Preparation and Application of Nonionic Polypropylene Oxide-graft-Polyethylene Glycol Copolymer Surfactants as Demulsifier for Petroleum Crude Oil Emulsions

This work aims to prepare new water soluble nonionic amphiphilic graft copolymers based on hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(propylene oxide) (PPO) at ambient temperature and normal atmospheric pressure. In this respect, poly(propylene oxide) were prepared and grafted with different molar ratios of maleic anhydride (MA) in the presence of dibenzoyl peroxide as an radical grafting initiator to produce PPO-MA grafts. The produced grafts were esterfied with different molecular weights of poly(ethylene glycol) momomethyl ether to produce PPO-MA-PEGME nonionic surfactants. The chemical composition and molecular weights of the prepared copolymers were determined from 1HNMR analyses. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for water in crude-oil emulsions that were pronounced at different ratios of crude oil: water at 60°C. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 100% based on demulsifier chemical compositions and concentrations.