Improving heavy oil recovery, part (I): synthesis and surface activity evaluation of some novel organometallic surfactants based on salen–M complexes

This study focuses on preparing a new family of organometallic surfactants based on five ion complexes, namely Co(2+), Ni(2+), Cu(2+), Fe(3+), and Mn(2+). The first step is the preparation of 5-chloromethyl salicylaldehyde (Salen, S). The second step is the formation of sodium alkoxide of Pluronic F-127 (AP). The third step is the formation of the modified AP–Salen (new ligand). This ligand was reacted with the metal chlorides as mentioned earlier to obtain the organometallic surfactants (OMS) named AP–Salen–M complexes. FT-IR, (1)H-NMR, SEM, and EDX justified the chemical structure of the as-prepared materials. The surface tension of these surfactants was measured for surfactant solutions at different concentrations to determine the CMC and calculate their surface–active properties. The interfacial tension at CMC was measured against heavy crude oil to predict the availability and use these surfactants in the enhanced oil recovery (EOR) process. From the results, this class of surfactants exhibited good surface–active properties and high efficiency on the interface adsorption; besides, they reduced the interfacial tension in the order between 10(−1) and 10(−2) mN m(−1), which gives a good indication to use these surfactants in EOR application for the heavy crude oil.