What is 1, 3-propylene glycol used for

Propylene glycol is a colorless viscous stable water-absorbing liquid, almost tasteless, odorless, flammable, and low toxic. It is miscible with water, ethanol and various organic solvents. Boiling point 187.3℃. Melting point -60℃. The relative density is 1.0381. Refractive index 1.4326. Surface tension (20℃)38mNm. Viscosity (20℃)60.5mPa-s. Specific heat capacity (20℃)2.49kj/(kg. ° C). Heat of vaporization (101.3kPa)7Ukj/kg. Heat of combustion (25℃)1824.OkJ/mol. Flash point (open cup) 99℃. Spontaneous ignition point 415.5℃. Critical temperature 352℃. Critical pressure 6.lMPa.
Propylene glycol is a commonly used chemical, mainly used in the manufacture of cosmetics, food, medicine and other products. Its function is as a solvent, regulator, antifreeze and so on.

The role of propylene glycol can be divided into the following aspects:
1. Solvent: Propylene glycol can be used as a good solvent, can dissolve many organic and inorganic substances, often used in cosmetics, drugs and so on as a solvent.
2. Regulator: Propylene glycol can be used as a regulator to adjust the viscosity and moisturizing properties of the product, and is often used in cosmetics, food, etc.
3. Antifreeze: Due to the low freezing point of propylene glycol, it can be used as an antifreeze, often used in automotive brake fluid, coolant, etc.
4. Antibacterial agent: propylene glycol can have a certain antibacterial effect, often used in oral care products, skin care products, etc.
Production process of propylene glycol
1. The direct water method of propylene oxide is pressurized non-catalytic hydrolysis method. It is prepared by direct hydration of propylene oxide and water at 150N160℃, 0.78 ~ 0.98MPa pressure, and the reaction product is evaporated and rectified to obtain the finished product.
2. The indirect aqueous method of propylene oxide is prepared by the indirect aqueous combination of propylene oxide and water with sulfuric acid as catalyst. The equation is the same as above.
3. Propylene direct catalytic oxidation method.
It should be noted that propylene glycol has a certain toxicity, and pay attention to protective measures when using it to avoid contact with eyes and skin. At the same time, when using propylene glycol to manufacture products, it is necessary to operate in accordance with relevant standards and regulations to ensure product safety and quality.