Question

A student decided to extract aspirin from a tablet. After the alumina filtration step, he stopped the experiment for a week. then he evaporated the methanol and completed the procedure. the melting point of his recovered material was 120-145 degrees Celsius. what does this wide range tell us? what might have happened?


(the normal melting point of aspirin is 135-136 dgrees celsius)

Answer 1

The evaporation procedure must be completed in 10-15 minutes right after isolating aspirin in the filtration step with alumina or the aspirin decomposes which will create more surface area on the molecule resulting a lower melting point and wider temperature range.