Kristallisationsverfahren für Gereinigte Terephthalsäure

Details

Veröffentlichungs-Nr.

EP4748821

Anmeldetag

26. November 2024

Veröffentlichung

27. Mai 2026

Rechtsraum

EP

IPC

C07C51/43, C07C63/26

Abstract

The invention relates to a crystallization method for purified terephthalic acid (PTA) to obtain crystalline PTA with an average crystal size of approx. 30-150 microns, the method comprising in the following order the steps of: (a) providing in a reactor a solution of 2-13 wt% of purified metalated salt of terephthalic acid (M-TP) in water at a pH of 7; (b) heating the M-TP solution to a crystallization temperature of 40-90°C and stirring the solution; (c) adding H<2>SO<4> dropwise at the crystallization temperature over a total addition time of at least 4 hours performing in the following order the steps of: (i) adding H<2>SO<4> in the amount of 0.10-0.15 molar equivalent to adjust the pH of the M-TP solution to 4.7 - 5.5 to receive a first suspension of purified terephthalic acid (PTA); (ii) adding H<2>SO<4> in the amount of 0.5-1.5 molar equivalent to the first suspension of PTA following a linear addition, a quadratic addition or a cubic addition, with a predefined addition rate, until the total addition time and 0.5-1.5 molar equivalent of H<2>SO<4> is reached receiving a second suspension of PTA; (d) cooling down the second suspension of PTA to room temperature; (e) filtering the cooled second suspension of PTA to collect crystalline PTA; f) washing the filtered crystalline PTA with cold water; and (g) drying the washed crystalline PTA.

Anmelder

Firma

DePoly SA

Land

🇨🇭 Schweiz

Fachgebiete