The Dipole Moments of Certain Organic Compounds

The dielectric constants and densities of dilute solutions of p-brombenaldehyde, p-tolualdehyde, p-hydroxybenzaldehyde and p-anisaldehyde in dioxane were measured at 25°. From the total polarization and the molecular refractivities the dipole moments were calculated to be 2.20, 3.27, 4.18 and 3.70x10-18 e.s.u., respectively. The angle between the aldehyde group moment direction and the line through the l, 4 C atoms of the benzene nucleus is calculated to be 51°. The angles between the directions of the OH and CHO group moments, and, between the CH3O and CHO group moments are 50° and 49°, respectively. The angle between the plane passing through the 1, 4 C atoms and those in which the moment vectors lie are 45° and 37°, respectively, for p-hydroxybenzaldehyde and p-anisaldehyde