Me(2)CHCOOCH(CHMe(2))CH(Me(2)) was oxyethylated with oxirane at 120 degrees C and 0.3-0.5 MPa in presence of NaOH to Me(2)CHCOOCH(CHMe(2))CH(Me(2))CH(2)O(CH(2)CH(2)O)(n)H (I) where n = 3-30. Thirteen I were analyzed for chem. compn. (gas chromatog.), crit. micelle concn., wetting angle (on carbon steel, ceramic tile and wooden panel), surface tension, cloud point and cloud no. The results were compared with resp. data detd. for com. nonionic surfactants (C(12-14) alc. oxyethylate, dodecylbenzenesulfonic acid). The I showed higher surface tension than the com. surfactants but its addn. to them resulted in substantial improvement of the surface activity of the mixt. This observation was explained by a synergy effect.