogen dual-fuel engine, hydrogen is supplied to improve the combustion characteristic of ammonia. In this study, an ammonia reformer was developed to supply hydrogen for 10 kW class ammonia-hydrogen dual-fuel engine. Thermodynamic characteristic and catalyst were investigated for ammonia reforming. Heat transfer was important for high ammonia conversion of ammonia reformer. 99% of ammonia conversion was obtained when 10 LPM of ammonia and 610℃ of hot gas were supplied to the ammonia reformer.