Preparation method of imino-disuccinic acid and salt thereof

Abstract

The invention relates to the technical field of preparation of organic compounds, in particular to the technical field of preparation of a metal-chelator. The invention particularly discloses a preparation method of imino-disuccinic acid and salt thereof. The method comprises the steps of mixing alkaline raw material liquid A containing butene diacid radical and alkaline raw material liquid B containing aspartic acid radical to have a reaction, enabling reaction liquid to be in a critical saturation state, and maintaining the reaction liquid to be boiled; continuously carrying out the reaction until end to obtain imino-disuccinate; continuously feeding inorganic acid into the product to obtain imino-disuccinic acid precipitate, filtering, and recrystallizing to obtain white imino-disuccinic acid crystal. The method has the advantages of being short in reaction time, high in reaction yield, low in energy consumption and low in cost; the prepared product is high in purity and good in performance, thus being suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of preparation of organic compounds, in particular to the technical field of preparation of a metal chelating agent. Background technique [0002] Iminodisuccinic acid and its salts (chemical abbreviation: IDS or IDHA) is a new type of green chelating agent, which has a strong ability to chelate metal ions. Compared with traditional polycarboxylic acid chelating agents (such as EDTA ), also has excellent degradability, is environmentally friendly, and can solve the problem of environmental pollution that is difficult to degrade when heavy metal ions are combined with traditional chelating agents. It can be widely used in many fields such as petrochemical industry, textile industry, and heavy metal extraction. [0003] The synthesis and preparation method of IDS is mainly prepared by closed high-pressure reaction of maleic anhydride and ammonia water under alkaline conditions. The disadvantages are: the yield...

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Problems solved by technology

[0003] The synthesis and preparation method of IDS is mainly prepared by closed high-pressure reaction of maleic anhydride and ammonia water under alkaline conditions. The disadvantages are: the yield of the product iminodisuccinate is less than 80%, there is ammonia gas residue in the reaction process, and It requires high temperature and high pressure operation, high potential safety hazards, high requirements for equipment and management, large investment and high energy consumption

[0004] There is another preparation method of iminodisuccinate chelating agent reported in the literature, adopting raw material is maleic anhydride / salt or derivative thereof and aspartic acid / salt or derivative thereof in the presence of alkali metal hydroxide The reaction preparation realizes the reaction under normal pressure, and provides a relatively simple method for the industrial preparation of iminodisuccinate, but there are still the following disadvantages: the reaction time of the process is relatively long, which is 6h~30h, and the yield is relatively low. The low is 70%~85%, and because 15~30% of the raw materials are unreacted or side-reacted, it is easy to form salt and precipitate under alkaline conditions, and because iminodisuccinate and reaction raw materials or by-products The cost of separation is high, so it is generally provided to users in the form of a mixture generated by the final reaction. The higher the residual rate of raw materials or the more by-products, the effect in practical applications will be reduced, such as weakened chelation effect, unreacted Precipitation of raw materials or by-products, etc.