Treatment process of by-product sodium hypophosphite in phosphorane preparation process

By introducing carbon dioxide gas during the preparation of phosphine to draw an acidification curve and combining it with calcium hydroxide suspension and cation exchange resin, impurity ions can be selectively removed, solving the problem of low purity of sodium hypophosphite and achieving efficient resource recovery and improved product purity.

CN120757084APending Publication Date: 2025-10-10CANGZHOU BOHAI NEW DISTRICT SHENGTAI CHEM CO LTD
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Patent Information

Application Number
CN202510962147.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-07-14
Publication Date
2025-10-10

AI Technical Summary

Technical Problem

In the prior art, the purity of sodium hypophosphite, a by-product in the preparation of phosphine, is low, and impurities are not completely removed, resulting in low resource recovery and utilization rates and a lack of efficient quantitative treatment processes.

Method used

By introducing carbon dioxide gas into the reaction mother liquor, drawing acidification curves of pH and conductivity, formulating an acidification process, combining calcium hydroxide suspension and macroporous strong acid cation exchange resin, impurity ions are selectively removed to ensure the stability of the target component. Finally, a high-purity hypophosphorous acid product is obtained through concentration.

Benefits of technology

The purity and resource utilization of sodium hypophosphite are significantly improved, the impurity removal selectivity is high, and the product purity can reach more than 99.5%, which has good industrial application prospects.

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Abstract

The invention provides a treatment process of a byproduct sodium hypophosphite in a phosphorane preparation process, and aims to efficiently remove impurities and prepare a high-purity hypophosphorous acid product. The process comprises the following steps: carrying out small-volume sampling on reaction mother liquor, introducing carbon dioxide gas, and drawing an acidification curve of pH and conductivity; according to the plateau phase of an acidification curve, the CO2 flow rate and the pH value are controlled, step-by-step selective precipitation of impurities such as PO4 < 3->, HPO4 < 2->, Fe < 3 + >, AsO4 < 3-> and S < 2-> is achieved, and loss of a target component H2PO4 < 2-> is avoided; calcium hydroxide turbid liquid is introduced at a proper time to supplement Ca < 2 + > and promote efficient removal of phosphorus, arsenic and sulfur impurities; and subsequently removing excessive Na < + > and Ca < 2 + > through cation exchange, and concentrating to obtain a hypophosphorous acid product with the purity of more than or equal to 99.5%. The method is accurate in process control, thorough in impurity removal and good in repeatability and industrial adaptability, and the resource utilization efficiency of by-products and the added value of products are remarkably improved.
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