Diethylene glycol butyl ether is an organic compound with the chemical formula C8H18O3, HO(CH2)2O(CH2)2O(CH2)3CH3. It can be mixed with water in any proportion and is soluble in ethanol, ether, oils, and many other organic solvents. It is commonly used as a solvent for nitrocellulose, varnish, printing ink, oils, resins, etc., and as an intermediate in the synthesis of plastics.