·
Empirical Formula (Hill Notation) H2O2
·
Molecular Weight 34.01
·
Beilstein Registry
Number 3587191
Hydrogen peroxide is a chemical compound with the
formula H2O2. In its pure form, it is a
colourless liquid, slightly
more viscous than water. Hydrogen peroxide is the simplest peroxide (a
compound with an oxygen–oxygen single bond).
Detailed description
It is used as an oxidizer, bleaching agent
and disinfectant. Concentrated
hydrogen peroxide, or "high-test peroxide",
is a reactive oxygen species and has been used as a propellant in rocketry.[4] Its chemistry
is dominated by the nature of its unstable peroxide bond.
Hydrogen peroxide is unstable and slowly decomposes
in the presence of base or a catalyst. Because of its instability, hydrogen
peroxide is typically stored with a stabilizer in a weakly acidic solution.
Hydrogen peroxide is found in biological systems including the human body.
Enzymes that use or decompose hydrogen peroxide are classified as peroxidases.
Applications
Industrial
About 60% of the world's production of hydrogen
peroxide is used for pulp- and paper-bleaching.[20] The second
major industrial application is the manufacture of sodium percarbonate and sodium perborate which are used
as mild bleaches in laundry detergents.
It is used in the production of various organic peroxides with dibenzoyl peroxide being
a high volume example. This is used in polymerisations,
as a flour bleaching agent and as a treatment for acne. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic
acid are also typically produced using hydrogen
peroxide.
Hydrogen peroxide is used in certain waste-water
treatment processes to remove organic impurities. This is achieved by advanced oxidation
processes, such as the Fenton reaction,[34][35] which use it
to generate highly reactive hydroxyl radicals (·OH). These
are able to destroy organic contaminates which are ordinarily difficult to
remove, such as aromatic or halogenated compounds.[36] It can also
oxidize sulfur based
compounds present in the waste; which is beneficial as it generally reduces
their odour.[37]
Medical
Hydrogen peroxide can be used for the sterilization
of various surfaces,[38] including
surgical tools[39] and may be
deployed as a vapour (VHP) for room sterilization.[40] H2O2 demonstrates
broad-spectrum efficacy against viruses, bacteria, yeasts, and bacterial
spores.[41] In general,
greater activity is seen against Gram-positive than Gram-negative bacteria;
however, the presence of catalase or other peroxidasesin these organisms
can increase tolerance in the presence of lower concentrations.[42] Higher
concentrations of H2O2 (10 to 30%) and longer
contact times are required for sporicidal activity.[43]
Hydrogen peroxide is seen as an environmentally safe
alternative to chlorine-based bleaches, as
it degrades to form oxygen and water and it is generally recognized
as safe as an antimicrobial agent by the U.S. Food and Drug
Administration (FDA).[44]
Historically hydrogen peroxide was used for
disinfecting wounds, partly because of its low cost and prompt availability
compared to other antiseptics. It is now thought
to slow healing and lead to scarring because it destroys newly formed skin
cells.[45] Only a very
low concentration of H2O2 can induce healing, and
only if not repeatedly applied.[46] Surgical use
can lead to gas embolism formation.[47][48]Despite this it is
still used for wound treatment in many developing countries.[49][50]
Dermal exposure to dilute solutions of hydrogen
peroxide cause whitening or bleaching of the skin due to microembolism caused
by oxygen bubbles in the capillaries.[51]
Cosmetic applications
Diluted H2O2 (between 1.9% and 12%) mixed with ammonium hydroxide is
used to bleach human hair. The chemical's
bleaching property lends its name to the phrase "peroxide blonde".[52] Hydrogen
peroxide is also used for tooth whitening and can be
mixed with baking soda and salt to make a home-made toothpaste.[53]
Hydrogen peroxide may be used to treat acne,[54] although benzoyl peroxide is a more
common treatment.
Use in alternative medicine
Practitioners of alternative medicine have advocated the use of hydrogen peroxide for the
treatment of various conditions, including emphysema, influenza, AIDS and in particular cancer,[55] although the
effectiveness is scientifically questionable and in some cases it may even be
fatal.
