Concentration effects in the base-catalyzed hydrolysis of oligo(ethylene glycol)- and amine-containing methacrylic monomers

Oleg A Kazantsev,Dmitry V Orekhov,Alexey P Sivokhin,Denis M Kamorin,Maria V Savinova

doi:10.1080/15685551.2016.1231034

Abstract

Concentration effects in the base-catalyzed hydrolysis of water-soluble methacrylates (3-(N,N-dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs)) have been studied. These monomers are rapidly hydrolyzed in the presence of bases at the room temperature in dilute aqueous solutions, but the reaction rate decreases sharply in highly concentrated solutions. A clear correlation was found between a form of the viscosity isotherm for DMAEMA solutions and the concentration dependence of the autocatalytic hydrolysis rate which indicates the connection of process kinetics with the structure of solutions. These data should be considered when carrying out homo- and copolymerization of the previously mentioned monomers in aqueous solutions.

Highlights

3-(N,N-Dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs) are the most commonly used water-soluble methacrylic esters
Water-soluble copolymers of OEGMAs are used as superplasticizers for concrete compositions, as superabsorbents, have a good potential in pharmaceutics. [1,2] HEMA copolymers are used for producing coatings and adhesives,[3,4] DMAEMA copolymers are effective flocculants and additives to paper.[5,6]
The mechanism and kinetics of the base-catalyzed hydrolysis of esters in dilute solutions are studied in detail. [13,14] According to the classical kinetic equation[15] the rate of the base-catalyzed hydrolysis of esters is proportional to the concentration of an ester and hydroxyl ions

Summary

Introduction

3-(N,N-Dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs) are the most commonly used water-soluble methacrylic esters. [1,2] HEMA copolymers are used for producing coatings and adhesives,[3,4] DMAEMA copolymers are effective flocculants and additives to paper.[5,6] In most cases, the preparation of such polymers is carried out in aqueous media The monomers such as OEGMAs or DMAEMA salts are often obtained, stored and used in the form of concentrated aqueous solutions.[7]. Ethoxylated methacrylates, in some cases, are copolymerized in water with amine-contaning methacrylic monomers (DMAEMA or N-[3-(dimethylamino)propyl] methacrylamide),[11,12] i.e., when the system contains free amino groups In this connection, the study of hydrolytic stability of the water-soluble amine-containing and ethoxylated (meth)acrylates in the presence of basic catalysts is very topical.

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