QUANTITATIVE-ANALYSIS OF MIXTURES OF SYMMETRICAL AND MIXED ANHYDRIDES

HPLC and GC methods were developed for the determination of symmetrical and mixed anhydrides. Both symmetrical and mixed anhydrides and their respective acids were determined in a single reversed-phase HPLC run using acetonitrile-water as the mobile phase. GC was useful for the quantitative analysis of a mixture of mixed anhydrides symmetric anhydrides. Similar results were obtained from the HPLC and GC analyses of mixtures containing mixed anhydrides of fatty acids with benzoic acid and their corresponding symmetrical anhydrides and acids. These methods are useful in the investigation of anhydride chemistry, the routine analysis of raw materials and the quality control and purity determination of polymers and other compounds containing anhydrides.