Bleach

History

The Chlore was discovered in 1774 by the Chimiste Swedish Scheele.
Claude Louis Berthollet studies a few years after the bleaching properties of chlorine and in the car a process of bleaching of the fabrics using a solution of potassium chloride and hypochlorite: it has just invented the " detergent of BERTHOLLET" , soon called bleach following the localization of its first production site; the manufacture of chemicals built in 1777 in the village of Javel, in the west of Paris, which will give its name to the product.

The bleach quickly was a sharp success like bleaching agent (Before, the fabrics were to be exposed with the Sun during months to bleach them).

In 1820, the pharmacist Antoine Germain Labarraque studies disinfecting qualities of the chlorinated derivatives and sodium and potassium hypochlorites. It develops a solution of sodium chloride and hypochlorite which it calls “ liquor of Labarraque ”. In 1900 one called bleach the hypochlorite of potassium, and water of Labbaraque, the sodium hypochlorite. Later, the manufactoring process replaced potassium by sodium, without name change.

As from the 19th century, the bleach is usually used like disinfecting and for the treatment of drinking water (see Verdunisation).

bleaching chlorides : hypochlorites of sodium (bleach) and of calcium (chloride of lime) were the first outlet of chlorine. They were obtained by action of chlorine on the soda solutions or the extinct Chaux. Liquid chlorine replaced little by little the Chloride of lime which is a mixture of hypochlorite of calcium and calcium chloride, used like active agent fading before bleach (until in 1925).

Presentation

The bleach is presented in form Liquide (in bottles or Berlingot S) or in solid form (in pastilles). To avoid the accidents, Javel and the effluents while containing are stored in Emballage S out of matters plastic S. the precise INRS that glass is usable, but in bottles protected by a suitably adjusted metal envelope.

The bleach is marketed under several levels of dilution. The quantity of chlorine is expressed as a percentage active chlorine (c.a.). The percentage of active chlorine represents the mass of dichlore formed starting from 100 G of bleach. One finds for example bleach bottles to active chlorine 2.6% and water bladders of Javel concentrated to active chlorine 9.6%.

The bleach pastilles are in fact of the pastilles of. When these pastilles are dissolved in water, the sodium dichloroisocyanurate reacts with water to give sodium hypochlorite and Cyanuric acid .

Today, the bleach is built-in Détergent S to offer products “2 into 1”, which clean and désinfectent.
The bleach must be preserved safe from the light and heat.

Use

The commercial product changes name according to dilution and one will speak:

of extracts from Javel for a product titrating 40° chlorometric minimum.
of bleach if the concentration lies between 9,6° and 35° chlorometric.
of water of Labarraque for a product titrating 2° chlorometric.

The bleach disinfects water during the treatment of drinking water. Chlorine has remanent properties, which means that its disinfecting action is valid on all along the water distribution network.

The bleach can be used to disinfect the medical S, the grounds, the sinks and the straw mattresses. She is sometimes added to the Lessive for “ to bleach ” the linen.

She is also used to disinfect the water of the swimming pools.

Effects on health and the environment

Toxicology (Effects on the Health)

Javel is Toxique and corrosive. It causes burns on the Peau, the mucous membranes (eyes in particular), especially in concentrated form.
Son inhalation can cause a respiratory reaction (bronchial irritation, with edema in the serious cases accompanied by a fall of the pressure partial of oxygen in blood) appearing by a dyspnea (lack of breath, feeling of suffocation) and a cough (which can persist several years).
L' hypochlorite of sodium reacts with the nitrogenized Azote and substances, of which those emitted by the Man in the swimming pools (nitrates of dissolved agricultural origin in water, Sueur and traces of Urine…) as it can react with animal and vegetable proteins at the time of the operations of disinfection of buildings or of the plants, or in the sewers or plugs of sink. It then produces chlorinated derivatives of which some are suitable for degas in the air.

Toxicocinétique and metabolisation

The traditional ways of absorption are ingestion, the transcutané passage and the inhalation.
Chez the animal, oral ingestion induced a maximum plasmatic rate 2 hours after (in the rat with jeun, and after 4 a.m. in a nourished animal).
Half life: It takes 44 hours to divide by two the blood rate in the rat with jeun and 88,5 hours if it is nourished.
Métabolisation : aqueous solutions of - sodium hypochlorite is metabolized by the rat in Ion S Chlorure S found (96 hours after in greater quantity in the plasma, then in total blood, but also in the osseous Moelle, the Testicule S, the Rein S and the Poumon.

