IMPROVING COLD FLOW PROPERTIES OF BIODIESEL BY UNSATURATED FATTY ACID ESTERS WITH BRANCHED-CHAIN ALKOXY GROUP

Abstract

Biodiesel as the important alternative energy resource is a role to replacement Petroleum-diesel that has insufficient quantities. Although biodiesel has advantages over Petroleum-diesel, the significant disadvantages are the flow properties at low temperature (cold flow properties). One way to solve this problem is adding the chemical additives. In this research, the chemical additives were synthesized in form of the ester of oleic and linoleic acid with branched-chain alkoxy by 3 steps reaction which comprised esterification, epoxidation and alkoxylation respectively. The synthetic additives were characterized with H1-NMR techniques and blended in palm biodiesel at 150,000 ppm for testing cloud point (CP) and pour point (PP) followed American Society for Testing and Materials (ASTM). The results showed that, the all of additives could reduce CP and PP of palm biodiesel by the series of linoleate additives more slightly reduced than the series of oleate additives along to stericity. The others effect from the structure of branched-chain alkoxy were not only stericity but also size of molecule and dipole moment of alkoxy group. Especially, 2, 2-dimethyl propoxy isopropyl linoleate could reduce CP and PP of palm biodiesel to 4 oC and 2.4 oC respectively. Because it properly has size of molecule, stericity and being ester of linoleate.