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Names | |||
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IUPAC name
Hydrogen peroxide–urea (1/1)
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Systematic IUPAC name
Peroxol–carbonyl diamide (1/1) | |||
Other names
Urea peroxide, percarbamide, UHP
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Identifiers | |||
3D model (
JSmol)
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|||
ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.004.275 | ||
PubChem
CID
|
|||
UNII | |||
CompTox Dashboard (
EPA)
|
|||
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Properties | |||
CH6N2O3 | |||
Molar mass | 94.070 g·mol−1 | ||
Appearance | White solid | ||
Density | 1.50 g/cm3 | ||
Melting point | 75 to 91.5 °C (167.0 to 196.7 °F; 348.1 to 364.6 K) (decomposes) | ||
Pharmacology | |||
D02AE01 ( WHO) | |||
Hazards | |||
GHS labelling: [1] | |||
![]() ![]() | |||
Danger | |||
H272, H315, H318 | |||
P210, P220, P264, P280, P302+P352, P305+P351+P338 | |||
Flash point | 60 °C (140 °F; 333 K) | ||
Safety data sheet (SDS) | External MSDS | ||
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Hydrogen peroxide–urea (also called Hyperol, artizone, urea hydrogen peroxide, and UHP) is a white crystalline solid chemical compound composed of equal amounts of hydrogen peroxide and urea. It contains solid and water-free hydrogen peroxide, which offers a higher stability and better controllability than liquid hydrogen peroxide when used as an oxidizing agent. Often called carbamide peroxide in dentistry, it is used as a source of hydrogen peroxide when dissolved in water for bleaching, disinfection and oxidation.
For the preparation of the complex, urea is dissolved in 30% hydrogen peroxide (molar ratio 2:3) at temperatures below 60 °C. upon cooling this solution, hydrogen peroxide–urea precipitates in the form of small platelets. [2]
Akin to water of crystallization, hydrogen peroxide cocrystallizes with urea with the stoichiometry of 1:1. The compound is simply produced (on a scale of several hundred tonnes a year) by the dissolution of urea in excess concentrated hydrogen peroxide solution, followed by crystallization. [3] The laboratory synthesis is analogous. [4]
The solid state structure of this adduct has been determined by neutron diffraction. [5]
Hydrogen peroxide–urea is a readily water-soluble, odorless, crystalline solid, which is available as white powder or colorless needles or platelets. [2] Upon dissolving in various solvents, the 1:1 complex dissociates back to urea and hydrogen peroxide. So just like hydrogen peroxide, the (erroneously) so-called adduct is an oxidizer but the release at room temperature in the presence of catalysts proceeds in a controlled manner. Thus the compound is suitable as a safe substitute for the unstable aqueous solution of hydrogen peroxide. Because of the tendency for thermal decomposition, which accelerates at temperatures above 82 °C, [6] it should not be heated above 60 °C, particularly in pure form.
The solubility of commercial samples varies from 0.05 g/mL [7] to more than 0.6 g/mL. [8]
Hydrogen peroxide–urea is mainly used as a disinfecting and bleaching agent in cosmetics and pharmaceuticals. [3] As a drug, this compound is used in some preparations for the whitening of teeth. [3] [9] [10] It is also used to relieve minor inflammation of gums, oral mucosal surfaces and lips including canker sores and dental irritation, [11] and to emulsify and disperse earwax. [12]
Carbamide peroxide is also suitable as a disinfectant, e.g. for germ reduction on contact lens surfaces or as an antiseptic for mouthwashes, ear drops or for superficial wounds and ulcers.
In the laboratory, it is used as a more easily handled replacement for hydrogen peroxide. [4] [13] [14] It has proven to be a stable, easy-to-handle and effective oxidizing agent which is readily controllable by a suitable choice of the reaction conditions. It delivers oxidation products in an environmentally friendly manner and often in high yields especially in the presence of organic catalysts such as cis-butenedioic anhydride [15] or inorganic catalysts such as sodium tungstate. [16]
It converts thiols selectively to disulfides, [15] secondary alcohols to ketones, [16] sulfides to sulfoxides and sulfones, [17] nitriles to amides, [17] [18] and N-heterocycles to amine oxides. [17] [19]
Hydroxybenzaldehydes are converted to dihydroxybenzenes ( Dakin reaction) [17] [20] and give, under suitable conditions, the corresponding benzoic acids. [20]
It oxidizes ketones to esters, in particular cyclic ketones, such as substituted cyclohexanones [21] or cyclobutanones [22] to give lactones ( Baeyer–Villiger oxidation).
The epoxidation of various alkenes in the presence of benzonitrile yields oxiranes in yields of 79 to 96%. [23]
The oxygen atom transferred to the alkene originates from the peroxoimide acid formed intermediately from benzonitrile. The resulting imidic acid tautomerizes to the benzamide.
