PRODUCTS

SODIUM PERBORATE

Sodium perborate is chemical compound whose chemical formula may be written NaH2BO4, Na2H4B2O8, or, more properly, [Na+]2[B2O4(OH)4]2−.
Sodium perborate name is sometimes abbreviated as PBS (not to be confused with phosphate-buffered saline).
Sodium perborate is an oxidative preservative that is used in Genteal lubricating eye drops.

CAS Number: 10486-00-7
EC Number: 234-390-0
IUPAC Name: disodium 3,3,6,6-tetrahydroxy-1,2,4,5-tetraoxa-3,6-diboranuidacyclohexane
Chemical Formula: B2H4Na2O8

Other names: Perboric acid, sodium salt, monohydrate, sodium;oxidooxy(oxo)borane;hydrate, Y9UKD0XE6F, Sodium perborate monohydrate [USAN], Sodium perborate monohydrate (USAN), Caswell No. 784A, Sodium borate, monohydrate, EPA Pesticide Chemical Code 011105, Sodium perborate hydrate, UNII-Y9UKD0XE6F, SODIUM BORATE MONOHYDRATE, DTXSID9035676, MFCD00149230, FT-0696526, SODIUM PERBORATE MONOHYDRATE [MART.], SODIUM PERBORATE MONOHYDRATE [WHO-DD], D07066, Perboric acid (HBO(O2)), sodium salt, monohydrate, Q18212089, perboric acid, Perboric acid (HBO3), Perboric acid (HBO(O2)), UNII-HC4C3M1FO2, HC4C3M1FO2, 14034-78-7, HBO3, DTXSID9058602, DB13235, disodium tetrahydroxidodi-mu-peroxido-diborate, Na2H4B2O8, SCHEMBL22455, 15120-21-5, CHEMBL3707333, JBUKJLNBQDQXLI-UHFFFAOYSA-N, Na2[B2(O2)2(OH)4], Sodium perborate tetrahydrate, Reagent Grade, Q415507

Sodium perborate is commonly encountered in anhydrous form or as a hexahydrate (commonly called "monohydrate" or PBS-1 and "tetrahydrate" or PBS-4, after the early assumption that NaBO3 would be the anhydrous form).
They are both white, odorless, water-soluble solids.

This salt is widely used in laundry detergents, as one of the peroxide-based bleaches.
Sodium perborate is an oxidative preservative that is used in Genteal lubricating eye drops.
With topical application, sodium perborate is converted by catalase to water, oxygen, and hydrogen peroxide.

Sodium perborate antimicrobial properties are attributed to oxidization of cell membranes, membrane-bound enzymes, and disruption of protein synthesis.
Also, sodium perborate has demonstrated efficacy against Aspergillus niger.

However, most ophthalmic solutions that contain sodium perborate produce the byproduct, hydrogen peroxide, at levels between 30 and 100 ppm, which can cause ocular stinging.
Less is known about the histopathologic corneal and conjunctival changes associated with topical sodium perborate.

Sodium perborate is used in the detergent industry as a bleaching agent.
The crystalline reagent is available inexpensively as a hydrate with the general formula NaBO3 • n H2O (n: 1-4).

The reagent offers low toxicity and a long shelf life.
Sodium perborate is a useful reagent in organic synthesis as a substitute for the unstable, highly concentrated hydrogen peroxide solutions that can pose a significant explosion hazard and are not commercially available.

Sodium perborate is soluble in water and releases hydrogen peroxide, but Sodium perborate is not merely a mixture of hydrogen peroxide and sodium borate.
NMR and Raman spectroscopy indicate that in dilute solution, an equilibrium exists that still contains peroxoborate anions.
These peroxoborate species are able to deliver the hydroperoxide anion at a lower pH than when H2O2 is used.

Sodium perborate is activated toward nucleophilic oxidation, and also buffers the reaction medium.
For oxidations of organoboranes, Kabalka notes that H2O2 sometimes requires quite harsh conditions that are incompatible with many functional groups, while Sodium perborate offers an interesting mild alternative.
He assumes that the mild nature of the oxidant is a result of having borate as a leaving group as compared to hydroxide, which is formed in hydrogen peroxide oxidations.

Mixing sodium perborate with acetic acid generates even more powerful oxidation species.

Sodium perborate is considered as a source of active hydrogen used in detergents, cleaning products, laundry detergents and bleaches.
Sodium perborate finds application as a tooth bleaching agent utilized for tooth.

