Refluxing Conditions (refluxing + condition)

Distribution by Scientific Domains


Selected Abstracts


Heck Reaction Catalyzed by Palladacycle in Neat Water,

CHINESE JOURNAL OF CHEMISTRY, Issue 7 2003
Jian-Jun Hou
Abstract Cyclopalladated ferrocenylimine has been found to be a type of excellent phosphine-free catalyst for Heck reactions in neat water with both higher yields and turnover numbers than those reported in the literature up to now. Some commercial emulsifying agents, including the commonly used quaternary ammonium salts, have been proved to be excellent additives in the catalysis of the reactions. Not only aromatic iodide, but also aromatic bromide could be coupled with the olefins. All reactions were able to be conducted in air under refluxing condition. [source]


Studies on Properties of p -Nitrophenylazo Calix[4]arene Derivatives

CHINESE JOURNAL OF CHEMISTRY, Issue 2 2003
Jin Chuan-Ming
Abstract The p -nitrophenylazo calix[4]arene derivatives 1a-1d with nonlinear optical (NLO) properties were prepared by the diazo-coupling reaction of calix[4]arene with p -nitrophenyl diazonium. The diazotization reaction of p -nitroaniline was carried out with isoamyl nitrite as a source of nitrous add in EtONa/EtOH under refluxing condition. X-Ray crystallographic analysis and 1H NMR spectra reveal that they exist as cone conformation in crystal state or in solution. HRS measurements at 1064 nm in THF indicate that p -nitro-phenylazo calix[4]arenes have higher hyperpolarizability ,z values than the corresponding reference compound 4-(4-nitrophenylazo)-2, 6-dimethyl-phenol, without red shift of the charge transfer band. The tetrakis p -nitrophenylazo calix[4]arene (2) with longer alkyl chains can form monolayer at the air/water interface. [source]


Synthesis of a Hexadentate Hexameric Aluminum Imide and Its Metathesis Reactions

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2003
N. Dastagiri Reddy
Abstract The reaction of AlH3·NMe3 with one equivalent of 2-cyanothiophene in toluene afforded [HAlNCH2(C4H3S)]6 (2) in good yield. Treatment of 2 with SiMe3Br and SiMe3Cl in toluene under refluxing conditions resulted in the formation of compounds [BrAlNCH2(C4H3S)]6 (3) and [ClAlNCH2(C4H3S)]6 (4), respectively. In a similar way [PhC,CAlNCH2(C4H3S)]6 (5) was readily obtained from the reaction between 2 and PhC,CH. When 2 was treated with PhSH the Al-N cluster core dissociated and a four-membered ring compound [(PhS)2AlNHCH2(C4H3S)]2 (6) was formed. In contrast, a similar hexameric aluminum imide (HAlNCH2Ph)6 (1) retains its Al-N network when treated with PhSH to yield (PhSAlNCH2Ph)6 (7). An exchange of ethyl groups and hydrides occurred when 2 was treated with excess of ZnEt2, forming [EtAlNCH2(C4H3S)]68. Compounds 2,4 and 6,8 were characterized by X-ray single-crystal analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]


Microwave-assisted synthesis and characterization of heterocyclic, and optically active poly(amide-imide)s incorporating L -amino acids

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2008
Abdol R. Hajipour
Abstract N,N,-Pyromelliticdiimido-di- L -alanine (1), N,N,-pyromelliticdiimido-di- L -phenylalanine (2), and N,N,-pyromelliticdiimido-di- L -leucine (3) were prepared from the reaction of pyromellitic dianhydride with corresponding L -amino acids in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The microwave-assisted polycondensation of the corresponding diimide-diacyl chloride monomers (5,7) with 4-phenyl-2,6-bis(4-aminophenyl) pyridine (10) or 4-(p -methylthiophenyl)-2,6-bis(4-aminophenyl) pyridine (12) were carried out in a laboratory microwave oven. The resulting poly(amide-imide)s were obtained in quantitative yields, and they showed admirable inherent viscosities (0.12,0.55 dlg,1), were soluble in polar aprotic solvents, showed good thermal stability and high optical purity. The synthetic compounds were characterized by IR, MS, 1H NMR, and 13C NMR spectroscopy, elemental analysis, and specific rotation. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Synthesis and Characterization of Novel Super Microporous Tin-doped Zirconium Oxide

CHINESE JOURNAL OF CHEMISTRY, Issue 12 2005
Yan Kong
Abstract The super microporous tin-doped zirconium oxides were successfully synthesized by sol-gel method using zirconyl chloride as Zr source, tin chloride as Sn source and cetyltrimethylammonium bromide (CTMAB) as template under hydrothermal or refluxing conditions. The structures of the resultant materials were characterized by XRD, BET, FTIR, TG-DTA, XRF and HRTEM techniques. Experimental results indicated that the framework of the samples is typically ordered hexagonal structure. The surface area and pore volume of the materials prepared by refluxing method were larger than by hydrothermal method, but the ordering of pore distributions is lower. The thermal stability of the samples was relatively high (>773 K) and decreased with the increment of tin content. [source]