Abstract: The new compounds consist essentially of ethylene oxide/propylene oxide block polymer units and oxyalkyleneated alkylphenol/aldehyde resin units, which are linked by methylene groups. They are prepared by reacting a block polymer of ethylene oxide and propylene oxide and an oxyalkyleneated alkylphenol/aldehyde resin with formaldehyde. The new compounds constitute especially advantageous breaking agents for petroleum.

Abstract: A condensation product obtained by first preparingA. an addition product of aliphatic aldehydes and phenol in a molar ratio of about 1 : 1 to 3 : 1, at temperatures in the range of from about 50.degree. to 80.degree. C, in the presence of an alkaline catalyst,And separately therefromB. a block polymer, obtained from a polypropylene glycol having a molecular weight from about 1500 to 2500 by the addition of about 30 to 50% by weight of ethylene oxide in the presence of an alkaline catalyst,And subsequentlyC. condensing about 0.5 to 4 moles of a) with 1 mole of b), after previous neutralization, if necessary in the presence of inert solvents, at 80.degree. to 150.degree. C, and removing the reaction water formed,And its use as demulsifying agent for the separation of water from crude oil emulsions.