Benzene laboratory data

Laboratory data indicate that the reactions proceed irreversibly without a catalyst at temperatures in the range of 1,200-1,270°F with approximately 75 mol% of the toluene converted to benzene and approximately 2 mol% of the benzene produced in the hydrodealkylation reaction converted to biphenyl. Since the reactions occur in series in a single processing unit, just a single reaction operation is positioned in the flowsheet, as shown in Figure 4.16. The plant capacity is based on the conversion of 274.2 Ibmol/hr of toluene, or approximately 200 MMlb/yr, assuming operation 330 days per year. 

Figure 3 Laboratory data from ion trap MS analysis of water samples that were obtained during towed-deployment of the quadrupole MS system. The m/z78 ion is diagnostic of benzene and the m/z 91 ion is diagnostic of toluene. Analyses of samples are compared with 1 ppb standards. (Reprinted with permission from Short RT, Fries DP, Kerr ML, Lembke CE, Toler SK, etal. (2001) Underwater mass spectrometers for in situ chemical analysis of the hydrosphere. Journal of the American Society for Mass Spectrometry 12 676-682 The American Society for Mass Spectrometry.)...

Sauer, T.C., Jr, Sackett, W.M. Jeffrey, L.M. (1978) Volatile liquid hydrocarbotrs in the surface coastal waters of the Gulf of Mexico. Marine Chem., 1, 1-16 Seifert, B. Abraham, H.-J. (1982) Indoor air concentratiotrs of benzene and some other aromatic hydrocarbons. Ecotoxicol. environ. Saf, 6, 190-192 Shah, J.J. Heyerdahl, E.K. (1988) National Ambient Volatile Organic Compounds (VOCs) Data Base Update (EPA 600/3-88/0 lOA), Research Triangle Park, NC, Environmental Protection Agency, Atmospheric Sciences Research Laboratory ... 

Spectroscopy data Infrared (proton [5830] grating [33038]), nuclear magnetic resonance (proton [6575] C-13 [2936]) and mass spectral data have been reported (Sadtler Research Laboratories, 1980 Lide Milne, 1996) Solubility Very soluble in water (954 g/L) and ethanol slightly soluble in benzene and diethyl ether (Lide Milne, 1996 Verschueren, 1996)... 

Our constitutional scheme is based on different kinds of information. The first type of information comes from an analytical study of milled spruce wood lignin prepared according to Bjorkman (3). The analytical data considered comprise the elemental composition of lignin, its content of methoxyl groups and other ether bonds, the types and amount of its different hydroxyl groups, carbonyl, and lactone groups, and the kind and number of its biphenylyl linkages and other bonds in which the benzene nucleus is involved. The work that led to data of this kind has been carried out in various laboratories and has been described previously (9,11). 

The aromatic solvents show very small but reasonably systematic increases in negative charge donated to I2 as the degree of methylation increases (Table 5), although to discern this effect it is necessary always to compare data from the same laboratory. In the case of benzene, X-ray diffraction of the frozen solutions shows that the I2 molecules are capped at each end by C6H6 molecules lying perpendicular to the I-I axis. The interaction is therefore between the filled alg 7i-orbital of the benzene and the iodine a orbital as acceptor. Similar structures are likely to apply for the methylated benzene complexes. 

Animal data confirm that benzene is rapidly absorbed through the lungs. Inhalation studies with laboratory dogs indicate that distribution of benzene throughout the animal s body is rapid, with tissue values dependent on blood supply. A linear relationship existed between the concentration of benzene in air (200-1,300 ppm) and the equilibrium concentration in blood (Schrenk et al. 1941). At these exposures, the concentrations of benzene in the blood of dogs exposed to benzene reached a steady state within 30 minutes. 

Data regarding metabolism of benzene in humans have come primarily from studies using inhalation exposures. Benzene is excreted both unchanged via the lungs and as metabolites in the urine. The rate and percentage of excretion via the lungs are dependent on exposure dose and route. Qualitatively, the metabolism and elimination of benzene appear to be similar in humans and laboratory animals, but no directly comparable studies are available (Henderson et al. 1989 Sabourin et al. 1988). 

Salanitro (1993) has summarized the aerobic degradation rates for BTEX in laboratory subsoil-groundwater slurries and aquifers. The data indicate that decay rates for benzene are highest (19-52% per day) for benzene concentrations less than 1 ppm when initial dissolved oxygen levels are about 8 ppm. Rates are significantly reduced (0-1.1% per day) when benzene levels are 1-2 ppm, and no degradation was observed when benzene levels were greater than 2 ppb. 

As part of the Third National Health and Nutrition Evaluation Survey (NHANES III), the Environmental Health Laboratory Sciences Division of the Center for Environmental Health and Injury Control, Centers for Disease Control and Prevention, will be analyzing human blood samples for benzene and other volatile organic compounds. These data will give an indication of the frequency of occurrence and background levels of these compounds in the general population. 

Model Reaction. The benzene hydrogenation on nickel-kiesel-guhr has been selected as a model reaction. This reaction is well understood and can serve as a typical representative of hydrogenation reactions. Butt (4 5) and Pexider et al.(11) have studied this reaction in laboratory and pilot plant reactors respectively. Pexiderfs data have been obtained from a nonadiaba-tically operated reactor. The reaction rate expression has ... 

A 1980 Naval Research Laboratory report provides data on the toxic combustion products evolved by burning polyphosphazene foams, with and without fire retardants. Toxicants produced were CO, CO2, 2-chlorobutane, 1-chlorobutane, benzene, toluene, and trichloroethylene (for foams not coated with fire-retardant paints) (11). 

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