Peroxoborate anion

In aqueous solution, all the sodium peroxoborates dissociate for the most part into boric acid, or its anion, and hydrogen peroxide. Peroxoborate species are also present in these solutions, depending on the pH and the concentration for the species type. The nature of these species has been extensively examined by classical physicochemical methods (13), by nmr, and by Raman spectroscopy (14—17). Both monomeric and polymeric species are usually present. There is some evidence (18) suggesting that these peroxoborates are more reactive than hydrogen peroxide alone under similar conditions. 

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. 

The reaction of borate salts with hydrogen peroxide in alkaline aqueous solution results in formation of peroxoborates. This reaction is rapid and occurs by nucleophilic attack of the perhydroxyl anion on boric acid,... 

The only significant peroxoborate species present in dilute solution is the [(HOlsBOOHj anion (Fig. 22). Peroxoborate salts, commonly referred to as perborates, can be selectively crystallized from solution as various alkali and... 

Perborates, or peroxoborates, are usually written as if the perborate anion were BO3. The three known sodium perborates are therefore conunonly referred to as the mono-, tri-, and tetrahydrates, NaB03 H20, where n = 1, 3, and 4. However, these actually contain the cyclic dianion (8). On the basis of this structure, these compounds are more correctly referred to as anhydrous, tetrahydrate, and hexahydrate. 

HOO oxidizes bleachable soils and stains. The most used source of hydrogen peroxide is sodium perborate, known as sodium peroxoborate tetrahydrate, NaB03-4H20, that in crystalline form contains the per-oxodiborate anion [4, 17]. 

The sodium perborate oxidation of morpholine and A-methylmorpholine is first order in the oxidant and substrates peroxoborate anion acts as the oxidizing species... 

Dissolution of perborate in the wash bath principally delivers the perhydroxide anion, although peroxoborate species will also be present. The level of the latter depends on the pH of the wash bath and the concentration of persalt used [9-11]. These species may also take part in the bleaching process. 

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