Abstract  Heavy benzene is the byproduct in the benzene recovery workshop of a coking plant in China Heavy benzene fetched from the bottom of a crude benzene distillation column was separated by distillation, and the fractions with a boiling point range of 160-185 degrees C were analyzed by gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) spectroscopy A Ni-Mo/gamma-Al2O3 catalyst was prepared for hydrogenating the model compounds, including styrene and 1,3,5-trimethylbenzene (TMB), which was found in the fraction of heavy benzene Catalytic activity was evaluated in a 17 mL autoclave at 80-200 degrees C, 3 0-7 0 MPa cold hydrogen pressures, and 8-30 min reaction time The results indicated that TMB was almost not reactive in such conditions, however, the styrene conversion and corresponding selectivity of ethyl benzene increased with the increase of the reaction temperature, reaction time, H-2 pressure, and catalyst dosage The optimum conditions for maximum styrene conversion were 150 degrees C, 15 min, 5 MPa cold H-2 pressure, and 2 wt % (of reactant) catalyst dosage The results can offer some ideas for the hydrogenation process to Improve the quality of heavy benzene

Abstract  The synthesis of the tris(triflate) 4 (Scheme 1) has been achieved by means of a straightforward three-step reaction sequence. After initial lithiation of mesitylene, treatment of the obtained trilithium compound C6H3(CH2Li)3 (2) with oxirane results in the formation of 1,3,5-tris(3-hydroxypropyl)benzene (3), which is then transformed to 4 by reaction with (CF3SO2)2O in the presence of pyridine. Whereas 4 reacts with Na2[Os(CO)4] in a somewhat complicated manner, similar reactions with Na[Re(CO)5] and LiPPh2 give the hydrocarbon-bridged tris(rhenium) complex C6H3[(CH2)3Re(CO)5]3 (5) and the tris(phosphane) C6H3[(CH2)3PPh2]3 (6), respectively. Employing the high-dilution method, from 6 and Cl2Pt(NCPh)2 the nanoscaled tri- and hexaplatinacyclophanes 7 and 9 are available. Owing to the optimal geometry and flexibility of the cage in 7, 1,2-dichloroethane can be reversibly encapsulated. The molecular structure of 7 7 1,2-Cl2C2H4 was determined by an X-ray structure analysis. The utility of the reactive metal centers in 7 has been demonstrated by replacing the chloro ligands by acetonitrile to give the cationic platinacyclophane 8, in which, according to NMR studies, the cage-like structure is preserved.

Abstract  The synthesis of the tris(triflate) 4 (Scheme 1) has been achieved by means of a straightforward three-step reaction sequence, after initial Lithiation of mesitylene, treatment of the obtained trilithium compound C6H3(CH2Li)(3) (2) with oxirane results in the formation of 1,3,5-tris(3-hydroxypropyl)benzene (3), which is then transformed to 4 by reaction with (CF3SO2)(2)O in the presence of pyridine, Whereas 4 reacts with Na-2[Os(CO)(4)] in a somewhat complicated manner, similar reactions with Na[Re(CO)(5)] and LiPPh2 give the hydrocarbon-bridged tris(rhenium) complex C6H3[(CH2)(3)Re(CO)(5)](3) (5) and the tris(phosphane) C6H3[(CH2)(3)PPh2](3) (6), respectively. Employing the high-dilution method, from 6 and Cl2Pt(NCPh)(2) the nanoscaled tri- and hexaplatinacyclophanes 7 and 9 are available. Owing to the optimal geometry and flexibility of the cage in 7, 1,2 dichloroethane can be reversibly encapsulated. The molecular structure of 7 . 7 1,2-Cl2C2H4 was determined by an X-ray structure analysis. The utility of the reactive metal centers in 7 has been demonstrated by replacing the chloro Ligands by acetonitrile to give the cationic platinacyclophane 8, in which, according to NMR studies, the cage-like structure is preserved.

