A novel pour point depressant with diesel cold-flow properties: Performance evaluation of benzene-containing ternary copolymers

The addition of pour point depressants (PPDs) represents the most direct and efficient approach for improving the cold-flow properties of diesel. Nevertheless, the high doses of additives have consistently been a constraining factor. To address this challenge, the study synthesized tetradecyl methacrylate–N-hydroxymethacrylamide–benzyl acrylate (C14MC–NMA–BA), tetradecyl methacrylate–N-hydroxymethacrylamide–4-pentenoic acid benzyl ester (C14MC–NMA–PB), and tetradecyl methacrylate–N-hydroxymethacrylamide–10-undecenoic acid benzyl ester (C14MC–NMA–UB) at various molar ratios (1:1:1, 5:1:1, 10:1:1, 15:1:1, and 20:1:1) as PPDs for diesel. The aim of these PPDs is to efficiently improve the cold-flow properties of diesel at low doses. The cold filter plugging point (CFPP) and solidification point (SP) of diesel were tested before and after treatment with PPDs. The results confirmed that C14MC–NMA–UB with longer carbon chains exhibited superior performance compared to C14MC–NMA–PB and C14MC–NMA–BA. Considering both cost-effectiveness and performance metrics, 400 ppm C14MC–NMA–UB (5:1:1) was identified as the optimal choice for significantly enhancing diesel cold-flow properties, leading to reductions of CFPP and SP by 11 °C and 25 °C, respectively. Furthermore, the study delved into the inhibitory mechanisms of PPDs by examining the crystallization behavior of diesel at low temperatures, utilizing techniques such as differential scanning calorimetry, viscosity-temperature profiles, and polarized optical microscopy.