Method of breaking crude oil emulsions using ethylene carbonate adducts of alkylphenol-formaldehyde resins

A method of breaking crude oil emulsion, which comprises treating said emulsion with an effective amount of an emulsion breaker represented by a product obtained by reacting, in anhydrous condition, for at least one hour, an alkyl substituted phenol-formaldehyde polymer having the structure:

• ##STR7## wherein R is a linear or branched alkyl group having from 4-20 carbon atoms, and wherein m and n are both independent integers, the sum of which is sufficient to achieve a molecular weight of at least 1000 and further that m, but not n, may be zero;
• with (b) ethylene carbonate, said reaction being further accomplished in an oleophilic solvent having a boiling point of at least 180.degree. C., the reaction further at a temperature of at least 160.degree. C. in the presence of an alkaline catalyst, said catalyst being present at a concentration, based on total weight of reactants a & b, of at least about 0.1 weight percent.