- MOFs as acid catalysts with shape selectivity properties
-
MOFs permit the paraalkylation of large polyaromatic compounds with nearly 100% of regioselectivity, offering new alternatives to standard zeolite catalysts. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Ravon, Ugo,Domine, Marcelo E.,Gaudillere, Cyril,Desmartin-Chomel, Arnold,Farrusseng, David
-
-
Read Online
- Effect of produced HCl during the catalysis on micro- and mesoporous MOFs
-
This paper reports the influence of alkylation reaction byproducts, particularly HCl, on MOF-5. Reaction between tert-butyl chloride and toluene or biphenyl in the presence of MOF-5 as a catalyst generates an unusual structural transformation which was proved to be due to the formation of byproduct HCl by means of powder X-ray diffraction analysis. Despite this, the highly desirable catalytic performance in terms of high conversions (>99%) and selectivity (>98%) toward the less bulky para-oriented products is maintained.
- Fernandez, Carlos A.,Thallapally, Praveen K.,Liu, Jun,Peden, Charles H. F.
-
-
Read Online
- Oxidative C-C bond formation reactivity of organometallic Ni(II), Ni(III), and Ni(IV) complexes
-
The use of the tridentate ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) and the cyclic alkyl/aryl C-donor ligand-CH2CMe2-o-C6H4-(cycloneophyl) allows for the synthesis of isolable organometallic NiII, NiIII, and NiIV complexes. Surprisingly, the fivecoordinate NiIII complex is stable both in solution and the solid state, and exhibits limited C-C bond formation reactivity. Oxidation by one electron of this NiIII species generates a six-coordinate NiIV complex, with an acetonitrile molecule bound to Ni. Interestingly, illumination of the NiIV complex with blue LEDs results in rapid formation of the cyclic C-C product at room temperature. This reactivity has important implications for the recently developed dual Ni/photoredox catalytic systems proposed to involve high-valent organometallic Ni intermediates. Additional reactivity studies show the corresponding NiII species undergoes oxidative addition with alkyl halides, as well as rapid oxidation by O2, to generate detectable NiIII and/or NiIV intermediates and followed by C-C bond formation.
- Watson, Michael B.,Rath, Nigam P.,Mirica, Liviu M.
-
-
- An N-heterocyclic carbene-based nickel catalyst for the Kumada–Tamao–Corriu coupling of aryl bromides and tertiary alkyl Grignard reagents
-
In this study, nickel-catalyzed coupling reactions between arylhalides and tert-alkyl Grignard reagents were developed. Our original bicyclic NHC ligands reduced the formation of isomerized products, and we found that NMP as a co-solvent suppressed the reduction process. Under the optimal conditions we developed, the catalyst loading was lowered to 0.5?mol?%, and catalyst loading using ortho-substituted aryl bromides was also applicable at the level of 2.0?mol?%.
- Ando, Shin,Mawatari, Mai,Matsunaga, Hirofumi,Ishizuka, Tadao
-
supporting information
p. 3287 - 3290
(2016/07/11)
-
- Synthesis and catalytic reactivity of mononuclear substituted tetramethylcyclopentadienyl molybdenum carbonyl complexes
-
The reactions of five dinuclear carbonyl complexes [(η 5-C5Me4R)Mo(CO)3]2 [R = allyl, n Bu, t Bu, Ph, Bz] with I2 in chloroform solution gave the corresponding mononuclear substituted tetramethylcyclopentadienyl molybdenum carbonyl complexes [(η 5-C5Me4R)MoI(CO)3] [R = allyl (1), n Bu (2), t Bu (3), Ph (4), Bz (5)]. The molecular structures of complexes 2, 3 and 5 were determined by X-ray diffraction analysis. The results show that the substituent in the ring can directly affect the Mo-I bond distances; the more sterically hindered the substituent, the longer the Mo-I bond. Friedel-Crafts reactions of aromatic compounds with a variety of alkylation reagents catalyzed by the complexes showed that all of these mononuclear molybdenum carbonyl complexes have catalytic activity in Friedel-Crafts alkylation reactions. Indeed, compared with traditional catalysts, these mononuclear metal carbonyl complexes have obvious advantages such as higher activities, mild reaction conditions, high selectivity, simple post-processing, and environmentally friendly chemistry.
- Ma, Zhi-Hong,Lv, Lin-Qian,Wang, Hong,Han, Zhan-Gang,Zheng, Xue-Zhong,Lin, Jin
-
p. 225 - 233
(2016/02/20)
-
- Synthesis and catalytic activity of monobridged bis(cyclopentadienyl)rhenium carbonyl complexes
-
Thermal treatment of three monobridged biscyclopentadienes (C5H5)R(C5H5) [R?=?C(CH3)2 (1), C(CH2)5 (2), Si(CH3)2 (3)] with Re2(CO)10 in refluxing mesitylene gave the corresponding complexes [(η5-C5H4)2R][Re(CO)3]2 [R?=?C(CH3)2 (4), C(C5H10) (5), Si(CH3)2 (6)], which were separated by chromatography, and characterized by elemental analysis, IR, and 1H NMR spectroscopy. The molecular structures of complexes 5 and 6 were characterized by X-ray crystal diffraction analysis and show that both are monobridged bis(cyclopentadienyl)rhenium carbonyl complexes in which the molecule consists of two [(η5-C5H4)Re(CO)3] moieties linked by a single bridge, in which each of the two Re(CO)3 units is coordinated to the cyclopentadienyl ring in an η5 mode. All three of these monobridged bis(cyclopentadienyl)rhenium carbonyl complexes have good catalytic activities in Friedel–Crafts alkylation reactions.
