Preparation method of polymaleic acid

Abstract

The invention discloses a preparation method of polymaleic acid, belonging to the field of chemical technology and aiming at providing a preparation method of polymaleic acid with high product yield, low bromine number and stable quality, and meanwhile, the polymaleic acid average molecular weight of which is more than 5500 is suitable for commercial process. The preparation method has the technical key points that 1 part by weight of maleic anhydride, 1.2 to 1.4 parts by weight of distilled water and 0.015 to 0.02 parts by weight of mixture of transition metal ion M compound and ammonium salt are put into a reaction kettle once to be heated from 40 to 60 DEG C to be totally dissolved; then perhydrol is slowly added to polymerize under the condition of continuous stirring, polymerization reaction temperature is controlled to be 90 to 100 DEG C, and heat preservation reaction time is 1 to 2 hours, so that the polymaleic acid whose average molecular weight is bigger than 5500 can be obtained. The yield can be more than 99.0% (counted by maleic anhydride), bromine number is smaller than 30mg / g, and products have stable quality. The preparation method for polymaleic acid has environmentally-friendly and clean technology, produces no three wastes and has the advantages of convenient operation and low production cost, thus the preparation method of polymaleic acid is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a preparation method of polymaleic acid, which belongs to the technical field of chemical industry. Background technique [0002] Polymaleic acid (HPMA), commonly known as hydrolyzed polymaleic anhydride, is a water treatment agent and high-efficiency dispersant with excellent performance and a wide range of uses. [0003] At present, the preparation of polymaleic acid: one is radiation polymerization. This method uses cobalt 60 to irradiate maleic anhydride to make it polymerize and obtain polymaleic anhydride. This is the earliest method for the preparation of polymaleic anhydride. First developed by Lang Pavelich and Clayey in 1961, the molecular weight of polymaleic anhydride produced is 19500, and the conversion rate is 5%. They broke through the forbidden zone of homopolymerization of maleic anhydride, changed people's long-term belief that maleic anhydride can only be copolymerized with other monomers, but not homopol...

AI Technical Summary

Problems solved by technology

Beijing University of Chemical Technology uses hydrogen peroxide as the initiator and water as the solvent. The obtained polymaleic acid product has a low bromine value, a high average molecular weight, and good scale inhibition performance.