A kind of synthetic method of hydrolysis polymaleic anhydride

Abstract

The invention discloses a method for synthesizing hydrolyzed polymaleic anhydride. Specifically, at a temperature of 55-80°C, a single system or a composite system containing an azo-type water-soluble initiator is used to trigger the generation of maleic anhydride in an aqueous solution or in a molten state. Polymerization to synthesize hydrolyzed polymaleic anhydride with a molecular weight of 1000~3000. Wherein the azo water-soluble initiator can be 2,2 ， ‑Azobisisobutyramide hydrochloride, 2,2 ， ‑Azobis (2‑methyl‑N‑(1,1‑dimethylol‑2‑hydroxyethyl) propionamide), etc. or its complex system with reducing substances. The method adopts water-soluble azo substances as an initiator for initiating the double bond polymerization of maleic anhydride at low temperature, and has high initiation efficiency, relatively high product molecular weight, good water solubility, few by-products, and a yield of up to 95%; Water is used as a solvent, the reaction conditions are mild, and the reaction monomer decomposition rate is low, which is beneficial to realize industrial production.

Description

technical field [0001] The invention belongs to the field of organic polymerization chemistry, in particular to a method for synthesizing hydrolyzed polymaleic anhydride. Background technique [0002] Hydrolyzed polymaleic anhydride polymers and their salts are easily soluble in water, non-toxic and harmless, have extremely high thermal and chemical stability, and have good scale inhibition for carbonates below 300 °C Dispersing effect, usually used as dispersant, antiscalant, detergent additive and chelating agent. Moreover, within a certain range, the performance of the polymaleic anhydride polymer increases as the molecular weight of the hydrolyzed polymaleic anhydride increases. [0003] However, in the molecular structure of maleic anhydride (MA), due to the 1,2-disubstitution steric hindrance on the carbon-carbon double bond, the steric hindrance is relatively large, and free radicals are easy to lose activity and chain termination occurs, so a larger molecular weight...

AI Technical Summary

Problems solved by technology

In 1981, U.S. Patent No. 4,260,724 disclosed that a kind of acetic anhydride was used as a solvent, and the maleic anhydride polymerization was initiated by a 50% hydrogen peroxide aqueous solution by mass percentage, and the liquid component was removed by distillation, and the solid polymer was obtained by drying. Method Although the product yield is increased by adding inorganic acids such as phosphorous acid, sulfuric acid, etc. or organic acids such as oxalic acid, citric acid, adipic acid, etc., the use of initiator peroxide will decompose monomers and generate a large amount of carbon dioxide, which is not conducive to the production of products. Increase in total yield

And the use of a large amount of organic solvents in the synthesis process, on the one hand, brings a lot of trouble to the post-processing, resulting in increased costs; on the other hand, the output of a large amount of organic wastewater in the process is not conducive to work safety and environmental protection