Diethylene glycol butyl ether (2-(2-Butoxyethoxy)ethanol), a Glycol ether solvent, is a clear liquid with a very low odour and high boiling point.
D 1737 (OTTO) Diethylene glycol butyl ether, puriss, 99%+ - used in the manufacture of nitrocellulose. In brake fluid, it is used as an additive.