Synthesis and Characterization of Dicarboxylate Esters as Environmentally Friendly Palm Biodiesel Pour Point Depressants

The alternative renewable energy of Palm BioDiesel (PBD) is gaining eminence to be used in transportation and industrial applications. However, its regular usage in temperate countries has the main issue to be solved due to its poor cold flow properties. The Pour Point Depressant (PPD) is required to enhance the PBD cold flow properties to a certain acceptable range. In this work, environmentally green PPD diesters for PBD were synthesized through the acid catalyst esterification process between selected dicarboxylic acids (succinic, suberic, and dodecanedioic) with branched alcohols (2-butyl-1-octanol and 2-ethyl-1-hexanol) in the presence of sulphuric acid. The resultant synthesized dicarboxylate esters were successfully produced at high yield percentages in the range of 85-98%. The chemical structures of dicarboxylate esters were confirmed by using FT-IR, H-1, and C-13 NMR. The results showed that green PPDs derived from the dicarboxylic acids with the same carbon chain length of the respective branched alcohol have more capability to reduce PBD pour point. On the other hand, green PPDs derived from the same alcohol of the respective increasing dicarboxylic acids carbon chain length showed a slight reduction in PBD pour point. A selected blending green PPD of di(2-butyloctyl) suberate (D2BOsub) into PBD has produced the lowest PBD pour point down to 3(degrees)C. Therefore, properly chosen green PPDs capable of reducing the PBD pour point are to be regularly used as an alternative fuel in tropical countries. It is plausible for the synthesized PPD to be used together with petrol -diesel blends in selected proportions or as a full substitute for diesel engines.