Process for preparing methacrylic anhydride of high purity

摘要

The invention concerns a method consisting in making a mixed (meth)acrylic anhydride of formula (I) by reacting an alkaline (meth)acrylate of formula (II) and a chloroformate of formula (III), carrying out said reaction in an aqueous medium and in the absence of amines, the mol ratio chloroformate (III)/alkaline (meth)acrylate (II) being at least equal to 1.15. R1 represents H or CH3; R2 represents an alkyl, alkenyl, aryl, alkaryl or aralkyl residue; and M is an alkaline metal.