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

A method of pretreating a pyridine ring-comprising chelate resin, the method comprising:

• filling the pyridine ring-comprising chelate resin in a column, and
• (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),
• a volume expansion of the pyridine ring-comprising chelate resin during (ii) is greater than 1.00 and up to 1.40 times, and
• (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 fluidizing the resin;
• and continuously feeding the acetic acid solvent in (ii) from the bottom of the column in the up-flow stream, thereby contacting the acetic acid solvent with the pyridine ring-comprising chelate resin and fluidizing the resin.