How does dipropylene glycol compare to propylene glycol as a solvent?

How does dipropylene glycol compare to propylene glycol as a solvent?
Dipropylene glycol (DPG) and propylene glycol (PG) are both glycol ethers but differ in molecular weight and performance. DPG, a dimer of PG, has a higher boiling point (around 230°C) and lower volatility, making it suitable for slow-evaporation applications like fragrance fixatives, inks, and coatings. It is less hygroscopic than PG, offering moderate moisture retention without excessive water pickup. DPG also exhibits better solvency for oils, resins, and fragrance compounds, which is why it dominates perfume concentrates. PG is lighter, more polar, and often used in food, pharmaceutical, and antifreeze applications. For formulators, choosing between them depends on evaporation rate, odor, and compatibility. DPG's low odor and high flash point make it safer for consumer products, while PG's regulatory acceptance in food limits its use in ingestible goods.