Hydroformylation of branched olefins catalyzed by Co₂(CO)₈ for synthesis of branched alcohol ethoxylates and their surfactant properties

Branched-chain surfactants have lower equilibrium surface tension, superior wettability and emulsifying performance, making them suitable for exclusive applications. Linear α -olefins are rich in coal-based Fischer–Tropsch synthesized liquid products and are promising building blocks for the synthesis of branched-chain surfactants via dimerization and subsequent C=C bond functionalization. Herein, a new series of branched ethoxylate non-ionic surfactants (MDC 6 E n ) were prepared using 2-butyl-1-octene (1-hexene dimer, DC 6 ), obtained by the dimerization of coal-based Fischer-Tropsch synthesized 1-hexene, as the hydrophobe via hydroxylation and ethoxylation. In particular, the hydroxylation of DC 6 was carried out in a one-pot tandem hydroformylation and hydrogenation over unmodified Co 2 (CO) 8 under mild conditions (140 °C and 4–8 MPa, CO:H 2 = 1:1). A thorough investigation of their surfactant properties was carried out, including equilibrium surface tension, dynamic surface tension, foaming properties, wetting power, and emulsifying power. The results indicate that MDC 6 E 9 performs comparably to a commercially available branched-chain surfactants, the iso-tridecyl alcohol ethoxylates (MULTISO 1390). This research provides a new direction for the synthesis of branched nonionic surfactants using Fischer–Tropsch synthesized products, further promoting the development of coal-based fine chemicals.