Study of influence of some additives on the rate of H_2O_2 decomposition in liquid phase. II: Influence of vitamins B_c, B_1 and C Chemistry

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∙10–4M 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∙10–3M, W also decreases the radical-chain run catalyzed by Fe(II) cations HP decomposition.