PETROLEUM SCIENCE AND TECHNOLOGY, 19(1&2), 107–118 (2001) INTERFACIAL PROPERTIES OF THE PRODUCTS OF OZONOLYSIS OF HAMACA CRUDE OIL Gast´ on Escobar, Pedro Pati˜ no, S ´ ocrates Acevedo, Optal´ ı Escobar, Mar´ ıa A. Ranaudo, and Juan Carlos Pereira Escuela de Qu´ ımica, Facultad de Ciencias, Universidad Central de Venezuela, 47102, Caracas 1041, Venezuela ABSTRACT A sample of extra-heavy Hamaca crude oil, dissolved in car- bon tetrachloride, was oxidated with ozone for a few minutes. The reaction mixture was washed with a concentrated solution of HCl, neutralized with sodium carbonate, and the products were extracted from the aqueous phase. The products were characterized by us- ing gel permeation chromatography (GPC), elemental analysis, 1 H nuclear magnetic resonance (NMR), and Fourier transformed in- frared (FTIR) techniques. The results of the analyses show that the products have lower molecular weights, lower aromatic character, and higher oxygen content than the original sample. They also indi- cated that these products were mainly carboxylic acids, aldehydes, and/or ketones, with a higher affinity for water than for carbon tetrachloride, the organic solvent that was used. Interfacial tension γ measurements (water–toluene) performed with these products showed a linear dependence with concentration, where γ dropped from 32 to about 7.7 dinas/cm at the apparent critical Micelle con- centration (cmc) (2 g/L). Larger quantities of a commercial sample of nonylphenol ethoxylated were needed for an equivalent γ drop. In another experiment the above oxidated product was mixed with 107 Copyright C  2001 by Marcel Dekker, Inc. www.dekker.com