Synthesis of phosphinoacetic acids

A process for preparing at least one P,P-dihydrocarbylphosphinoacetic acid comprising the steps of:

• (a) reacting at least one 2-methyl-4,4-dialkyl-2-oxazoline, wherein each of the two alkyl groups can contain 1-6 carbon atoms, with at least one basic compound of the formula MZ, wherein M is an alkali metal and Z is selected from the group consisting of --H, --OR', --NH.sub.2, --NHR' and --N(R').sub.2, with R' being an alkyl or cycloalkyl group having 1-8 carbon atoms, at a temperature not to exceed about 0.degree. C. for a time period of at least about 1 second;
• (b) adding to the reaction mixture obtained in step (a), at a temperature not to exceed about 0.degree. C., at least one halodihydrocarbylphosphine having the general formula R.sub.2 PX, wherein X is Cl or Br or I, and each R is selected from the group consisting of alkyl groups containing 1-10 carbon atoms, cycloalkyl groups containing 3-10 carbon atoms and aryl groups containing 6-12 carbon atoms;
• (c) heating the mixture obtained in step (b) to a temperature of above about 0.degree. C. and maintaining the mixture at that temperature for a time of at least about 1 minute;
• (d) contacting the reaction mixture obtained in step (c) with at least one mineral acid under such conditions as to form said at least one P,P-dihydrocarbylphosphinoacetic acid;
• and
• (e) recovering said at least one P,P-dihydrocarbylphosphinoacetic acid from the reaction mixture obtained in step (d).