Perborate, sodium

Sodium perborate is used in laundry detergents and bleaches. It releases more hydrogen peroxide than borax when it reacts with water. Hydrogen peroxide acts as a bleach, and its action is aided by the alkaline solution that is also produced by the reaction. 

Sodium perborate (more correctly sodium peroxoborate) (NaB02(0H)2 3 H2O) 

The first step, the formation of sodium metaborate from borax and sodium hydroxide, is carried out at temperatures up to 90°C. When impure borax is used the solution is filtered. The second step is carried out at 25 °C and the mixture subsequently cooled to 15°C and the precipitated sodium peroxoborate hexahydrate filtered off. Stabilizers for the perborate, such as silicates or magnesium salts, may be added to the reaction mixture. Residual moisture (3 to 10%) is removed in a hot air drier. The mother liquor from the second step can be returned to the first step. 

The end product contains ca. 10.1 to 10.4% active oxygen (theoretically 10.38%). The bulk density of the perborate is adjusted to that of the other components in detergents ( light perborate ) by special steps in the process. Older manufacturing processes, which started from sodium peroxide or use electrochemical processes, are no longer used. 

Step I Formation of nietaborate from borax and sodium hydroxide Step 2 Reaction of metaborate with H2O2 forming perborate, which is then filtered off from the cooled solution and dried 

Sodium perborate. Red atoms are oxygen yellow atom is boron and turquoise atom is sodium. Gray sticks indicate double bonds, publishers RESOURCE GROUP 

Sodium perborate tetrahydrate is prepared by reacting hydrogen peroxide with borax (Na2B407). 

Because of concerns about replaced in many applica- 

If the water is displaced from the perborate by the action of hydrogen peroxide it is possible to increase the content of active oxygen in the product up to about 30 % but suoh products are not sufficiently stable. A more stable product containing up to 20% of active oxygen can be prepared by dehydration of the oompound NaB02. H202.3 H20 over sulphurio aoid, or phosphorus pentoxide, or by drying under reduced pressure at a maximum temperature of 50 °C. 

At least three boric acids of the definite compositions shown by the formulas H3BO3, HBO2, H2B4O7 can be prepared in the solid form. These are all obtainable from the anhydride B203, and they differ only in the degree of hydration of the B203. 

Hydrogen peroxide differs from water in that it possesses the divalent negative radical 02 instead of the ordinary divalent 0 radical of water. (Compare page 160.) 

Materials borax, Na2B4O7-10H2O,24 grams = 0.0625 F.W. NaOH, 5 grams. 

To 50 cc. of water, add 1 cc. of KI solution and 1 cc. of starch emulsion. Note absence of blue color. To half of this starch-iodide solution, add a few crystals of sodium perborate and then a drop or two of acetic acid until a blue color appears. To the other half of the starch-iodide, add a few drops of hydrogen peroxide and note a blue color which disappears when a drop or two of 6 N NaOH is added. Write equations and compare the action of sodium perborate and hydrogen peroxide. 

To 50 cc. of water, add 1 gram of sodium perborate and 10 cc. of 6JV H2S04. Dissolve 0.1 gram of potassium permanganate in 10 cc. of water and add 5 cc. of QN H2S04. Pour this solution 

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By far the most commercially important boron compound in terms of dollar sales is Na2B407.5H20. This pentahydrate is used in very large quantities in the manufacture of insulation fiberglass and sodium perborate bleach. 

Detecting the presence of small, even invisible, amounts of blood is routine. Physical characteristics of dried stains give minimal information, however, as dried blood can take on many hues. Many of the chemical tests for the presence of blood rely on the catalytic peroxidase activity of heme (56,57). Minute quantities of blood catalyze oxidation reactions between colorless materials, eg, phenolphthalein, luco malachite green, luminol, etc, to colored or luminescent ones. The oxidant is typically hydrogen peroxide or sodium perborate (see Automated instrumentation,hematology). 

Bis (trimethyl silyl) peroxide (CH2)3SiOOSi(CH2)3 can be used with triflic acid (CF SO H) and acts as an effective hydroxylating agent of aromatics such as toluene, mesitylene and naphthalene (165). Sodium perborate (a safe and inexpensive commercial chemical) can be used in conjunction with the triflic acid to hydroxylate aromatics (166). 

Neutralizing Lotion. The principal active ingredient of cold wave neutralizers is usually an oxidizing agent. The most popular is hydrogen peroxide [7722-84-1J, employed at a concentration of 1—2% it continues to find widespread use. Aqueous solutions of sodium bromate [7789-38-0] at a concentration of 10—20% occasionally are used and are technically preferred over the peroxide formulations because of excellent stabiUty and absence of hair bleaching. Neutralizing powders appear to be on the decline but formulations stiU in use consist of sodium perborate [7632-04-4] combined with hexametaphosphates to improve solubiUty in hard water. 

