NMR Investigation of the Thermolysis of Citric Acid

Article abstract of DOI:10.1366/0003702953963229

The thermolytic decomposition of citric acid in the presence of tin/lead solder has been investigated.The solid reaction products were first examined by solid-state 13C NMR.The samples were then dissolved in D2O, and 1H and 13C 1D and 2D (HMQC, TOCSY) spectra were obtained.Results indicate the presence of a series of compounds including 3-hydroxyglutaric, citraconic, itaconic and aconitic acids, and anhydrides.Solution- and solid-state NMR data are provided for citric acid and a number of metal and alkali metal citrate salts.Results of this work are related to the use of citric acid as a solder flux and to the elimination of chlorofluorocarbon cleaning processes in the electronics industry.Index Headings: NMR; Solid-state NMR; Citric acid; Thermolysis.