Synthesis of petroleum sulfonate via gas-phase sulfonation in rotating packed bed: Process optimization and interfacial tension-composition relationship

This study presents the synthesis of petroleum sulfonate (PS) via gas-phase SO3 sulfonation in a rotating packed bed (RPB) and the relationship between the interfacial tension (IFT) at the oil-aqueous interface and the composition of PS. Through the process optimization, the content of active matter in the prepared PS could reach up to 42.5%, which was significantly higher than that in the industrial production (38%). Moreover, the oil-aqueous IFT could reach an ultra-low value of 1.41×10-3 mN/m. The analysis results of PS composition and IFT indicated that the oil-aqueous IFT was mainly affected by the content of alkyl benzene, alkyl indane, alkyl acenaphthylene and alkyl naphthalene sulfonates in PS. In addition, a correlation coefficient, which was consistent with the interfacial tension, was established for evaluation of the similarity between PS samples.