STUDY OF INFLUENCE OF SOME ADDITIVES ON THE RATE OF $\mathrm{H}_2\mathrm{O}_2$ DECOMPOSITION IN LIQUID PHASE. II: INFLUENCE OF VITAMINS $\mathrm{B_c}$, $\mathrm{B_1}$ AND C

Abstract

The influence of vitamins Bc (folic acid, FA), B₁ (thiamine, TA) and C (ascorbic acid, AA) on H₂O₂ (HP) decomposition rate in aqueous solutions was studied using gasometric method. In alkaline medium in the presence of FA the reactions are carried out at [H₂O₂]₀=[HOO^–]=0.5 M. [FA]0 is changed in the range 0–2.8∙10^–3 M. It is established that the reaction rate (W) decreases more than twofold. It is assumed that FA effectively reacts with HO^• and HOO^•, which are chain carriers. So the reaction runs by radical-chain mechanism. In acidic medium (pH 3.5) catalyzed by Fe(II) cations HP decomposition occurs mainly by radicalchain mechanism. TA (0–2.5∙10^–4 M) also decreases W more than 4 times. At pH 3.5, [TA∙HCl]₀ ≥ 1∙10^–4 M there is no O₂ evolution. The AA influence on the HP decomposition, W is studied at pH 3.5. In the presence of AA, [AA]₀≈1.25∙10^–3 M, W also decreases the radical-chain run catalyzed by Fe(II) cations HP decomposition.