Dynamic interfacial tension measurement of heavy crude oil±alkaline systems The role of the counterion in the aqueous phase
Autor
Acevedo, Sócrates
Ranaudo, María Antonieta
Escobar, Gastón
Gutiérrez, Xiomara
Institución
Resumen
The dynamic behaviour of the interfacial tension at the oil±water interface g (t) for oleic acid and a 90% v/v Cerro Negro±xylene solution
had been studied under alkaline conditions. For the system oleic acid in paraf®n, aqueous sodium carbonate with or without added sodium
chloride, the usual g (t) behaviour was observed, i.e. g drops to low or ultralow values at short times, remains low during a short period, and
then rises to high ( . 1 N m21) values. However, when alkyl amines (ethyl, diethyl and triethyl amine) were used as alkalis in the aqueous
phase, g (t) ®rst dropped to a relatively high value (1.5,g,3 N m21) and then remained almost constant afterwards. The presence of sodium
chloride in the aqueous phase was required to observed the aforementioned usual g (t) behaviour. From these results it is clear that the presence
of sodium ions is esential for both reducing (to very low values) and increasing g (t). It is suggested that ultralow transient (values and the
formation of spontaneous emulsion are due to a phase inversion (from w/o to o/w) going through a microemulsion intermediate. q1999
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