Melting Points

Several solids have been filtered from solutions containing both metal cations and curcumin.  Especially when it comes to iron(III), the identity of the filtered solid has been questionable.  It was possible that the solid was iron oxide and not the curcumin-iron complex.  As a method of identifying the solid, we attempted to find the melting point of the black crystals that were removed from solution.
The melting point of curcumin is 183°C.  The melting point of iron oxide is far beyond the limitations of the melting point apparatus at 1500°C.  The black crystals did not melt at 250°C, although they did begin to change color.  The limitations of the machine made further analysis of the black crystals impossible.

The melting point apparatus was also utilized to confirm the identity of orange crystals extracted from a turmeric solution.  

The melting point of the crystals was 179°C.  Because the melting points of the curcuminoids are all slightly different, the "impurity" caused by having all three curcuminoids together reduced the melting point, meaning that the crystals were confirmed as curcumin by the melting point testing.

7/12/18

-Alex Griffith