Combinatorial identification of a highly soluble phase-selective organogelator with high gelling capacity for crude oil gelation†
Excellent solution-based gelators are generally advantaged by a short gelling time and low gelator loading when compared to powder gelators having a structurally similar backbone. However, high solubility in essentially non-toxic carrier solvents such as ethanol and ethyl acetate still presents a significant bottleneck to their commercial use in large-scale treatment of marine oil spills. In this work, we present a molecular strategy for rapid evolution of a highly soluble POSG (6a-Phe-C4) with high gelling ability toward seven types of (un)weathered crude oils at room temperature. Discovered from a total of 116 PSOGs, gelator 6a-Phe-C4 possesses a record-high solubility of 380 mg mL−1 in a mixed carrier solvent (ethyl acetate : ethanol = 3 : 2, v/v). This value is even higher than the solubility of 359 mg mL−1 for NaCl in water. Moreover, its gelling abilities toward two types of heavy crude oils and three types of highly weathered crude oils at room temperature are much better than those of the best solution-based gelator F-Leu-C4 recently developed by us. As such, the amounts of carrier solvent required now can be reduced markedly to 1.8–5.7 vol% of oil to be gelled, which are 0.4–5.8 times smaller than those needed for F-Leu-C4.