Preparation and characterization of polyesters with controlled molecular weight method

p-Toluene sulfonic acid (p-TSA) as an efficient catalysts has been used for the preparation of various polyesters via controlled molecular weight method using of adipic acid ,mono /di/triethylene glycol, 2-ethyl-2-(hydroxymethyl)propane-1,3diol and 1,4 Butanediol as starting materials. The resulting polyesters were prepared in high yields and were characterized by the using of FT-IR, 1 H-NMR and 13 C –NMR spectroscopy. The effect of the catalysts on the rate of the reaction has been investigated.