[en] Quadrupole coupling constants and asymmetry parameters have been determined for the methyl group deuterons in toluene-d₈, C₆D₅CD₃, and in ortho- and para-xylene, o-C₆D₄ (CD₃)₂ and p-C₆D₄(CD₃)₂, at 77 K. The coupling constant values are equal within experimental uncertainty, whereas the asymmetry parameters are not. The considerable disparity in effective asymmetry parameters observed in these three compounds shows that significant differences must arise in the rigid bond coupling constants of the individual methyl group deuterons

[en] In this contribution, we describe the method used to produce deuterated polyethylene (C2D4) targets. The modification of method based on polyethylene dissolution in hot xylene resulted with stable thin C2D4 targets.

[en] Absolute rate constants for the reaction of OH radicals with a series of aromatic hydrocarbons have been determined at room temperature using a flash photolysis-resonance fluorescence technique. The rate constants (k₁ x 10¹² cm³ molecule^-1 sec^-1 ) obtained are as follows: benzene, 1.24 +- 0.12; toluene, 5.78 +- 0.58; o-xylene, 15.3 +- 1.5; m-xylene, 23.6 +- 2.4; p-xylene, 12.2 +- 1.2; 1,2,3-trimethylbenzene, 26.4 +- 2.6; 1,2,4-trimethylbenzene, 33.5 +- 3.4; 1,3,5-trimethylbenzene, 47.2 +- 4.8. These absolute rate constants are in good agreement with those determined recently for benzene and toluene and with those derived for a series of aromatic hydrocarbons from a relative rate study in an environmental chamber. (auth)

No abstract available

[en] Ninety-six bacterial isolates were isolated from the soil samples collected from MADA Rice Experimental Plot, Kedah. Many of the isolates were Gram-positive bacteria suggesting this type of bacteria makes up the majority of the culturable populations residing in the plots investigated. These isolates were studied for their abilities to hydrolyse carboxymethyl cellulose (CMC) and xylan. Ability to hydrolyse CMC was observed in 61.5% of the isolates. Whilst 62.5% of the isolates exhibiting the ability to hydrolyse xylan. Active isolates were further confirmed by the presence of the respective gene(s) via molecular approaches. These isolates were later screened by restriction fragment length polymorphism (RFLP), and sequencing of representative 16S rDNAs. Majority of identified isolates were members of common soil microbe such as members of the genera Bacillus. (Author)

[en] In this study, a nation-wide field measurement has been carried out in Chinese residence to obtain BTEX(benzene series) concentration levels and characteristics. Concentrations of benzene series (benzene, toluene, xylene and ethylbenzene) indoor were sampled in 223 dwellings covering 5 climate zones in China during 2016.12-2017.12. The arithmetic mean concentrations of benzene, toluene, xylene and ethylbenzene were 6.78μg/m³, 17^g/m³, 17.68μg/m³ and 9.87μg/m³, respectively. Higher concentration of BTEX and higher standard limit were founded in China than that in other countries and organizations. We identify some reasonable sources for specific data group, impact factors on decoration year, frequency of smoking and cooking of benzene series concentration were studied. Toluene concentration decreased with increase of decoration year, and concentration of benzene concentration in smoking families were higher than that in non-smoking families. No direct correlation between cooking frequency and indoor benzene concentration were founded. This study also provided statistical data on benzene exposure in new decorated residences and a discussion on setting limit values for standard. (paper)

[en] Zr-benzendicarboxylate structure, UiO-66 was prepared in 1-L batch scale by using a unique sonochemical-solvothermal combined synthesis method. The produced UiO-66 showed uniform particles of ca. 0.2 µm in size with the BET surface area of 1,375 m²/g in high product yield (>95%). The UiO-66 showed 198 and 84 mg/g CO₂ adsorption capacity at 273 K and 298 K, respectively, with excellent CO₂ selectivity (CO₂:N₂=32:1) at ambient conditions. The isosteric heat of CO₂ adsorption varied from 33 to 25 kJ/mol as the adsorption progressed. The UiO-66 tested for xylene isomer separation in a liquid-phase batch mode confirmed preferential adsorption of the adsorbent for o-xylene over m-, and p-xylene

[en] Use of selected microorganisms for the degradation and/or detoxification of hazardous organic compounds is gaining wide acceptance as an alternative waste treatment technology. The INEL Biotechnology Unit is developing the technology for the in-plant treatment of waste industrial solvents. The work centers around the use of microorganisms specially selected for their ability to degrade common industrial solvents such as benzene, toluene, xylene, etc. Because these waste solvents are often contaminated with other materials (heavy metals, water, detergents, etc.) they are difficult and expensive to dispose and many times are not economical to recover through recycling. Even if the disposal option is used, the generator is still faced with continued liability in the event of mishandling or improper disposal of the waste. Biological treatments offers the option of reducing these solvents into harmless by-products provided that both the requisite microorganisms and the proper processing technology are successfully brought together. Work on the optimization of a bioreactor process for the degradation of xylene will be discussed. 15 figs., 7 refs

[en] Formation of radical cations from the OH adducts of methylated benzenes in acidic aqueous solutions is demonstrated. The radical cation is formed as an intermediate species in the water elimination reaction in which the OH adduct is transformed into the corresponding methylbenzyl radical. The radical cations are also produced in neutral aqueous solution by reacting SO₄^- radical ions with the methylated benzenes. The cations have two absorption bands, an UV band, 280-300 nm, and a visible band, 430-470 nm, with extinction coefficient of about 6500 and 2000 M^-1 cm^-1, respectively. The formation of the radical cations from the OH adducts depends on the hydrogen ion concentration, k/sub OH adduct+H⁺/ = (1.5 +- 0.5) x 10⁹ M^-1 s^-1. The radical cations decay in acid solution exclusively into the corresponding methylbenzyl radicals

[en] Short communication