Propylene Glycol, normally a colourless viscous liquid, nearly odourless, slightly sweet in fine smell, highly hygroscopic, miscible with water, ethanol and many organic solvents. Propylene glycol is divided into 1,2-propanediol and 1,3-propanediol. 1,2-propanediol, with the molecular formula C3H8O2, is commonly found in the market.
1. Propylene oxide hydrate method
Propylene oxide reacts with water at 200℃ and 1～20MPa to produce 1,2-propanediol. The waste emission is small, the equipment is less corrosive, the product purity is high and the stability is strong, but the reaction is harsh and the equipment investment is relatively large.
At present, domestic and foreign companies using propylene oxide hydration process mainly include Lyondell, Dow, Basf, China Sea Shell and so on.
2. Ester exchange method
Under the condition of atmospheric pressure and 65℃, using sodium methanol as catalyst, propylene carbonate (PC) and methanol undergo ester exchange reaction to produce 1,2 propylene glycol. The method has low production cost, complicated single product refining process, slightly poor quality relative to 1, serious environmental pollution and low yield.
At present, most domestic manufacturers use the ester exchange method to produce 1,2 propanediol.
3. 1,2 Dichloropropane hydrolysis method
The 1,2 dichloropropane method is divided into two types: direct hydrolysis and esterification followed by hydrolysis. Direct hydrolysis is generated by hydrolysis of 1,2 dichloropropane in weak alkali solution; first esterification and then hydrolysis is the reaction between 1,2 dichloropropane and acid salt to generate ester, and the ester is hydrolysed to alcohol.
This method has high environmental pollution and high cost.
- Food, beverage and food additives
- Pharmaceuticals
- Cosmetics
- Cosmetics
- Tobacco
- Intermediates
- Industrial antifreeze
It is preferable to use galvanised iron drums, aluminium or stainless steel containers, stored in a place with a berm, air circulation, as well as free from sunlight, not close to open flames and other sources of heat, to keep the container airtight, and to keep it dry.
