Diethylene glycol (DEG) is an organic compound with the chemical formula C₄H₁₀O₃. It is a colorless, odorless, and hygroscopic liquid that is commonly used as a solvent, plasticizer, and intermediate in the production of other chemicals. DEG is part of the ethylene glycol family, which includes monoethylene glycol (MEG) and triethylene glycol (TEG), with DEG being positioned between MEG and TEG in terms of molecular structure and properties.

Common Applications of Diethylene Glycol:

Solvent:
DEG is widely used as a solvent in the pharmaceutical, cosmetic, and chemical industries. It is a good solvent for a variety of substances, including resins, oils, and waxes, and is used in inks, paints, and dyes.
Antifreeze:
While monoethylene glycol (MEG) is more commonly used for antifreeze formulations, diethylene glycol can also be used in coolants and antifreeze products due to its ability to lower the freezing point of water.
Humectant:
DEG is used in cosmetic formulations and personal care products (such as lotions, creams, and shampoos) as a humectant, helping to retain moisture in the skin and products.
Plasticizer:
Diethylene glycol serves as a plasticizer in the production of polyurethane foams, plastics, and rubber, improving the flexibility and workability of materials.
Intermediate in Chemical Synthesis:
DEG is an intermediate in the production of various chemicals, including polyesters, plasticizers, and surfactants. It is also used to manufacture triethylene glycol (TEG) and other higher glycols.
Hydraulic Fluids:
DEG can be found in some hydraulic fluids, particularly in applications where low temperature fluidity is needed.