Nitrobenzene as a material for the fast-respond degenerate four-wave mixing

We have revealed a possibility of using nitrobenzene (NB) as a promising for time-resolving degenerate four-wave mixing (DFWM). The DFWM efficiency versus time delay between the probe and pump beams was revealed. The four time-retarded maxima of the DFWM are caused by specific electron–vibration interactions in the NB. An essential contribution of acoustical vibrations is demonstrated. Molecular dynamics geometry optimisation of the NB molecule is done taking into account intermolecular interactions. Superposition of all possible molecular conformations with appropriate weighting factors and higher-order intermolecular multiple interactions is considered. The observed DFWM behavior is explained within the framework of ab inito quantum chemical calculations with inclusion of excited configuration interaction (CI) states. We considered both harmonic as well anharmonic electron–vibration interactions. The average lifetime of MO levels contributing to the third-order nonlinear and time kinetics of the observed DFWM dependences is estimated. Advantages and drawbacks of the prosposed method are discussed.     

Catalyst preparation and deactivation issues for nitrobenzene hydrogenation in a microstructured falling film reactor

Hydrogenation of nitrobenzene to aniline in ethanol was performed continuously in a microstructured falling film reactor at 60 °C, 1–4 bar hydrogen pressure and residence time 9–17 s. Palladium catalyst was deposited as films or particles via sputtering, UV-decomposition of palladium acetate, incipient wetness or impregnation. Deactivation was observed and was particularly pronounced for the sputtered and UV-decomposed catalysts. Catalysts prepared through incipient wetness or impregnation were more stable and activity could be recovered by oxidation at 130 °C. The main causes of deactivation were determined to be deposition of organic compounds and palladium loss.     

松花江和北江水污染事件中的城市供水应急处理技术

总结了近期在我国突发性水污染事件中所采用的城市供水应急处理技术。在松花江水污染事件中,采用了投加粉末活性炭和粒状活性炭过滤来吸附水中的硝基苯,其中在水厂取水口处投加粉末活性炭,把安全屏障前移是应急处理的关键措施。在广东北江镉污染事件中,紧急确定了弱碱性混凝处理的除镉技术,除镉处理的pH控制在9。经采用应急处理技术,在水源水中特征污染物超标数倍的情况下,水厂出水中污染物的浓度远远低于饮用水水质标准的限值,应急处理取得了成功。介绍了有关水污染事件的概况,总结了城市应急供水的应对措施和实施效果,并系统归纳了所用应急处理技术的要点,对全国城市供水应急系统的建设有重要的指导意义和参考价值。     

硝基苯加氢制苯胺催化剂研究

介绍了硝基苯加氢制苯胺催化剂的制备方法。通过实验考察了氧化铜含量对催化剂稳定性和活性的影响,以及助剂铬、钼、碱金属对催化剂性能的改进作用。同时考察了温度和氢油摩尔比对催化剂活性的影响。     

硝基苯、苯胺混合废水的生化处理实践

硝基苯（NB）、苯胺（An）废水均属难降解废水。针对这一特性,采用生化法进行综合处理,根据调试数据显示,发现效果比较理想,处理后的出水水质达到国家规定的一级排放标准（GB8978—1996）：An〈1 mg／L,NB〈2mg／L．COD〈100mg／L,此工艺方法是可行性。     

STUDIES OF DYNAMIC VISCOSITY AND GIBBS ENERGY OF ACTIVATION OF BINARY AND TERNARY MIXTURES OF BENZYLCHLORIDE + NITROBENZENE + ISOBUTANOL FROM T = (288.15 TO 313.15) K

Densities and viscosities of ternary mixtures of benzylchloride + nitrobenzene + isobutanol and three corresponding binary mixtures (benzyl chloride + isobutanol, benzyl chloride + nitrobenzene, and nitrobenzene + isobutanol) have been determined over the whole concentration at a temperature range of 288.15 to 313.15 K under atmospheric pressure. Experimental data of resulting mixtures were used to calculate viscosity deviations, Δln η, and excess energies of activation of viscous flow, ΔG*^E, of the ternary system. The calculated data for binary mixtures have been fitted by the Redlich-Kister equation to determine the appropriate coefficients. In order to determine the coefficients of ternary data, Cibulka, Singh, and Nakata equations were used. The results have also provided a test for the Grunberg and Nissan equation for correlating the dynamic viscosities of binary and ternary mixtures with mole fractions.     