Sodium perborate has antiseptic properties and acts as disinfectant as well as preservative in eye drops.
Further, Sodium perborate is mixed with suitable activator, tetraacetylethylenediamine in order to release oxygen at lower temperatures.

Perboric acid is mainly found in its salt form of sodium perborate and it can be found as a monohydrate or tetrahydrate.
Sodium perborate is one of the peroxy acid salts with very wide functionalities in industrial settings.

Perboric acid in the form of sodium perborate is approved by Health Canada since 2004 to be used as a disinfectant of medical instruments.
By the FDA, sodium perborate is approved as an ointment for the protection of poison ivy dermatitis.

Sodium perborate is an inorganic sodium salt widely used in laundry detergents and in peroxide-based bleaches, such as tooth whitening products.
Sodium perborate also has antiseptic and disinfectant properties and is therefore used as an oral debriding agent or oral wound cleanser.

Sodium perborates are salts composed of a sodium cation and the conjugate base anion of some inorganic or organic acids.
They can be formed by the neutralization of such acids with sodium hydroxide.

Categorization of Sodium Perborate:

Sodium perborates can be categorized into:
Sodium perborates of carboxylic acids (e. g. sodium formate, HCOONa, the Sodium perborate of formic acid or sodium acetate, CH3COONa, the Sodium perborate of acetic acid, etc.) and
Sodium perborates of inorganic acids (sulfonic acids etc.)

Organic Sodium perborates:
Drugs:
In pharmaceutical technology acidic pharmaceutical substances are often converted into Sodium perborates, because they are more stable, more soluble or membrane-permeable (bioavailable) than the base compound.

Examples of such Sodium perborates are (selection):
Bispyribac, bithionol, bosentan, brequinar, bromfenac, Cefmenoxime, ceftiofur, citicoline, diclofenac , Floxacillin, fosinopril, Mordant brown 33, naproxen, Netobimin, ozagrel, pantoprazole, pemetrexed, secobarbital, sitamaquin, sitaxentan, sulfamiderazin, sulfapyridine, sulfaquinoxaline, sulfathiazole, sulfazecin, thiamylal and mesna.

The Disodium perborate of cromolyn is also used as drug.
Most of these salts are Sodium perborates of organic carboxylic acids or sulfonic acids.

Plant protection agents:
Herbicides are often used as Sodium perborates for the reasons discussed above.
One example is the Sodium perborate of methylflupyrsulfuron (CAS-No. 144740-54-5).

Cosmetics:
Sodium perborates of long chain sulfonic acids (e.g. sodium lauryl sulfate) are often included in toothpaste and shampoo.
The Sodium perborates of fatty acids may serve as soaps and can therefore be called sodium soaps.

Dye production:
Sodium perborates of certain aromatic sulfonic acids - particularly naphthalenesulfonic acid - are used in the preparation of azo dyes.

Inorganic Sodium perborates:
Examples of important inorganic Sodium perborates are sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate, sodium bicarbonate and sodium carbonate.
Sodium amide (NaNH2) is the Sodium perborate of ammonia (NH3).

Uses of Sodium Perborate:
Sodium perborate serves as a stable source of active oxygen in many detergents, laundry detergents, cleaning products, and laundry bleaches.
Sodium perborate is a less aggressive bleach than sodium hypochlorite and other chlorine-based bleaches, causing less degradation to dyes and textiles.

Borates also have some non-oxidative bleaching properties.
Sodium perborate releases oxygen rapidly at temperatures over 60 °C.
To make Sodium perborate active at lower temperatures (40–60 °C), one must mix Sodium perborate with a suitable activator, typically tetraacetylethylenediamine (TAED).

Sodium perborate is also present in some tooth bleaching formulas for non vital root treated teeth.
Sodium perborate is inserted in the root canal and left in place for an extended period of time to allow Sodium perborate to diffuse into the tooth and bleach stains from the inside out.
However, this use has been banned in the European Union.

Sodium perborate has antiseptic properties and can act as a disinfectant.
Sodium perborate is also used as a "disappearing" preservative in some brands of eye drops.

Sodium perborate is also used as an oxidizing reagent in organic synthesis.
For example, Sodium perborate converts thioethers into sulfoxides and sulfones.

