Continuous process and device for synthesizing sodium bis(2-hydroxyethyl) 5-sulphonatoisophthalate with high ester exchange rate through catalytic reaction rectification

Abstract

The invention discloses a continuous process and device for synthesizing sodium bis(2-hydroxyethyl) 5-sulphonatoisophthalate with a high ester exchange rate through catalytic reaction rectification. Materials are subjected to pre-transesterification through a full-mixing reaction kettle and then enter a final transesterification reaction rectifying tower, so a transesterification rate is further improved; a sodium bis(2-hydroxyethyl) 5-sulphonatoisophthalate solution continuously extracted from the bottom of the reaction rectifying tower is fed into a product blending tank; ethylene glycol isadded for blending to obtain an end product, and the end product is sent to a finished product tank to obtain a final product. The device comprises a pulping tank, the pre-transesterification reactionkettle, a final transesterification reaction rectifying tower, a product blending tank and the finished product tank, wherein a condensing tower is arranged at the top of the pre-transesterificationreaction kettle; a condenser is arranged at the top of the final transesterification rectifying tower; and the condensing tower at the top of the pre-transesterification reaction kettle and the condenser at the top of the final transesterification reaction rectifying tower are connected with a methanol tank. The sodium bis(2-hydroxyethyl) 5-sulphonatoisophthalate produced by the method has the advantages of high ester exchange rate, reduced side reaction and stable product quality.

Description

technical field [0001] The invention belongs to the technical field of modified polyester production, and relates to a two-stage transesterification reaction between ethylene glycol (EG) and dimethyl isophthalate-5-sodium sulfonate (SIPM) under catalytic reaction rectification conditions The continuous process method adopts a two-stage continuous transesterification process to synthesize the production process and device of bishydroxyethyl isophthalate-5-sodium sulfonate (SIPE) with high transesterification rate. Background technique [0002] Polyester is difficult to dye, and the preparation of cationic dye-dyeable polyester is one of the important ways to solve the difficulty of polyester dyeing. Bishydroxyethyl isophthalate-5-sodium sulfonate (SIPE) is a polyester dyeing modifier, which is added as the third monomer of the reaction. Because the modified polyester contains sulfonic acid groups, it has good affinity for cationic dyes. After dyeing, the fiber has bright col...

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Problems solved by technology

[0004] In the traditional SIPE batch process production, the transesterification reactor has the functions of beating and transesterification reaction, the operation cycle is long, the production efficiency is low, and because of the different conditions of beating and transesterification reaction, the heat demand of the transesterification reactor changes greatly. The operation of the heat medium system fluctuates periodically, and the process conditions of each batch of production, such as: reaction time, heating rate, molar ratio of EG and SIPM, catalyst type and dosage, nitrogen replacement conditions, etc., will have a large impact on the transesterification rate. effect, resulting in batch-to-batch variance

If the transesterification rate is too high, SIPE is prone to self-polymerization; if the transesterification rate is too low, there will be more methanol residues, resulting in methanol (MA) bumping and accumulating on the wall of the kettle after the material is added to the high-temperature polymerization system, causing the system to form Black foreign matter, product appearance becomes darker and performance deteriorates

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