Abstract
(+)-1:3-Dimethylbutyl methacrylate has been prepared, by the reaction of methacrylyl chloride with optically pure (+)-1:3-dimethyl-butanol in the presence of pyridine, and polymerised by means of benzoyl peroxide to a hard clear glass. (+)-1:3-Dimethylbutyl pivalate was similarly prepared by the reaction of pivalyl chloride with (+)-1:3-dimethylbutanol. The molecular rotations of the poly-((+)-1:3-dimethyl-butyl methacrylate) and the (+)-1:3-dimethylbutyl pivalate,in solution in sym-tetrachloroethane, were determined for five wavelengths at 25. The effect on the rotatory power of the polymer of change in concentration of its solutions, in molecular size, and from benzoyl peroxide to a:a'-azo-isobutyronitrile as initiator has been investigated and has been shown to have little effect on the optical rotation. Comparison of the molecular rotation of the pivalate with that of the poly-((+)-1:3-dimethylbutyl methacrylate) has been used in applying the method of molecular rotation differences to an analysis of the rotatory power of the polymer in terms of various aspects of its structure. It is concluded that dissymmetric coiling of the main chain in this polymer contributes to its rotatory power. Copolymers of (+)-1:3-dimethylbutyl methacrylate with methyl methacrylate, acrylonitrile, styrene, and diethyl fumarate have been prepared, and the rotatory powers of solutions of these copolymers in sym-tetrachloroethane determined for five wavelengths. The structure and dissymmetry of the copolymers are discussed, and the molecular rotations of the optically pure (+)-polymer and of the (+)-pivalate are applied in molecular rotation difference calculations. The contributions to the rotatory power made by chain-coiling of units derived from the optically inactive monomers are estimated.