Synthesis, refractometric constants, and some other physical properties of a homologous series of branched alkenes

The preparation of eleven terms of the homologous series of the 2‐methyl‐1‐alkenes (2‐methyl‐α‐alkenes) is described. The purity of the preparations obtained was determined by measuring the melting curves. The densities and refractive indices of the synthesized compounds at 20° C and 25° C were determined; the measurements of the refractive indices were carried out at nine wave‐lengths. From the values of the densities and the refractive indices the molecular refractions were determined according to the formula of Lorentz‐Lorenz. By the method of the least squares we derived, with the aid of these data, the values of the refraction equivalent of the CH2‐group and the increment of the double bond. The densities and refractive indices determined experimentally appeared to correspond excellently with values calculated from empirical formulae. Besides densities and refractive indices the final melting points, the boiling points and the infra‐red spectra of the synthesized compounds were determined.