| 摘要 |
Process for preparing (meth)acrylates of the formula (I) CH2═C(R1)—CO—O—R2   (I) in which R1 is hydrogen or methyl and R2 is a saturated or unsaturated, linear or branched, aliphatic or cyclic alkyl radical having 6 to 22 carbon atoms, or a (C6-C14)-aryl-(C1-C8)-alkyl radical; by reacting a (meth)acrylate of the formula II CH2═C(R1)—CO—OR3   (II) with an alcohol of the formula (III) HO—R2   (III) in the presence of an amount of a suitable catalyst which catalyses the reaction and of an amount of a phenolic polymerization inhibitor or a combination of two or more phenolic polymerization inhibitors which is sufficient to inhibit undesired polymerization; the reaction being undertaken with input or introduction into the reaction mixture resulting from the reaction of an amount of oxygen or of an oxygenous gas mixture sufficient to inhibit undesired polymerization, and the process is characterized in that the specific total oxygen input is less than or equal to 1.0 l/kg, measured in litres of oxygen per kilogram of (meth)acrylate of the formula (I), where the volume of oxygen introduced is calculated at a temperature of 25° C. and a pressure of 101 325 pascal. The resulting (meth)acrylates can surprisingly be processed to particularly high molecular weight emulsion polymers which are, for example, outstandingly suitable for use as flow resistance reducers in mineral oil extraction.
|
