- Autocatalytic Oxidation of Thiamine Hydrochloride (Vitamin B1) by Permanganate in Aqueous Sulfuric Acid Medium: A Kinetic and Mechanistic Study
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The reaction kinetics of autocatalytic oxidation of thiamine hydrochloride (vitamin B1) by the permanganate ion in aqueous sulfuric acid medium has been investigated spectrophotometrically under the pseudo-first-order condition at 25°C. The observed stoichiometry is 6:5 in terms of the mole ratio of permanganate ions and thiamine hydrochloride. Formation of products was confirmed by UV-vis, IR, GC-MS, and NMR spectral data. Usually in the permanganate oxidation-reduction reactions, one of the products, Mn2+ autocatalyzes the reaction, but in the present investigation the autocatalytic effect is due to the (4-methyl-thiazol-5-yl) acetic acid, a product formed from the oxidation of vitamin B1, which is a rare case. The added Mn2+ does not have any significant effect on the rate of reaction. The reaction is first order with respect to both permanganate and thiamine hydrochloride concentrations. An increase in the sulfuric acid concentration decreases the rate of reaction. A composite scheme and rate laws were proposed. The activation parameters with respect to the slow step and reaction constants involved in the mechanism were determined and discussed.
- Savanur, Anita,Teradale, Amit,Lamani, Shekappa,Chimatadar, Shivamurti
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- Synthesis method of 4-methylthiazole-5-formaldehyde
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The invention provides a synthesis method of 4-methylthiazole-5-formaldehyde. The method comprises the following steps: 1) dissolving 4-methylthiazole-5-ethanol in a solvent, and carrying out oxidation reaction in the presence of a catalyst to obtain 4-methylthiazole-5-acetic acid; and 2) carrying out heating reaction on the 4-methylthiazole-5-acetic acid obtained in the step 1) in the presence of oxygen and a metal salt catalyst to obtain the 4-methylthiazole-5-formaldehyde. According to the method, 4-methylthiazole-5-ethanol is used as a raw material, the raw material is green, cheap and easy to obtain, the reaction process is mild in condition and environmentally friendly, the result selectivity is good, the yield is high, good economic benefits are achieved, and the method is suitable for industrial production.
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Paragraph 0028; 0031-0033; 0036-0038; 0041-0043
(2021/05/01)
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