Interactions between Benzoic Acid and Magnesium Oxide

Various ingredients are added to pharmaceuticals. DSC allows simple verification of whether or not the ingredients have converted due to interactions. This example shows an examination of interactions between benzoic acid and magnesium oxide. Curve 1 shows the result of measurement of benzoic acid alone.
Melting is observed at 122.7°C. Curve 2 shows the result of measurement of magnesium oxide alone and no changes are observed. Curve 3 shows the result of DSC measurement of a 1:1 mixture of benzoic acid and magnesium oxide, mixed mechanically. This shows a completely different pattern from the DSC curves when the two components were analyzed individually. It suggests some kind of interaction between the two substances.

Fig.1 Interaction between benzoic acid and magnesium oxide

Instrument DSC-60
Sample name (curve 1) Benzoic acid
Sample weight 4.83 mg
Sample name (curve 2) Magnesium oxide
Sample weight 4.38 mg
Sample name (curve 3) Benzoic acid and magnesium oxide
Sample weight 2.18 mg
[Temperature program]
Heating rate  10°C/min
Hold temperature 180°C

Thermal Analysis

DSC-60 Plus

The DSC-60 Plus is an indispensable thermal analyzer for materials characterization in R&D and quality control applications in such areas as polymers, pharmaceuticals, electronic parts , foods , etc .