Abstract: A process for producing a polyester having 2,5-furandicarboxylate units, which process includes: a) providing or producing a starting composition including 2,5-furandicarboxylic acid or a diester thereof and an aliphatic diol, b) subjecting the starting composition to esterification conditions to produce an ester composition, and c) contacting the ester composition with an aluminum containing catalyst and a phosphorous compound at polycondensation conditions to produce a polyester comprising 2,5-furandicarboxylate units, where the phosphorous compound includes one or more compounds of phosphoric acid based compounds that include an aromatic moiety.