Mel-Temp melting point apparatus

The picture below shows a Mel-Temp melting point apparatus. This type of melting point apparatus uses melting point capillary tubes to hold the sample being analyzed.

Fill the capillary tube with the sample and place it in the apparatus.

The rate of temperature increase in the vicinity of the melting point must be small, about 2 degrees C per min. This insures that the temperature of the hot plate, thermometer, and sample will be in thermal equilibrium. Increase the temperature rapidly at first and then slowly as the melting point is approached in the following manner:

  1. Set the power level to 5.
  2. When the temperature is about 15 degrees below the anticipated melting point, change the setting to that indicated on the chart below.

Observe the crystals with your eye about 6" from the lens to prevent accidentally touching the hot apparatus. Record the temperatures at which melting begins and at which the last crystal disappears.

When you do not know the melting point of a compound, first take a crude melting point by heating rapidly. Then cool the apparatus to 20 degrees below the crude melting point by placing the aluminum cylinder on it, and proceed to take a more careful melting point on a second sample of the compound

This is what a Mel-Temp melting point apparatus looks like.

Note that you have to turn on both the heating block (green switch) and the thermometer (small switch on top).

Please be sure to switch off the thermometer and the heating block when done.

Tuning off the thermometer saves batteries.