Abstract  Dehydrogenation rates of four 4, 5-disubstituted 9, 10-dihydrophenanthrenes to the corresponding phenanthrenes by 10% palladium on charcoal for the substituents, H, OCH3, F and CH3, appear to be related to the size of the substituents. The preparation of three new phenanthrenes, viz. 4, 5-dichlorophenanthrene, 4, 5-difluoro- phenanthrene and 4, 5-bis(trifluoromethyl)phenanthrene, is described. Treatment of mesitylene with either 10% palladium on charcoal at reflux or 2, 3-dichloro-5, 6- dicyano-l, 4-benzoquinone gives an appreciable yield of mesityl(3’, 5’-xylyl)methane. © 1987 ASEG.

Abstract  Defective silicalite, an efficient and selective catalyst in the gas phase Beckmann rearrangement reaction, has been characterised by infrared spectroscopy and by molecular modelling techniques. We report a detailed IR study on the effect of outgassing treatments at increasing temperature on silanols bands and on framework modes. The effect of a temperature decrease up to 100 K (during the IR measurement) on the H-bonding interactions has also been investigated. The interaction of silanols with mesitylene, a probe molecule which cannot penetrate the channels, has been studied in order to distinguish between internal and external OH groups. Molecular mechanics and ab initio methods have also been used to model the structure and the vibrational features of a properly designed nest in order to support the assignments of the IR spectrum.

Abstract  

The transalkylation reaction between mesitylene and naphthalene has been studied over pentasil zeolites, type H-ZSM-11. The main product was 2-methylnaphthalene. The influence of external and total surface area of the catalysts on catalytic activity and selectivity was investigated. From these observations, it was found that the external surface of zeolites played a key role in the synthesis of 2-methylnaphthalene.

Abstract  The article focuses on a study which examined various solvents such as diglyme, toluene and mesitylene for the synthesis of high molecular weight living ring opening ε-caprolactone polymerization. It is noted that the polymerization mechanism employed coordinative anionic type and is the same to that of conventional metal alkoxides.

Abstract  

Abstract  This paper describes the procurement and the production quality control system of Pseudocumene, the scintillator solvent of the solar neutrino detector Borexino at the Laboratorio Nazionale del Gran Sasso (Italy). This material constitutes about 99.9% of the scintillator total mass, therefore being the most critical element for the radiopurity of the detector. (C) 2011 Elsevier B.V. All rights reserved.

Abstract  Nanosized mesoporous AlKIT-1 molecular sieve was hydrothermally synthesized in the absence of organic salts. The samples were characterized by X-ray diffraction, electron microscopy (TEM and SEM), N-2 adsorption isotherm, and NH3-TPD methods. The AlKIT-1 has a particle size of about 60-100 nm, and a three-dimensional network structure with average pore size of 2.7 nm. The sample exhibits good hydrothermal stability and catalytic performance for 1,2,4-trimethylbenzene, suggesting its promising applications in the conversion of large molecules.

Abstract  Toluene solutions of M2(NMe2)6 and mesitylene thiol react at 80°C to yield M2(S-mes)6 compounds (M = Mo and W) with the liberation of HNMe2. Similarly M2(OBut)6 in toluene reacts with mesitylene thiol under reflux to yield M2(S-mes)6 compounds. In all cases the reactions also yield some decomposition products. The compounds M2(SBut)2(NMe2)4 react with mesitylene thiol in hexane at room temperature to give M2(S-mes)6 compounds without significant side reactions. The M2(S-mes)6 compounds are the first examples of compounds containing triple bonds between molybdenum and tungsten atoms supported exclusively by thiolate ligands. Pertinent bond distances (Å) and angles (°) are: MM = 2.228(1) (Mo), 2.312(2) (W); MS = 2.325(2) (Mo), 2.32(1) (W); MMS = 96.6(1) (Mo), 97.2(6) (W). The preparations of the new compounds W2(SBut)2(NMe2)4 and W2(OBut)2(S-mes)4 are reported. © 1985.

Abstract  The surface adsorption sites of titanium chloride films that can be used as model Ziegler-Natta polymerization catalysts have been investigated with temperature-programmed desorption (TPD) of various probe molecules. The adsorption sites can be differentiated depending on the heat of desorption of the molecule. Two titanium chloride films were produced by electron-induced chemical vapor deposition of TiCl4 and co-deposition of Mg and TiCl4 on gold substrates. The surfaces of both films were chlorine-terminated. 1,3,5-Trimethylbenzene (mesitylene) was found to be an effective and non-destructive molecule for TPD characterization of adsorption sites on the model catalysts. The film produced by the electron-induced chemical vapor deposition had a distribution of adsorption sites that were not thermodynamically stable and subject to high-temperature annealing, while the film prepared by the co-deposition had a stable surface structure that was composed of domains of the MgCl2(001) basal plane structure. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract  Relative permittivity of binary mixtures of highly polar N-formylmorpholine + benzene, + toluene, + ethylbenzene, + o-xylene, + m-xylene, + p-xylene and + mesitylene were studied over the whole mole fraction range at 298.15 K. The excess polarizability, DeltaP and excess permittivity, Deltae calculated show that at least two types of molecular interactions occur in these binary mixtures. One of these increases the polarizability sharply, which corresponds to parallel configurations of nearest dipoles and the second decreases the polarizability, which corresponds to antiparallel configuration of the dipoles. Dielectric theory of Frolich successfully predicted the permittivity and dielectric behaviour of a binary mixture, containing polar-non polar solvents. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract  Differential scanning calorimetry (DSC), Thermogravimetry (TG) and X-ray showed the formation of two solid solvates of C-60 With 1,3,5-trimethylbenzene. Temperatures and enthalpies of decomposition of both solvates were measured by DSC. TG and DSC were applied to determine the composition of solvates. The influence of solvates on solubility of C-60 in 1,3,5-trimethylbenzene was discussed. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract  The catalyzed benzoylation of anisole and mesitylene is slow (hours) in the 120 - 130-degrees-C temperature range. When the reactions are run separately, mesitylene reacts faster (by a factor three). However, when the two reactions are run jointly, competition favors anisole (also by a factor three).

