Macrocyclic oligoesters and compositions comprising macrocyclic oligoesters
are prepared from intermediate molecular weight polyesters. In one embodiment,
a diol is contacted with a dicarboxylic acid or a dicarboxylate in the presence
of a catalyst to produce a composition comprising a hydroxyalkyl-terminated polyester
oligomer. The hydroxyalkyl-terminated polyester oligomer is heated to produce a
composition comprising an intermediate molecular weight polyester which preferably
has a molecular weight between about 20,000 Daltons and about 70,000 Daltons. The
intermediate molecular weight polyester is heated and a solvent is added prior
to or during the heating process to produce a composition comprising a macrocyclic
oligoester. An optional step is to separate the macrocyclic oligoester from the
composition comprising the macrocyclic oligoester.