| abstract |
A process for the production of polytrimethylene terephthalate (PTT), wherein the process comprises: (i) one or more esterification steps, wherein terephthalic acid (TPA) or an alkyl diester of terephthalic acid is reacted with 1,3-propanediol (PDO); and (ii) one or more subsequent polycondensation steps, wherein the process further comprises the addition of a protic acid, other than terephthalic or isophthalic acid, before and/or during the one or more esterification steps, wherein the protic acid has a dissociation constant of at most 4 (pKa measured in water at 25 °C), and wherein the total amount of protic acid added before and/or during the one or more esterification steps is in the range of from 0.001 to 10 millimole of acid per kilogram of polytrimethylene terephthalate produced. |