Propylene glycol is scientifically named as "1,2-propanediol", and has a chemical formula of CH3CHOHCH2OH and a molecular weight of 76.10. There is a chiral carbon atom in the molecule. Its racemate is a hygroscopic viscous liquid and is slightly spicy. It has a specific gravity of 1.036 (25/4 °C), a freezing point of-59 °C, and a boiling point of 188.2 °C, respectively 83.2 °C (1,333 Pa). It is miscible with water, acetone, ethyl acetate and chloroform, and is soluble in ether. It is soluble in many essential oils, but is not miscible with petroleum ether and paraffin oil. It is relatively stable to heat and light, and is more stable at low temperatures. Its L-isomer has a boiling point of 187 to 189 °C and a specific optical rotation [α] of D20-15.0°. It can be oxidized at high temperatures to propionaldehyde, lactic acid, pyruvic acid and acetic acid.
Item | Specification | Inspection methods | Result |
Appearance | Colorless and transparent, viscous liquid without sediment and suspended matter | Visual inspection | Colorless and transparent, viscous liquid without sediment and suspended matter |
Pg content wt%≥
| ≥99.5
| GB 29216-2012
| 99.8
|
Initial melting point,ºC
| ≥185
| GB/T 7534-2004
| 185
|
Dry point,ºC
| ≥189
| GB/T 7534-2004
| 185
|
Relative density(25ºC,25ºC)
| 1.0350-1.0370
| GB/T 4472-2011
| 1.0371
|
Moisture,w,%
| ≤0.20
| GB/T 6283-2008
| 0.08
|
Acid content(Consumption of lye),ml
| ≤1.67
| GB 29216-2012
| 0.44
|
Burning residue,%
| ≤0.007
| GB 29216-2012
| 0.0007
|
Lead (Pb)
| ≤1
| GB 5009.12-2017
| 0.0016
|
Product grade
| high quality | ||
Inspection
| Qualified |