Synthesis method of high-concentration polyepoxysuccinic acid and salt thereof

Abstract

The invention discloses a synthesis method of high-concentration polyepoxysuccinic acid and salt thereof. The method comprises the following main processes: simultaneously adding maleic anhydride and sodium hydrate into water in a mode of feeding in batches; controlling the pH value of solution at 5-7 and the reaction temperature at 40-60 DEG C; adding sodium tngstate into a hydrolysis product as expoxidation catalyst at 50-60 DEG C; carrying out expoxidation reaction by adding hydrogen peroxide; adding sodium hydrate solution at the same time; controlling the pH value at 4-7; finishing the expoxidation reaction; stirring; raising the temperature to above 80 DEG C; adding initiator calcium oxide; and after polymerization, lowering the temperature and filtering to obtain the polyepoxysuccinic acid and salt solution thereof. In the preparation method, a one-pot synthesis is adopted, and therefore, the preparation method has the advantages of simple and unique technology, high product concentration, high raw material conversion rate, ideal molecular weight distribution and favorable industrial operability.

Description

technical field [0001] The invention refers to a method for synthesizing industrially produced high-concentration polyepoxysuccinic acid and its salts (PESA). Background technique [0002] Polyepoxysuccinic acid and its salts are a new water treatment scale inhibitor and dispersant in the 1990s. They have good biodegradability and are environmentally friendly, so they are called green scale inhibitors and dispersants. The market prospect is promising. This product can also be widely used in formulas such as daily chemical cleaning products and toothpaste to replace phosphorus-containing additives. Its molecular formula is as follows: [0003] [0004] (I) In the formula, n represents the degree of polymerization and is an integer ≥ 2. M is H + 、Na + 、K + , NH 4 + , Ca 2+ , Mg 2+ or a mixture thereof. [0005] U.S. Patent No. 5,028,415 has described the synthetic method of PESA, is about to neutralize with sodium hydroxide after the hydrolysis of maleic anhydride...

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Problems solved by technology

[0006] Due to the problems of low solubility of intermediate products and difficult stirring during the hydrolysis of maleic anhydride, the concentration of epoxidized products obtained is low

When it is crystallized, a large amount of acetone needs to be used, and it is difficult to recycle and process, and it is difficult to carry out industrial production

If the epoxide is directly polymerized without crystallization, the resulting polymer concentration is low (about 20% or lower), and other concentration methods are required to obtain a high-concentration product, and the molecular weight distribution of the low-concentration polymerization is not ideal, and the scale inhibition effect is not good.

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