Method for producing diesters of terephthalic acid with circulation of the reaction mixture

A process for preparing a terephthalic diester which comprises reacting terephthalic acid with at least one alcohol, wherein

• a) suspending terephthalic acid in the alcohol in a dispersing tank to obtain a preliminary suspension,
• b) passing the preliminary suspension from the dispersing tank into a reactor and converted in the presence of an esterification catalyst,
• c) drawing off a reaction suspension from a region between the upper region and the lower region of the reactor, the reaction suspension drawn off is divided, a first stream of the reaction suspension is recycled into the upper region of the reactor and a second stream of the reaction suspension is introduced into the lower region of the reactor, and the reaction suspension is thus mixed,
• d) wherein the stream drawn off and/or the first stream is passed through a heat exchanger outside the reactor and heated,
• e) distilling off water of reaction together with the vapor as alcohol-water azeotrope, the vapor is at least partly condensed, the condensate is separated into an aqueous phase and an organic phase and the organic phase is at least partly recycled into the reaction system and
• f) preparing the terephthalic diester.