- Functional Ionic Liquids as Efficient and Recyclable Catalysts for the Methylation of Formaldehyde with Aromatics
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Abstract: Methylation of formaldehyde with various aromatics under functional ionic liquids catalysis has been developed. Among the ionic liquids investigated, triphenyl-(4-sulfobutyl)-phosphonium triflate ([TTPBs][CF3SO3]) showed high activity and afforded excellent yields of diarylmethane derivatives. A mechanism for the catalytic performance of [TTPBs][CF3SO3] is proposed. Besides, the catalyst can simply be separated from the reaction mixture by centrifugation and be recycled ten times without noticeable loss of activity. Graphical Abstract: Diarylmethane derivatives were successfully synthesized from the methylation of formaldehyde with aromatics using efficient and recyclable functional ionic liquids as catalysts, excellent yields and selectivities were obtained under solvent free conditions. The catalyst was reused at least ten consecutive recycles without noticeable loss in its catalytic activity. Meanwhile, the usability of catalyst was explored.[Figure not available: see fulltext.]
- Song, Heyuan,Jin, Fuxiang,Jin, Ronghua,Kang, Meirong,Li, Zhen,Chen, Jing
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p. 1264 - 1272
(2016/07/06)
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- Dihalogen-halogenomethyl complexes of indium(III) X2InCH2X (X = Br, I): Simultaneous coordination of soft and hard ligands
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Halogenomethyl-dihalogen-indium(III) compounds X2InCH2X (X = Br, I) obtained from indium monohalides and methylene dihalides were reacted with the soft donor ligands dialkylsulfides, R2S (R = CH3, CH2
- Peppe, Clovis,de Andrade, Fabiano Molinos,Vargas, Jaqueline Pinto,Mello, Melina de Azevedo,Barcellos, Railander Alves,Burrow, Robert A.,da Silva, Rubia Mara Siqueira
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experimental part
p. 2228 - 2233
(2009/10/23)
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- Diamino compounds and methods for preparing them
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An object of the invention is to propose diamino compounds expressed by the following general formula (1) which are suitable to obtain a raw material, a polyimide resin, for a liquid crystal aligning film without any image sticking and with a high voltage holding ratio at from a low temperature to a high temperature as well as the preparation thereof: STR1
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- Structural requirements for decarbonylative α,α-diarylation reaction of 2-methoxyalkanoic acids in phosphorus pentoxide-methanesulfonic acid mixture yielding 1,1-diarylalkane homologs
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2-Methoxyalkanoic acids were found to undergo consecutive decarbonylative α,α-diarylation in P2O5-MsOH instead of Friedel-Crafts type arylation on the carbonyl carbon. The influence of the substituents of the arenes and the carboxylic acids in this reaction was elucidated based on the reaction yields. The reaction behavior was found to be primarily governed by the electron-withdrawing/releasing property of the α-substituents on the carboxylic acids as well as the positive species-accepting ability of the arenes. The steric hindrance was shown to participate in determining the reaction feasibility as a secondary factor.
- Yonezawa, Noriyuki,Hino, Tetsuo,Tokita, Yoshimi,Matsuda, Kazuhisa,Ikeda, Tomiki
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p. 14287 - 14296
(2007/10/03)
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- Acidity of Dibasic Acids I: the Second Acidity Constant of 9,10-Dihydroanthracene and its 9,10-Substituted Derivatives: Effect of Substituent and Counter Ion
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The second equilibrium ion pair acidity constants (pK2) of 9,10-dihydroanthracene, 9-phenyl-9,10-dihydroanthracene, 9,10-diphenyl-9,10-dihydroanthracene and 9-cyano-9,10-dihydroanthracene with sodium, potassium and rubidium have been determined in tetrahydrofuran (THF) at 25 deg C in the concentration range 10-5-10-2 mol dm-3.Equilibria were monitored by UV-VIS and 1H NMR spectroscopies and the spectra of the dimetallic and monometallic salts reported.The dimetallic salts of all the dibasic carbon acids studied behave as contact ion pairs in THF.The pK2 of 9,10-dihydroanthracene is insensitive to substituent effect but is strongly dependent on the cation.
- Shapiro, Israel O.,Nir, Malka,Hoffman, Roy E.,Rabinovitz, Mordecai
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p. 1519 - 1524
(2007/10/02)
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- Selective Alkylation of p-Xylene with 2-Methylpropene by 12-Tungstophosphoric Acid
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Solid H3PW12O40 catalyzed the alkylation of p-xylene with 2-methylpropene to t-butyl-p-xylene with 75percent-selectivity, while the selectivity with H2SO4 was only 7percent.The selectivity of heteropolyacids tended to increase with the acid strength.
- Soeda, Hironobu,Okuhara, Toshio,Misono, Makoto
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p. 909 - 912
(2007/10/02)
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- Hydride Transfers During Friedel-Crafts Reactions of 5,5-Dimethyl-4,5-dihydrofuran-2(3H)-one
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5,5-Dimethyl-4,5-dihydrofuran-2(3H)-one (4,4-dimethylbutyrolactone) reacts with toluene and with p-xylene in the presence of anhydrous aluminium chloride to give 4-methylpentanoyl benzenes with one, two or three methyls on the benzene ring.Reduction of the side chain has taken place by hydride transfer from an aromatic methyl, the resulting benzylic carbocation going on to form diarylmethanes by reaction with solvent molecules.
- Rae, Ian D.,Woolcock, Mark L.
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p. 1023 - 1029
(2007/10/02)
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