Direct synthesis of carbon and nitrogen–carbon nanospheres from aromatic hydrocarbons

In the present work, a controlled production of carbon nanospheres (CNS) via pyrolysis of benzene, aniline and nitrobenzene at 950 °C has been examined. The nature of the carbonaceous product has been characterized by transmission electron microscopy (TEM), N₂ adsorption/desorption, X-ray diffraction (XRD), elemental analysis (CHN), temperature-programmed oxidation (TPO) and X-ray photoelectron spectroscopy (XPS). Time-on-stream served to enhance the spherical morphology of the product, as well as its crystalline character. Nitrogen inclusion resulted in an enhanced curvature of the graphene layers, as well as the incorporation of lattice defects, resulting in a less crystalline material. The reactive nature of the feed influenced the amount of nitrogen incorporated into the carbon matrix, as well as the kind and distribution of nitrogen functionalities.     

苯胺装置扩产改造开车运行分析

介绍了南化公司硝基苯加氢制苯胺装置扩产改造后的开车过程,有效地解决了开车过程中存在的问题,并对运行情况进行了分析和总结。     

Synchrotron X-ray microtomography of Raney-type nickel catalysts prepared by gas atomisation: Effect of microstructure on catalytic performance

Synchrotron X-ray microtomography (SXRM) was used to examine the microstructure of various Ni–Al alloys prepared by gas atomisation. The resulting Raney-type nickel catalysts that were activated by chemical treatment with a concentrated sodium hydroxide solution (20 wt% in water) were also studied. The main objective of this work is to correlate the microstructure of various Ni–Al alloys prepared by gas atomisation and the catalytic performance of the resulting Raney-type nickel catalysts. It appears that a NiAl₃/Ni₂Al₃ ratio around 2.3 in the precursor alloy prepared by gas atomisation favours the formation of a dendritic network in the atomised spherical particle. The spherical shape of the particle and the dendritic network are still present after the leaching process in the Raney-type nickel catalysts. After activation, the interdendritic space forms a macroporous network that is directly linked to the catalytic performance. Parameters of the precursor alloy, i.e. particle size, phase composition, are chosen to obtain an optimal catalytic performance. In this way, an activity is obtained that is at least a factor of 2 higher than that of alloys prepared by the commercial cast-and-crush method. Inductively coupled plasma optical emission spectroscopy (ICP-OES) and BET measurements were used for bulk analysis and determination of the surface area, respectively. Hydrogenation of nitrobenzene and butyraldehyde were used as test reactions. A model that directly correlates the microstructure of a precursor alloy processed by gas atomisation and the catalytic performance of the resulting catalyst is proposed.     

Biodegradation potential of pure and mixed bacterial cultures for removal of 4-nitroaniline from textile dye wastewater

Environmentally toxic aromatic amines including nitroanilines are commonly generated in dye contaminated wastewater in which azo dyes undergo degradation under anaerobic conditions. The aim of this study was to develop a process for biological treatment of 4-nitroaniline. Three bacteria identified as Acinetobacter sp., Citrobacter freundii and Klebsiella oxytoca were isolated from enrichment cultures of activated sludge on 4-nitroaniline, after which the isolates and the mixed culture were studied to determine optimal conditions for biodegradation. HPLC analyses showed the mixed culture was capable of complete removal of 100 μmol/L of 4-nitroaniline within 72 h under aerobic conditions. There was an inverse linear relationship (R² = 0.96) between the rate of degradation (V) and 4-nitraoaniline concentrations [S] over 100-1000 μmol/L. The bacterial culture was also capable of decolorizing structurally different azo dyes (Acid Red-88, Reactive Black-5, Direct Red-81, and Disperse Orange-3) and also degraded nitrobenzene. Our findings show that enrichment cultures from activated sludge can be effective for the removal of dyes and their toxic intermediates, and that treatment may best be accomplished using an anaerobic-aerobic process.