Sodium metaperiodate, selective oxidation

Alumina supported sodium metaperiodate, which can be prepared by soaking the inorganic support with a hot solution of sodium metaperiodate, was also found to be a very convenient reagent for the selective and clean oxidation of sulphides to sulphoxides79. The oxidation reaction may be simply carried out by vigorous stirring of this solid oxidant with the sulphide solution at room temperature. As may be expected for such a procedure, solvent plays an important role in this oxidation and ethanol (95%) was found to be... 

Silica gel supported sodium metaperiodate was used for the selective oxidation of dibenzyl sulphide80. Metaperiodate anion soaked on strongly basic-ion-exchange resins Amberlite IRA-904 or Amberlyst A-26 was found to be able to oxidize sulphides into the corresponding sulphoxides in 82-99% yield81. 

The selective oxidation of the sulphide grouping in the presence of the disulphide bond was observed when a methanolic solution of amide 46 was treated with an aqueous solution of sodium metaperiodate(equation 20). 

Water insoluble tetrabutylammonium metaperiodate, which can be prepared from sodium metaperiodate and tetrabutylammonium hydrogen sulphate in aqueous solution, was found to be a useful reagent for the selective oxidation of sulphides in organic solvents . The reaction was generally carried out in boiling chloroform and gave dialkyl, alkyl aryl and diaryl sulphoxides in yields which are comparable with those reported for sodium metaperiodate in aqueous methanol solution (Table 4). In the case of diaryl sulphoxides, the yields decrease with prolonged reaction time. 

This method is based on the preferential oxidation of the disordered regions by sodium metaperiodate [266,267], Conditions are selected so that the reaction is confined as far as possible to the Malaprade course resulting in the formation of 2,3-dialdehyde units. The course of the reaction is followed by measuring the oxidant consumption from the amount of periodate consumed. From plots of log oxidant consumption against time, a measure of the fraction of ordered material can be calculated analogous to that of the acid hydrolysis method. 

The oxidation of sulfides (thioethers) gives the corresponding sulfoxides or sulfones m both, depending on the reaction conditions employed (equation 13). ° In order to obtain sulfoxides selectively it is necessary to add equimolar or sli tly excess amounts of oxidants to the sulfides under mild conditions. Among a variety of oxidants so far employed for this reaction are MCPBA, TBHP, PhICk, PhIO and sodium metaperiodate (NaI04). All appear to be particularly useful far obtaining sulfoxides selectively in good yields. 

Cellulose-based natural fiber can be oxidized using oxidizing agent with acidic catalyst. Oxidation reactions applied to cellulose in fiber for chemical modifications [43]. Oxidation reactions occur on cellulose selectively at particular position. The reaction of sodium metaperiodate with cellulose in wood fiber in the presence of sulfuric acid catalyst at 120°C and 85 KPa pressure yielded the oxidized product. Sodium metaperiodate reacts with hydroxyl groups of cellulose and produce 2,3-dialdehyde cellulose which improved the physical and mechanical properties of polymer composites [44]. 

---