Sodium perborate, preparation

A Simple and Convenient Method for the Oxidation of Organoboranes Using Sodium Perborate Preparation of (+)-Isopinocampheol. 

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 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. 

Tertiary alkyl primary amines can be oxidized to nitro compounds in excellent yields with KMn04.39S This type of nitro compound is not easily prepared in other ways. All classes of primary amine (including primary, secondary, and tertiary alkyl as well as aryl) are oxidized to nitro compounds in high yields with dimethyldioxirane.399 Other reagents that oxidize various types of primary amines to nitro compounds are dry ozone,4,111 various peracids,401 including peracetic and peroxytrifluoroacetic acids, f-butyl hydroperoxide in the presence of certain molybdenum and vanadium compounds,402 F7-H20-MeCN,41123 and sodium perborate.403... 

The best known member among the various classes of these iodanes is undoubtedly [hydroxy(tosyloxy)iodo]benzene (HTIB), sometimes called Koser s reagent. It is prepared readily from (diacetoxyiodo)benzene and p-toluenesul-fonic acid monohydrate in acetonitrile. The same method using p-nitroben-zenesulfonic acid or 10-camphorsulfonic acid leads to the corresponding sul-fonyloxy analogs [41,42]. Of special interest are some iodanes of this type coming from a chiral ether. Their preparation was effected by direct oxidation with sodium perborate and the isolated diacetoxy derivatives were separately treated with p-toluenesulfonic acid in acetonitrile (Scheme 8) [43]. 

Sodium perborate has been for some time in use mixed with soap, borax, alkali, etc., and is sold for laundry work under such names as Persil, Glarax, and Ozonite. It possesses detergent and bleaching properties. Since 1914 the salt NaBOj, 4H20 has been produced by electrolysis, and many recent patents deal with this process. Formerly, the only means available for preparation was that of mixing borax with hydrogen peroxide. 

Although several methods are available for the preparation of the title compounds, in practice the starting material is (diacetoxyiodo)benzene (DIB). The standard method for its preparation is direct oxidation of iodobenzene with either peracetic acid [ 1 ] or sodium perborate in acetic acid [2], The first method appears to be preferable it requires great care in maintaining temperature at exactly 40°C at a lower... 

Hydrogen peroxide is prepared in industrial scale by an electrochemical method. A convenient source is the inexpensive sodium perborate, NaBO3.4H30 this yields hydrogen peroxide when its aqueous solution is heated ... 

A comparative analysis of oxidants used for the preparation of Met(O) derivatives from the related N -protected amino acid (Table 1) indicates that sodium perborate is apparently the most convenient reagent, since only negligible amounts of the sulfones are formed. In all cases a heterogeneous mixture of the two sulfoxide diastereoisomers is obtained with an (S,SIR,R) ratio of ca. 1 in the case of the perborate oxidation. ... 

A long-standing reaction is the oxidation of aryl boronic acids to phenols by alkaline peroxide, usually in the work-up of a borate-organolithium reaction, without isolation of the boronic acid, i.e. an efficient ArBr ArOH conversion. A variant under milder conditions uses sodium perborate (for the conversion of 5-bromopyrimidines), and, using oxone, oxindoles can be prepared from 1-Boc indoles via direct... 

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

A modification of this method consists of the oxidative diacetoxylation of iodoarenes in acetic or trifluoroacetic acid using appropriate oxidants, such as periodates [149-151], chromium(VI) oxide [152], sodium percarbonate [153], m-chloroperoxybenzoic acid (mCPBA) [130, 154-158], potassium peroxodisulfate [159,160], HaOa-urea [161], Selectfluor [33] and sodium perborate [132]. The oxidation of iodoarenes with sodium perborate in acetic acid at 40 °C is probably the most general procedure that has been used for the small-scale preparation of numerous (diacetoxyiodo)-substituted arenes and hetarenes (Scheme 2.14) [132,133,162-166]. For example, the chiral diacetate 31 and several analogous... 

C. Preparation and Reactions of Sodium Perborate Tetrahydrate, NaB03 4H20... 

The preparation of sodium perborate tetrahydrate, NaB03 4H20, can be considered formally in two steps. Balance the following equations to help understand these steps. Also write the overall reaction neglecting the intermediate formation of sodium metaborate, NaB02. 

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