Smith and Kmet (12) show the same generalWe would like to thank Dr. Henry Sable of Case trend as ours; namely, that J ortho and J meta Western Reserve for obtaining the 100 MHz spectra of the 2,4-dinitrohalobenzenes, Dr. J. Thomas Gerig of the are both increased when interaction University of California at Santa Barbara for obtaining between p-substituted groups can occur. the 100 MHz spectra of 2,4-dinitroacetanilide, andIt is significant to note that Schaefer did not Oberlin College for the use of their Varian A-60 n.m.r. study compounds where a strong resonance effect could occur. As in Schaefer's study, our para coupling constants show no consistent change with change of structure.
ConclusionSolubility considerations did not allow the use of CC1,. The use of the additivity scheme for this series of compounds is open to challenge since the monosubstituted values used in this scheme were determined in CCI,. Schaefer et al. (2) indicate that values 0.1 Hz greater than predicted will occur in an acetone solvent system. The lack of large changes in coupling constants of 2,4-dinitrophenol in .different polar solvent systems indicates that an explanation involving more than intramolecular hydrogen bonding is necessary to explain the observed deviation of ortho coupling constants from the additivity scheme encountered in this study. The extent of solvent-solute hydrogen bonding will vary in these solvent systems but the small changes in coupling parameters support the resonance interpretation as a partial explanation for the observed deviations.spectrometer.This research was partially supported by NSF Grant GY-7494.
Oxygen Solubility Measurements in Liquid Paraffin1
D. RUPPEL
Atomic Energy of Canada Limited, Whiteshell Nuclear Research Establishment Pinawa, ManitobaReceived June 1 1 , 1971The solubility of O2 in liquid paraffin was determined over the temperature range from 31 to 90 OC under an Oz pressure of 736 Torr. The solubility was also determined at 35 "C over the pressure range from 290 to 834 Torr.
Introductionsolutions, it became necessary to know the soluIn the course of flash photolysis experiments bility of 0, in liquid paraffin from approximately using 0, as a triplet state quencher in viscous 30 to 90 "C, in order to determine concentrations in solution from gas pressure data.
