Separation and purification method of glycerine and iminodiacetic acid

Abstract

The invention discloses a separation and purification method of glycerine and iminodiacetic acid. The method includes following steps: 1), subjecting mixed liquid containing glycerine and iminodiacetic salt and inorganic salt to decoloring treatment, enabling the mixed liquid to enter homogeneous membrane electrodialysis through a filter, and desalting until salt in a thin chamber is lower to 3-7wt%; performing heterogeneous membrane electrodialysis on a solution in the thin chamber to for deep desalting until the salt in the diluted chamber is lowered to lower than 0.1wt%; obtaining a glycerine water solution in the thin chamber and an iminodiacetic salt solution containing the inorganic salt in a thick chamber, and further concentrating the glycerine water solution to obtain a glycerine product; 2), further concentrating the iminodiacetic salt solution containing the inorganic salt to obtain the inorganic salt and mother liquid containing the iminodiacetic salt, adding acid to acidize the mother liquid until pH is 1, and performing crystallization, suction filtering, water washing and drying at 35 DEG C to obtain an iminodiacetic product. The method is environment-friendly and can effectively separate glycerine, the iminodiacetic acid and the inorganic salt.

Description

Technical field [0001] The invention belongs to the field of chemical engineering, and specifically relates to a method for separating and purifying glycine and iminodiacetic acid. Background technique [0002] Glycine, also known as aminoacetic acid, is an important fine chemical synthesis intermediate, mainly used in the synthesis of pesticide glyphosate. At present, it has also been widely used in the fields of medicine, food, chemicals, pesticides, etc. The food and pharmaceutical industries have gradually become the largest demand areas for the use of glycine, and the market demand is very large. In 2010, the global demand will be close to 1000kt. [0003] There are many preparation processes for glycine. Domestic companies mainly adopt the chloroacetic acid method, while foreign companies mainly adopt the Strecker reaction and direct hydantoin reaction. Among them, the Strecker reaction is the direct ammoniation, alkaline hydrolysis and acidification of hydroxyacetonitrile, ...

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Problems solved by technology

Chinese patent CN1962611B records that hydroxyacetonitrile and ammonia water are reacted to obtain an ammonia solution of aminoacetonitrile, and an inorganic base is added to the solution to obtain an alkali hydrolysis solution containing glycine salt, and the alkali gas hydrolysis solution is deaminated, neutralized and decolorized with an inorganic acid , concentrated fractional crystallization and recrystallization, glycine and inorganic salts are obtained respectively; the disadvantages of this method are: the reaction route is long, the process operation conditions are harsh, the desalination operation after the reaction is complicated, the product is not easy to refine, glycine and imino di The separation of acetic acid and nitrilotriacetic acid is difficult, and the glycine crystallization mother liquor is difficult to recycle, the loss of glycine is relatively large, a large amount of low-value inorganic salts and a large amount of difficult-to-treat waste water are produced, and the production cost is high

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