Sodium Peroxoborate Tetrahydrate. The compound sodium peroxoborate tetrahydrate [28962-65-4] (sodium perborate trihydrate), Na2B2(02)2[(0H)J 4H20, was formerly written as NaBO 3H20. A number of procedures have been pubHshed (13) for producing this hydrate most... 

Sodium Peroxoborate. Sodium peroxoborate [10332-33-9] (sodium perborate monohydrate), Na2[82(02)2(011)4], formerly written as NaBO H20, is known only as a microcrystalline powder, made by dehydrating the hexahydrate. The crystal stmcture has not been deterrnined, but the vibrational spectmm (27) indicates the presence of the same cycHc peroxodiborate anion (4) as that in the hexahydrate as well as in the tetrahydrate. 

Anhydrous Sodium Perborate. Anhydrous sodium perborate [7632-04-4] NaBO, is an ill-defined, powdery material, made by heating... 

Precipitate formation can occur upon contact of iajection water ions and counterions ia formation fluids. Soflds initially preseat ia the iajectioa fluid, bacterial corrosioa products, and corrosion products from metal surfaces ia the iajectioa system can all reduce near-weUbore permeability. Injectivity may also be reduced by bacterial slime that can grow on polymer deposits left ia the wellbore and adjacent rock. Strong oxidising agents such as hydrogen peroxide, sodium perborate, and occasionally sodium hypochlorite can be used to remove these bacterial deposits (16—18). 

Perbora.tes, Sodium perborate [7632-04-4] is the most widely used soHd peroxygen compound. Commercially it is available as a tetrahydrate [10486-00-7] and a monohydrate [10322-33-9]. The tetrahydrate is produced by treating a borax solution with hydrogen peroxide and sodium hydroxide ... 

R can be a variety of stmctures. Z is a leaving group and typically the conjugate base of a weak acid whose piC can range from 5 to 20 (86). The hydrogen peroxide is typically incorporated into the bath by a dding a soHd source of peroxide such as sodium percarbonate or the mono- or tetrahydrate of sodium perborate (86). 

Industry sources indicate worldwide production of hydrogen peroxide and sodium perborate mono- and tetrahydrate, which are used almost exclusively for bleach appHcations, is 1.1 x 10 t per year and 6.4 x 10 t per year, respectively, in 1990. 

Sodium Perborate Hydrates. Peroxyborates are commonly known as perborates, written as if the perborate anion were BO . X-ray crystal stmcture has shown that they contain the dimeric anion [(H0)2B(02)2B(0H)2] (7) (92). Three sodium perborate hydrates, NaBO XH2O (x = 1, 3, and 4), are known. Only the mono- and tetrahydrate are of commercial importance, primarily as bleaching agents (qv) in laundry products. 

Commercial preparation of sodium perborate tetrahydrate is by reaction of a sodium metaborate solution, from sodium hydroxide and borax pentahydrate, and hydrogen peroxide followed by crystallization of tetrahydrate (95). The tnhydrate and monohydrate can be formed by reversible dehydration of the tetrahydrate. 

Sodium perborate tnhydrate, NaBO 3H2O or Na2B2(02)2(0H)4 4H2O, triclinic, contains 11.8 wt % active oxygen (96). It has been claimed to have better thermal stabiUty than the tetrahydrate but has not been used commercially. The tnhydrate can be made by dehydration of the tetrahydrate or by crystallization from a sodium metaborate and hydrogen peroxide solution in the present of tnhydrate seeds. Between 18 and 50°C the tnhydrate is more stable but slower to crystallize than the tetrahydrate. Below 15°C the tnhydrate is spontaneously converted into the tetrahydrate. 

Sodium perborate monohydrate, NaBO H2O or Na2B2(02)2(0H)4, 16.0 wt % active oxygen, is commercially prepared by dehydration of the tetrahydrate. The monohydrate has the same peroxyborate anion (7), as the higher hydrates and is the anhydrous sodium salt of this anion. Further dehydration results in decomposition of the peroxyborate. 

In 1986, Turkey produced nearly one million metric tons of mineral concentrate, whereas production of refined borate chemicals was 89,500 metric tons. Annual production capacities of chemicals at Eskiseher were pentahydrate borax, 160,000 t anhydrous borax, 60,000 t and decahydrate borax, 17,000 t. Capacities at Bandermes were decahydrate borax, 55,000 t boric acid, 33,000 t and sodium perborate, 64,000 t (103). 

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