Abstract  The interaction of [RuCl2(PPh3)(3)] with one equivalent of N,N'-bis[2-(diphenylphosphanyl)benzyl]-1R,2R-cyclohexanediamine [1R,2R-P(NH)(NH)P] in dichloromethane at room temperature gave trans-[RuCl2{kappa(3)-1R,2R-P(NH)(NH)P}(PPh3)] (1). When heated under reflux in toluene under a nitrogen atmosphere, I was converted into trans-[RuCl2{kappa(4)-1R,2R-P(NH)(NH)P}] (2). However, when 1 was stirred at room temperature in air, it was oxidized to trans-[RuCl2{kappa(3)-1R,2R-PN(NH)P}(PPh3)] (3). Depending on the reaction conditions, 3 was converted into trans-[RuCl2{kappa(3)-1R,2R-P(NH)(NH)P=O}(PPh3)] (4) when heated to 80 degreesC in toluene in air, to cis-[RuCl2{kappa(4)-1R,2R-PN(NH)P}] (5) when stirred at room temperature in acetone in air, or to trans-[RuCl2{kappa(4) -1R,2R-P,N(NH)P}] (6) when heated under reflux in acetone under a nitrogen atmosphere. When heated under reflux in toluene under a nitrogen atmosphere, 5 isomerized to 6 quantitatively. When heated under reflux in mesitylene under a nitrogen atmosphere, 6 was slowly reduced to 2. The solid state structures of 3 and 5 were ascertained by X-ray crystallography. Catalytic studies showed that I could catalyze the oxidation of alkanes and alkenes with molecular oxygen.

Abstract  Gas-phase hydrogenation of mesitylene to cis- and trans-1,3,5-trimethylcyclohexane was studied in a differential microreactor at atmospheric pressure and 418-493 K over an Ni/Al2O3 catalyst. Rapid reversible deactivation of the freshly reduced catalyst prompted reactivation before every kinetic measurement and extrapolation of the steady state activity to initial activity. Reaction orders were close to zero for mesitylene and ranged from 0.6 (418 K) to 2.0 (493 K) for hydrogen. A rate maximum for the production of the saturated compounds was observed at about 450 K, Varying with the pressure ratio of the reactants. The results were in line with previously reported results on xylene hydrogenation. (C) 1999 Elsevier Science B.V. All rights reserved.

Abstract  Thin films of titanium chloride, with and without MgCl2 have been produced, characterized, and used for in situ propylene polymerization with AlEt3. The oxidation states of Ti in the film are mainly 4+, 3+ and 2+, and their distribution varies with deposition method. Temperature programmed desorption (TPD) of mesitylene and tetramethylcyclopentadiene shows that the surface of titanium chloride film without MgCl2 has more homogeneous adsorption site distribution. Both films produce highly isotactic polypropylene. The polypropylene film grown on the titanium chloride film without MgCl2 has a rough surface, compared to that with MgCl2.

Abstract  Inelastic incoherent neutron scattering (IINS) study of the lattice and low-frequency internal vibrations (libration of methyl groups and benzene ring deformations) of mesitylene molecules were carried out at various temperatures. In solid phase at ca. 20 K1 the above enumerated vibrations are represented in form of well-separated peaks in the low-temperature IINS spectrum. The experimental data are compared with the results of quantum chemistry (QC) calculations. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract  The interaction of [RuCl2(PPh3)3] with one equivalent of N,N'-bis[2-(diphenylphosphanyl)benzyl]-1R,2R-cyclohexanediamine [1R,2R-P(NH)(NH)P] in dichloromethane at room temperature gave trans-[RuCl2{κ³-1R,2R-P(NH)(NH)P}(PPh3)] (1). When heated under reflux in toluene under a nitrogen atmosphere, 1 was converted into trans-[RuCl2{κ⁴-1R,2R-P(NH)(NH)P}] (2). However, when 1 was stirred at room temperature in air, it was oxidized to trans-[RuCl2{κ³-1R,2R-PN(NH)P}(PPh3)] (3). Depending on the reaction conditions, 3 was converted into trans-[RuCl2{κ³-1R,2R-P(NH)(NH)P=O}(PPh3)] (4) when heated to 80 °C in toluene in air, to cis-[RuCl2{κ⁴-1R,2R-PN(NH)P}] (5) when stirred at room temperature in acetone in air, or to trans-[RuCl2{κ⁴-1R,2R-PN(NH)P}] (6) when heated under reflux in acetone under a nitrogen atmosphere. When heated under reflux in toluene under a nitrogen atmosphere, 5 isomerized to 6 quantitatively. When heated under reflux in mesitylene under a nitrogen atmosphere, 6 was slowly reduced to 2. The solid state structures of 3 and 5 were ascertained by X-ray crystallography. Catalytic studies showed that 1 could catalyze the oxidation of alkanes and alkenes with molecular oxygen.

