m-Xylene transformation has been studied on as-prepared H-Y and a series of dealuminated Y zeolite catalysts. The conversion of m-xylene was found to increase initially with acidity, however, decreases subsequently. It has been proposed that the high concentration of acid sites in the H-Y catalyst increases paring reaction, in addition to the well-known isomerization and disproportionation path...

Xylenes transformations have been investigated over ZSM-5 zeolite in a riser simulator that mimics closely the operation of commercial fluidized-bed reactors. P-xylene was found to be more reactive than the other isomers followed by o-xylene and m-xylene was found to be least reactive. The order of reactivity is consistent with the order of diffusivity. At low temperature (400°C), isomerization...

Various alkylbenzenes were depleted during growth of an anaerobic, sulfate-reducing enrichment culture with crude oil as the only source of organic substrates. From this culture, two new types of mesophilic, rod-shaped sulfate-reducing bacteria, strains oXyS1 and mXyS1, were isolated with o-xylene and m-xylene, respectively, as organic substrates. Sequence analyses of 16S rRNA genes revealed th...

Anaerobic sulfate-reducing bacteria were enriched from contaminated aquifer samples with naphthalene, o-, and m-xylene as sole carbon and energy source in the presence of Amberlite-XAD7, a solid adsorber resin. XAD7 served as a substrate reservoir maintaining a constantly low substrate concentration in the culture medium. In equilibration experiments with XAD7, the aromatic hydrocarbons needed ...

Exposure to low levels of chemicals indoors is often to a mixture of volatile organic compounds (VOCs). It is of interest to determine if the symptomatic and sensory responses can be attributed to a single chemical or to a mixture of chemicals. To determine if sensory or symptomatic responses differ with exposure to single or mixed VOCs, 100 female subjects participated in a 6-hr exposure study...

The rotational spectra of m-xylene, (CH3)2C6H4, and of m-xylene-d10, (CD3)2C6D4, have been recorded between 6 and 26.5 GHz using pulsed beam Fourier transform microwave spectroscopy. The clue for the assignment of the internal rotation multiplets was the inertial defect derived from the A1A1 species transitions. The rotational constants for m-xylene and m-xylene-d10 are A = 3572.1117(1) MHz / 2...

The objective of this study was to assess the occupational exposure of jeepney drivers to selected volatile organic compounds (VOCs) in Manila, Philippines. Personal sampling was conducted on 15 jeepney drivers. Area sampling was conducted to determine the background VOC concentration in Manila as compared to that in a rural area. Both personal and area samples were collected for 5 working days...

Global sensitivity analysis (SA) was used during the development phase of a binary chemical physiologically based pharmacokinetic (PBPK) model used for the analysis of m-xylene and ethanol co-exposure in humans. SA was used to identify those parameters which had the most significant impact on variability of venous blood and exhaled m-xylene and urinary excretion of the major metabolite of m-xyl...