Abstract: Macrocyclic poly(alkylene dicarboxylate) oligomers are prepared in high yield by the reaction of a dicarboxylic acid chloride such as terephthaloyl chloride with at least one bis(hydroxyalkyl) ester such as bis(4-hydroxybutyl) terephthalate, in the presence of a highly unhindered amine or a mixture thereof with at least one other tertiary amine such as triethylamine, in a substantially inert organic solvent such as methylene, chlorobenzene or a mixture thereof. The concentration of the reagents in the reaction mixture are at least 0.08M.

Abstract: The present invention is directed to a method for reducing PCB concentration in an electrical induction apparatus containing a dielectric fluid with greater than 500 ppm PCB to a level of less than about 50 ppm PCB. Dielectric fluid containing greater than 500 ppm PCB is drained from an electrical induction apparatus, and the drained apparatus then is filled with tetrachloroethylene as a first interim dielectric fluid. The apparatus is then electrically operated with the first interim dielectric fluid so as to attain about an equilibrium PCB concentration in the first fluid. The first interim dielectric fluid then is drained from the apparatus and replaced with fresh tetrachloroethylene as a second interim dielectric fluid. The apparatus then is electrically operated with the second interim dielectric fluid so as to attain about an equilibrium PCB concentration in the second fluid.