Physicochemical properties of biodiesel produced by WO₃/CuFe₂O₄ magnetic catalyst and their limits^a.

Biodiesel properties	Unit	Test methods	ASTM D6751 limits	Present study
Kinematic viscosity (at 40 °C)	mm2 s−1	D445	1.9–6.0	4.7
Density (at 20 °C)	g cm−3	D6890	0.875–0.900	0.881
Acid value	mg KOH g−1	D664	0.5 max	0.21
Flash point	°C	D93	130 min	155
Cold filter plugging point	°C	D6371	NS	0
Copper strip corrosion	—	D130	3 max	1a
Oxidative stability	h	EN 14112	3 min	4.8

^aNS = not specified.