Abstract  A novel method for the synthesis of benzyl chlorides and diarylmethanes from methylarenes and CCl4 in the presence of nitrile-activated catalysts based on the Mn(acac)(3) and Mo(CO)(6) complexes was developed. The reaction proceeds through the chlorination of one of the methyl groups in methylarenes by carbon tetrachloride to form the corresponding benzyl chlorides, which then alkylate in situ the starting methylarenes to diarylmethanes via the Friedel-Crafts reaction. The reaction is common for the entire methylarene series, including toluene, para-, meta-, and ortho-xylenes, pseudocumene, and durene. The effects of the central atom and its ligand environment in the catalyst and of the reaction conditions on the yield of benzyl chlorides and diarylmethanes were studied.

Abstract  A poly (methacrylamide-co-methylmethacrylate) (abbreviated PMAA-MMA) polymer support was studied for supporting a heteropolyacid (tungstophosphoric acid, H(3)PW(12)O(40)) with its surface positively charged in the polymerization step. PMAA-MMA supports could be obtained in a porous form by eliminating template reagent molecules (benzylmalonic acid) combined with properly selected monomer (methacrylamide). The amount of amine groups in PMAA-MMA directly determined the amount of H(3)PW(12)O(40) impregnated, because the amine groups induced a positive charge on the PMAA-MMA surface. Finally, H(3)PW(12)O(40)/PMAA-MMA showed better acid catalytic activities than unsupported H(3)PW(12)O(40) in alkylation of 1,3,5-trimethylbenzene with cyclohexene, which confirmed that PMAA-MMA supported H(3)PW(12)O(40) effectively.

Abstract  Equilibrium swelling of natural rubber composites containing aluminium powder has been investigated in a series of aromatic hydrocarbon solvents, such as benzene, toluene, xylene, and mesitylene. These composites were vulcanized by four vulcanizing systems, viz. conventional, efficient, dicumyl peroxide, and a mixture, consisting of sulfur and dicumyl peroxide. In each system, the effect of aluminium powder with and without bonding agent was studied. The results showed that addition of bonding agent reduced the swelling considerably, and its effect is more pronounced in the conventional system due to increased adhesion. The dependence of the diffusion coefficient on the crosslinking system and the solvent–polymer interaction parameter were calculated from diffusion data. These results are also indicative of the improved adhesion with hexa-resorcinol–silica bonding system in these composites.

Abstract  4-Tritylbenzoic acid crystallises via the carboxy dimer supramolecular synthon to produce a wheel-and-axle host lattice that includes different aromatic solvents in its microporous framework. The clathrate structures were characterised by single crystal X-ray diffraction. Solvents like xylenes, chlorobenzene and anisole are included in a channel of cross-sectional area 42 Angstrom(2) with 2:1 host-guest stoichiometry while mesitylene occupies a channel of 71 Angstrom(2) as a 1:1 clathrate. The host architecture is robust and yet adaptive. The carboxy dimer synthon together with the phenyl-phenyl interactions (edge-to-face, ef and offset face-to-face, off) produce recurring, zigzag tapes of wheel-and-axle supermolecules. A plethora of aromatic ef and off motifs in the intra- and inter-tape regions modulate the cavity area to accommodate solvents of different size/shape. The ability to tune the pore volume and still retain the target wheel-and-axle topology is a notable feature in this family of isomorphous structures. The unsolvated acid adopts a different crystal packing with the triphenylmethyl groups filling the voids in the structure.

