Nine 4-benzyl-4-methylmorpholinium salts were synthesized by quaternization of methylmorpholine with PhCH(2)Cl and following exchange of the Cl ion with NO(3), HSO(4), BF(4), PF(6), SCN, CH(3)SO(3), CF(3)SO(3) and (CF(3)SO(2))(2) ions in aq. or MeOH solns. at room temp. The salts were studied for chem. structure (by NMR), viscosity and thermal properties (by thermogravimetry). The SCN salts was successfully used for removal of glycerol from biodiesel by extn.