Synthesis and effect of alkyl glycerol ether on cold flow property of biodiesel from palm oil

Abstract

The etherification reaction between glycerin and alkenes (ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene) over acidic heterogeneous catalysts (Amberlyst-15, S100, S200, Al-SBA-15, Pr-SO3H-SBA-15, Zeolite Beta and Zeolite Y) were carried out. Strong acidity with mesopore size of Amberlyst-15 gave the highest activity in propylation and butylation of glycerin. S200 resin, strong acidity with non porous type, showed low reaction in glycerin etherification with propylene and 1-butene. S100 resin, strong acidity with non porous type, gave the lowest reaction in glycerin propylation and gave no reaction of glycerin butylation. Weak acidity with high pore size of Al-SBA-15, Pr-SO3H-SBA-15, Z-Beta and Z-Y gave no reaction on glycerin etherification with propylene and 1-butene. The propylation of glycerin over Amberlyst-15 at 100 °C after 24 h showed mixed propyl glycerol ethers (PGE) which composed of mono-propyl glycerol ether (MPGE) 24.99%, di-propyl glycerol ether (DPGE) 20.84% and tri-propyl glycerol ether (TPGE) 54.17%. TPGE was obtained as a sole product through propylene alkylation of MPGE and DPGE, over Amberlyst-15 at 100 °C after 48 h. The butylation product of glycerin over Amberlyst-15 at 100 °C after 48 h composed of mono-butyl glycerol ether (MBGE) 79.40%, dioxan derivative 9.71% and di-butyl glycerol ether (DBGE) 10.89%. The mixed PGE and TPGE reduced cloud point and pour point of blended palm biodiesel with diesel, reduced cetane index of diesel and B100, and increased RON and MON in gasoline when 10% of mixed PGE or TPGE was added.