3.OPINION
3.1.Chemical and Physical Specifications
3.1.1.Chemical identity
3.1.1.1. Primary name and/or INCI name
Hydrogen peroxide,dihydrogen dioxide, hydrogen dioxide, hydrogen oxide, oxydol,peroxide.
Carbamide peroxide,urea peroxide,hydrogen peroxidecarbamide, urea hydrogen peroxide, urea, compd. with hydrogenperoxide (1:1).
3.1.1.2. Chemical names
3.1.1.3. Trade names and abbreviations
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3.1.1.4. CAS / EINECS number
Hydrogen peroxide:CAS:7722-84-1
EINECS:231-765-0
Carbamide peroxide:CAS:124-43-6
EINECS:204-701-4
3.1.1.5. Structural formula
3.1.1.6. Empirical formula
Hydrogen peroxide:H2O2
Carbamide peroxide:CO(NH2)2 .H2O2
3.1.2. Physical form
Hydrogen peroxide:Colourless liquid
Carbamide peroxide: Whitecrystals or crystal powder
3.1.3. Molecular weight
Hydrogen peroxide: Mol.weight 34.0
Carbamide peroxide: Mol.weight 94.1
3.1.4. Purity, composition and substance codes
Commercial products:
Hydrogen peroxide:Hydrogen peroxide – watersolutions. Commerciallysupplied as a 33-37% aqueous solution. Common stabilisersinclude phosphoric or other mineral acid (to keep the productacidic), pyrophosphate salts (complexing agents to inhibitmetal-catalysed decomposition) and stannate (a colloid-forminginhibitor).
Commercial solutionscontain low (<0.1%) levels oforganic impurities (totalorganic carbon) and very low levels (<10 ppm) ofinorganic impurities, with total heavy metals usually <2ppm.Carbamide peroxide:Products containing minimum 97% of thehydrogen peroxide –Urea adducts areavailable.
3.1.5.Impurities / accompanying contaminants
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3.1.6.Solubility
Hydrogen peroxide ismiscible with water.Carbamide peroxide issoluble in water.
3.1.7.Partition coefficient (Log Pow)
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3.1.8.Additional physical and chemical specifications
Pure H2O2 (not commercially available inEU)
Melting point:-0.4°C
Boiling point:150-152°C
Density: 1.4425 g/cm3
Vapour pressure:3 hPa
Melting point:75-85°C
Boiling point:not available
Density:1.4 g/cm3
Vapour pressure: not available
Comment
Possible impurities inhydrogen peroxide andcarbamide peroxide are notknown. Likewise is the stability of hydrogen peroxide andcarbamide peroxide in oral hygiene unknown.
3.2. Function and uses
Hydrogen peroxide iscapable of undergoing numerous reactions (e.g., molecularadditions, substitutions, oxidations and reductions). It is astrong oxidant and can form free radical by hom*olytic cleavage.Carbamide peroxide is anadduct of urea and hydrogenperoxide which on contact with water break down to urea andhydrogen peroxide. For example, a 10% carbamide peroxide gelwould yield a maximum of 3.6% hydrogen peroxide. 750,000 tonneshydrogen peroxide (calculated as 100%H2O2) were produced in Europe in 1995.About 300 tonnes of carbamide peroxide were used.
The main usage ofhydrogen peroxide is inproduction of chemicals (approx. 40%), bleachingpulp and paper (approx.30%) and bleaching textiles (approx. 20%). Small quantities areused in cosmetics. Hydrogen peroxide is used for hair bleachingand for oxidation in permanent hair dyes and in oral hygieneproducts such as mouth-rinses and dentifrices as well as intooth bleaching products.
