Synthesis of Aspirin

Liu, Yuchen

Professor Ho

10 September 2016

Melting Point Determination

Purity and Identify of Crystalline Organic Compounds

I. Purpose: This experiment is to determine the melting point of organic compounds.

II. Procedure:

-Take proper amount of a organic compound sample using a capillary tube.

-Put the capillary tube into a oil bath heater which has a thermometer attached to, switch the heater on and turn to level 50% of power.

-Observe the sample, record the temperature when the compound starts to melt.

-Repeat all the procedures above until each sample’s melting point is determined.

III. Observation:

-All organic compound samples were colorless crystal at room temperature.

-Different samples started to melt at different temperatures.

-All samples melted to colorless liquid.

-Data is shown below:

Table 1. Melting point of pure organic compounds and mixtures

[pic 2]

Figure 1. Mixture melting point versus percent amount of Benzoic Acid

[pic 3]

Table 2. Unknown compound melting point determination

[pic 4]

IV. Calculation

N/A

V. Conclusion

Part A: As shown in Table 1 and Figure 1, when the percent amount of Benzoic Acid increases, the melting point of the mixture goes down the goes up and reaches the lowest at 50% of Benzoic Acid and 50% of trans-Cinnamic Acid. So the purer the mixture is, the higher melting point it has.

Part B: Melting points of unknown organic compound are determined and shown in Table 2. Then it is determined that unknown #1 is Benzoic Acid; unknown #2 is p-Nitrotoluene; unknown #3 is Benzophenone; unknown #4 is Benzamide; unknown #5 is Maleic Acid; unknown #7 is Adipic Acid and unknown #8 is trans-Cinnamic Acid.

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