The i.r. and 1H n.m.r. spectra of the product of condensation of acetaldehyde with methylamine are more complex than those expected for the simple azomethine N-ethylidenemethylamine. They are explained in terms of an equilibrium between the monomeric azomethine and two conformers of its cyclic trimer, 1,2,3,4,5,6-hexamethyI-
Studies have been made of the variation with ketone pressure of the quantum yield for the decomposition of hexafluoroacetone, excited by 3130 A, at 25 and 78 "C, and of the relative yield of the total emission at several temperatures. These are described in considerable detail with a view to discerning possible sources of systematic error. No large systematic error could be identified except that of decreased yields caused by deactivation by mercury vapor. The decomposition data support the weak collision mechanism for vibrational relaxation in the excited singlet state unless an as yet unknown source of large systematic error can be identified.A description is offered of the path of the decomposition in terms of simplified diatomic representations of the nr* singlet and triplet states and of a repulsive state arising from the radicals CF3 and CF3C0 in their ground electronic states. On the basis of that description an activation energy >, 11 kcal mole-1, derived from the combined decomposition and emission data, is to be ascribed to the first-order decomposition of triplet state molecules in vibrational equilibrium with their surroundings.Canadian Journal of Chemistry. 46, 175 (1968) Introduction An earlier publication (1) offered a reinterpretation of literature data as they pertain to the mechanism of the primary process in the photolysis of hexafluoroacetone following excitation by the 3130 group of the mercury arc. The present paper describes in detail the new data cited there, reports additional new data bearing on the primary photodecomposition, and describes a study of some aspects of the emission from the excited states of this ketone. Two brief studies of other aspects of the overall investigation of the primary process have been reported recently (2,3).Near the com~letion of the oresent work the investigations of Bowers and Porter, which are now published (4, 5), came to our attention. There are two important quantitative discrepancies between those results and those reported here. One of these discrepancies can be attributed to the quenching of the triplet state of this ketone by mercury vapor, which was reported recently (3) and since has been confirmed (6, 7). It seems probable that the method used by Bowers and Porter (8) also eliminated a substantial fraction of the mercury from their reactant. Thus their result that 4, -0.2 at room temperature is closer to the unquenched value than that found here (-0.025). The discrepancy (9) regarding the shape of plots of 114 vs. pressure at low pressures cannot be explained as readily.Because of the unexplained discrepailcies the experimental work is described in greater detail here than is usually the case and a discussion is given of possible sources of systematic errors. This description is divided into two sections of which the first describes the experiments on the photodecomposition and the second those on the emission. Experimental ( I ) P/~oton%cotnpositior~The cylindrical quartz photolysis cell (10 crn long, 5 cm diameter) was housed in a cyli...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.