New Developments in Demulsifier Chemistry

Abstract

Sixteen new demulsifier chemicals were prepared based on dendrimer chemistry. They were designed to be amphiphilic with hydrophilic ethoxylated blocks, hydrophobic polyester dendrimer cores and alkyl chains. Three different factors were investigated in the synthesis of Boltorn H311 with the alkyl ether carboxylic acids - the percentage coverage of the dendrimer surface (50 to 100%), the number of the ethylene oxide units (2-10), and the length of the carbon chains (C12/C14 and C16/C18). GPC, IR and NMR were successfully used to characterise the reaction products. The products were systematically investigated as emulsion breakers for resolving water-in-oil (W/O) emulsions by bottle testing on three different crude oils. The best performing products were found to give water separations of >80%. The main trends were improved water separation on increasing coverage of the dendrimer surface, increasing length of EO units and less significantly increasing carbon chain length. Measurements of residual emulsion (BS) were also important in the evaluation of demulsifier performance. The products had a strong affinity for adsorbing at the interface of water droplets in water-in-oil (W/O) emulsions. The demulsifier performance of the best performing products was also correlated to reduction of interfacial tension (IFT) for the 90% coverage range of products. Biodegradation and ecotoxicity were investigated for the product range (1-16). The products had biodegradation measurements between 20-30% on day 28, with the exception of product 5 (15%). EC50 was used as the measure of toxicity. For all the products EC50 was > 10 mg/L. Fifteen of the products were classified as Y2.