One hour only after sodium hypochlorite ingestion, the plasma and the intestinal contents of rats (nourished or with jeun) contained trichloroacetic Acide, dichloroacetic Acide and Dichloroacétonitrile. After 96 hours, 51.2% of the initial amount only were eliminated (to 36.4% in the urine and 14.8% in the excrements). After 120 hours, one still found in these rats of the significant traces of the product (- sodium hypochlorite).

Acute toxicity

Environment Institute, 1995., ====

Acute toxicity is initially related to the corrosive character of the sodium hypochlorite

- oral DL50: 5800 mg/kg in the mouse;

- cutaneous DL50: higher than 10000 mg/kg at the Rabbit;

- CL50 by inhalation: higher than 10.5 mg/l for a one hour exposure at the Rat.

Inhalation: At the Mouse, RD50 (amount inducing a reduction of 50% of the respiratory frequency) is of 4.1 [[ppm]] for an atmosphere of hypochlorite measured out of free chlorine (figure is close to the RD50 of pure chlorine (6.7 ppm).
Ingestion: Of the burns oropharyngées, œsophagiennes and gastric are noted in the dog for 100 ml of a solution at 5.25%. With the tops of 5 ml/kg, corrosive lesions appear.
cutaneous Exposure: it induces a thickening of the skin in the mouse (for a proportioning of 1 g/l, applied 10 minutes per day during 4 days). The basal cells of the skin are less viable in the guinea-pig (for a solution at 0.5% applied to the skin during 2 weeks).
La skin of rabbit is corroded after 15 to 30 mn of application of a solution at 3.5%. Irritation increases with the amount.
Les mucous is naturally more sensitive there; in rabbit, a solution at 0.5% causes a sharp pain on the eye, with a reversible irritation of 24 hours. To 5% one notes a momentary obscuration of the Cornée, an edema of the conjunctive one, who are reversible of 24 hours if the eye were rinsed with water in the 30 seconds (if not, the lesions persist one week). In the monkey, the lesion - with identical amount - is more quickly reversible. At 15%, the pain is acute and - without ocular Lavage immediate - is accompanied by a Hémorragie by the Conjonctive and nose, of a edema of the conjunctive one. The cornea becomes vitreous (+ light hématome); the lesion is partially reversible into 2 to 3 weeks (after-effects).

Chronic exposure

Up to 4000 mg/l, the sodium hypochlorite introduced via the drink water does not influence the survival of rats, mouse (up to 2754 mg/l) or of guinea-pig (50 mg/l) in experiments exposed, but of the genotoxic effects seems possible (shown in the mouse). A study also shows that the rats drink less water when it is rather strongly chlorinated, youngest growing bigger slightly. Javel, in contact with the air breaks up slowly (with room temperature, more quickly with the sun and/or exposed to heat, or in contact with metals) into forming Chlorate S and Sodium chloride, while releasing from dioxygene according to the reactions:

3 NaClO => + 2 NaCl

2 NaClO => 2 NaCl +

Many metals (of which the Copper (often used for pipings), the Nickel and their Alliage S) can have a catalytic effect and accelerate its decomposition of Javel.

Javel used for the disinfection of the grounds or WC is present via the domestic effluents, of the buildings tertiary or industrial in the sewer S and certain purification plants, where it loses its capacity quickly oxidizing because of the great quantity of oxydable matter which is present there, but it could contribute there to select organizations chlororésistants or to produce undesirable metabolites.
Because of its corrosive and super-oxidizing action, any accidental or chronic rejection direct in natural environment can have local ecotoxicological consequences (the Plancton is for example very sensitive to low dose chlorine). The active organic matter incineration containing of Javel should be avoided because of the stable risk of production of Organochloré S such as Furane S and Dioxine S.

Precautions for use

In the event of projection, to rinse lengthily and abundantly with clear water.
Les the most frequent accidents is related on voluntary ingestion (suicide attempt) or involuntary, and to the mixtures with other products (It must especially not be mixed with the Acide S which cause a violent one gaseous emission of Dichlore, very poison.
Les pastilles must be held out of reach children, because they are likely to be confused with Bonbon S.

The bleach must be preserved in opaque packing and at the expenses, because the ions hypochlorite are degraded by solar UV S and heat. It should not be mixed with warm water, nor mixed with other cleaning biocides or agents (possible emanations Toxique S). Combined with the Ammonium (present in certain products of cleaning), it produces Chloramines (with possible nitrogen release). Combined with acids, for example of the acids hydrochloric or sulphuric or even of the soft acids present in certain products of cleaning or pickling solutions it reacts violently, by emitting chlorine vapor, very toxic (to the vinegar or juice of lemon are enough to produce this type of reaction).

