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97-65-4Relevant articles and documents
Efficient conversion of bio-renewable citric acid to high-value carboxylic acids on stable solid catalysts
Li, Zhaowei,Liu, Haichao,Wen, Xin
, p. 1650 - 1658 (2022/03/07)
Citric acid is an important biomass-derived platform chemical for the synthesis of high-value organic acids, such as itaconic acid (ICA), 2-methylsuccinic acid (MSA) and tricarballylic acid (TCA). However, these reactions frequently encounter low efficiency and severe leaching of catalysts imposed by the acidity of citric acid under hydrothermal conditions, limiting their practical applications. Here, we report that highly acid- and etching-resistant monoclinic zirconium dioxide (m-ZrO2) exhibited high catalytic efficiency in the conversion of citric acid to ICA via sequential dehydration and decarboxylation steps, providing a high yield of 70.3% at 180 °C on m-ZrO2 (calcined at 300 °C). The correlation between the activity of the m-ZrO2 catalysts and their acid-basicity demonstrates that the synergistic effect of acidic and basic sites facilitates the rate-determining dehydration step for the citric acid conversion to ICA. On the bifunctional catalysts, Pt and Pd nanoparticles supported on P25 and anatase TiO2, citric acid can be selectively converted to MSA and TCA, respectively, with yields as high as 83.1% and 64.9%. The hydrogenation activity of the bifunctional catalysts was found to be crucial for regulating the relative rates of the decarboxylation and hydrogenation steps involved in the selective conversion of citric acid to MSA and TCA. These catalysts showed excellent stability and recyclability in acidic aqueous solutions. This study provides a rationale for tuning catalytic functions required for the green production of important carboxylic acids from citric acid and other biomass-derived feedstocks. This journal is
METHOD FOR THE PRODUCTION OF METHYLSUCCINIC ACID AND THE ANHYDRIDE THEREOF FROM CITRIC ACID
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Page/Page column 15, (2018/04/21)
A process for the preparation of methylsuccinic acid in any form, including its salts, its mono- and diester derivatives and the anhydride thereof, which comprises reacting citric acid or a derivative thereof in decarboxylation conditions, said process comprising (i) reacting citric acid or mono- and diester derivatives thereof in a non- aqueous solvent, specifically excluding alcohols, on a metallic catalyst at a temperature between 50 to 400°C and under a partial hydrogen pressure from 0.1 to 50 bar or (ii) reacting citric acid or any salt thereof or mono-, di- and triester derivatives thereof on a metallic catalyst in solvents comprising at least 5% water, at a temperature of from 50 to 400°C under a hydrogen partial pressure from 0.1 to 400 bar
Methacrylic acid production method
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Page/Page column 9; 14-15, (2018/12/11)
A method of producing methacrylic acid using a hydrotalcite catalyst and subcritical water is described.
