AbstractThe reaction of bisphenol A‐diglycidyl ether (BADGE) with butane‐1,4‐diol (BD) in the presence of Mg(ClO4)2leads to linear and branched oligomers. The formation ratio of these products depends on the reaction temperature. In experiments at 100°C, an epoxide consumption of up to 70% can be observed using HPLC. In this range all products show good solubility in THF, so that it is possible to follow the increasing molar mass by using SEC. A characteristic relation of the molar mass against the conversion rate is derived and SEC data of a branched product are dis