Sample records for 2-methylpropene

  1. Kinetics and Rate Law Determination of 2-Methylpropene Hydrogenation in a Packed-Bed Microreactor


    VAJGLOVÁ, Zuzana


    This study focuses on hydrogenation of C4 fraction, more specifically on development of the methodology of kinetic data collection and evaluation. The hydrogenation of 2- methylpropene on platinum catalyst was investigated as a model reaction.

  2. Improved direct production of 2,3-dimethylbutenes and 3,3-dimethylbutene from 2-methylpropene on tungsten hydride based catalysts

    KAUST Repository

    Garron, Anthony


    2-Methylpropene in the presence of W-H/Ni 1%-Al 2O 3-(500) is transformed in high selectivity into a mixture of 2,3-dimethylbutenes (2,3-DMBs = DMB-1 and DMB-2) and neohexene. 2,3-DMBs arise from the unfavoured 2-methylpropene self-metathesis reaction whereas the neohexene originates from a cascade reaction: 2-methylpropene dimerisation followed by cross metathesis. © 2012 The Royal Society of Chemistry.

  3. An investigation of the electronic structure of some 3-monosubstituted-2-methylpropenes through computational chemistry and photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Schuquel, Ivania T.A.; Ducati, Lucas C.; Custodio, Rogerio [Chemistry Institute, State University of Campinas, Caixa Postal 6154, 13084-971 Campinas, SP (Brazil); Rittner, Roberto [Chemistry Institute, State University of Campinas, Caixa Postal 6154, 13084-971 Campinas, SP (Brazil)], E-mail:; Klapstein, Dieter [Department of Chemistry, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 1C0 (Canada)


    The photoelectron (PE) spectra of some 3-monosubstituted 2-methylpropenes H{sub 2}C=C(CH{sub 3})CH{sub 2}X [X = Cl, Br, I, OH, OMe, OEt, SH, SMe, SEt, N(Me){sub 2} and N(Et){sub 2}] have been recorded. A preliminary analysis is presented indicating some trends in the ionization potentials associated with application of OVGF method and NBO analysis from MP2/6-31G(d,p) and cc-pVDZ level of theory indicating that the more effective hyperconjugation effect leads to the most stable conformers. The sensitivity of the outermost ionization energies of selected molecules with respect to the level of theory was analyzed. Application of the CASPT2 method with ANO basis set and geometries from MP2 calculations provided results in excellent agreement with the experimental data.

  4. C2-C10 hydrocarbon emissions from a boreal wetland and forest floor

    Directory of Open Access Journals (Sweden)

    S. Haapanala


    Full Text Available Emissions of various C2-C10 hydrocarbons and halogenated hydrocarbons from a boreal wetland and Scots pine forest floor were measured by static chamber technique in south-western Finland. Isoprene was the main non-methane hydrocarbon emitted by the wetland but also small emissions of ethene, propane, propene, 1-butene, 2-methylpropene, butane, pentane and hexane were detected. The isoprene emission from the wetland was observed to follow the commonly used isoprene emission algorithm. The mean emission potential of isoprene was 224 μg m−2 h−1 for the whole season. This is lower than the emission potentials published earlier and probably least partly due to the cold and cloudy weather during the measurements. No emissions of monoterpenes or halogenated hydrocarbons from the wetland were detected. Highest hydrocarbon emissions from the Scots pine forest floor were measured in spring and autumn. Main emitted compounds were monoterpenes. Isoprene emissions were negligible. Highest monoterpene emissions were measured in spring after the snow had melted. Emissions dropped in the summer and increased again in autumn. The total monoterpene emission rates varied from zero to 373 μg m−2 h−1. Probable source for these emissions is decaying plant litter. Also small emissions of chloroform (100–800 ng m−2 h−1, ethene, propane, propene, 2-methylpropene, cis-2-butene, pentane, hexane and heptane were detected.

  5. Biogenic Emissions of Light Alkenes from a Coniferous Forest (United States)

    Rhew, R. C.; Turnipseed, A. A.; Martinez, L.; Shen, S.; De Gouw, J. A.; Warneke, C.; Koss, A.; Lerner, B. M.; Miller, B. R.; Smith, J. N.; Guenther, A. B.


    Alkenes are reactive hydrocarbons that play important roles in the photochemical production of tropospheric ozone and in the formation of secondary organic aerosols. The light alkenes (C2-C4) originate from both biogenic and anthropogenic sources and include C2H4 (ethene), C3H6 (propene) and C4H8 (1-butene, 2-butene, 2-methylpropene). Light alkenes are used widely as chemical feedstocks because their double bond makes them versatile for industrial reactions. Their biogenic sources are poorly characterized, with most global emissions estimates relying on laboratory-based studies; net ecosystem emissions have been measured at only one site thus far. Here we report net ecosystem fluxes of light alkenes and isoprene from a semi-arid ponderosa pine forest in the Rocky Mountains of Colorado, USA. Canopy scale fluxes were measured using relaxed eddy accumulation (REA) techniques on the 28-meter NCAR tower in the Manitou Experimental Forest Observatory. Updrafts and downdrafts were determined by sonic anemometry and segregated into 'up' and 'down' reservoirs over the course of an hour. Samples were then measured on two separate automated gas chromatographs (GCs). The first GC measured light hydrocarbons (C2-C6 alkanes and C2-C5 alkenes) by flame ionization detection (FID). The second GC measured halocarbons (methyl chloride, CFC-12, and HCFC-22) by electron capture detection (ECD). Additional air measurements from the top of the tower included hydrocarbons and their oxidation products by Proton Transfer Reaction Mass Spectrometry (PTR-MS). Three field intensives were conducted during the summer of 2014. The REA flux measurements showed that ethene, propene and the butene emissions have significant diurnal cycles, with maximum emissions at midday. The light alkenes contribute significantly to the overall biogenic source of reactive hydrocarbons and have a temporal variability that may be associated with physical and biological parameters. These ecosystem scale measurements