A process for the preparation of polyethylene terephthalate by making use of non antimony catalysts is described. The Ti complex catalyst is pre-dispersed in the polymer matrix selected from PET, PBT, PCTG, PETG, PCT, PEN, PPT, PTT or any other related polyesters and prepared as a master batch. The key feature of the process is that the polyester obtained is having good whiteness, as against the yellowness normally encountered with Ti based catalysts, and also the polyester has very good clarity with minimum haze.