Process for preparing tertiary alkyl esters of (meth) acrylic acid having at least 4 carbon atoms in the alkyl radical

A process for preparing tertiary alkyl esters of (meth)acrylic acid having at least 4 carbon atoms in the alkyl radical, comprising the steps of:

• (1) reacting (meth)acrylic acid with at least one olefin of the general formula I:
• in which R1 and R2 may be the same or different and are each an alkyl radical, and R3 is a hydrogen atom, an alkyl radical, a cycloalkyl radical, an aryl radical, an alkylcycloalkyl radical which is bonded to the olefinically unsaturated carbon atom via an aliphatic or cycloaliphatic carbon atom, an alkylaryl radical which is bonded to the olefinically unsaturated carbon atom via an aliphatic or aromatic carbon atom, a cycloalkylaryl radical which is bonded to the olefinically unsaturated carbon atom via a cycloaliphatic or aromatic carbon atom, or an alkylcycloalkylaryl radical which is bonded to the olefinically unsaturated carbon atom via an aliphatic, cycloaliphatic or aromatic carbon atom;
• in homogeneous phase in the presence of an acidic catalyst in a reactor,
• (2) discharging the resulting reaction mixture (1) from the reactor,
• (3) separating the discharged reaction mixture (2) into a mixture (3.1) which comprises the catalyst and a mixture (3.2) which comprises the tertiary alkyl ester of (meth)acrylic acid having at least 4 carbon atoms in the alkyl radical, and
• (4) removing the tertiary alkyl ester of (meth)acrylic acid having at least 4 carbon atoms in the alkyl radical from the mixture (3.2),
• which comprises,
• (5) in process step (4), adding at least one compound S which comprises at least one N-oxyl group, as stabilizer.