The structure of thin films. Part XI.— Oxygenated derivatives of benzene

Abstract

The object in view when commencing this research was to try and find films of substances containing the benzene nucleus lying flat on the surface of water, in order to measure the cross section of this fundamental unit of Organic Chemistry, parallel to the plane of the ring. The cross section perpendicular to the plane of the benzene ring was measured in Part IV of this series of papers, and found to be approximately 24 sq. A.U., a figure in good agreement with the X-ray measurements on naphthalene, anthracene, and benzene. To achieve this object, it would be necessary not only to know that the benzene nuclei of the molecules chosen were lying flat, but also they must be known to be in contact and not separated from other benzene heads in neighbouring molecules, through some portion of the long hydrocarbon chains attached to the nuclei resting on the surface. To be sure that both these conditions are fulfilled, it would be necessary to find a film in which the area was large, corresponding to the benzene nucleus lying flat ; also the area must not alter appreciably with lateral compression, and there must not be any bulky substituents in the nucleus.