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Arynes (aromatic systems containing, formally, a carbon-carbon triple bond) are among the most versatile of all reactive intermediates in organic chemistry. They can be 'trapped' to give products that are [...]

This experiment performed was to determine the effect of the length of incubation time on the generation of benzene from ascorbic acid and potassium benzoate in Sierra Mist Free. The results would provide useful information on storage methods for soda which might allow people to reduce their benzene intake from soda, thus decreasing their carcinogen accumulation and possibly lowering their risk for developing associated cancers. A headspace gas chromatography and mass spectrometry method was used for the analysis of benzene. Quantitation was preformed using Agilent Enhanced Chem Station D.01.02. A calibration curve was generated by creating dilutions of benzene in deionized water. The range of detection was between 0.52 ng/mL and 20.0 ng/mL. Each sample of Sierra Mist Free was prepared for incubation by adding 10 mL of Sierra Mist Free to a headspace vial. There were 4 samples per group. Groups 1-8 were incubated at 50 °C for a certain amount of time over a 14 day period. Group 9 was the control group, incubated at room temperature. The data showed that no benzene was generated in any sample for any given period of incubation time at 50 °C or room temperature. The hypothesis, which stated that samples incubated at for a longer time at 50 °C would generate more benzene than samples incubated at 50 °C for a shorter period of time or at room temperature, was rejected, and the null hypothesis, which stated that incubation time would have no effect on the amount of benzene generated, was accepted., Introduction Anyone who indulges in Coke, Sprite, Mountain Dew, or other sodas generally recognizes the negative effects of drinking carbonated drinks: for example, the caffeine, the high sugar, the empty [...]

Photochromic systems can convert light energy into mechanical energy, thus they can be used as building blocks for the fabrication of prototypes of molecular devices that are based on the photomechanical effect. Hitherto a controlled photochromic switch on surfaces has been achieved either on isolated chromophores or within assemblies of randomly arranged molecules. Here we show by scanning tunneling microscopy imaging the photochemical switching of a new terminally thiolated azobiphenyl rigid rod molecule. Interestingly, the switching of entire molecular 2D crystalline domains is observed, which is ruled by the interactions between nearest neighbors. This observation of azobenzene-based systems displaying collective switching might be of interest for applications in high-density data storage. scanning tunnel microscopy | molecular switches | photochromic system | data storage

ABSTRACT Stenotrophomonas maltophilia T3-c, isolated from a biofilter for the removal of benzene, toluene, ethylbenzene, and xylene (BTEX), could grow in a mineral salt medium containing toluene, benzene, or ethylbenzene [...]

BTEX and two chemical warfare simulants, half mustard and dissopropylmethyl phosphonate, are placed in water and adsorbed into fiberglass supported activated carbon filters. Removal of the contaminants, the pressure drops of the filters, and the regeneration of the FGAC filter is graphed.

Research indicates that photocatalytic reduction of halogenated benzene derivatives is possible. As a result, a decrease in toxicity is achieved. Accompanying charts and graphs provide additional statistical data.

University researchers investigated the sorption of ionizable organic solutes such as benzene, phenol and aniline on surfactant-modified zeolite.

Experiments on the absorption of toluene, 0-xylene and benzene to wood are described. The results could be used to help predict organic contaminant transport at landfills, which often contain up to 25% wood waste by weight.

Study of the effects of airflow rate, air channel spacing, and porous media type on NAPL removal, using a lab-scale reactor with vertical air channels. Increased channel spacing caused the NAPL removal efficiency to decrease.

Trigonometric basis set functions can be applied to orbital symmetry and to the C-H stretching and deformation motions of benzene for undergraduate chemistry courses. It is difficult to show the form of the corresponding symmetry coordinates when dealing with the relatively simple group theoretical treatment that gives the symmetry species of the vibrational modes of a molecule and their infrared and Raman activities. Without the form of the symmetry coordinates the discussion is rather abstract. Thus a simple way to get the symmetry coordinates is valuable. The basis functions in this form can be applied to all axial groups. With a second angular variable the cubic and icosahedral groups can be covered.

The history of the benzene problem offers an excellent example of the scientific method in process, because chemists accepted or rejected models of the structure of benzene by testing predictions based on these models. In the early 1900s many benzene structures were discussed, but since the new models did not predict the results of observations better than the old models, they were not adopted.

A study investigates the rate-limited sorption of homologous series hydrophobic organic compounds such as polycyclic aromatic hydrocarbons, alkylated benzenes, chlorinated benzenes and chlorinated alkenes by two soils with humic and fulvic acid. Results revealed that the solutes sorbed more strongly to the humic-dominated soil than the fulvic-dominated soil. Sorbate shape and structure appear to have a secondary influence on the total equilibrium sorption.

Recent studies have proven that the presence of organohalogens in relatively unpolluted environments are caused by the natural halogenation of organic macromolecules. No evidence of chlorinated aromatic structures can be found in samples taken from fresh plant matter. The two samples, fresh and decaying plant materials which were isolated by acidic solvolysis and spruce forest and meadow grass soil samples with high molecular weight, yielded several benzoic acid derivatives after undergoing oxidative degradation.

