13C NMR Spectra of organic peroxides

A study has been made of the13C NMR spectra of hydroperoxides, peroxides, peroxy esters, and diacyl peroxides. The signal of the carbon atoms of a hydrocarbon radical present in the α-position relative to the peroxide group is shifted downfield in comparison with the nonperoxide analog. The replacement of -O- by an -OO-group at a carbonyl carbon produces an upfield shift of the signal from this atom. © 1982 Plenum Publishing Corporation

13C NMR spectroscopy of peroxide derivatives of cyclanes and cyclic peroxides

1. The13C NMR spectra of peroxide derivatives of cyclanes and cyclic peroxides have been investigated. 2. Replacement of the exocyclic OH group by OOH for saturated cyclic systems leads to a displacement of the signals from the α-carbon downfield by 13.0 ppm, while the β-carbon is displaced upfield by 4.5 ppm, without any dependence on the size or conformational structure of the rings. Replacement of the transannular 00 group by CH2CH2 or CH2O increases the shielding of the quaternary carbon adjoining it. © 1987 Plenum Publishing Corporation

Air entrainment through free-surface cusps

In many industrial processes, such as pouring a liquid or coating a rotating cylinder, air bubbles are entrapped inside the liquid. We propose a novel mechanism for this phenomenon, based on the instability of cusp singularities that generically form on free surfaces. The air being drawn into the narrow space inside the cusp destroys its stationary shape when the walls of the cusp come too close. Instead, a sheet emanates from the cusp's tip, through which air is entrained. Our analytical theory of this instability is confirmed by experimental observation and quantitative comparison with numerical simulations of the flow equations