Potassium metaperiodate

Only a few perbromates have so far been prepared [844] the stability of Br04 is about the same [851] as C104 and I04. KBr04 decomposes (548—553 K) exothermally to KBr03 which is stable [852]. Potassium metaperiodate decomposes [853] (529—561 K)... 

Periodic acid, sodium metaperiodate, and potassium metaperiodate are now commercially available. Trisodium paraperiodate, NasPWOe, may be... 

An aqueous solution of periodic acid, free from metal ions, may be prepared through the conversion of potassium metaperiodate to the slightly soluble barium dimesoperiodate, Ba2l207, which, through reaction with an equivalent amount of sulfuric acid, yields pure periodic acid.107 Hudson found that nitrate as an impurity in periodic acid gives rise to erroneous results in this field.239 ... 

Another factor to be considered in the use of periodate ion as oxidizing agent is the desired pH. Potassium metaperiodate in solution gives29 a pH value of about 4. For values of pH below 3 to 4, pure periodic acid or acid-salt solutions must be used. For values of pH above 5, solutions containing potassium hydroxide and potassium metaperiodate must be employed.246... 

It was found29,111 114 122 124 126 127 131 136 137 174 that, if an equimolar mixture of sodium metaperiodate and potassium chloride was used, partial precipitation of potassium metaperiodate occurred, and the resulting, low, constant concentration of periodate ion evoked less overoxidation. ... 

The oxidation of sugar enamines [1465 and 1466, R2 = —CH=C (COOEt)2] with potassium permanganate and potassium metaperiodate in a 1 1 mixture of acetone and water at ambient temperature gave a-hy-droxy amides [1465 and 1466, R2 = COCOH(COOEt)2] and AMbrmyl amino sugars (1465 and 1466, R2 = CHO) 42-52% and 15-28% yields, respectively [89JCS(P1) 1923]. 

Catalyzed oxidations.1 In catalytic procedures with Ru04, periodate or hypochlorite are generally used as the stoichiometric oxidants. The addition of acetonitrile, which is inert to oxidation but an effective ligand for lower valent transition metals, results in much higher yields. A third solvent, chloroform, also plays a significant part. The ruthenium tetroxide is generated in situ from RuCl, (H20)n or Ru02 with sodium or potassium metaperiodate sodium hypochlorite is less effective. 

Potassium Metaperiodate. This compound can be obtained in good yield by oxidation of the iodate with chlorine in alkaline solution. Since the soluble salt K4I2O9 exists in alkaline solution instead of the insoluble KIO4,1 no precipitation occurs until all of the alkali is neutralized. 

The same salt may be prepared from potassium metaperiodate by adding two equivalents of potassium hydroxide and proceeding as with the sodium salt. 

Potassium metaperiodate, 171 Potassium nitrocarbamate, 68, 70 Potassium trioxalatoaluminiate, 36 Potassium trioxalatochromiate, 37 Potassium trioxalatocobaltiate, 37 Potassium trioxalatoferriate, 36... 

Among the other oxidizing agents, potassium dichromate and potassium bromate may be used as primary standards without any standardization. The solids should be dried at 150°C before weighing. Potassium metaperiodate K5I06 may also be used as a primary standard. It is stable if prepared in alkaline solution. 

An aqueous solution of sulfuric acid and a salt of periodic add, trisodium paraperiodate, or one of the potassium periodates, has been used frequently as a substitute for pure periodic add. When the product of the oxidation reaction is to be isolated, the effect of the presence of metal ions on the yield should be considered. If the product is volatile or slightly soluble, or is isolated either as a slightly soluble derivative or by extraction with organic solvents, the presence of metal ions should not reduce the yield. In the Case of certain methylhexosides34 which were oxidized by periodic acid formed from potassium metaperiodate and an equivalent of sulfuric add in aqueous solution, the presence of potassium ions was found to cause a low yield of the crystalline strontium salt prepared by the strontium hypobromite oxidation of the dialdehyde resulting from the periodic add reaction. Oxidation by pure periodic add, a solution of which is prepared either from crystalline paraperiodic add or by the previously mentioned method from potassium metaperiodate, is desirable when the presence of difficultly removed metal ions affects the yield adversely. 

Oxidation of the a-Benzyl Ether of Glycerol.92 The Use of an Emulsifying Agent. A mixture of 10 g. of the a-benzyl ether of glycerol, 15 g. of potassium metaperiodate, 6.6 g. of sulfuric acid, 2 g. of Gardinol, CH3(CH2)nOS03Na, and 200 cc. of water is shaken mechanically at room temperature for thirty minutes and then extracted with ether. 

Potassium hydrogen fluoride, 1 140 Potassium iodide, for use as a primary standard, 1 163 Potassium metaperiodate, 1 171 Potassium molybdoeyanide dihydrate, 3 160... 

Overend and coworkers have employed ruthenium tetraoxide in carbon tetrachloride for the oxidation of single hydroxyl groups in acetals of methyl glycosides. Similar oxidations may be performed in the presence of sulfonic ester groups, the oxidant being continuously regenerated with potassium metaperiodate. 

An aqueous solution of periodic add free from metals can be prepared from commerdal potassium metaperiodate this salt can be converted in high yield to the slightly soluble barium dimesoperiodate, Ba2l20g, which through reaction with an equivalent amoimt of sulfuric add yields a solution of pure periodic add. ... 

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