Abstract  IR spectroscopy has been used to characterize the hydroxy groups of a series of HEMT samples dealuminated by steaming (framework Si/Al ratios between 4.5 and 52) and their interaction with pyridine. Three OH bands are observed in the spectrum of the non-dealuminated sample (HEMT 4.5): at 3631 cm(-1) [assigned to (HF)OH located in the large cages]; at 3551 cm(-1) [(LF)OH located in the sodalite cages]; and at 3740 cm(-1) (terminal defect SiOH groups). A large number of new OH bands appear in dealuminated samples; two of them, present in mildly dealuminated samples and located at 3599 and 3525 cm(-1) correspond to protonic sites stronger than those corresponding to the (HF) and (LF)OH bands. These bands were assigned to (HF) and (LF)OH groups interacting with cationic extraframework aluminium species located in sodalite cages. The other bands which correspond to extraframework species or to SiOH groups are generally slightly acidic or non-acidic. However, a band appearing at 3610 cm(-1) in the more dealuminated samples is due to very acidic OH groups of silica alumina debris. With all the samples, the number of Br<empty set>sted sites was found to be lower than the number of framework aluminium atoms, the difference being particularly pronounced for the less dealuminated samples. This can be explained by the inaccessibility to pyridine of some of the (LF)OH groups, by the partial exchange of protonic sites by cationic extraframework aluminium species and, with HEMT 4.5, by a partial dehydroxylation during pretreatment. The maximum activity per protonic site for m-xylene transformation, found with the mildly dealuminated samples, was attributed to the presence of very strong acid sites resulting from the interaction of the OH groups with extraframework species. Transition state shape selectivity in the hypocages is proposed to explain the low value of the disproportionation/isomerization ratio and the preferential formation of 1,2,4-trimethylbenzene found with all the HEMT samples (compared to that with HFAU zeolites).

Abstract  The first and second ionization energies of trimethyl substituted analogs of benzene and pyridine are determined by means of mass spectrometry in conjunction with synchrotron radiation. The first ionization energy of 1,3,5-trimethylbenzene amounts to (8.38 ± 0.05) eV and the second ionization energy to (22.8 ± 0.1) eV. The first ionization energy of 2,4,6-trimethylpyridine is determined as (8.65 ± 0.05) eV and the second ionization energy as (23.0 ± 0.1) eV. The ionization energies are compared with those of unsubstituted benzene and pyridine and the effects of the methyl groups are evaluated by means of isodesmic reactions. As expected, it is found that the electron-donating effect of the methyl groups stabilizes neutral pyridine and doubly charged pyridine more than neutral benzene and doubly charged benzene, respectively. Surprisingly, the opposite effect is found for the radical cations, which is ascribed to the unfavorable degenerate electronic structure of benzene radical-cation, which disappears upon the methyl substitution.

Abstract  Rates of hydrogen atom attack on o-fluorotoluene (o-FTOL) and m-fluorotoluene (m-FTOL) at temperatures of 988-1144 K and pressures of 2-2.5 bar have been determined in a single-pulse shock tube study. Hydrogen atoms, generated from the decomposition of hexamethylethane, were allowed to react with the substrates and the characteristic products observed. Rate constants for two reaction channels, displacement of fluorine or methyl, were determined relative to displacement of methyl from 1,3,5-trimethylbenzene (135TMB). Evidence is presented that abstraction of F is unimportant over the studied temperature range. With k(H + 135TMB --> m-xylene + CH3) = 6.7 x 10(13) exp(-3255/T) cm(3) mol(-1)s(-1), the following rate expressions have been derived:

k(H + o-FTOL --> C6H5CH3 + F) = 8.38 x 10(13) exp(-6041/T) cm(3) mol(-1)s(-1); (1012-1142 K)

k(H + o-FTOL --> C6H5F + CH3) = 2.37 x 10(13) exp(-2938/T) cm(3) mol(-1)s(-1); (988-1142 K

k(H + m-FTOL --> C6H5CH3 + F) = 1.33 x 10(14) exp(-6810/T) cm(3) mol(-1)s(-1); (1046-1144 K)

k(H + m-FTOL --> C6H5F + CH3) = 2.04 x 10(13) exp(-3104/T) cm(3) mol(-1)s(-1); (1008-1144 K)

Uncertainties in the relative rate constants are estimated to be factors of about 1.1, while the above absolute values have estimated expanded uncertainties of about a factor of 1.4 in rate, 10 kJ mol(-1) in the activation energy, and a factor of 3 in the A-factor The present data are compared with relevant literature data. From our data and the thermochemistry, a model of the elementary steps comprising displacement of F is developed. On the basis of the model fit to our data, rate constants for the addition of atomic fluorine to toluene at 1100 K are derived. Rate expressions for fluorination reactions of toluene are also determined. The significance of the present results is discussed in the context of the formation of fluorinated byproducts in high-temperature systems.

