| abstract |
Macrocyclic polyester oligomer compositions comprising alkylene isophthalate or terephthalate units or the like are prepared by the reaction of a diol with a diacid chloride in the presence of at least one amine characterized by substantially no steric hindrance around the basic nitrogen atom. The reaction is conducted under substantially anhydrous conditions and at a temperature form about -25 DEG to about +25 DEG C. The resulting macrocyclic oligomers may be converted to linear polyesters by contact with catalysts including alkali metal salicylates, stannous alkoxides and organotin compounds. |