SYNTHESIS AND CHARACTERIZATION OF OLIGOETHYLENE BIBENZOATE WITH HYDROXYETHYL END-GROUPS

In the process of exploring the potential advantage of 4,4'-biphenyl d icarboxylic acid (BDA) as a comonomer in poly(ethylene terephthalate) (PET), it was found that BDA needs to be derivatized for effective inc orporation in PET specifically if high levels of BDA incorporation are desired. Bis-hydroxyethylbibenzoate (HEB) was synthesized with the an ticipation that it would be compatible with both the continuous PET pr ocess which uses high-purity terephthalic acid as well as the batch PE T process which utilizes dimethyl terephthalate. This article describe s the synthesis of HEB and some of the oligoethylene bibenzoates produ ced in the process. Diethylene glycol is produced as an undesirable by -product during the reaction. In an effort to produce a minimum amount of diethylene glycol, a catalytic process was investigated which resu lted in diethylene glycol levels of less than 0.5%. Quantitative analy sis of diethylene glycol, performed by gas chromatography, and the oli gomer structure studies performed by H-1- and C-13-NMR are described. (C) 1996 John Wiley & Sons, Inc.