Potassium perchlorate
| |||
Names | |||
---|---|---|---|
Other names
Potassium chlorate(VII); Perchloric acid, potassium salt; peroidin
| |||
Identifiers | |||
3D model (
JSmol ) |
|||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard
|
100.029.011 | ||
EC Number |
| ||
PubChem CID
|
|||
RTECS number
|
| ||
UNII | |||
UN number | 1489 | ||
CompTox Dashboard (EPA)
|
|||
| |||
| |||
Properties | |||
KClO4 | |||
Molar mass | 138.55 g/mol | ||
Appearance | colourless/ white crystalline powder | ||
Density | 2.5239 g/cm3 | ||
Melting point | 610 °C (1,130 °F; 883 K) decomposes from 400 °C[4][5] | ||
0.76 g/100 mL (0 °C) 1.5 g/100 mL (25 °C)[1] 4.76 g/100 mL (40 °C) 21.08 g/100 mL (100 °C)[2] | |||
Solubility product (Ksp)
|
1.05·10−2[3] | ||
Solubility | negligible in alcohol insoluble in ether | ||
Solubility in ethanol | 47 mg/kg (0 °C) 120 mg/kg (25 °C)[2] | ||
Solubility in acetone | 1.6 g/kg[2] | ||
Solubility in ethyl acetate | 15 mg/kg[2] | ||
Refractive index (nD)
|
1.4724 | ||
Structure | |||
Rhombohedral | |||
Thermochemistry | |||
Heat capacity (C)
|
111.35 J/mol·K[6] | ||
Std molar
entropy (S⦵298) |
150.86 J/mol·K[6] | ||
Std enthalpy of (ΔfH⦵298)formation |
-433 kJ/mol[7] | ||
Gibbs free energy (ΔfG⦵)
|
-300.4 kJ/mol[2] | ||
Hazards | |||
GHS labelling: | |||
[5] | |||
Danger | |||
H271, H302, H335[5] | |||
P220, P280[5] | |||
NFPA 704 (fire diamond) | |||
Safety data sheet (SDS) | MSDS | ||
Related compounds | |||
Other anions
|
Potassium chloride Potassium chlorate Potassium periodate | ||
Other cations
|
Ammonium perchlorate Sodium perchlorate | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Potassium perchlorate is the inorganic
Production
Potassium perchlorate is prepared industrially by treating an aqueous solution of sodium perchlorate with potassium chloride. This single precipitation reaction exploits the low solubility of KClO4, which is about 1/100 as much as the solubility of NaClO4 (209.6 g/100 mL at 25 °C).[8]
It can also be produced by bubbling chlorine gas through a solution of potassium chlorate and potassium hydroxide,[citation needed] and by the reaction of perchloric acid with potassium hydroxide; however, this is not used widely due to the dangers of perchloric acid.
Another preparation involves the electrolysis of a potassium chlorate solution, causing KClO4 to form and precipitate at the anode. This procedure is complicated by the low solubility of both potassium chlorate and potassium perchlorate, the latter of which may precipitate onto the electrodes and impede the current.
Oxidizing properties
KClO4 is an oxidizer in the sense that it exothermically transfers
- 3 KClO4 + C6H12O6 → 6 H2O + 6 CO2 + 3 KCl
The conversion of solid glucose into hot gaseous CO2 is the basis of the explosive force of this and other such mixtures. With
As an oxidizer, potassium perchlorate can be used safely in the presence of sulfur, whereas potassium chlorate cannot. The greater reactivity of chlorate is typical – perchlorates are kinetically poorer oxidants. Chlorate produces chloric acid, which is highly unstable and can lead to premature ignition of the composition. Correspondingly, perchloric acid is quite stable.[9]
In commercial use it is mixed 50/50 with potassium nitrate to create Pyrodex
Medicine use
Potassium perchlorate can be used as an
The administration of known
Treatment of thyrotoxicosis (including Graves' disease) with 600-2,000 mg potassium perchlorate (430-1,400 mg perchlorate) daily for periods of several months or longer was once common practice, particularly in Europe,[10][12] and perchlorate use at lower doses to treat thyroid problems continues to this day.[13] Although 400 mg of potassium perchlorate divided into four or five daily doses was used initially and found effective, higher doses were introduced when 400 mg/d was discovered not to control thyrotoxicosis in all subjects.[10][11]
Current regimens for treatment of
Prophylaxis with perchlorate containing water at concentrations of 17
However, when the average perchlorate absorption in perchlorate plant workers subjected to the highest exposure has been estimated as approximately 0.5 mg/(kg d), as in the above paragraph, a 67% reduction of iodine uptake would be expected. Studies of chronically exposed workers though have thus far failed to detect any abnormalities of thyroid function, including the uptake of iodine.
To completely block the uptake of Iodine-131 by the purposeful addition of perchlorate ions to a populace's water supply, aiming at dosages of 0.5 mg/(kg d), or a water concentration of 17 ppm, would therefore be grossly inadequate at truly reducing radioiodine uptake. Perchlorate ion concentrations in a regions water supply, would need to be much higher, at least 7.15 mg/kg of body weight per day or a water concentration of 250
The continual distribution of perchlorate tablets or the addition of perchlorate to the water supply would need to continue for no less than 80–90 days, beginning immediately after the initial release of radioiodine was detected, after 80–90 days had passed released radioactive iodine-131 would have decayed to less than 0.1% of its initial quantity at which time the danger from biouptake of iodine-131 is essentially over.[17]
References
- ^ "Potassium Perchlorate MSDS". J.T. Baker. 2007-02-16. Retrieved 2007-12-10.
- ^ a b c d e "potassium perchlorate". chemister.ru. Retrieved 14 April 2018.
- ^ "Ksp solubility product constants of many popular salts at SolubilityOFthings".
- ISBN 978-0387952697.
- ^ a b c d Sigma-Aldrich Co., Potassium perchlorate. Retrieved on 2022-02-17.
- ^ a b Potassium perchlorate in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-05-27)
- ISBN 978-0-618-94690-7.
- ISBN 0-7506-3365-4.
- ^ PMID 12204829.
- ^ PMID 9549759.
- PMID 4290684.
- PMID 16231171.
- ^ PMID 8768854.
- PMID 11014310.
- PMID 10224590.
- ^ "Nuclear Chemistry: Half-Lives and Radioactive Dating - For Dummies". Dummies.com. 2010-01-06. Retrieved 2013-01-21.