This invention relates to a process for the production of a polyoxyalkylene derivative of a phenolic resin, by reacting under base-catalyzed conditions the phenolic resin with the appropriate alkylene oxide(s) so that the polyoxyalkylation is carried out by: A) using a phenolic resin which has a water content of less than 0.5% w/w, B) reacting the phenolic resin initially with about one mole of the alkylene oxide(s) per mole of the resin in the absence of a base catalyst in an inert atmosphere at a temperature below 140.degree. C. until the partial pressure of the alkylene oxide(s) reactant is substantially neutralized, and C) reacting the product from step (B) above with the remainder of the alkylene oxide(s). These derivatives are good emulsifiers and demulsifers.