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  • Articles  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 2709-2726 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, XVIII Reaction of an Aminalester with Carboxylic and Thiocarboxylic Acid Amides or EstersAt room temperature, bis(dimethylamino)-tert-butoxymethane (1) reacts with carboxamides and thiocarboxamides at the amino group; at higher temperatures, further formylation takes place at the α-CH2 group. Esters of carboxylic and thiocarboxylic acids also react at the α-CH2 group.
    Notes: Carbonsäure- und Thiocarbonsäureamide reagieren mit Bis-dimethylamino-tert.-butyloxymethan (1) an der NH2-Gruppe, bei höherer Temperatur auch an der α-CH2-Gruppe unter Formylierung. Ebenfalls an der α-CH2-Gruppe erfolgt die Reaktion bei Carbonsäure- und Thiocarbonsäureestern.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 3711-3713 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 246-252 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigation of the Effectiveness of Various 1-Dialkylamino-1-methoxycarbenium Methyl Sulfates in the Course of AcetalizationThe rate of dimethyl ketal formation from acetone and methanol in the presence of several 1-dialkylamino-1-methoxycarbenium methyl sulfates 1a, 5a - g is studied. The fastest rate was observed in the case of 5c. In the presence of 5c, the reaction of carbonyl compounds with either methanol or 1,2-diols gave the dimethyl ketals 6 and 1,3-dioxolanes 7, respectively.
    Notes: Es wird die Geschwindigkeit der Dimethylketalbildung des Acetons aus Methanol und Aceton in Gegenwart verschiedener 1-Dialkylamino-1-methoxycarbenium-methylsulfate 1a, 5a - g untersucht. Die größte Ketalbildungsgeschwindigkeit wurde bei 5c beobachtet, mit dessen Hilfe aus Carbonylverbindungen und Methanol oder 1,2-Diolen die Dimethylacetale 6 bzw. die 1,3-Dioxolane 7 dargestellt wurden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2020-03-19
    Description: Global dust storms on Mars are rare1,2 but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere3, primarily owing to solar heating of the dust3. In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars4. Recent observations of the water vapour abundance in the Martian atmosphere during dust storm conditions revealed a high-altitude increase in atmospheric water vapour that was more pronounced at high northern latitudes5,6, as well as a decrease in the water column at low latitudes7,8. Here we present concurrent, high-resolution measurements of dust, water and semiheavy water (HDO) at the onset of a global dust storm, obtained by the NOMAD and ACS instruments onboard the ExoMars Trace Gas Orbiter. We report the vertical distribution of the HDO/H2O ratio (D/H) from the planetary boundary layer up to an altitude of 80 kilometres. Our findings suggest that before the onset of the dust storm, HDO abundances were reduced to levels below detectability at altitudes above 40 kilometres. This decrease in HDO coincided with the presence of water-ice clouds. During the storm, an increase in the abundance of H2O and HDO was observed at altitudes between 40 and 80 kilometres. We propose that these increased abundances may be the result of warmer temperatures during the dust storm causing stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapour to lower altitudes through gravitational fall and subsequent sublimation of ice crystals3. The observed changes in H2O and HDO abundance occurred within a few days during the development of the dust storm, suggesting a fast impact of dust storms on the Martian atmosphere.
    Description: Published
    Description: 521–525
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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