Cyclohexene

About: Cyclohexene is a research topic. Over the lifetime, 7295 publications have been published within this topic receiving 126499 citations. The topic is also known as: Benzene tetrahydride & Tetrahydrobenzene.

High-Performance Nanocatalysts for Single-Step Hydrogenations

Abstract: Bimetallic nanoparticles (Ru6Pd6, Ru6Sn, Ru10Pt2, Ru5Pt, Ru12Cu4, and Ru12Ag4) anchored within silica nanopores exhibit high activities and frequently high selectivities, depending upon the composition of the nanocatalyst, in a number of single-step (and often solvent-free) hydrogenations at low temperatures (333−373 K). The selective hydrogenations of polyenes (such as 1,5,9-cyclododecatriene and 2,5-norbornadiene) are especially efficient. Good performance is found with these nanoparticle catalysts in the hydrogenation of dimethyl terephthalate to 1,4 cyclohexanedimethanol and of benzoic acid to cyclohexanecarboxylic acid or to cyclohexene-1-carboxylic acid, and also in the conversion of benzene to cyclohexene (or cyclohexane), the latter being an increasingly important reaction in the context of the production of Nylon. Isolated atoms of noble metals (Pd, Rh, and Pt) in low oxidation states, appropriately complexed and tethered to the inner walls of nanoporous (ca. 3 nm diameter) silica, are very promi...

Evidence for an Additional Oxidant in the Photoassisted Fenton Reaction

Abstract: The photo-Fenton reaction (Fe3+ + H2O2 + UV) has potential applications in wastewater treatment. This reaction was compared to H2O2 photolysis and other reactions that produce only hydroxyl radicals (OH•) in order to probe for additional or alternative intermediates that may contribute to the recognized potency of photo-Fenton as an oxidant of organic compounds. Distinct differences were found between photo-Fenton and genuine OH• reactions. The kinetic deuterium isotope effect (KDIE) for cyclohexane in the photo-Fenton reaction increases from 1.2 to 1.4 with increasing concentration of OH• scavenger, tert-butyl alcohol; whereas the KDIE in genuine OH• reactions (H2O2/UV, Fe3+/UV, and Fe2+ + H2O2) is 1.1 and unchanged in the presence of tert-butyl alcohol. Photo-Fenton catalyzed the epoxidation of cyclohexene at a much greater rate than H2O2/UV. The relative yields of chlorinated organic acids from 1,1,2-trichloroethane, trichloroethene, and tetrachloroethene oxidation were markedly affected by the presenc...

Particle phase acidity and oligomer formation in secondary organic aerosol.

Abstract: A series of controlled laboratory experiments are carried out in dual Teflon chambers to examine the presence of oligomers in secondary organic aerosols (SOA) from hydrocarbon ozonolysis as well as to explore the effect of particle phase acidity on SOA formation. In all seven hydrocarbon systems studied (i.e., α-pinene, cyclohexene, 1-methyl cyclopentene, cycloheptene, 1-methyl cyclohexene, cyclooctene, and terpinolene), oligomers with MW from 250 to 1600 are present in the SOA formed, both in the absence and presence of seed particles and regardless of the seed particle acidity. These oligomers are comparable to, and in some cases, exceed the low molecular weight species (MW < 250) in ion intensities in the ion trap mass spectra, suggesting they may comprise a substantial fraction of the total aerosol mass. It is possible that oligomers are widely present in atmospheric organic aerosols, formed through acid- or base-catalyzed heterogeneous reactions. In addition, as the seed particle acidity increases, larger oligomers are formed more abundantly in the SOA; consequently, the overall SOA yield also increases. This explicit effect of particle phase acidity on the composition and yield of SOA may have important climatic consequences and need to be considered in relevant models.