- Li, Zhen,Ma, Zhi-Hong,Wang, Hong,Han, Zhan-Gang,Zheng, Xue-Zhong,Lin, Jin
-
p. 647 - 653
(2016/07/29)
-
- Activity investigation of imidazolium-based ionic liquid as catalyst for friedel-crafts alkylation of aromatic compounds
-
N-Methylimidazolium ionic liquids were synthesised from N-methylimidazole and 1-bromobutane by two-step method. The alkylation of benzene and other aromatic compounds through improved Friedel-Crafts reaction was investigated in these ionic liquids. The imidazolium-based ionic liquids showed both high activity and high selectivity for this reaction. In particular, remarkable enhancement of the catalytic effect of the imidazolium-based ionic liquids was observed for the ionic liquids containing the PF6- anion. The effects of various types of anions, ionic liquid dosage, reaction temperature and molar ratio of aromatic compound to 1-bromobutane/tertbutyl alcohol were explored using [Bmim]PF6 or its mixture with AlCl3 as catalyst. The synthesis yielded improved results over those obtained using either neat AlCl3 or other imidazolium-based ionic liquids as catalyst. The ionic liquids can also be recycled and reused in contrast to traditional solvent-catalyst systems.
- Cai, Mingjian,Wang, Xiuge
-
p. 649 - 653
(2015/01/30)
-
- Indium(III) triflate - A catalyst for greener aromatic alkylation reactions
-
An environmentally friendly method for alkylating aromatic compounds with simple alcohols in the presence of a catalytic amount of indium(III) triflate is reported. Ionic liquids are used as solvents and energy-efficient heating is provided by microwave radiation. Good yields are obtained with benzyl, secondary, and tertiary alcohols. Simple primary alcohols are not effective alkylating agents under these conditions. With tertiary alcohols, activated aromatic compounds such as toluene and anisole must be used to obtain good yields. The catalyst, which is immobilized in a water-insoluble ionic liquid, can be easily recycled without significant loss of activity.
- Mack, Ryan,Askins, Grant,Lowry, Jacob,Hurley, Nathan,Reeves, Perry C.
-
p. 1262 - 1265
(2014/01/06)
-
- Vapor phase alkylation of toluene using various alcohols over H 3PO4/MCM-41 catalyst: Influence of reaction parameters on selectivity and conversion
-
A mesoporous MCM-41 molecular sieve material with a molar ratio of SiO 2/Al2 O3 = 70 and loaded with H3 PO4 was used as a catalyst for the alkylation of toluene, using various alcohols, namely methanol, iso-propanol, and tert-butanol, as alkylating agents. Para-alkylated toluene was the predominant product, formation of which was enhanced by moderate temperature, low amounts of the alkylating agents in the feed, and high carrier gas flow rate. Time on stream was found to exert a profound effect on the selectivity and conversion to the different products. TUeBITAK.
- Abbaspourrad, Alireza,Kalbasi, Roozbeh Javad,Zamani, Farzad
-
experimental part
p. 875 - 885
(2011/08/06)
-
- Non-catalytic conversion of C-F bonds of benzotrifluorides to C-C bonds using organoaluminium reagents
-
A facile method for the conversion of C-F bonds of benzotrifluorides to C-C bonds has been developed using aluminium reagents in the absence of catalysts.
- Terao, Jun,Nakamura, Misaki,Kambe, Nobuaki
-
scheme or table
p. 6011 - 6013
(2010/11/16)
-
- Electrophilic Aromatic Alkylation by Hydroperoxides. Competition between Ionic and Radical Mechanisms with Phenols
-
Tertiary hydroperoxides have been utilized for the electrophilic alkylation of activated aromatic substrates, particularly phenols and phenol ethers. Cumyl (1) and tert-butyl (2) hydroperoxides have shown a greatly different behavior as concerns the catalysis and the regioselectivity. The best catalyst for 1 is TiCl4, which is completely inactive with 2. With the latter an effective catalyst is FeCl3, which, however, can give rise to a combination of electrophilic and radical reactions with alkyl phenols. 2,2′-Dihydroxy-3,3′-di-tert-butyl-5,5′-dimethyldiphenyl is obtained in high yields from p-cresol.
- Liguori, Lucia,Bjorsvik, Hans-Rene,Fontana, Francesca,Bosco, Dino,Galimberti, Laura,Minisci, Francesco
-
p. 8812 - 8815
(2007/10/03)
-
- Selenium and Tellurium Tetrachlorides as Reagents for the Conversion of Alcohols to Alkyl Chlorides and Tellurium Tetrachloride as a Lewis Acid Catalyst for Aromatic Alkylation
-
Selenium tetrachloride(SeCl4) reacts smoothly with alcohols in various nonpolar solvents to give the corresponding alkyl chlorides in 44-97percent yield.Similar reaction also proceeds with tellurium tetrachloride(TeCl4), while the treatement of benzyl, 1-phenylethyl, and t-butyl alcohols with TeCl4 in aromatic solvents results in a high yield formation of alkylated aromatics instead of alkyl chlorides.Such Friedel-Crafts aromatic alkylation hardly occurs in the SeCl4 case.The chlorination species is not chlorine which might be evolved by dissociation of SeCl4 or TeCl4, but the metal chloride itself.The conversion of optically active R-(+)-1- phenylethanol to 1-phenylethyl chloride proceeds with nearly complete racemisation.
- Yamauchi, Takayoshi,Hattori, Kaneaki,Mizutaki, Shoichi,Tamaki, Kentaro,Uemura, Sakae
-
p. 3617 - 3620
(2007/10/02)
-