Acetic acid, occurrence

The occurrence and extent of rearrangement of the 2-butyl cation have also been investigated by solvolysis studies using isotopic labeling. When 2-butyl tosylate is solvolyzed in acetic acid, C-2/C-3 rearrangement occurs only to the extent of 9% in the 2-butyl acetate which is isolated.Thus, under these conditions, most of the reaction proceeds by direct participation of the solvent. 

Ammodendrine, C jH oONj, HjO (No. 1, table, p. 116). The base has m.p. 73 °, becomes anhydrous at 70-80°, and then melts at 50-60°, Wd i 0°. The salts are amorphous and deliquescent except the hydriodide B. HI, which forms a crystalline precipitate, m.p. 218-20°, from alcohol, and the perchlorate, m.p. 199-200°. An amorphous A-benzoyl derivative was obtained. With methyl iodide ammodendrine behaves as a secondary base, yielding first A-methylammodendrine hydriodide (a crystalline precipitate, m.p. 183-5°, from a mixture of alcohol and acetone), and at the second stage iV-methylammodendrine methiodide, m.p. 163-5°. On hydrogenation ammodendrine furnishes a dihydro-base, which is hydrolysed into acetic acid and 2 3 -dipiperidyl, C oHjoNj, and must be dZ-A-acetyl-3-a-piperidylpiperidine. Ammodendrine should therefore be acetyltetrahydroanabasine and is of biological interest as the first recorded occurrence of this type of alkaloid in the Leguminoss. ... 

The occurrence of the same cis-trans isomerization observed in chlorinated hydrocarbons was finally tested for substituted c/i-stilbenes in two protic solvents, acetic acid and methanol, where the counteranion is a Br instead of a Br3". 

The occurrence of an average CH3-CO resonance line position from acetic acid and TBT acetate is a consequence of rapid chemical exchange of the tributyltin group. It represents the CH3-CO protons in a time-averaged environment. 

In accordance with this view, the occurrence of the unusual peaks on the cyclic voltammograms observed in acetic acid/acetate system was ascribed to a one-electron transfer process of acetic acid/acetate ions according to the equations [180] ... 

The occurrence of a similar reaction has recently been indicated by studies carried out in this laboratory (7). If p-hydroxybenzyl alcohol (XXXVI) was oxidized with sodium bismuthate, the spirocyclic epoxy-cyclohexadienone (XXXVII) was obtained. The epoxide ring of this compound was hydrolyzed almost instantaneously by 2N aqueous hydrochloric acid and in a few hours by 10% aqueous acetic acid. However, the expected glycol (XXXVIII) could not be isolated since it decomposed immediately into equimolar amounts of hydroquinone and formaldehyde. (Attempts are now being made to prepare compounds analogous to XXXVIII but containing, in addition to the HOCH2 group, a carbon sub-... 

Displacement of nitro groups from aromatic nuclei by nucleophiles is a. common occurrence (78T2057). Thermal decomposition of 2,4-dinitro-3-thienyl iV,iV-dimethyldithiocarbamate (267) in refluxing glacial acetic acid gave... 

Petersen3 was enabled to wholly confirm the earlier statements regarding the electrolysis of acetic acid by Murray,4 who investigated the influence of the concentration, current strength, and temperature upon the course of the electrolysis and found, like earlier investigators, carbonic acid, oxygen, hydrogen, ethane, and methyl acetate. Murray disputes only the occurrence of ethylene which Kolbe and Kampf declare they found. 

In general, carboxylic acids are hydrogenated with difficulty under mild conditions over usual metallic catalysts. However, it has been recognized that acetic acid may be reduced over platinum oxide under very mild conditions in the presence of perchloric acid.1 Kaplan observed that acetic acid was reduced rapidly over rhodium catalysts at room temperature and pressure, but the reduction stopped abruptly after a very small conversion.2 The occurrence of these reductions may lead to appreciable errors in the amounts of absorbed hydrogen when hydrogenations are carried out in acetic acid as solvent, although the reductions usually proceed only to limited extents, probably due to formation of some poisonous products. These undesired reductions of acetic acid solvent may be depressed in the presence of a substrate that may be adsorbed more strongly than acetic acid. 

Because of the widespread occurrence of peroxidase in plant tissues, Nagle and Haard (1975) have suggested that it plays an important role in the development and senescence of plant tissues. It plays a role in biogenesis of ethylene in regulating ripening and senescence in the degradation of chlorophyll and in the oxidation of indole-3-acetic acid. 

RDX forms orthorhombic crystals with a melting point of 206 Celsius. 1 Gram dissolves in 25 milliliters of acetone, but its solubility in alcohol, ether, ethyl acetate, and glacial acetic acid is even less. It is insoluble in water, carbon tetrachloride, and carbon disulfide. RDX is one of the most important military explosives known to man. It is highly versatile, being resistant to heat, shock and percussion, and is capable of being alloyed with many different secondary explosives. RDX is very well known in several of the most important explosives compositions. These compositions include semtex, C4, and composition B, all of which are widely used in military operations. RDX is by far one of the most important explosives in occurrence, and it is manufactured on an industrial scale. 

Kobayashi, M., Suzuki, T., Fujita, T, et al. 1995. Occurrence of enzymes involved in biosynthesis of indole-3-acetic acid from indole-3-acetonitrile in plant-associated bacteria. Agrobacterium and Rhizobium. Proceedings of the National Academy of Science USA, 92 714-8. 

Hansen, H.R., Pickford, R., Thomas-Oates, J., Jaspars, M., Feldmann, J. 2-dimethylarsinothioyl acetic acid identified in a biological sample the first occurrence of a mammalian arsinothioyl metabolite. Angew. Chem. Int. Ed. 43, 337-340 (2004)... 

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