Search results for "toluene"
showing 10 items of 429 documents
Reactions of Tris(ethanediolato)tungsten and Tungsten Oxytetrachloride with Aminotris(phenol)s: Alkoxide, Chloro, and Alkyl Derivatives of Oxotungst…
2005
Trisdiolatotungsten(VI) complex [W(eg)3] (eg = 1,2-ethanediolato dianion) reacts in refluxing toluene solution with phenolic ligand precursors tris(2-hydroxy-3,5-dimethylbenzyl)amine (H3LMe) and tris(2-hydroxy-3,5-di-tert-butylbenzyl)amine (H3LtBu) to form monomeric oxotungsten(VI) complexes [WO(LMe)(Heg)] and [WO(LtBu)(Heg)], respectively. These complexes undergo chloride-for-alkoxide substitution when treated with SOCl2 in CH2Cl2, which leads to the formation of corresponding chloro complexes [WO(LMe)Cl] and [WO(LtBu)Cl]. Identical chloro complexes are also formed in the reaction between these phenolic ligand precursors and [WOCl4]. The reaction of [WO(LR)Cl] complexes with Grignard reage…
UV photocatalytic oxidation of paint solvent compounds in air using an annular TiO2-supported reactor
2010
BACKGROUND: One of the most important industrial sources of volatile organic compounds (VOCs) is related to coating and painting applications. In this sense, photocatalytic oxidation can become an innovative and promising alternative for the remediation of air polluted by VOCs. In this study the UV photodegradation of m-xylene, toluene and n-butyl acetate, as representative compounds of paint solvents, was carried out in an annular reactor using a TiO2–glass wool supported catalyst. RESULTS The removal of each component and their mixture, simulating an industrial emission, was evaluated under different operational conditions. A maximum elimination capacity of 12, 18 and 80 mg C m−3 s−1 was …
ChemInform Abstract: Synthesis of a Fullerene Derivative of Benzo(18)crown-6 by Diels-Alder Reaction: Complexation Ability, Amphiphilic Properties, a…
2010
A fullerene derivative 1 of benzo[18]crown-6 was obtained by Diels-Alder addition of fullerene[60](C60) to the ortho-quinodimethane prepared in situ from 4,5-bis(bromomethyl)benzo[18]crown-6 (3) with Bu4NI in toluene. Extraction experiments show that the complexation of K+ ions strongly increases the solubility of 1 in protic solvents like MeOH. Using Langmuir-Blodgett techniques, monolayers of the highly amphiphilic fullerene-derived crown ether 1 and its K+ ion complex were prepared. An X-ray crystal structure was obtained from a benzene clathrate of comparison compound 2, synthesized by Diels-Alder reaction of C60 with the ortho-quinodimethane derived from 1,2-bis(bromomethyl)-4,5-dimeth…
Densities and viscosities of imidazolium and pyridinium chloroaluminate ionic liquids
2013
Abstract The chloroaluminate ionic liquids are used in various types of reactions. However, due to their particular vulnerability on water, their physical properties have not been previously investigated very extensively. The densities and viscosities of series imidazolium and pyridinium chloroaluminate ionic liquids having alkyl (butyl, hexyl, octyl) or aralkyl (benzyl, ethylphenyl) chain at the cation, various effective molar fraction of AlCl 3 (χ AlCl3 = 0.5, 0.65, 0.7), as well as they mixture and mixture with common organic solvents (hexane, toluene) were measured at the temperature range 293.15–343.15 K (20–70 °C). Densities, and particularly viscosities decrease with the increase of…
Determination of the Pore Topology of Zeolite IM-5 by Means of Catalytic Test Reactions and Hydrocarbon Adsorption Measurements
2000
Abstract The pore topology of a recently synthesized zeolite IM-5 has been determined by means of catalytic test reactions, i.e., n -decane hydroisomerization–cracking, m -xylene isomerization–disproportionation, n -hexadecane isodewaxing, and adsorption–microcalorimetry of molecules with different sizes and shapes ( n -hexane, toluene, m -xylene, and 1,3,5 trimethylbenzene). It has been found that the channel network consists of a system of unidirectional 10 MR with lobes or side pockets, or crossing 10 membered ring pores with a pore diameter somewhat smaller than those in ZSM-5. This structure offers interesting shape selectivity features for catalytic reactions.
Herstellung, charakterisierung und lösungseigenschaften von einheitlichen styrol-α-methylstyrol block-copolymeren
1977
An improved anionic polymerization technique for the preparation of highly uniform styrene/α-methylstyrene linear two-block copolymers is described. Three sets of samples with molecular weights M were prepared under equal experimental conditions, namely polystyrenes (2 · 105 < M < 3 · 106), poly(α-methylstyrene)s (7 · 104 < M < 4 · 106), and block copolymers (2 · 105 < M < 2,5 · 106). Ultracentrifugation in a density-gradient does not show any chemical heterogeneities in the block copolymers. The molecular polydispersity U = Mw/Mn–1 is U = 0,03 or less as estimated from GPC-measurements. The high molecular and chemical homogeneity of the block copolymers and the optical similarity of the tw…
Quantum-chemistry calculations of surface complex and orbital control in para/ortho toluene alkylation catalyzed by big pore zeolites
1994
Summary By means of MNDO-PM3 semiempirical quantum-chemistry calculations, the mechanism for alkylation of toluene by methanol on two zeolite clusters with Al and Ga as T III has been studied. The process variables controlled through the hypersurface of the reaction were: the distances of methyl group to the cluster of zeolite and to the toluene molecule; and the distances of the hydrogen atom of the toluene to be transfered to the zeolite cluster and to the toluene. The energetic factor associated with the electronic interaction between the molecular orbitals (LUMO of the zeolite-methoxy and HOMO of toluene) have been calculated by a PMO analysis for two geometries: the transition state an…
ChemInform Abstract: Polystannanes. Part 5. Polystannanes Ph3Sn-(tBu2Sn)n-SnPh3 (n: 1-4) A Route to Molecular Metals?
1988
Solutions of the starting compounds (I) in toluene and/or THF react like equilibrium mixtures of different compounds (I) with (II) at -78 °C to give the all-trans-configurated title compounds (III).
Endor Determined Structure and Conformation of Spin-Labeled Methyl L-Phenylalanate in Frozen Solutions
1990
The conformation of L-phenylalanine and methyl L-phenylalanate acylated at the amino nitrogen position with the nitroxyl spin-label 2,2,5,5-tetramethyl- l-oxypyrroline-3-carboxylic acid has been determined by ENDOR spectroscopy and computer based molecular modeling. ENDOR spectra of spin-labeled L- phenylalanine and the corresponding methyl ester of L-phenylalanine and of their 8-fluoro and £-fluoro derivatives in perdeuterated methanol or chloroform/toluene exhibited well resolved resonance absorptions from protons and fluorines of the amino acid moiety. From the analysis of the dependence of the ENDOR spectra on Hq, we have identified principal hyperfine coupling (hfc) components of each …
[5,10,15,20-Tetrakis(4-tert-butylphenyl)-porphyrinato-κ4N] zinc(II) toluene solvate
2007
The structure of the title compound, [Zn(C60H60N4)]·C7H8, represents a typical clathrate containing a host molecule of [5,10,15,20-tetrakis(4-tert-butylphenyl)porphyrinato]zinc(II) and a toluene guest molecule. The Zn atom occupies an inversion center and exhibits ideal square-planar coordination, while the porphyrin group remains perfectly flat. The toluene molecule lies on an inversion center and is disordered.