Pretreatment method for chelate resin having pyridine ring used for collecting catalyst in terephthalic acid production process

摘要

In pretreating a pyridine ring-containing chelate resin which is used in the step for adsorption and collection of a heavy metal ion and a bromide ion derived from a catalyst from the oxidation reaction mother liquid in the process of producing a terephthalic acid, there may occur phenomena such as swelling of the resin, heat generation of the resin, and air bubbles generation, thereby causing fracture and deterioration of the resin. As a first treatment, Br− conversion, under a certain condition, of a pyridine ring-containing chelate resin with an aqueous solution of hydrobromic acid is performed, and then as a second treatment, replacement with acetic acid solvent is performed, thereby making it possible to prevent fracture and deterioration of the resin.

主权项

1. A method of pretreating a pyridine ring-comprising chelate resin, the method comprising:
(i) first, converting the pyridine ring-comprising chelate resin into a Br− form in hydrobromic acid aqueous solution having an HBr content of from 0.05% to 5% by mass and an acetic acid amount of from 0 to 30% by mass, based on the total weight of the hydrobromic acid aqueous solution; and (ii) second, replacing the hydrobromic acid aqueous solution in (i) with an acetic acid solvent, wherein the pyridine ring-comprising chelate resin is suitable for collecting a liquid-phase oxidation catalyst in a process of producing terephthalic acid, and the method is capable of preventing or reducing volume expansion and heat generation of the pyridine ring-comprising chelate resin during (ii), and wherein (i) comprises continuously feeding the hydrobromic acid aqueous solution from a bottom of the column in an up-flow stream, at a rate of from 0.5 to 8 m/hr as a linear velocity based on an empty column, thereby contacting the hydrobromic acid aqueous solution with the pyridine ring-comprising chelate resin; and (ii) comprises continuously feeding the acetic acid solvent from the bottom of the column in the up-flow stream, thereby contacting the acetic acid solvent with the pyridine ring-comprising chelate resin.