Preparation of Amides of Carboxylic Acid Herbicides for Gas Chromatographic Analysis

Publisher Website
Google Scholar
Abstract
Amides of 14 carboxylic acid herbicides were prepared by reacting the free acid with the amine in toluene for 1 hr at 80[ddot]C in the presence of PCl3 or P2I4. The acids include phenoxyacetic acids, arylacetic acids, and benzoic acids. Aniline, o-toluidine, 3,5-bis(trifluoromethyl)aniline, piperidine, and tetrahydroquinoline were the amine components. Excess of reagents and by-products of the reaction were removed by partitioning into aqueous acid and base. Retention times relative to 2,4-D anilide on 1% OV-22 and FSOT RSL-150 columns are listed for the anilides and should be useful for confirmation purposes. The anilides of 2,4-D, silvex and 2,4,5-T were obtained in better than 90% yield.