Abstract  Reactivity of benzene and certain alkylbenzenes (toluene, p-xylene, mesitylene) during benzylation with benzylchloride and some derivatives (α-chloroethylbenzene, benzhydrylchloride, chloromethylmesitylene) has been determined under non-isomerizing conditions, in the temperature range -10° and -120°, in ethyl chloride solution with AlCl3 as a catalyst. Steric effects are found to play a major role in the reactivity when benzylchloride derivatives are used as benzylating agents. Isomer distribution in the benzylation of toluene has been investigated as a function of the temperature and of the benzylating agent. Experimental data are related to the results obtained in the low temperature polymerisation of benzylchloride and α-chloroethylbenzene. © 1971.

Abstract  The reaction of pentafluorobenzyl magnesium bromide with phosphorus trichloride in a 2:1 molar ratio led to the disubstituted product, bis(pentafluorobenzyl)bromophosphine 1, which, upon reaction with lithium aluminium hydride, was converted to bis(pentafluorobenzyl) phosphine 3. The reaction of 3 with oxygen led to bis(pentafluorobenzyl)phosphine oxide 4. The reaction of 1, 3 and 4 with di-mu-chloro-bis-[(eta(6)-mesitylene)chloro-retenium(II)] 5 yielded the eta(6)-mesitylene-phosphinedichloro-ruthenium(II) complexes 6-8. Single-crystal X-ray structure determinations are described for the phosphinous acid-ruthenium(II) complex 8 and for the by-product 1,2-bis (pentafluorophenyl) ethane 2, formed during the Grignard reaction of magnesium and pentafluorobenzylbromide. In 8, the Ru-C bond lengths can be categorised as four short (219-222 pm) and two long (224-228 pm). A weak intramolecular P-OH ... Cl contact (O ... Cl, 304 pm) is observed. (C) 1997 Elsevier Science S.A.

Abstract  Adlayers of toluene, p-xylene, o-xylene, and mesitylene on a Rh(111) electrode in HF solution were investigated by using in situ scanning tunneling microscopy (STM). In situ STM images showed that all molecules were adsorbed with flat-lying orientation on the Rh(111) surface. High-resolution imaging revealed not only the packing arrangement but also the internal structure of each molecule. Methyl functional groups on the benzene ring were clearly discerned. Toluene molecules were arranged nearly hexagonally on Rh(111). The benzene ring of a toluene molecule was assigned to a hollow site on Rh(111). p-Xylene molecules were adsorbed at bridge sites, and a highly ordered c(2root3 x 4)rect adlayer was formed. The o-xylene adlayer showed a nearly hexagonal arrangement of molecules, and benzene rings were located at bridge sites. Mesitylene molecules appeared triangular in the STM image, which were assigned to hollow sites. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract  Ruthenium arenecyclopentadienyl complexes [Ru(5-C5R5)(6-arene)]+ (1, R = H, arene = C6H6; 2, R = Me, arene = C6H6; 3, R = H; arene = C6H3Me3; 4, R = Me, arene = C6H3Me3; 5, R = H, arene = C6Me6; 6, R = Me, arene = C6Me6; 7, R = Me, arene = C10H8) and [Ru(5-C9H7)(6-C6H6)]+ (8) have been studied by cyclic voltammetry; the complexes are capable of both reduction and oxidation. The reduction peak potential values for 16 become more negative by about 31 mV for each Me-group at the arene ring and 61 mV for each Me-group at the cyclopentadienyl ring. Reduction of naphthalene complex 7 proceeds by two one-electron processes; the first one is reversible and the second one is irreversible. Two reversible reduction peaks were observed for indenyl complex 8. The following reactions occur on reduction of benzene complexes 1, 2 and 8 with sodium amalgam in tetrahydrofuran (THF): hydrogen atom addition to and decoordination of benzene ligand as well as dimerization of ligand-to-ligand type. Mesitylene compounds 3 and 4 form dimers [(5-C5R5)Ru(-5:5-Me3H3C6C6H3Me3)Ru(5-C5R5)] (14, R = H; 15, R = Me) in both chemical and electrochemical reduction processes. Reaction of [Ru(5-C5H5)(6-C6Me6)]+ (5) with sodium amalgam in THF leads to the dimer [(5-C5H5)Ru(-5:5-Me6C6C6Me6)Ru(5-C5H5)] (16) as the major product; products of H-atom addition to both hexamethylbenzene and cyclopentadienyl ligands, [Ru(5-C5H5)(5-C6Me6H)] (17) and [Ru(4-C5H6)(6-C6Me6)] (18), are also formed in low yields. In the case of permethylated 6 only H-atom addition to hexamethylbenzene was observed and the mixture of endo-H and exo-H isomers [Ru(5-C5H5)(5-C6Me6H)] (19a,b) was isolated. Reduction of 7 gives [Ru(5-C5Me5)(5-C10H9)] (20). The modes of reaction of 19-electron radicals formed by reduction of 18 depend on electronic and steric properties of ligands.