118-90-1Relevant articles and documents
Surfactant-assisted assembly of nanoscale zinc coordination compounds to enhance tandem conversion reactions in water
Huang, Chao,Zhu, Kaifang,Zhang, Yingying,Lu, Guizhen,Shao, Zhichao,Gao, Kuan,Mi, Liwei,Hou, Hongwei
, p. 16008 - 16016 (2019)
Precise control over the morphology and size of coordination polymers (CPs) is crucial for extending these inorganic-organic materials to many advanced applications, in particular for heterogeneous catalysis. In this work, two Zn-based CPs, {[Zn3(idbt)2(4,4′-dmbpy)2]·H2O}n (1) and {[Zn3(idbt)2(H2O)3]·H2O}n (2) (H3idbt = 5,5′-(1H-imidazole-4,5-diyl)-bis-(2H-tetrazole), 4,4′-dmbpy = 4,4′′-dimethyl-2,2′-bipyridine), were synthesized through solvothermal reactions. The morphologies and particle sizes of 1 and 2 could be controlled from large scale to nanoscale by regulating the amount of poly(vinyl alcohol) (PVA). Furthermore, for the conversion reactions of nitromethylbenzenes into benzoic acids, the catalytic properties of nanoscale 1 and 2 were much more efficient than those of large size of 1 and 2, because of the benefit of readily accessible active sites in the nanoscale sized particles, which provide a tunable and functionalizable platform for the conversion reaction by minimizing the diffusion distance but do little for the selectivity.
Steric effect of substituents in haloarenes on the rate of cross-coupling reactions
Khaibulova, T. Sh.,Boyarskaya,Boyarskii
, p. 360 - 365 (2013)
The relative reactivity of ortho- and para-methyl-substituted iodoarenes in the Sonogashira reaction and palladium-catalyzed methoxycarbonylation, as well as of similarly substituted bromoarenes in the Suzuki reactions and cobalt-catalyzed methoxycarbonylation, was studied. Introduction of a methyl group into the para position of aryl halide slows down the cross-coupling. o-Methylhaloarenes are less reactive in palladiumcatalyzed reactions as compared to both unsubstituted haloarene and para-substituted analog. The presence of a methyl group in the ortho position with respect to the reaction center accelerates cobalt-catalyzed methoxycarbonylation.
Experimental and theoretical investigation of the oxidative carbonylation of toluene to toluic acid catalyzed by palladium(II) in the presence of vanadium and molecular oxygen
Behn, Andrew,Zakzeski, Joseph,Head-Gordon, Martin,Bell, Alexis T.
, p. 91 - 97 (2012)
The mechanism and kinetics of the liquid-phase, oxidative carbonylation of toluene to toluic acid over Pd(II) in the presence of trifluoroacetic acid (TFAH), trifluoroacetic anhydride (TFAA), and molecular oxygen were investigated through a combination of experimental and theoretical approaches. The experimental results are consistent with the previously proposed mechanism for the oxidative carbonylation of arenes. The reaction is initiated by coordination of toluene to the Pd(II) complex and activation of a CH bond in the benzene ring. This initial step becomes rate limiting when a sufficiently high (NH 4VO3)/Pd ratio is used for the reoxidation of Pd(0) to Pd(II). Both processes are found to be dependent on the electron withdrawing and donating capability of the anionic ligands. Overall catalyst activity peaks for ligands of intermediate basicity, and diminishes for both more and less basic ligands. Theoretical analysis of the coordination of toluene and activation of the CH bond on the benzene ring reveals that the basicity of the ligands affects the two processes in opposite ways. Weakly basic ligands promote the coordination of toluene but have the opposite effect on the activation of the CH bond. The tradeoff in these two effects leads to a maximum in the apparent rate coefficient with pKa of the conjugate acid of the anionic ligands. The absence of significant product stereoselectivity is due to a lack of steric hindrance in the binding of toluene to the Pd(II) complex.
ARYL RADICALS FROM ORGANOMETALLIC SOURCES. PREFERENTIAL ATTACK ON THE SIDE CHAIN OF TOLUENES BY THE o-TOLYL RADICALS.
Battaglia, Luigi Pietro,Nardelli, Mario,Pelizzi, Corrado,Predieri, Giovanni,Chiusoli, Gian Paolo
, p. C19 - C22 (1986)
The o-tolyl radicals, formed by the reaction of o-chlorotoluene with (dppe = Ph2PCH2CH2PPh2) or by the decomposition of o-toluoyl peroxide, prefrentially attack the methyl group of toluenes giving rise to bibenzyls.In contrast the m- and p-tolyl radicals preferentially attack the aromatic nucleus.
Cetyltrimethylammonium dichromate: A phase-transferring oxidant
Patel, Sabita,Kuanar, Minati,Nayak, Biswa B.,Banichul,Mishra, Bijay K.
