Aconitic acid

The enzyme acomtase catalyzes the hydration of aconitic acid to two products citric acid and isocitnc acid Isocitnc acid is optically active citric acid is not What are the respective con stitutions of citric acid and isocitnc acid" ... 

In the presence of the enzyme acomtase the double bond of aconitic acid undergoes hydra tion The reaction is reversible and the following equilibrium is established... 

Decomposition. When heated above 175°C, citric acid decomposes to form aconitic acid [499-12-7] citraconic acid [498-25-7], itaconic acid [97-65 ], acetonedicarboxyhc acid [542-05-2], carbon dioxide, and water, as shown in Figure 1. 

For purification the acid is crystallized from about 150 cc. of glacial acetic acid, using an acid-resistant filter for the hot solution (Note 7). Aconitic acid separates as small, colorless needles weighing 50-60 g., and about 10 g. more can be secured by concentrating the mother liquor under reduced pressure to one-third of its volume. The material is dried in the air and then in a desiccator containing sodium hydroxide in order to remove all traces of acetic acid. One crystallization usually is sufficient to bring the point of decomposition to 198-199° (Note 6). 

By filtering at this point rather than at a lower temperature a separation from a small amount of low-melting material is accomplished without much loss of aconitic acid. 

When heated in a capillary tube aconitic acid decomposes rather suddenly with vigorous gas evolution at a temperature which is highly dependent upon the rate of heating and the temperature at which the sample is introduced. In the literature melting points ranging from 182.5° iQ4-5° > 16 recorded. The uncrystallized aconitic acid, when introduced at 180° into a small bath provided with mechanical agitation and heated at the rate of 2-3° per minute, usually decomposed at 189-190°. The... 

Aconitic acid has been prepared from citric acid by the action of sulfuric acid or hydrogen chloride, or by heating. It has been prepared also from methyl acetylcitrate and from acetylcitric anhydride. The method described is essentially that of Hentschel. Phosphoric acid (85 per cent) can be used in place of sulfuric acid, but much closer regulation of the conditions seems necessary and the yield is not greatly improved. 

Sansemeria zeylanica. An alkaloid is present in the roots and rhizomes. The juice contains aconitic acid. (Scheindlin and Dodge, Amer. J. Pharm., 1947, 119, 232.)... 

Acetylene, derivatives 359, 361, 362 Acetylsalicylic acid 308 ACFB = 2-amino-5-chloro-2 -fluorobenzo-phenone 227 Aconitic acid 249... 

An attempt was made to convert aconitic acid (2 g) to isocitric acid using 25 ml. of 30% aqueous hydrogen peroxide, time and temperature unspecified. A crystalline product precipitated which exploded on grinding in a mortar. 

Miller, Robert Ellsworth, and Cantor, Sidney M., Aconitic Acid, a By-product in the Manufacture of Sugar, VI, 231-249... 

Aconitic acid, p206 Acrolein, p203 Acrolein diethyl acetal, d312 Acrolein dimethyl acetal, d521 Acrylaldehyde, p203... 

One-half gram of troro-aconitic acid per 100 ml of distilled water, to which KOH had been added to reach pH 4.5. Fifty milligrams of sodium metabisulfite had also been added to 100 ml of buffer for stabilization of vitamin B12 analogs. 

Acid yellow (Aquashade), herbicide/algicide for aquaculture in U.S., 3 214t Acitretin, 25 790 a-c Josephson effect, 15 750 Aclame, 24 232 ac losses, 23 845-846 Acne, vitamin A treatments for, 25 789 cis-Aconitic acid, in citric acid cycle, 6 633 Aconitine, 2 103... 

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