Diethylene glycol

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Other names: Diethylene glycol, diethylene glycol, di(hydroxyethyl) ether.

Abbreviation: DEG

Molecular formula: C₄H₁₀O₃

Molecular weight: 106.12

CAS number: 111-46-6

Structural formula: HOCH₂CH₂OCH₂CH₂OH.

Physicochemical properties

Colorless or slightly yellow transparent viscous liquid, pungent and slightly sweet taste, flammable and low in toxicity, hygroscopic. Relative density (20℃): 1.115～1.118, boiling point: 245℃, boiling range (≥95%): 241～248℃, freezing point: -10.5℃, melting point: -6.5℃, surface tension (20℃): 44.8 mN/m.

Diethylene glycol and triethylene glycol are miscible with water, alcohols, ethers, acetone, and ethylene glycol, but insoluble in benzene and carbon tetrachloride.

Diethylene glycol is virtually non-toxic. The acute oral LD₅₀ in rats is 14.8 g/kg, and the dermal LD₅₀ in rabbits is 11.9 g/kg.

Preparation

Diethylene glycol can be obtained by reacting ethylene oxide with ethylene glycol. The process of preparing ethylene glycol from ethylene oxide and water can produce diethylene glycol and triethylene glycol as byproducts.

Properties and Uses

Mainly used in unsaturated polyester resins. Used as a gas dehydrating agent and aromatic hydrocarbon extraction solvent. Also used as a lubricant, softener, and finishing agent for textiles. It can also be used as a solvent, textile auxiliary agent, plasticizer for rubber and resins, humectant, sizing agent, and solvent for nitrocellulose, resins, and oils.

In the field of polyurethane, it can be used to synthesize aromatic polyester polyols and adipic acid-based aliphatic polyester polyols, and can be used as a chain extender for polyurethanes and an initiator for polyether polyols.