Process for the production of iminodibenzyl

By using techniques such as polyphosphoric acid dropwise addition, vacuum distillation, and gradient crystallization in the production of iminodibenzyl, the problem of achieving pharmaceutical-grade purity and color in traditional processes has been solved, thus realizing the production of high-purity and high-efficiency iminodibenzyl.

CN122233987APending Publication Date: 2026-06-19HUBEI HUAZHOU PHARM CO LTD
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Applications(China)
Current Assignee / Owner
HUBEI HUAZHOU PHARM CO LTD
Filing Date
2026-04-21
Publication Date
2026-06-19

AI Technical Summary

Technical Problem

In the existing production process of iminodibenzyl, the contradiction between reaction kinetics and impurity control makes it difficult for the purity and color of the product to meet the requirements of pharmaceutical grade. Traditional catalytic systems have insufficient catalytic activity at low temperatures and are prone to coking reactions at high temperatures. Post-processing steps are also difficult to completely separate colloidal impurities.

Method used

The method involves dropwise addition of diaminodibenzyl distillate to polyphosphoric acid at 240-270℃, combined with vacuum distillation, multi-stage purification, and gradient crystallization. By precisely controlling the temperature, vacuum level, and pH value, the method utilizes the complexation reaction of phosphoric acid with alkaline impurities to remove colloids, and nitrogen replacement to prevent oxidation, thereby achieving efficient separation and purification.

Benefits of technology

This improved the purity and physical appearance of the iminodibenzyl product, increased the reaction conversion rate and overall product recovery rate, reduced the amount of waste acid to be treated and the washing load, and ensured the stability and safety of the process.

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Abstract

This invention provides a production process for iminodibenzyl, relating to the field of organic chemistry. The technical solution includes: initially reacting diaminodibenzyl distillate with polyphosphoric acid at 240-270℃, followed by cyclization at 275-285℃; the resulting cyclized solution is then subjected to vacuum distillation, dissolution preheating, multi-stage phosphoric acid purification, washing to neutrality, and gradient crystallization to obtain wet iminodibenzyl. The process also encompasses a complete synthetic chain starting from o-nitrotoluene and integrates dynamic mother liquor reuse, waste acid recovery and utilization, and a fully vacuum-sealed transfer mechanism to prevent oxidation. This invention significantly improves the yield and purity of iminodibenzyl through two-stage high-temperature control and a specific purification logic, resulting in a product with high whiteness and achieving resource utilization of the byproduct phosphoric acid.
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