Ketone based peroxide

EP-4 developed by ERDL is a very flexible polyester based on polyethylene glycol with molecular weight-200 (PEG-200), isophthalic acid (IPA) and maleic anhydride (MAn). Before its use, it is blended with styrene monomer (1 1) and cured at room temperature using cobalt naphthenate (as an accelerator) and methyl ethyl ketone (MEK) peroxide (as a catalyst). This meets the requirements of the main inhibitor and is used for inhibition of DB and CMDB propellants after the application of a barrier coat (generally a rigid polyester such as PR-3). However, it is observed during manufacture of EP-4 that there is a lot of batch-to-batch variation in properties in spite of the strict quality control measures adopted during its manufacture. 

Incompatibilities with Other Materials Aluminum, bases, alkali metals, ketones, organic peroxides, nitric acid, strong oxidizing agents, strong reducing agents, liquid ammonia, amines. 

In the presence of base, di-Z f/-alkyl peroxides are stable, however primary and secondary diaLkyl peroxides undergo oxygen—oxygen bond cleavage, forming alcohols, aldehydes, and ketones (44,66) ... 

Polyesters. Unsaturated polyester resins based on DCPD, maleic anhydride, and glycols have been manufactured for many years. At least four ways of incorporating DCPD into these resins have been described (45). The resins are mixed with a cross-linking compound, usually styrene, and final polymerization is accompHshed via a free-radical initiator such as methyl ethyl ketone peroxide. 

DMSO, molybdenum peroxide, benzene, reflux, 7-20 h, -60% yield. This method was used to monoprotect 1,2-diols. The method is not general, because oxidation to a-hydroxy ketones and diketones occurs with some substrates. Based on the mechanism and on the results, it would appear that overoxidation has a strong conformational dependence. 

One of the exciting results to come out of heterogeneous catalysis research since the early 1980s is the discovery and development of catalysts that employ hydrogen peroxide to selectively oxidize organic compounds at low temperatures in the liquid phase. These catalysts are based on titanium, and the important discovery was a way to isolate titanium in framework locations of the inner cavities of zeolites (molecular sieves). Thus, mild oxidations may be run in water or water-soluble solvents. Practicing organic chemists now have a way to catalytically oxidize benzene to phenols alkanes to alcohols and ketones primary alcohols to aldehydes, acids, esters, and acetals secondary alcohols to ketones primary amines to oximes secondary amines to hydroxyl-amines and tertiary amines to amine oxides. 

The benzotriazolyl derivative of acrolein acetal, compound 882, is lithiated, treated with chlorodiphenylphosphine, and the obtained intermediate is oxidized with hydrogen peroxide to phosphine oxide 883 (Scheme 145). The relatively acidic proton in derivative 883 is easily removed by a base, and the obtained anion adds to a carbonyl group of aldehyde or ketone. Subsequent rearrangement and elimination of the phosphorane group generates diene 884. For the derivatives of aldehydes (884, R2 = H), (E)-(E) stereoselectivity of the elimination is observed. Acidic alcoholysis of dienes 884 affords esters of P,y-unsaturated carboxylic acids 885 < 1997JOC4131>. 

The biomimetic protocol was invented by Julia and Colonna, and involves the use of polyamino acids (such as poly-(L)-leucine) as the catalysts for peroxide oxidation of chalcones, styryl alkyl ketones and conjugated alkenones. The substrate range is broad, especially when using immobilized catalysts and an organic solvent containing the substrate, urea-hydrogen peroxide and an organic base (Scheme 22)[101]. 

Bentley et al.m recently improved upon Julia s epoxidation reaction. By using urea-hydrogen peroxide complex as the oxidant, l,8-diazabicyclo[5,4,0]undec-7-ene (DBU) as the base and the Itsuno s immobilized poly-D-leucine (Figure 4.2) as the catalyst, the epoxidation of a, (3-unsaturated ketones was carried out in tetrahydrofuran solution. This process greatly reduces the time required when compared to the original reaction using the triphasic conditions. 

O3yhydroperoxides. Peroxides of the oxyhydro type are obtained by the addition of hydrogen peroxide to ketones. High yields of alkyl radicals are then often obtained by reaction with ferrous salts. 1-Meth-oxycyclohexyl hydroperoxide is easily obtained from cyclohexanone and hydrogen peroxide in methanol. It gives rise to the 5-(methoxy-carbonyl)-pentyl radical, which has been used to alkylate protonated heteroaromatic bases in high yield [Eq. (6)]. 

Other procedures for a oxidation of ketones are based on prior generation of the enolate. The most useful oxidant in these procedures is a molybdenum compound, MoOs-pyridine-HMPA, which is prepared by dissolving M0O3 in hydrogen peroxide, followed by addition of HMPA. This reagent oxidizes the enolates of aldehydes, ketones, esters, and lactones to the corresponding a-hydroxy compound.189 190 191... 

Several other processes have been developed. Most of these are based on oxidation of ammonia, using different oxidizing agents. In one such process, ammonia is oxidized with hydrogen peroxide in the presence of methyl ethyl ketone, acetamide and disodium hydrogen phosphate at 50°C ... 

Strukul and coworkers have carried out the catalytic epoxidation of a,/3-unsaturated ketones with H2O2 mediated by a series of platinum diphosphine based complexes, that confirm the ability of the Pt(II) center to increase the nucleophilicity of hydrogen peroxide . Interestingly, this transformation may be accomplished in enantioselective fashion when chiral diphosphines such as those in 53 are used (ee up to 63%). 

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