What properties should be tested for propylene glycol? And its detection method
Propylene glycol is a chemical also known as 1, 2-propylene glycol or 1, 2-propylene glycol. It is a colorless, odorless, sweet organic compound with the formula C3H8O2. It is an important industrial raw material for the preparation of polyethers, polyurethanes, acrylics and acrylates, as well as for the preparation of coatings, solvents, fragrances, medicines and food.
The following are the main properties of propylene glycol to be tested and the corresponding detection indicators:
What properties should be tested for propylene glycol? And its detection method
| property | Detection index |
|---|---|
| appearance | The appearance is colorless transparent liquid |
| purity | Purity ≥99.5% |
| hydration | Moisture content ≤0.2% |
| acidity | Acidity (measured by HAc) ≤0.001% |
| Specific gravity | Specific gravity (20℃) 1.118-1.124 |
| Refractive index | Refractive index (20℃) 1.431-1.435 |
| Heavy metal | Lead ≤0.1ppm; Copper ≤0.1ppm; Zinc ≤0.1ppm; Cadmium ≤0.1ppm; Mercury ≤0.1ppm |
| Non-volatile residues | Non-volatile residue ≤0.001% |
| oxide | Propylene glycol oxide content ≤0.05% |
Detection method
The following is a test method for the main properties of propylene glycol:
Appearance: Directly observe whether the appearance of the sample is a colorless transparent liquid.
Purity: can be detected by gas chromatography, liquid chromatography, ultraviolet spectrophotometry and other methods.
Moisture: can be detected by Karl Fischer method, specific gravity method, drying method and other methods.
Acidity: It can be detected by acid-base titration, potentiometric titration, ultraviolet spectrophotometry and other methods.
Specific gravity: It can be measured using a hydrometer or hydrometer method.
What properties should be tested for propylene glycol? And its detection method
Refractive index: Can be measured using a refractometer.
Heavy metals: Atomic absorption spectrometry, inductively coupled plasma mass spectrometry and other methods can be used for detection.
Non-volatile residues: can be detected by drying method, ash method and other methods.
Oxide: It can be detected by titration, spectrophotometry and other methods.
In short, different detection methods are required for different performance indicators of propylene glycol, and the detection methods should ensure accuracy and reliability. In the actual production and use process, the quality of propylene glycol should be tested in accordance with the corresponding standards to ensure that it meets the relevant requirements.