Effects of comb-like poly-α-olefins on the cold flow properties of diesel fuel.

1. Synthetic route of copolymer. 2. Possible mechanism of (C16-AM, C16-IM and C16-SM) for improving the fluidity of diesel oil at low temperature. [Display omitted] • Comb-like PAOs were synthesized from long-chain olefin and benzene containing olefin. • Comb-like PAOs can effectively improve the low temperature cold flow of diesel fuel. • The properties of synthetic PAOs and commercial PPDs were compared during oxidation. • The crystallization behaviors of Comb-like PAOs were studied. Pour point depressants (PPDs) represent an efficient and economical approach to enhance diesel's low-temperature fluidity, yet their efficacy is influenced by molecular structure and surfactant moieties. To achieve highly effective PPDs, a series of comb-structured poly-alpha-olefins (PAOs) were synthesized in this paper, designated as 1-hexadecene-styrene (C16-SM), 1-hexadecene- allyl benzene (C16-AM), and 1-hexadecene-indene (C16-IM). The copolymers' impact on diminishing diesel's solid point (SP) and cold filter plugging point (CFPP) was thoroughly investigated. Notably, with a 1-hexadecene to styrene monomer molar ratio of 20:1, the most favorable inhibitory effect of C16-SM was observed, exhibiting a reduction of 10 °C for CFPP and 30 °C for SP. Comparing C16-SM to commercial pour point depressants (CPPDs) after subjecting them to an accelerated oxidation test revealed that the C16-SM performance was more stable under oxidative conditions. To address stability and environmental pollution concerns associated with PPDs, this study aims to develop a stable, eco-friendly PAO PPD and assess the influence of various benzene ring-based monomers on diesel's cold fluidity in low-temperature conditions. Furthermore, a novel mechanism elucidating the change in crystal morphology and size by PAOs is proposed. [ABSTRACT FROM AUTHOR]