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- Antonsen, Simen, et al.
(författare)
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Atmospheric Chemistry of tert-butylamine and AMP
- 2017
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Ingår i: Energy Procedia. Volume 114, 2017, Pages 1026-103213th International Conference on Greenhouse Gas Control Technologies, GHGT 2016; Lausanne; Switzerland; 14 November 2016 through 18 November 2016. - : Elsevier BV. - 1876-6102.
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Konferensbidrag (refereegranskat)abstract
- © 2017 The Authors. The atmospheric chemistry of (CH 3 ) 3 CNH 2 (tert-butylamine, tBA) and (CH 3 ) 2 (CH 2 OH)CNH 2 (2-amino-2-methyl-1-propanol, AMP) has been studied by quantum chemistry methods and in photo-oxidation experiments in the EUPHORE chamber in Valencia (Spain). Aerosol formation and composition has been quantified. Yields of nitramines and other products in the photo-oxidations have been determined and complete photo-oxidation schemes including branching between the major reaction routes have been obtained. Published by Elsevier Ltd.
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| 2. |
- Tan, Wen, et al.
(författare)
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Theoretical and Experimental Study on the Reaction of tert-Butylamine with OH Radicals in the Atmosphere
- 2018
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 122:18, s. 4470-4480
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 American Chemical Society. The OH-initiated atmospheric degradation of tert-butylamine (tBA), (CH 3 ) 3 CNH 2 , was investigated in a detailed quantum chemistry study and in laboratory experiments at the European Photoreactor (EUPHORE) in Spain. The reaction was found to mainly proceed via hydrogen abstraction from the amino group, which in the presence of nitrogen oxides (NO x ), generates tert-butylnitramine, (CH 3 ) 3 CNHNO 2 , and acetone as the main reaction products. Acetone is formed via the reaction of tert-butylnitrosamine, (CH 3 ) 3 CNHNO, and/or its isomer tert-butylhydroxydiazene, (CH 3 ) 3 CN=NOH, with OH radicals, which yield nitrous oxide (N 2 O) and the (CH 3 ) 3 Ċ radical. The latter is converted to acetone and formaldehyde. Minor predicted and observed reaction products include formaldehyde, 2-methylpropene, acetamide and propan-2-imine. The reaction in the EUPHORE chamber was accompanied by strong particle formation which was induced by an acid-base reaction between photochemically formed nitric acid and the reagent amine. The tert-butylaminium nitrate salt was found to be of low volatility, with a vapor pressure of 5.1 × 10 -6 Pa at 298 K. The rate of reaction between tert-butylamine and OH radicals was measured to be 8.4 (±1.7) × 10 -12 cm 3 molecule -1 s -1 at 305 ± 2 K and 1015 ± 1 hPa.
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| 3. |
- Umereweneza, Daniel
(författare)
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Discovery of Secondary Metabolites from Rwandese Medicinal Plants : Isolation, Characterization and Biological Activity
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Plants have served as the principal source of medicines in different parts of the world through the ages. Herb-derived medicines have been used as decoctions, infusions, tinctures or single substance drugs. Due to their impressive possibility of diversification, plants have also provided an immense universe of creativity for synthetic chemists, who constantly make useful new molecules inspired by the natural molecular architecture.The goal of this thesis work was to investigate secondary metabolites isolated from selected Rwandese medicinal plants. It focused specifically on the isolation, the characterization and the determination of the biological activity of natural products. The investigated plants belong to the families of Myrtaceae (Eucalyptus melliodora and Eucalyptus anceps), Fabaceae (Eriosema montanum), Lamiaceae (Clerodendrum myricoides) and Asteraceae (Senecio mannii). These were selected from the Rwandese flora based on information collected from traditional healers, and from the literature. The study made use of chromatographic, spectroscopic and spectrometric methods for separation, purification and structure elucidation of the plant constituents.In paper I, the chemical composition and antifungal activity of essential oils of E. melliodora and E. anceps were discussed. The essential oils were composed of mono- and diterpenes, and their alcohol derivatives. The essential oil mixtures exhibited antifungal activity against food spoilage fungi.In paper II, E. montanum was investigated and a total of 20 compounds were isolated including two new prenylated dihydrochalcones and eighteen known secondary metabolites. Their antibacterial activities and cytotoxicity were determined. In paper III, the isolation of three new and two known iridoid glycosides from C. myricoides was reported along with the antiviral activities of the crude extract and of the isolates. In paper IV, the phytochemical investigation of S. mannii was reported. It afforded one new silphiperfolanol angelate ester, two new macrocyclic pyrrolizidine alkaloids, and five known secondary metabolites. Two new synthetic derivatives were obtained by structural modification of 2-angeloyloxy-5,8-dihydroxypresilphiperfolane. The relative stereochemistry of senaetnine was investigated by NAMFIS and confirmed to be 7R, 12R, and 13R.The new compounds isolated in this study have shown biological activities, and may provide lead compounds for drug discovery and technological applications.
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