R. C. Herman

Vibration Spectra and Molecular Structure V. Infra‐Red Studies on Light and Heavy Acetic Acids

The infra‐red absorption spectra of CH3COOH and CH3COOD between 1 and 15.5μ have been obtained with a rocksalt prism spectrometer. The association of CH3COOD has been studied and a value of the heat of dissociation obtained. Positions of the hydrogen and deuterium bonded O–H–O and O–D–O frequencies are given. Making certain assumptions, a value for the shorter O–H and O–D distances in the dimer rings is found to be 1.07A.

Vibration Spectra and Molecular Structure VII. Further Infra‐Red Studies on the Vapors of Some Carboxylic Acids

The monomer and dimer spectra of the vapors of CD3COOD, CD3COOH, C2H5COOH and C2H5COOD have been obtained in the near infra‐red with a rocksalt spectrometer. The association of C2H5COOD has been studied and the value of the heat of association obtained is 7000 calories per mole per bond.

Vibration Spectra and Molecular Structure VIII. Absorption Spectra of Light and Heavy Phenol and Aniline Vapors

The near infra‐red spectra of light and heavy phenol and aniline vapors have been obtained with a rocksalt spectrometer. Comparisons have been made between the spectra of the light compounds as found in various phases, and an interpretation of certain changes occurring in the spectrum of phenol is suggested. The spectra of the heavy compounds have suggested certain assignments, such as the δ (OD) vibration at 913 cm—1 in heavy phenol and the δ (OH) vibration at 1177 cm—1 in light phenol.

Vibration Spectra and Molecular Structure IX. Further Studies of the Vapors of the Fatty Acid Series

The monomer spectra of the vapors of C3H7COOH, C3H7COOD and C4H9COOH have been obtained in the near infra‐red with a rocksalt spectrometer. The association of each of the following molecules: HCOOH, HCOOD and C3H7COOD has been studied in the vapor phase by measuring the variation with temperature and pressure of the intensity of some association band. The bond strengths obtained for these fatty acids are 6.2, 6.4 and 6.9 kcal. per mole per bond, respectively. The fact that the bond strengths for light and heavy formic acids agree within the experimental error although the determinations were carried out with different bands is further evidence that the spectroscopic method is satisfactory. The lower value obtained for the bond strength in formic acid by this method compared to the vapor density value is discussed. In addition, it is suggested from the experimental data available at the present time, that it does not seem possible to claim the existence of a simple linear relationship between the bond stre...