Method for preparing 2-alkenyl-2-oxazolines

Abstract

The process comprises the steps of: (A) reacting by contacting an anhydrous or substantially anhydrous 2-alkyl-2-oxazoline with formaldehyde in a molar ratio of at least about 1.5 moles of 2-alkyl-2-oxazoline per mole of formaldehyde, thereby forming 2-(.alpha.-hydroxymethylalkyl)-2-oxazoline, (B) recovering the 2-(.alpha.-hydroxymethylalkyl)-2-oxazoline from the reaction product of step (A), and (C) reacting by contacting the 2-(.alpha.-hydroxymethylalkyl)-2-oxazoline and step B with an alkali or alkaline earth metal hydroxide, thereby forming 2-alkenyl-2-oxazoline. As an example, step A was conducted by reacting 2-ethyl-2-oxazoline (4 moles) having less than 1,000 ppm of water with paraformaldehyde (1 mole) at a reaction temperature of 100.degree. C. for approximately 5.5 hours. The excess oxazoline reactant was removed along with water as "overheads" by fractional distillation of the reaction product, leaving the 2-(.alpha.-hydroxymethylethyl)-2-oxazoline in approximately 96 percent yield. Step C was then conducted by continuously adding the 2-(.alpha.-hydroxymethylethyl)-2-oxazoline to a stirred solution of sodium hydroxide in the mono-methyl ether of triethylene glycol at a temperature of from 100.degree.-105.degree. C. Under these conditions, the 2-isopropenyl-2-oxazoline and water were volatilized and recovered from the overheads. The product yield was approximately 98 percent of theory.

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