Peroxomonosulphuric acid

When incorporating sulphuric acid into a hydrogen peroxide/alcohol mixture there will be an explosion whereas a sulphuric acid/peroxide mixture poured onto alcohol would not cause any fire. Everything here is linked to the concentration of peroxomonosulphuric acid in alcohol. 

A solution of hydrogen peroxide at 50%, in excess, converts sulphuric acid into peroxomonosulphuric acid, which is very unstable and a particularly strong oxidant. 

When it is mixed with small quantities of sulphuric acid and in the presence of water traces, it is thought to form permanganic acid, HMn04, which is very unstable and a violent oxidant. Thus, this system incandesces in the presence of ammonia. Mixtures of potassium permanganate /peroxomonosulphuric acid have also been used to measure sulphur in the presence of carbon. However, this is not recommended since it is highly likely to detonate. 

Silver catalyses the explosive decomposition of hydrogen peroxide. The same goes for peroxomonosulphuric acid at 92%, which has a peroxidic bond. 

Nitronium ion has been found to catalyse decomposition in strong sulphuric acid solutions . The reaction is found to be first-order in peroxomonosulphuric acid above 95 % sulphuric acid and inverse first-order below 91 %, in addition to second-order dependence, over the whole region, on nitric acid. A mechanism has been proposed. 

Peroxomonosulphuric acid is not in rapid equilibrium with sulphate under the conditions of kinetic studies so far made. Even under conditions where decomposition was proceeding rapidly, no such exchange was detected Many rate studies have involved samples of peroxomonosulphuric acid containing appreciable amounts of hydrogen peroxide. No kinetic study of its reactions with the period seems to have been made, though difficulty due to its presence has been noted especially for pH values greater than 10. 

In the acid-catalysed process, dominant for pH less than 2, the products isolated may be oxygen (below 0.5 Af acid), peroxomonosulphuric acid, a mixture of the two, or may contain detectable amounts of hydrogen peroxide or ozone. The formation of hydrogen peroxide (at 98 °C in 2 M HjSO ) has been examined and shown to be catalysed by a number of metal ions. Under all conditions examined the oxygen liberated arises entirely from the peroxide . Exchange between S-labelled sulphate and peroxodisulphate proceeds very slowly, if at all, in this region . Further, it appears probable that this particular decomposition path does not involve intermediates which react at appreciable rate with cerium-(III) It has been suggested that the initial, overall, reaction is... 

The peroxomonosulphuric acid so formed is supposed to decompose rapidly to form oxygen at acid concentrations less than or equal to 0.5 M under the experimental conditions used. The result of the oxygen-tracer experiment (O2 from S20 ) resembles observations of hydrogen peroxide decompositions. The reaction does not show inhibition related to the concentration product [H ]... 

In strongly acid solutions ([H" ] > 0.5 M) the major products of the decomposition are peroxomonosulphuric acid and hydrogen peroxide (Kolthoff and Miller ), viz. 

Peroxomonosulphuric acid (Caro s acid), H2SO5, has the structure (1). 

Caro s acid EINECS 231-766-6 Peroxymonosulfuric acid Peroxomonosulphuric acid. Used In dye manufacture, oxidizing agent, bleaching. Viscous liquid. 

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