Use of alkoxylated polyalkanolamines for splitting oil-water emulsions

A method of splitting oil-water emulsions, comprising adding polyalkanolamines to an oil-water emulsion, wherein polyalkanolamines are alkoxylated polyalkanolamines (III) which are obtained by the following process:

• (A) condensing at least one trialkanolamine of the general formula N(R1—OH)3 (Ia) and/or at least one dialkanolamine of the general formula R2—N(R1—OH)2 (Ib) to give a polyalkanolamine (II),
• where
• the R1 radicals are each independently a divalent, linear or branched aliphatic hydrocarbon radical having from 2 to 6 carbon atoms,
• the R2 radicals are each hydrogen and/or linear or branched aliphatic, cycloaliphatic and/or aromatic hydrocarbon radicals having from 1 to 30 carbon atoms, and
• the resulting polyalkanolamines (II) have a mean molar mass of from 1000 g/mol to 20 000 g/mol,
• (B) alkoxylating the resulting polyalkanolamine (II) with ethylene oxide and propylene oxide to form alkoxylated polyalkanolamines (III) which contains polyoxyalkylene groups, where
• the polyoxyalkylene groups formed have block structure of the general formula —(CH2CH2O)x(CH2CH(CH3)O)yH, and where x and y are each from 3 to 100, and
• the y/x ratio is >1.