Ethyl sulfate process in which ethylene is reacted with sulfuric acid to produce ethyl sulfate followed by hydrolysis, but this method has been mostly replaced by direct hydration of ethylene. Ethyl sulfate can be produced in a laboratory setting by reacting ethanol with sulfuric acid under a gentle boil, while keeping the reaction below 140 °C. The sulfuric acid must be added dropwise or the reaction must be actively cooled because the reaction itself is highly exothermic. If the temperature exceeds 140 °C, the ethyl sulfate product tends to react with residual ethanol starting material, producing diethyl ether. If the temperature exceeds
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