Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 274-778-7 | CAS number: 70693-62-8
Endpoint summary
Administrative data
Description of key information
Phototransformation in air
Potassium peroxomonosulfate and Caro’s acid degrade in the atmosphere with a DT50 value of 4.011 days (24-hr day; corresponding to 96.264 hours) and 3.875 days (24-hr day; corresponding to 93.009 hours), respectively. As both substances contain no olefinic carbon-carbon double and acetylic triple bonds, they are not expected to react with ozone.
Hydrolysis
KMPStriple salt can be degraded abiotically by hydrolysis to H2O2 and by disproportionation to O2 and to H2O. In both cases, potassium and hydrogensulfate ions are formed.
KHSO5 + H2O -> K+ + HSO4- + H2O2 (hydrolysis)
KHSO5 -> K+ + HSO4- + ½ O2 (disproportionation)
The degradation of KMPS triple salt in aqueous solution is pH and temperature dependant.
Additional information
Hydrolysis
KMPStriple salt, can be degraded abiotically by hydrolysis to H2O2 and by disproportionation to O2 and to H2O. In both cases, potassium and hydrogensulfate ions are formed.
KHSO5 + H2O -> K+ + HSO4- + H2O2 (hydrolysis)
KHSO5 -> K+ + HSO4- + ½ O2 (disproportionation)
The degradation of KMPS triple salt in aqueous solution is pH and temperature dependant.
In the study, the degradation of KMPS triple salt was measured by determining the loss of active oxygen by iodometric titration. As the hydrolysis of KHSO5 does not result in a net loss in active oxygen (see equation above) but only in a transfer of the active oxygen from KHSO5 to water, which leads to the formation of hydrogen peroxide, only the degradation by disproportionation was determined in the above test.
The degradation of KMPS in aqueous solution is pH and temperature dependant. Degradation is accelerated with increasing temperature and increasing pH. While KMPS has a half-life of above 800 h (at 20°C) in a buffered solution of pH 4, the half-life at pH 7 is 145 hours and only 2.8 hours at pH 9. Degradation in seawater is considerably faster (DT50 = 5.5 hours, pH 8.0-8.2, 20°C) than in freshwater (DT50 = 215 hours, pH 7.8-8.2, 20°C).
The reason for the faster degradation of KMPS in seawater is the so-called Haber-Will-Statter Reaction. In this, the sodium chloride of the seawater is oxidised by KMPS so that chlorine is released.
HSO5- +2Cl- + 2H+ -> HSO4- + Cl2 +H2O
The chlorine reacts with water to form hypochlorous acid:
Cl2 +H2O -> HOCl +HCl
Hypochlorous acid (HOCl) is only of transient nature, hypochlorous acid is extremely rapidly eliminated in the environment due to reaction with ammonia and organic material which act as reductants.
In the recent study on the “Depletion of Potassium Monopersulfate in Synthetic Pool Water”, it was shown that the decomposition of KMPS triple salt in water is very dependent on the presence of oxidisable contaminants. The addition of a ‘body fluid analog’ to the synthetic pool water used in this laboratory test reduced the half-life for decomposition of KHSO5 from ca. 120 hours (synthetic pool water without ‘body fluid analog’) to ca. 3 hours. This is explained by the consumption of KHSO5 in many different oxidation reactions with reduced amine substrate components of the added ‘body fluid analog’, according to the general reaction:
KHSO5 + X -> KHSO4 + X=O.
It can be assumed that KHSO5 is degraded at similar rates in natural waters, such as pond and river water. The higher the concentration of oxidisable organic substrate is in the water, the faster KHSO5 will be degraded.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