The compound acts as a strong oxidizing agent and can cause skin irritation and severe eye damage. [24] Urea–hydrogen peroxide was also found to be an insensitive high explosive, capable of detonation by strong impulse under heavy confinement. [25] [26]
{{
cite book}}
: |periodical=
ignored (
help)
| |||
![]() | |||
Names | |||
---|---|---|---|
IUPAC name
Hydrogen peroxide–urea (1/1)
| |||
Systematic IUPAC name
Peroxol–carbonyl diamide (1/1) | |||
Other names
Urea peroxide, percarbamide, UHP
| |||
Identifiers | |||
3D model (
JSmol)
|
|||
ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.004.275 | ||
PubChem
CID
|
|||
UNII | |||
CompTox Dashboard (
EPA)
|
|||
| |||
| |||
Properties | |||
CH6N2O3 | |||
Molar mass | 94.070 g·mol−1 | ||
Appearance | White solid | ||
Density | 1.50 g/cm3 | ||
Melting point | 75 to 91.5 °C (167.0 to 196.7 °F; 348.1 to 364.6 K) (decomposes) | ||
Pharmacology | |||
D02AE01 ( WHO) | |||
Hazards | |||
GHS labelling: [1] | |||
![]() ![]() | |||
Danger | |||
H272, H315, H318 | |||
P210, P220, P264, P280, P302+P352, P305+P351+P338 | |||
Flash point | 60 °C (140 °F; 333 K) | ||
Safety data sheet (SDS) | External MSDS | ||
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Hydrogen peroxide–urea (also called Hyperol, artizone, urea hydrogen peroxide, and UHP) is a white crystalline solid chemical compound composed of equal amounts of hydrogen peroxide and urea. It contains solid and water-free hydrogen peroxide, which offers a higher stability and better controllability than liquid hydrogen peroxide when used as an oxidizing agent. Often called carbamide peroxide in dentistry, it is used as a source of hydrogen peroxide when dissolved in water for bleaching, disinfection and oxidation.
For the preparation of the complex, urea is dissolved in 30% hydrogen peroxide (molar ratio 2:3) at temperatures below 60 °C. upon cooling this solution, hydrogen peroxide–urea precipitates in the form of small platelets. [2]
Akin to water of crystallization, hydrogen peroxide cocrystallizes with urea with the stoichiometry of 1:1. The compound is simply produced (on a scale of several hundred tonnes a year) by the dissolution of urea in excess concentrated hydrogen peroxide solution, followed by crystallization. [3] The laboratory synthesis is analogous. [4]
The solid state structure of this adduct has been determined by neutron diffraction. [5]
Hydrogen peroxide–urea is a readily water-soluble, odorless, crystalline solid, which is available as white powder or colorless needles or platelets. [2] Upon dissolving in various solvents, the 1:1 complex dissociates back to urea and hydrogen peroxide. So just like hydrogen peroxide, the (erroneously) so-called adduct is an oxidizer but the release at room temperature in the presence of catalysts proceeds in a controlled manner. Thus the compound is suitable as a safe substitute for the unstable aqueous solution of hydrogen peroxide. Because of the tendency for thermal decomposition, which accelerates at temperatures above 82 °C, [6] it should not be heated above 60 °C, particularly in pure form.
The solubility of commercial samples varies from 0.05 g/mL [7] to more than 0.6 g/mL. [8]
Hydrogen peroxide–urea is mainly used as a disinfecting and bleaching agent in cosmetics and pharmaceuticals. [3] As a drug, this compound is used in some preparations for the whitening of teeth. [3] [9] [10] It is also used to relieve minor inflammation of gums, oral mucosal surfaces and lips including canker sores and dental irritation, [11] and to emulsify and disperse earwax. [12]
Carbamide peroxide is also suitable as a disinfectant, e.g. for germ reduction on contact lens surfaces or as an antiseptic for mouthwashes, ear drops or for superficial wounds and ulcers.
In the laboratory, it is used as a more easily handled replacement for hydrogen peroxide. [4] [13] [14] It has proven to be a stable, easy-to-handle and effective oxidizing agent which is readily controllable by a suitable choice of the reaction conditions. It delivers oxidation products in an environmentally friendly manner and often in high yields especially in the presence of organic catalysts such as cis-butenedioic anhydride [15] or inorganic catalysts such as sodium tungstate. [16]
It converts thiols selectively to disulfides, [15] secondary alcohols to ketones, [16] sulfides to sulfoxides and sulfones, [17] nitriles to amides, [17] [18] and N-heterocycles to amine oxides. [17] [19]
Hydroxybenzaldehydes are converted to dihydroxybenzenes ( Dakin reaction) [17] [20] and give, under suitable conditions, the corresponding benzoic acids. [20]
It oxidizes ketones to esters, in particular cyclic ketones, such as substituted cyclohexanones [21] or cyclobutanones [22] to give lactones ( Baeyer–Villiger oxidation).
The epoxidation of various alkenes in the presence of benzonitrile yields oxiranes in yields of 79 to 96%. [23]
The oxygen atom transferred to the alkene originates from the peroxoimide acid formed intermediately from benzonitrile. The resulting imidic acid tautomerizes to the benzamide.
The compound acts as a strong oxidizing agent and can cause skin irritation and severe eye damage. [24] Urea–hydrogen peroxide was also found to be an insensitive high explosive, capable of detonation by strong impulse under heavy confinement. [25] [26]
{{
cite book}}
: |periodical=
ignored (
help)