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Photoacoustic calorimetry mechanism

Generation of Alkyl and Cycloalkyl Carbenes - Photolysis or thermolysis of a series of alkylchlorodiazirines (16) (Scheme 7) in the presence of alkenes, such as tetramethylethene, results in 1,2-H shifts, giving the corresponding vinyl chorides (18), in competition with additions of the carbenes (17) to the alkenes, yielding cyclopropanes (19). The mechanism of these reactions is discussed in the light of results obtained from photoacoustic calorimetry, and the ratio of vinyl chloride to cyclopropane seems to depend on the excited states of the carbene precursors and also on carbene-alkene complexes. Similar reactions of related diazirines have been investigated by flash photolysis. [Pg.320]

In Fig. 5 a typical setup for resonant photoacoustic spectroscopy as used in the authors laboratory is shown. The radiation of a cw laser is intensity modulated by a mechanical chopper of high precision. An electro-optic modulation device may also be employed or the laser beam is modulated directly by modulation of its power supply. As already discussed, vibrational excitation with an IR laser, for example, causes a modulated pressure change in the resonator via fast vibrational relaxation. This acoustic signal is detected with a microphone, because these devices provide the highest sensitivity. Detectors employed in calorimetry to measure the heating of a mpte such as thermistors or thermophi are less sensitive and p( sess a slower rise... [Pg.7]


See other pages where Photoacoustic calorimetry mechanism is mentioned: [Pg.149]    [Pg.3770]    [Pg.205]    [Pg.3769]    [Pg.563]    [Pg.222]    [Pg.223]    [Pg.121]    [Pg.111]    [Pg.324]    [Pg.150]    [Pg.342]    [Pg.635]    [Pg.816]   
See also in sourсe #XX -- [ Pg.192 ]




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