- Process for producing a carboxylic acid
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A nitrile compound or an amide compound is hydrolyzed in the presence of an inorganic acid or other acidic catalyst or an alkali metal hydroxide or other basic catalyst, and the by-produced ammonium salt of the acidic catalyst or the produced salt of a carboxylic acid and a base is electrodialysed to form an acid and ammonia or aqueous ammonia, or to form a base and ammonia. The obtained acid or base may be recycled as a catalyst for the hydrolysis of the nitrile compound or amide compound, and the obtained ammonia is reutilized as a nitrogen source for the nitrile compound or amide compound. Such amide compound may be produced by hydration of a nitrite compound in the presence of a manganese oxide.
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- The Influence of Hydrophobic Solvation on the Alkaline Hydrolysis of Ethyl Esters of Polar Substituted 2-Methylpropionic Acids in Water
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The rate constants of the alkaline hydrolysis of 2-methylpropionic acid ethyl ester, α-hydroxy, α-bromo, α-cyano, and α-nitro-2-methylpropionic acid ethyl ester have been measured in water between 5 deg C and 45 deg C with the help of an appropiate conductance bridge developed in our laboratory.The influence of the polar substituents on the rate constant, a powerful probe for discussing two-particle interactions in solutions, is characterized by an intramolecular structure parameter of the activated complex and a dielectric parameter of its surroundings.The dependence of the reaction rate on the structure parameter is compared to that of substituted acetic acid derivatives.The smaller dielectric parameter of 2-methylpropionic acid esters reveals the increasing hydrophobic solvation in comparison to acetic acid derivatives.
- Schmeer, G.,Riembauer, S.,Barthel, J.
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p. 1175 - 1190
(2007/10/02)
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- Biosynthesis of Sulfur Compounds. Investigations of the Biosinthesis of Asparagusic Acid.
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Investigations of the biosynthesis of the naturally occuring 1,2-dithiolane asparagusic acid (1) in Asparagus officinalis have shovn that the substance is derived from inobutyric acid via the intermediacy of methacrylic acid, 2-methyl-3-mercaptopropionic acid, and S-(2-carboxy-n-propyl) cysteine.The conversion of isobutyric acid to methacrylic acid in Asparagus has also been shown to proceed by oxidation of the 2-pro-S methyl group of isobutyrate.Finally, the absolute configuration of naturally occuring S-(2-carboxy-n-propyl)cysteine has been determined.
- Parry, Ronald J.,Mizusawa, A.E.,Chiu, I.C.,Naidu, M.V.,Ricciardone, M.
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p. 2512 - 2521
(2007/10/02)
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- MECHANISM OF CHLORAMINE-T OXIDATION OF METHYL VINYL KETONE AND ISOPROPYL METHYL KETONE IN AQUEOUS ALKALINE MEDIA
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The oxidation kinetics of methyl vinyl ketone and isopropyl methyl ketone by chloramine-T in aqueous alkaline solutions show first-order dependence on chloramine-T, both substrates and alkali.No effect of p-toluenesulphonamide was evident.Observed stoichiometry, negligible effect of ionic strength and a positive dielectric effect point to a mechanism involving interaction of enolate anions with chloramine-T in the rate determining step.Activation parameters and the isolation of the product formaldehyde are in agreement with the proposed mechanism.
- Singh, Bharat,Samant, A. K.,Saxena, B. B. L.
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p. 2591 - 2594
(2007/10/02)
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