2-Ethyl-2-oxazoline oxazolines towards ring-opening by chloride ions during protonation of the imine nitrogen. The direct reaction of propanoyl chloride with 2-chloroethylamine hydrochloride in the presence of triethylamine avoids the formation of water. Propanal reacts with 2-aminoethanol in "t"-butanol to 2-ethyl-2-oxazoline in the presence of the iodinating reagent 1,3-diiodo-5,5-dimethylhydantoin (DIH) and potassium carbonate. 2-Ethyl-2-oxazoline is a readily water-soluble, colorless liquid which is also soluble in a variety of organic solvents and possesses an amine-like smell. Aqueous solutions react alkaline. The compound is stable in alkaline but hydrolyses under acid action. In anhydrous form, 2-ethyl-2-oxazoline is mostly used as a monomer. The cationic
2-Ethyl-2-oxazoline dehydration of the N-(2-hydroxyethyl)propionamide in vacuo in the presence of iron(III)chloride, which delivers the product in 90% yield. An even higher yield of 96.2% is obtained by heating with zinc acetate. An economic one-pot reaction is heating the salt of propionic acid with ethanolamine at 200 °C in vacuo in the presence of zinc chloride yielding 82% 2-ethyl-2-oxazoline. From the water-containing distillate pure 2-ethyl-2-oxazoline can be isolated by extraction with diethylbenzene and subsequent distillation or by distillation only after addition of diethyl phosphite or dimethyldichlorosilane. The product can be dried to a residual water content of 10 ppm. In another