The practice calls for the daily consumption of
hydrogen peroxide, either orally or by injection and is, in general, based
around two precepts. First, that hydrogen peroxide is naturally produced by the
body to combat infection; and second, that human pathogens (including
cancer: See Warburg hypothesis)
are anaerobic and cannot
survive in oxygen-rich environments. The ingestion or injection of hydrogen
peroxide is therefore believed to kill disease by mimicking the immune response
in addition to increasing levels of oxygen within the body. This makes it
similar to other oxygen-based therapies, such as ozone therapy and hyperbaric oxygen
therapy.
Both the effectiveness and safety of hydrogen
peroxide therapy is scientifically questionable. Hydrogen peroxide is produced
by the immune system but in a carefully controlled manner. Cells called
by phagocytes engulf
pathogens and then use hydrogen peroxide to destroy them. The peroxide is toxic
to both the cell and the pathogen and so is kept within a special compartment,
called a phagosome. Free hydrogen
peroxide will damage any tissue it encounters via oxidative stress; a process which
also has been proposed as a cause of cancer.[61] Claims that
hydrogen peroxide therapy increase cellular levels of oxygen have not been
supported. The quantities administered would be expected to provide very little
additional oxygen compared to that available from normal respiration. It should
also be noted that it is difficult to raise the level of oxygen around cancer
cells within a tumour, as the blood supply tends to be poor, a situation known
as tumor hypoxia.
Large oral doses of hydrogen peroxide at a 3%
concentration may cause irritation and blistering to the mouth, throat, and
abdomen as well as abdominal pain, vomiting, and diarrhea.[56] Intravenous injection of hydrogen peroxide has been linked to several deaths.[58][59][60]
The American Cancer Society states that "there is no scientific evidence that
hydrogen peroxide is a safe, effective or useful cancer treatment."[57] Furthermore,
the therapy is not approved by the U.S. FDA.
Propellant
High-concentration H2O
2 is referred to as "high-test peroxide" (HTP). It can be used either as a monopropellant (not mixed with fuel) or as the oxidizer component of a bipropellant rocket. Use as a monopropellant takes advantage of the decomposition of 70–98% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber, where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over 600 °C (1,112 °F), which is expelled through a nozzle, generating thrust. H
2O
2 monopropellant produces a maximal specific impulse (Isp) of 161 s (1.6 kN·s/kg). Peroxide was the first major monopropellant adopted for use in rocket applications. Hydrazineeventually replaced hydrogen-peroxide monopropellant thruster applications primarily because of a 25% increase in the vacuum specific impulse.[62]Hydrazine (toxic) and hydrogen peroxide (less-toxic [ACGIH TLV 0.01 and 1 ppm respectively]) are the only two monopropellants (other than cold gases) to have been widely adopted and utilized for propulsion and power applications. The Bell Rocket Belt, reaction-control systems for X-1, X-15, Centaur, Mercury, Little Joe, as well as the turbo-pump gas generators for X-1, X-15, Jupiter, Redstone and Viking used hydrogen peroxide as a monopropellant.
2 is referred to as "high-test peroxide" (HTP). It can be used either as a monopropellant (not mixed with fuel) or as the oxidizer component of a bipropellant rocket. Use as a monopropellant takes advantage of the decomposition of 70–98% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber, where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over 600 °C (1,112 °F), which is expelled through a nozzle, generating thrust. H
2O
2 monopropellant produces a maximal specific impulse (Isp) of 161 s (1.6 kN·s/kg). Peroxide was the first major monopropellant adopted for use in rocket applications. Hydrazineeventually replaced hydrogen-peroxide monopropellant thruster applications primarily because of a 25% increase in the vacuum specific impulse.[62]Hydrazine (toxic) and hydrogen peroxide (less-toxic [ACGIH TLV 0.01 and 1 ppm respectively]) are the only two monopropellants (other than cold gases) to have been widely adopted and utilized for propulsion and power applications. The Bell Rocket Belt, reaction-control systems for X-1, X-15, Centaur, Mercury, Little Joe, as well as the turbo-pump gas generators for X-1, X-15, Jupiter, Redstone and Viking used hydrogen peroxide as a monopropellant.
PRICE
$323.75/KG OR $147.15/IB
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
No comments:
Post a Comment