Methyl 4-hydroxybenzoate, also called methyl paraben or nipagin, comprises the ester of p-hydroxybenzoic acid. It is present naturally in cloudberry, white wine and bourbon vanilla. Methyl 4-hydroxybenzoate has antimicrobial and antifungal functionality and is commercially used as a preservative in the food, cosmetic and pharmaceutical industry.
| Appearance | Colourless to off-white crystals or powder |
|---|---|
| Solubility | 100 mg soluble in 1 mL of alcohol |
| FTIR | Matches with the standard pattern |
| Melting range | 125 – 128°C |
| Chloride (Cl) | <= 0.005% |
| Sulfate (SO₄) | No turbidity should be produced within 10 minutes |
| Assay | (NaOH Titration/HPLC): 99.00 – 101.00% |
