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Hydrocarbon Molecules (hydrocarbon + molecule)
Selected AbstractsSurface of Metallic Catalysts under a Pressure of Hydrocarbon Molecules: Metal or Carbide?CHEMCATCHEM, Issue 6 2010Philippe Sautet Dr. What have I done to the surface? The nature of the surface of a solid catalyst can be modified by the reactants; molecular decomposition can produce new phases in the near-surface region, changing the catalytic properties in,situ. First-principle calculations show trends among transition metal catalysts for the formation of a surface carbide from a range of hydrocarbon molecules or CO. Pd, Ni, and Fe are most prone to carbon penetration in the subsurface. [source] Fate of air toxics and VOCs in the odor control scrubbers at the deer island treatment plantENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 4 2000Thomas Myslinski Process off-gases at the Deer Island wastewater treatment plant in Boston are collected and treated and its stack emissions regulated for selected gases including volatile organic compounds (VOCs), which are monitored as nonmethane hydrocarbons (NMHC). The air treatment processes of countercurrent wet oxidation scrubbing and granulated activated carbon adsorption are available for emissions control at Deer Island. In addition, since the wastewater treatment process of biochemical oxidation is fully enclosed at the site, microbial destruction of VOCs is an intrinsic treatment process for organic gases. Surveyed results of wastewater research literature indicate that the use of scrubbers for the removal of VOCs is controversial, as the fate of volatile hydrocarbon molecules across odor control scrubbers is complex and not fully understood. Continuous emission monitoring tests across the Deer Island scrubbers have consistently shown a VOC removal efficiency in excess of 50%. The fate of the scrubber inlet VOCs at Deer Island was researched as part of a plant-wide, on-going VOC study. Removal efficiencies across the pure oxygen bioreactors were also investigated. Preliminary results of this study indicate chemical reactions involving VOCs in odor control scrubbers partially oxidize and chlorinate derivatives possibly destroying a fraction of the compounds by complete oxidation. In addition, VOC reduction across the enclosed aerobic bioreactors was found to be significant. This article represents the opinions and(legal) conclusions of the authors and not necessarily those of the MWRA. [source] Electronic Contact Deposition onto Organic Molecular Monolayers: Can We Detect Metal Penetration?ADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Hagay Shpaisman Abstract Using a semiconductor as the substrate to a molecular organic layer, penetration of metal contacts can be clearly identified by the study of electronic charge transport through the layer. A series of monolayers of saturated hydrocarbon molecules with varying lengths is assembled on Si or GaAs and the junctions resulting after further electronic contact is made by liquid Hg, indirect metal evaporation, and a "ready-made" metal pad are measured. In contrast to tunneling characteristics, which are ambiguous regarding contact penetration, the semiconductor surface barrier is very sensitive to any direct contact with a metal. With the organic monolayer intact, a metal,insulator,semiconductor (MIS) structure results. If metal penetrated the monolayer, the junction behaves as a metal,semiconductor (MS) structure. By comparing a molecule-free interface (MS junction) with a molecularly modified one (presumably MIS), possible metal penetration is identified. The major indicators are the semiconductor electronic transport barrier height, extracted from the junction transport characteristics, and the photovoltage. The approach does not require a series of different monolayers and data analysis is quite straightforward, helping to identify non-invasive ways to make electronic contact to soft matter. [source] Application of CAMD in separating hydrocarbons by extractive distillationAICHE JOURNAL, Issue 12 2005Biaohua Chen Abstract The solvent is the core of extractive distillation, and a suitable solvent plays an important role in the economical design of extractive distillation. Computer-aided molecular design (CAMD) has been applied to rapidly screen the solvents for separating hydrocarbons by extractive distillation. The systems of propane/propylene, n-butane/1-butene, and n-heptane/benzene, respectively, as the representatives of C3, C4, and C6 hydrocarbons were investigated, and the potential solvents were selected by means of CAMD. The designed results were further proven by experiments and process simulation. The mechanism for separating hydrocarbons by extractive distillation is based on the different fluidities of the electron cloud of CC (no double bond), CC (one double bond), and ACH (aromatic carbon ring) bonds and thus different interactions between solvent and hydrocarbon molecules. To improve the separation ability of the main solvent, one strategy is to add some additive that can form hydrogen bonding with the main solvent to make into a mixture. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] Monodisperse magnetic nanoparticles for biomedical applicationsPOLYMER INTERNATIONAL, Issue 7 2007Chenjie Xu Abstract Magnetic nanoparticles that are superparamagnetic with high saturation moment have great potential for biomedical applications. Solution-phase syntheses have recently been applied to make various kinds of monodisperse magnetic nanoparticles with standard deviation in diameter of less than 10%. However, the surface of these nanoparticles is coated with a layer of hydrocarbon molecules due to the use of lipid-like carboxylic acid and amine in the syntheses. Surface functionalization leads to the formation of water-soluble nanoparticles that can be further modified with various biomolecules. Such functionalization has brought about several series of monodisperse magnetic nanoparticle systems that have shown promising applications in protein or DNA separation, detection and magnetic resonance imaging contrast enhancement. The goal of this mini review is to summarize the recent progress in the synthesis and surface modification of monodisperse magnetic nanoparticles and their applications in biomedicine. Copyright © 2007 Society of Chemical Industry [source] Surface of Metallic Catalysts under a Pressure of Hydrocarbon Molecules: Metal or Carbide?CHEMCATCHEM, Issue 6 2010Philippe Sautet Dr. What have I done to the surface? The nature of the surface of a solid catalyst can be modified by the reactants; molecular decomposition can produce new phases in the near-surface region, changing the catalytic properties in,situ. First-principle calculations show trends among transition metal catalysts for the formation of a surface carbide from a range of hydrocarbon molecules or CO. Pd, Ni, and Fe are most prone to carbon penetration in the subsurface. [source] Growth of Larger Hydrocarbons in the Ionosphere of TitanCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2008Claire More charge, more reactivity: In contrast to the neutral and monocationic counterparts, hydrocarbon dications CmHn2+ (m=7,11, n=6,8) react with methane via CC coupling concomitant with dehydrogenation (see graphic). With respect to the ionosphere of Titan, small steady-state concentrations of hydrogencarbon dications provide a viable mechanism for the growth of larger hydrocarbon molecules in the presence of methane. [source] | |||||||||||||