Process for reclaiming o-chlorobenzoic acid from mother liquor or waste water

Abstract

The invention discloses a process for reclaiming o-chlorobenzoic acid from mother liquor or waste water, which comprises that: alkalescent ion exchange resin or macroporous absorbent resin is loaded into an adsorption column; after conventional pretreatment, mother liquor of o-chlorobenzoic acid or waste water containing o-chlorobenzoic acid to be treated flows through the adsorption column, the adsorption temperature is controlled to be between 5 and 40 DEG C and the flow rate is controlled to be between 2 and 16 BV / h, and o-chlorobenzoic acid is exchanged or adsorbed on the resin; and after the resin is adsorbed by the adsorption column to saturation, 2 to 4 percent NaOH solution or KOH solution or an organic solvent of methanol, ethanol, acetone or aether and the like is used for desorption to generate sodium o-chlorobenzoic acid water solution or methanol, ethanol, acetone or aether water solution of o-chlorobenzoic acid, the flow rate is controlled to be between 1 and 3 BV / h and the temperature is controlled to be between 35 and 90 DEG C, and the methanol, ethanol, acetone or aether water solution of o-chlorobenzoic acid is distilled and separated to obtain the o-chlorobenzoic acid and the organic solvent. The reclaiming method is simple, the recovery rate of the o-chlorobenzoic acid reaches 92 to 96 percent, and the method has good economic benefit, reclaims the resources and simultaneously lightens the treatment burden of the waste water.

Description

technical field

[0001] The present invention relates to the recovery of o-chlorobenzoic acid, specifically, relate to the method for reclaiming o-chlorobenzoic acid with weakly alkaline or macroporous adsorption resin from mother liquor or waste water. Background technique

[0002] O-chlorobenzoic acid production mother liquor or the production mother liquor of o-chlorobenzoic acid by-product during the production of o-chlorobenzaldehyde contains about 0.24% o-chlorobenzoic acid. This kind of production mother liquor is sent to waste water treatment, which wastes resources and increases waste water treatment. load. Contents of the invention

[0003] The present invention is the technology that adopts resin recovery o-chlorobenzoic acid, specifically refers to a kind of adopting weakly basic or macroporous adsorption resin to absorb o-chlorobenzoic acid under the condition of 5-40 ℃ and flow velocity 2-16BV / h, and then dilute The lye (represented by sodium hydroxide soluti...