THE PREPARATION OF DIHYDROXYDIPHENYLMETHANES CONTAINING NITRO GROUPS. II. UNSYMMETRICALLY SUBSTITUTED COMPOUNDS

Characterization of some isomeric benzophenones by their mass spectra

Benzophenones have been described to undergo characteristic α-cleavage and rearrangement processes upon mass spectrometric fragmentation. Recently two series of new and isomeric benzophenones have been prepared from phenylbenzoates by Fries rearrangement or directly by Friedel Crafts acylation. It is shown that the above mentioned diagnostic fragmentation processes can be used to characterize the resulting isomeric ortho or para hydroxy and ortho or para methoxy benzophenones unambigously.

The Determination of the Reaction Rate for the First Step in a Consecutive Reaction A → B → C by Absorbance Measurements Using the Wavelength of the Isosbestic Point of B and C

Kinetic experiments are often followed by spectroscopic measurements in the visible or near ultraviolet region. The advantage is not only that the results can be recorded continuously, which makes very fast reactions accessible, but also that very low concentrations of substrates can be used. This means that only very small amounts are required and, more important perhaps, that reagents can be used in excess. Thus pseudomonomolecular conditions and first-order kinetics often can be achieved easily.