Abstract  Novel bis(arene)metal-containing polyacrylonitrile materials have been prepared by the polycyanoethylation reaction between acrylonitrile and (arene)2M (M = Cr or V; arene = PhH, C6H4Et2 or mesitylene) in the absence of solvent. The resulting star-shaped molecules consist of a central (arene)2M species with up to four polyacrylonitrile arms covalently bonded to the arene ligands. The materials are readily soluble and films can be cast from solutions in acetonitrile. The IR and solid state 13C NMR spectra (or EPR spectrum for the oxidized chromium-containing polymer) are consistent with the presence of a metal–arene bond and confirm the persistence of the sandwich structure. The properties of the thermolysed materials are consistent with the formation of conjugated naphthyridine-type structures. The value of |n2| determined by the degenerate four-wave mixing technique at 1064 nm with a 6 ns pulse duration for a solution in conc. H2SO4 (1 g l−1) of the chromium-containing polymer pyrolysed at 350 °C was found to be 0.8 × 10−13 cm2 W−1 corresponding to |lReχ(3)| = 0.4 × 10−11 esu.

Abstract  Benzene, 1,3,5-trichloro-2,4,6-trimethyl- (9CI) Mesitylene, 2,4, 6-trichloro- (8CI) 1,3,5-Trichloro-2,4,6-trimethylbenzene 2,4, 6-Trichloromesitylene

Abstract  Benzene, 2,4-dibromo-1,3,5-trimethyl- (9CI) Mesitylene, 2, 4-dibromo- (8CI)

Abstract  Hierarchical MFI zeolite was synthesized following a synthesis route using organic-inorganic hybrid surfactants; the resultant zeolite with mesoporous/microporous hierarchical structure exhibited remarkably high resistance to deactivation in catalytic activity of various reactions such as isomerization of 1,2,4-trimethylbenzene, cumene cracking, and esterification of benzyl alcohol with hexanoic acid, as compared with conventional MFI and mesoporous aluminosilicate MCM-41.

Abstract  Liquid-liquid extraction with triethylene glycol as solvent, water as cosolvent, and hexane as counter-solvent is being investigated as a process for the separation of phenolic compounds from neutral oils and nitrogen bases. To this end, liquid-liquid equilibria at 313.15 K and atmospheric pressure have been determined for the systems triethylene glycol + hexane + water + (phenol + aniline + benzonitrile + 5-ethyl-2-methyl pyridine + mesitylene) or (m-cresol + o-tolunitrile + o-toluidine + indene + pseudocumene + undecane) or (2,4-xylenol + 3,4-xylenol + 3,5-xylenol + indane + naphthalene + dodecane). From the experimental results it is concluded that triethylene glycol, hexane, and water are effective solvents for the separation of phenolic compounds from neutral oils and nitrogen bases by means of liquid-liquid extraction. LLE binary parameters for the NRTL equation were obtained for each of the three systems by regression of the equilibrium data. The NRTL equation fit the experimental data with a root-mean-square-deviation (RMSD) of 0.0037, 0.0100, and 0.0058 for the systems containing phenol, m-cresol, and the xylenol isomers, respectively.

Abstract  A series of Late Devonian to Early Mississippian type II kerogens with vitrinite reflectance values R-o 0.29-2.41% were analyzed using py-GC-MS. In addition, a low maturity kerogen with R-o 0.44% was separated into fractions via density gradient centrifugation, followed by py-GC-MS of the alginite and amorphinite maceral concentrates. Alkylbenzenes and n-alk-l-ene/n-alkane doublets represented the main compound classes identified in all pyrolysates. The pyrolysate from alginite featured 1,2,4-trimethylbenzene and toluene as the two most prominent alkylbenzenes. In contrast, alkylbenzenes in pyrolysates from amorphinite and low maturity bulk kerogens with R-o 0.29-0.63% were dominated by 1,2,3,4-tetramethylbenzene. With increasing thermal maturity, pyrolysates were increasingly dominated by (i) alkylbenzenes with fewer methyl groups, namely by tri- and dimethylbenzenes at medium maturity (R-o 0.69-1.19%), and (ii) by toluene at higher maturity (R-o 1.30-2.41%). With increasing maturity of kerogen type II, the decreasing abundance of highly methyl-substituted alkylbenzenes and the parallel increase in less methyl-substituted alkylbenzenes in flash pyrolysates suggest that demethylation is an important chemical process in the thermal maturation of kerogen type II. (c) 2008 Elsevier Ltd. All rights reserved.