Applications of Sodium Perborate:
Sodium perborate is considered as a source of active hydrogen used in detergents, cleaning products, laundry detergents and bleaches.
Sodium perborate finds application as a tooth bleaching agent utilized for tooth.

Hydrates:
Sodium perborate also crystallizes from water as the hexahydrate, Na2H4B2O8·6H2O, that is, Na2H16B2O14 or NaH8BO7.

The anhydrous compound is commonly but incorrectly called a "monohydrate" after the historical formulation NaBO3·H2O instead of the correct Na2H4B2O8.
Likewise, the hexahydrate is usually called "tetrahydrate" and formulated as NaBO3·4H2O.

Both forms are white, odorless, water-soluble solids.
The "monohydrate" and the "tetrahydrate" are the commercially important forms.

There does exist a true tetrahydrate Na2H4B2O8·4H2O, traditionally known as the "trihydrate", with no industrial significance.
There is a CAS number for each of the three traditional "hydrates", the three "peroxyborate" versions of each (interpreted as a hydrogen peroxide adduct) and the poorly-defined "anhydrate" NaBO3, totalling seven.

Chemistry of Sodium Perborate:
Sodium perborate undergoes hydrolysis in contact with water, producing hydrogen peroxide and borate.

More precisely, in solution the cyclic anion hydrolizes into two anions [B(OH)3(OOH)]−, which then enter in equilibrium with boric acid B(OH)3, hydrogen peroxide H2O2, the hydroperoxyl anion −OOH, and the tetrahydroxyborate anion [B(OH)4]−:
[(B(OH)2OO)2]2− + 2 H2O ⇌ 2 [B(OH)3(OOH)]−
[B(OH)3(OOH)]− ⇌ B(OH)3 + −OOH
B(OH)3 + −OOH + H2O ⇌ [B(OH)4]− + H2O2

As the concentration of the solution increases, other peroxoborate species become significant.
With excess H2O2, the anions [B(OH)2(OOH)2]−, [B(OH)(OOH)3]−, and eventually [B(OOH)4]− appear.
At high borate concentrations, the sodium perborate with dimeric anion crystallizes out, due to Sodium perborate relatively low solubility.

The "monohydrate" form dissolves faster than the "tetrahydrate" and has higher heat stability; Sodium perborate is prepared by heating the "tetrahydrate".
The commercial "anhydrate", or Oxoborate, is prepared by further heating of "monohydrate" and actually consists of sodium borate and boron–oxygen radical.

Pharmacology of Sodium Perborate:
Drug Indication:
In the industry, sodium perborate is used as a disinfectant.
Sodium perborate is also part of the ingredients for detergents, bleach powders, and personal care formulations.

In cosmetic products, perboric acid and mainly Sodium perborate salt are used as an oxidizing agent for dyeing or permanent waving.
In dentistry, sodium perborate monohydrate is used as an aid for the removal of phlegm, mucus or other secretions associated with an occasional sore in the mouth, for cleansing minor wounds, for temporary cleanse of canker sore or for the removal of foreign materials in minor wounds.

In ophthalmic preparations, sodium perborate is used as a preservative for products used for dry eye.
This use is approved as Sodium perborate rapidly degrades to harmless byproducts.

Preparation of Sodium Perborate:
Sodium perborate is manufactured by reaction of borax Na2B4O7 and sodium hydroxide NaOH to give sodium metaborate NaBO2, which is then reacted with hydrogen peroxide to give hydrated sodium perborate:
Na2B4O7 + 2 NaOH → 4 NaBO2 + H2O
2 NaBO2 + 2 H2O2 → Na2B2O4(OH)4

A surfactant may be added to control crystal size.
Sodium perborate may also be produced in the electrolysis of an aqueous solution of a solution containing borax, sodium carbonate and sodium bicarbonate (potassium dichromate is added to improve yield along with sodium silicate).
A copper pipe is used as a cathode and platinum for the anode, the current being 6 amperes at 7 to 8 volts, and the temperature 10 °C.

Structure of Sodium Perborate:
Unlike sodium percarbonate and sodium perphosphate, Sodium perborate is not simply an adduct with hydrogen peroxide known only since 1961.
Rather, Sodium perborate contains a perborate anion [(B(OH)2OO)2]2− consisting of a cyclic −B−O−O−B−O−O− core with two hydroxy groups attached to each boron atom.
The ring adopts a chair conformation.