Mixtures for improving or boosting the separation of water from fuels

A process for improving or boosting the separation of water from fuel oils and gasoline fuels, the process comprising:

• applying mixtures of
• olefin-carboxylic acid copolymers (A) with a number-average molecular weight Mn of from 0.5 to 10 kDa (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard), obtainable by
• in a first reaction (I), copolymerizing
• (Aa) at least one ethylenically unsaturated mono- or dicarboxylic acid or derivative thereof,
• (Ab) at least one α-olefin having from at least 12 up to and including 30 carbon atoms,
• (Ac) optionally, at least one further aliphatic or cycloaliphatic olefin which has at least 4 carbon atoms and is different than (Ab), and
• (Ad) optionally one or more further copolymerizable monomers other than monomers (Aa), (Ab), and (Ac), selected from the group consisting of
• (Ada) vinyl esters,
• (Adb) vinyl ethers,
• (Adc) (meth)acrylic esters of alcohols having at least 5 carbon atoms,
• (Add) allyl alcohols or ethers thereof,
• (Ade) N-vinyl compounds selected from the group consisting of vinyl compounds of heterocycles containing at least one nitrogen atom, N-vinylamides, and N-vinyllactams,
• (Adf) ethylenically unsaturated aromatics,
• (Adg) α,β-ethylenically unsaturated nitriles,
• (Adh) (meth)acrylamides, and
• (Adi) allylamines,
• followed by
• in a second optional reaction (II) partly or fully hydrolyzing and/or saponifying anhydride or carboxylic ester functionalities present in a copolymer obtained from (I), the second reaction being run at least when the copolymer obtained from reaction (I) does not comprise any free carboxylic functionalities;
• with
• at least one additive with detergent action selected from the group consisting of
• quaternary nitrogen compounds (B), and
• polyisobutenylsuccinimides (G),
• to the water containing fuel oils and gasoline fuels, and
• allowing an organic phase and aqueous phase to separate.