, p. 1033 - 1037 (2005)
A phase-transferring oxidant, cetyltrimethylammonium dichromate (CTADC) has been prepared and characterized from elemental analysis and spectral data. Application of this reagent to oxidize alcohols, aldehyde, and cinnamic acid is reported. Copyright Taylor & Francis, Inc.
An efficient approach for the deprotection of esters using ionic liquid as nucleophile
Wei, Benmei,Zhang, Zhiyong,Dai, Zhiqun,Guan, Jintao
, p. 6404 - 6406 (2013)
An efficient approach for the deprotection of esters has been developed using ionic liquid as nucleophile in the presence of protic acid. Using methyl benzoate as a model compound, the best result was obtained by the combination of 1-methylimidazolium bromide and methane sulfonic acid with a conversion of 96 % after 2 h at 120 C.
Electrochemical reduction of phthalide at carbon cathodes in dimethylformamide: Effects of supporting electrolyte and gas chromatographic injector-port chemistry on the product distribution
Pasciak, Erick M.,Hochstetler, Spencer E.,Mubarak, Mohammad S.,Evans, Dennis H.,Peters, Dennis G.
, p. 557 - 563 (2013)
Cyclic voltammetry and controlled-potential (bulk) electrolysis have been used to investigate the direct reduction of phthalide at carbon electrodes in dimethylformamide (DMF) containing 0.10 M tetramethylammonium perchlorate (TMAP) or tetra-n-butylammonium perchlorate (TBAP). Cyclic voltammograms recorded with a glassy carbon electrode exhibit a single cathodic peak and a corresponding anodic peak that arise, respectively, from one-electron reduction of phthalide to generate a radical-anion intermediate and from reoxidation of the intermediate. At a scan rate of 100 mV s-1, quasi-reversible behavior is observed (due to ring-opening of the radical-anion), whereas fully reversible behavior is seen at 5 V s-1 or higher. Digital simulation of cyclic voltammograms indicates that the lifetime of the radical-anion is 3.5 s. Bulk electrolysis of phthalide at a reticulated vitreous carbon cathode affords products that depend on the procedure used to analyze the catholyte. Direct injection of catholyte into a gas chromatograph shows phthalide and a 2-methylbenzoate ester bearing an alkyl moiety from the supporting-electrolyte cation. However, if the catholyte is partitioned between diethyl ether and aqueous hydrochloric acid before gas chromatographic analysis, phthalide and 2-methylbenzoic acid are observed. Thermally induced reactions that occur in the injector port of the gas chromatograph are responsible for the formation of the 2-methylbenzoate ester as well as for the phthalide found in all electrolyzed solutions.
Co and Mn polysiloxanes as unique initiator-catalyst-systems for the selective liquid phase oxidation of o-xylene
Foerster, Tobias,Schunk, Stephan A.,Jentys, Andreas,Lercher, Johannes A.
, p. 3254 - 3256 (2011)
Co and Mn polysiloxanes are unique catalyst/initiator systems for the liquid phase oxidation of o-xylene showing higher activity than Co naphthenates, which is related to the weak interaction of the polar products with the hydrophobic surface as well as the absence of hydroxyl groups and surrounding oxygenates limiting radical quenching.
Pd(OAc)2 promoted bis-N-heterocyclic carbene-catalyzed oxidative transformation of aldehydes
Yu, Ya-Han,Wang, Tsui,Chiu, Chien-Cheng,Lu, Ta-Jung,Lee, Dong-Sheng
, p. 202 - 205 (2020)
The bis-N-heterocyclic carbene-catalyzed (bis-NHC-catalyzed) oxidative transformation of aldehydes was successfully studied in water under air. The reaction rate increased through the use of Pd(OAc)2 as an additive. Notably, the catalytic system exhibited good tolerance toward aliphatic and aromatic aldehydes bearing halide and alkyl functional groups. In addition, gram-scale reaction was also tested in this study. The use of water and operational simplicity make this methodology environmentally benign and cost-effective.
Application of chloroaluminate ionic liquid as catalyst and medium for the dealkylation of esters
Wei, Ben-Mei,Zhang, Zhi-Yong,Dai, Zhi-Qun,Zhang, Kai-Cheng
, p. 1029 - 1033 (2011)
Dealkylation of esters to carboxylic acids was performed using chloroaluminate ionic liquids (PyHBr/AlCl3, PyHCl/AlCl3, Me3NHCl/AlCl3, Et3NHCl/AlCl3) as catalyst and medium. The catalytic activity of PyHBr/AlCl3 (X(AlCl3) = 0.67) proved to be superior to the other three ionic liquids for the dealkylation of methyl benzoate with a conversion of 97% after 3 h at 140 °C. After easy separation from the products the ionic liquid PyHBr/AlCl3 could be reused six times without loss of its activity.
