- Synthetic method of itaconic acid intermediate 3-carboxy-2-pentene-1,5-diacid
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The invention provides a synthetic method of an itaconic acid intermediate 3-carboxy-2-pentene-1,5-diacid. The synthetic method comprises the following steps: adding 310ml of cyclohexane, 1.3mol of 2-bromo-nitrobenzene solution, 1.6-1.9mol of 3-amino-1,3,5-pentanoic triacid solution and 0.56mol of cuprous chloride to a reaction vessel on which a stirrer, a thermometer and a dropping funnel are installed, controlling the stirring speed at 150-190rpm, raising the temperature of the solution to 110-115 DEG C, reacting for 3-5 hours, reducing the temperature of the solution to 60-65 DEG C, controlling the stirring speed at 200-230rpm, continuously reacting for 90-120 minutes, separating out a solid, carrying out suction filtration, adding the solid to 200ml of oxalic acid solution, stirring the materials for 30-50 minutes, carrying out suction filtration, adopting ethyl acetate for washing and a dehydrating agent for dehydration and carrying out recrystallization in nitromethane, thus obtaining the crystal 3-carboxy-2-pentene-1,5-diacid.
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Paragraph 0007; 0015; 0016
(2016/11/24)
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- NMR Investigation of the Thermolysis of Citric Acid
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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.
- Fischer, John W.,Merwin, Lawrence H.,Nissan, Robin A.
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p. 120 - 126
(2007/10/02)
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