Bleach, oxidant

Oxidative bleaching Oxidative carbonylation Oxidative coupling... 

There are two types of bleaching oxidative and reductive. Oxidative bleaching cleaves carbon—carbon double bonds thus destroying chromophores. Reductive bleaching reduces carbon—carbon double bonds to single bonds. The loss of extended conjugation in the chromophore leads to loss of color. 

The Gay-Lussac s law Sample Problem in this section indicates how carefully gases under pressure must be handled. Chlorine gas can cause serious respiratory problems and irritate the skin and mucous membranes. In extreme cases, death from suffocation could result from exposure to this gas. Yet chlorine is an important industrial product. Compounds of chlorine are used in bleaches, oxidizing agents, and solvents, and as intermediates in the manufacture of other substances. 

Figure 1 TEMPO-catalysed bleach-oxidation of alcohols using bromide as co-catalyst...

For comparison, the previously described silica and MCM-41 supported TEMPO catalysts were also employed in the bleach-oxidation of octan-2-ol under the chlorinated hydrocarbon solvent- and bromide-free conditions. As shown in figure 4, PIPO is the most active catalyst under these conditions. All silica and MCM-41 supported TEMPO systems gave comparable conversions and are more active than homogeneous TEMPO. On the other hand, the activities obtained under these environmentally benign conditions were lower than in the case of dichloromethane/bromide. 

Figure 4 Bleach oxidation of octan-2-ol using 1 mol% of nitroxyl catalyst (a) PIPO (3.19 mmol/g amine linker)15, ( ) MCM-41 TEMPO (0.60 mmol/g ether linker/2, ( ) Si02 TEMPO (0.87 mmol/g, amine linker/5, ( ) Si02 TEMPO (0.40 mmol/g, amide linker/, ( ) TEMPO...

Figure 5 Nitroxyl-catalysed bleach-oxidation of octan-2-ol followed by in situ IR...

In summary, we have developed a recyclable heterogeneous catalyst for the bleach oxidation of alcohols and polyols. In contrast to previously reported systems, neither a chlorinated hydrocarbon solvent nor a bromide cocatalyst is necessary to achieve good activity. Besides bleach-oxidation, PIPO is also effective in the CuCl/nitroxyl catalysed aerobic oxidation of benzyl alcohol. A further advantage of our system is that PIPO is readily prepared from inexpensive and commercially available raw materials. We believe that it will find wide application in organic synthesis. 

General procedure for the bleach-oxidation of alcohols with PIPO as catalyst In a glass reaction vessel was placed 2.5 mg of PIPO (8 pmol based on complete functionalisation degree of functionalisation = 3.2 mmol g 1). Then a CH2CI2... 

Function Bleaching, oxidizing agent starch modifier antimicrobial agent. 

The Chemistry of Lignin-Retaining Bleaching Oxidative Bleaching Agents... 

Reactions of some chemical warfare agents with bleach (oxidation reactions) are illustrated in Equations (3) and (4). 

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