INRS also reports that applied to finely divided materials (fiber textiles, wood paper or dust), the Javel extract can release from the steam containing a little chlorine. These materials becoming then more flammable in a dry state.

For the Disinfection of surfaces, it must be correctly diluted and only used after complete cleaning by a Détergent followed by a rinsing, for an effective disinfection, and not to support appearance of phenomenon of resistance to chlorine at some Microbe S and parasitic, of which the Cryptosporidie S (and in particular Cryptosporidium parvum; parasite (Protozoaire) which can develop in the swimming pools, and which quickly develops resistances to many Biocide S).
Certaines Bactérie S was shown also able after phenomenon of natural selection to develop resistances to important chlorine concentrations. Carpets of bacteria known as chlororésistantes were thus found in the Aa during several years, on several kilometers, following the use of significant amounts of disinfecting chlorinated in the process of a bordering factory of the river.
Pour to be effective, an open amount must be quickly used, and it is advisable to respect the deadline of use of the product.

Composition

Hypochlorite NaClO the sodium is a salt of Sodium of the Hypochlorous acid HClO. Into solution, hypochlorite NaClO the sodium breaks up into Ion S sodium Na + and hypochlorite Clo - .

NaClO → Na + + Clo -

HClO is a weak Acide whose combined Base is the ion ClO hypochlorite - . The acido-basic balance of the HClO couple/Clo - is written:

HClO ↔ H + + Clo - (1)

The composition of bleach depends on pH, according to both chemical balances following:

HClO ↔ H + + Clo - (1)

HClO + H + + Cl - ↔ + (2)

Properties

Disinfecting properties

This Biocide disinfects thanks to its capacity Oxydant, it is:

Bactericidal (Bacterium S Gram-plus and gram -),
Sporicide,
Fungicidal and
Virucide (Hepatitis and AIDS).

However, the bleach does not wash; To disinfect a surface, it should initially be cleaned with a Détergent, before applying bleach to clean surface.
L' bleach makes it possible to kill the bacteria and other microbes which come into contact with it or with some of its by-products (chlorine gas). For that one needs that the microbes are not protected in a Biofilm, in another organization which would make screen, or in a thick Mucus). The bleach can be used for the treatment of drinking water. To be completely effective, the bleach must act at least fifteen minutes.

The bleach is also the active ingredient of disinfecting Dakin Cooper Stabilisé of the laboratory Cooper (French Pharmaceutical Co-operation), with 500 active chlorine Mg for 100 ml (excipients: Permanganate of potassium, phosphate monosodic dihydrate, purified water).

Reaction with the acids

The bleach put in contact with an acid will release from the Ion S H + , chemical balance (2) will be moved towards the line. The following reaction will occur:

HClO + H + + Cl - → +

It then occurs a release of Dichlore which is a very toxic Gaz. Therefore the bleach should never be in contact with Acide S, which one finds for example in the scaling products or the Urine.

Reaction with ammonia

When they are put in presence, the hypochlorous acid (HClO) and the Ammoniac () give Chloramines according to the following reactions:

+ HOCl → +

ammonia + hypochlorous acid → monochloramine + water

then:

+ HOCl → +

monochloramine + hypochlorous acid → dichloramine + water

and then:

+ HOCl → +

dichloramine + hypochlorous acid → trichloramine + water

Gas chloramines are very irritating. Therefore one should not mix bleach with Ammoniaque.

It is the same reaction which takes place when a swimmer urinates in the water of a swimming pool disinfected with chlorine. The Urée contained in the Urine is a nitrogenized product. It thus will be formed irritating chloramines for the Muqueuse S and the Yeux.

Oxidizing properties

The bleach has properties Oxydant are due to the ion ClO hypochlorite - . The ion Clo - is oxidizing powerful. This active agent is at the origin of the bleaching capacity of bleach. The ion Cl - reducing is its combined. One defines the redox cell ClO - /Cl - . Reaction of reduction of the ion hypochlorite Clo - is written:

Clo - + 2 + + 2nd - → Cl - + 3

It should be noted that the decomposition of Javel in ion hypochlorite and hypochlorous acid strongly depends on the pH of the medium: with pH superiors to 8, Javel loses of its disinfecting activity because it releases nothing any more but 25% (approximately) of ion ClO biocide - . It is then necessary to have recourse to a complement, the Brome for example.

Other properties

pH of bleach is Basique and ranging between 11,5 and 12,5.

See too

Notes and references of the article

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