Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: yg7s7 on March 31, 2009, 11:19:10 PM
-
Cholesterol has melting point range of 147-150 C, and so does cholesteryl benzoate, but when I mixed those two and measured the melting point range in my teaching lab, the melting point range was much lower (120-125 C). I'm sure I used pure compounds, so how would I explain this?? ???
-
When a compound is melted with an impurity, do you expect a lower or higher melting point for that substance? A broader or tighter melting point range?
-
Look into colligative properties.
Also, interesting to note is that those two compounds actually have two separate melting points. They both have a transitional liquid-crystalline phase upon heating from solid to liquid. For cholesteryl benzoate, it melts at 145*C (cloudy liquid) and 175*C (clear liquid) or so.
-
Is it possible the two compounds are forming an eutectic mixture?