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- Skoglundh, Magnus, 1965, et al.
(författare)
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Combinations of platinum and palladium on alumina supports as oxidation catalysts
- 1991
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Ingår i: Applied Catalysis. - 0166-9834 .- 1873-3867. ; 77:1, s. 9-20
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Tidskriftsartikel (refereegranskat)abstract
- The effects of the total content of Pd+Pt, the mol-% ratio of Pd to Pt, hydrothermal treatment of the catalyst wash-coat, and the oxygen concentration on the light-off temperature, T50, for the complete oxidation of xylene isomers, propene, and carbon monoxide were studied. The alumina wash-coats were thermally treated at 500°C for 2 h in air or after the thermal treatment, hydrothermslly treated at 814°C for 2 h in 100-% steam. The catalysts were impregnated with 5, 10, and 20 micromol of Pd+Pt per gram of catalyst. The mol-% ratio of Pd to Pt was varied in the range from 0:100 to 100:O. The light-off temperatures had a minimum at a Pd:Pt mol-% ratio of 80:20, and decreased with increasing total metals concentration, increasing oxygen concentration and hydrothermal treatment of the alumina wash-coat.
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- Hvitt Strömvall, Ann-Margret, 1963, et al.
(författare)
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Ambient monoterpenes from stone groundwood pulp production
- 1990
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Ingår i: Holzforschung. ; 44, s. 449-452
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Tidskriftsartikel (refereegranskat)abstract
- Composition and ambient concentrations in air were studied for monoterpenes from stone groundwood production at a Swedish plant using exclusively pulp wood from Norway spruce. Field samples were taken on Tenax adsorption cartridges and analyzed by thermal desorption combined with temperature programmed capillary gas chromatography. The major monoterpenes emitted from the process were alpha-pinene(54-59 %) and beta-pinene(24-28 %). Limonene, 3-carene, beta-phellandrene, camphene and myrcene (1-10 % each) followed in decreasing relative proportions. Total ambient monoterpene concentrations above 500 microgram/m3 were assessed at ground level downwind from the emissions. Photo-oxidants formed in the monoterpene plumes are discussed with respect to forest damage and health hazards.
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- Hvitt Strömvall, Ann-Margret, 1963, et al.
(författare)
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Photooxidant-forming monoterpenes in air plumes from kraft pulp industries
- 1993
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Ingår i: Environmental Pollution. ; 79, s. 219-223
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Tidskriftsartikel (refereegranskat)abstract
- Monoterpenes emitted to air from two Swedish kraft (sulphate) pulp-mills were determined by sampling on the Tenax adsorbent followed by laboratory analysis using thermal desorption combined with high-resolution gas chromatography. The composition of the terpenes was found to be similar in the emissions from various parts of the process as well as in the mill plume. The bicyclic terpenes alpha-pinene and 3-carene, originating principally from wood of Scots pine (Pinus sylvestris), predominated among the thirteen assessed hydrocarbon monoterpenes. Terpinolene was the most prominent among the particularly reactive terpenes with a lifetime in ozone-rich air of only a few minutes. The rapid formation of photooxidants by chemical reactions of the terpenes with other components of the mill plume is discussed. It is concluded that a variety of phytotoxic photooxidants are formed which may contribute significantly to forest decline within 50 km of mills located along coasts.
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- Hvitt Strömvall, Ann-Margret, 1963, et al.
(författare)
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Terpenes emitted to air from TMP and sulphite pulp mills
- 1992
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Ingår i: Holzforschung. ; 46, s. 99-102
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Tidskriftsartikel (refereegranskat)abstract
- Terpenes were studied at two Swedish pulp mills processing wood from Norway spruce (Picea abies). Field samples were adsorbed from air on Tenax cartridges and analyzed in the laboratory by thermal desorption and gas chromatography.The emissions from a large thermomechanical pulp (TMP) plant consisted mainly of chemically unchanged hydrocarbon monoterpenes from the wood. The major monoterpenes were alpha-pinene (>50 %) and beta-pinene (20-30 %).The proportions of ten additional components were determined in the process emissions, which may be recovered to turpentine.The process emissions from a sulphite pulp mill consisted predominantly of the alkylbenzene para-cymene, formed from monoterpenes by acid reactions in the digestors. The contribution of the emissions to photo-oxidant formation in the surrounding region may be significant for both types of mills.
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- Ramnäs, Olle Jerker, 1941, et al.
(författare)
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Characterization of sixty alkenes in a cat-cracked gasoline naphtha by gas chromatography
- 1994
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Ingår i: Chromatographia. ; 38, s. 222-226
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Tidskriftsartikel (refereegranskat)abstract
- The alkene-rich petrol fraction from refinery fluid catalytic cracking (FCC) has been characterized by GC and GC-MS. Quantitative proportions and retention data of 52 acyclic and 11 cyclic C5–C7 alkenes are given. Relative retentions are reported for methylsilicone and aluminium oxide stationary phases as methylene units (MU). Applications of mass spectra, single-ion GC-MS monitoring and retention data for identifications are demonstrated.
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