Stable carbon isotopic analysis is an ideal tool for the remediation of contaminants such as benzene, toluene, ethylbenzene and xylenes (BETX). The process was effective in determining the concentrations and stable isotope values of BETX at a gasoline-contaminated site in southern California. The method, whereby purge-and-trap is connected to a gas chromatograph/ion trap mass spectrometer system, yielded varying concentrations of BETX that range from below detectable to highly detectable levels. Results indicate that toluene usually yield the highest concentrations.

The chlorination of resorcinol through dichlororesorcinol was evaluated using a series of chlorine-substituted resorcinol substrates. Their initial chlorination kinetics were examined over the pH range of two to 12 at 12 degrees Celsius. The apparent chlorination rates for each of the resorcinol substrates are a minimum in the pH range of three to six and a maximum in the pH range of eight to 11. A mechanism involving the reaction of HOCl with ArX(OH)2, ArX(OH)O- and ArX(O-)2 and an acid-catalyzed pathway at pH

The benzene molecule serves as a benchmark among the aromatic hydrocarbons and has been the subject of numerous experimental and theoretical studies. Despite such intensive investigations, the precise structure of the benzene cation ([C.sub.6][H.sub.6][sup.+]) is not known. Now, experiments measuring high-resolution state-to-state threshold photoionization spectra of benzene concretely establish the terms of vibronic levels in the distorted cation that are split by higher order Jahn-Teller coupling between its ²[E.sub.1g] electronic ground state and [v.sub.6] [e.sub.eg] in-plane ring-bending vibrational mode. This assignment, in turn, sets the absolute energy phase of the vibronic pseudorotation in this coordinate and thereby offers a definitive experimental determination of the shape of the benzene cation., Molecules with electronically degenerate ground states confound conventional notions of molecular shape and the ball-and-stick separability of electronic and internuclear degrees of freedom. Nuclear motions coupled with electronic degeneracy link [...]

A study was conducted on the heterogeneous combustion reactions of non-chlorinated C2 aliphatics. Acetylene was reacted with HCl/air between 300-600 degrees centigrade. Catalyst SiO2/metal oxide mixtures were then compared with municipal waste incinerator fly ash. Catalytic reaction of C2 aliphatic compounds at 600 degrees centigrade was found to have a significant contribution to the production of chlorination and nonchlorinated aromatic compounds in combustion processes.

Cations bind to the Π face of an aromatic structure through a surprisingly strong, non-covalent force termed the cation-Π interaction. The magnitude and generality of the effect have been established by gas-phase measurements and by studies of model receptors in aqueous media. To first order, the interaction can be considered an electrostatic attraction between a positive charge and the quadrupole moment of the aromatic. A great deal of direct and circumstantial evidence indicates that cation-Π interactions are important in a variety of proteins that bind cationic ligands or substrates. in this context, the amino acids phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp) can be viewed as polar, yet hydrophobic, residues., Noncovalent intermolecular forces play a major role in determining the structures of biological macromolecules and in mediating processes such as receptor-ligand interactions, enzyme-substrate binding, and antigen-antibody recognition. Although the hydrophobic [...]

The oxide-chloride exchange during the adsorption of chlorinated benzenes on magnesium oxide and calcium oxide particles with large surface areas were observed. The results showed the key role played by magnesium oxide, calcium oxide and the use of hydrogen as the flow gas in lowering the allowable temperature for the complete decompostion of chloroarenes. It also revealed the absence of chlorine-containing volatile product emissions from the magnesium oxide reactor bed.

The binding of Diederich's octamethoxy tetraoxaparacyclophane to p-xylene, benzene, p-cresol, p-dicyanobenzene and hydroquinone were analyzed using Monte Carlo simulations. The analysis yielded values of relative free energy that correlated well with experimental data. Some structural details accompanying the thermodynamic analysis are presented. This includes the effects of the hydration state of substituents in determining the order of binding affinities.

An atmospheric pressure ionization (API) source used with tandem mass spectrometry is effective in measuring dilute hydrocarbons in automobile exhaust. An API source and a triple quadrupole spectrometer can measure benzene and toluene at real-time rates as high as 100 hertz. In contrast, a low-pressure chemical ionization source used with tandem mass spectrometry is less sensitive than the API source method.

Experiments were conducted on a fluidized-bed reactor to investigate the effect of the flue gas temperature on the creation of chlorinated aromatic compunds during post-combustion in a solid waste incinerator. The study revealed the formation of polychlorinated dibenzo-p-dioxins, dibenzofurans, benzenes and biphenyls. It also demonstrated the existence of the four compounds as a function of both flue gas temperature and residence time in the reactor's cooling compartment.

The binding of molecular tweezers and clips, which contain naphthalene and benzene spacer units, to electron-deficient aromatic and aliphatic substrate in solution are examined. The temperature dependent liquid- and solid-state NMR spectroscopy is used to illustrate the dynamics of complex formation and substrate mobility.

Molecular-scale wires have many potential applications in nanotechnology. Such wires may be assembled from molecular units by exploiting intermolecular interactions, such as metal-ligand bonds or hydrogen bonds. Benzene rings may [...]

Electron-rich species such as benzene can interact with low-lying unoccupied orbitals of metal centers, for instance, when benzene adsorbs on metal surfaces. Mercury cations and organomercurials are known to have [...]

The replacement of volatile organic solvents with ionic liquids would reduce emissions of chemicals into the environment as well as promote energy-efficient separations. One concern, however, is that solvent interactions [...]