Urea/hydrogen peroxide

Solid and aqueous dissolved urea hydrogen peroxide (UHP) was theorized to be capable of providing antimicrobial activity in aqueous as well as particulate applied 

The levels of urea hydrogen peroxide that provide acceptable levels of antibacterial activity also create unacceptable osmolality levels. Antibacterial activities 

Note 1 10 pi of each material above, except sodium octanoate, NaCA 1, as pipetted onto a 6 mm paper disc. For NaCA 1, a small amount of the powder was placed directly onto the agar 

Note 2 Fungi spores from an active culture were suspended in 1 ml sterile 0.85 NaCl, then lawned on 150 mm Mueller-Hinton agar plates with a sterile cotton swab 

Material Proteus mirabilis Pseudomonas aeruginosa Staphylococcus aureus 

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Urea peroxohydrate is made commercially by Solvay Deutschland, Degussa (Germany), and Mitsubishi Gas Chemical. It is known commercially as urea hydrogen peroxide, hydrogen peroxide carbamide, Exterol, Hydroperit, Hydroperit, Hyperol, Orti2on, Percarbamid, Percarbamide, Perhydrit, Perhydrol-Urea, Thenardol, and UHP. In 1994 the U.K. price was J7—8/kg ( 10—12/kg). World production in 1993 was several hundred metric t. 

UREA HYDROGEN PEROXIDE UREA NITRATE UREA PEROXIDE... 

Chemical Designations - Synonyms Carbamide peroxide, Carbonyldiamine, Hydrogen peroxide carbamide, Percarbamide, Perhydrol-Urea, Urea hydrogen peroxide Chemical Formula ... 

H2O2 or urea hydrogen peroxide addition compound... 

A 250-mL, two-necked, round-bottomed flask equipped with a magnetic stirbar, thermometer, and a reflux condenser fitted with a rubber septum and balloon of argon is charged with a solution of methyltrioxorhenium (MTO) (0.013 g, 0.05 mmol, 0.1% mol equiv) in 100 mL of methanol (Note 1). Urea hydrogen peroxide (UHP) (14.3 g, 152 mmol) is added (Notes 1, 2, 3, 4), the flask is cooled in an ice bath, and dibenzylamine (9.7 mL, 50.7 mmol) is then added dropwise via syringe over 10 min (Notes 1, 5). After completion of the addition, the ice bath is removed and the mixture is stirred at room temperature (Note 6). A white precipitate forms after approximately 5 min (Note 7) and the yellow color disappears within 20 min (Note 8). Another four portions of MTO (0.1% mol equiv, 0.013 g each) are added at 30-min intervals (2.5 hr total reaction time). After each addition, the reaction mixture develops a yellow color, which then disappears only after the last addition does the mixture remain pale yellow (Note 9). The reaction flask is cooled in an ice bath and solid sodium thiosulfate pentahydrate (12.6 g, 50.7 mmol) is added in portions over 20 min in order to destroy excess hydrogen peroxide (Note 10). The cooled solution is stirred for 1 hr further, at which point a KI paper assay indicates that the excess oxidant has been completely consumed. The solution is decanted into a 500-mL flask to remove small amounts of undissolved thiosulfate. The solid is washed with 50 mL of MeOH and the methanol extract is added to the reaction solution which is then concentrated under reduced pressure by rotary evaporation. Dichloromethane (250 mL) is added to the residue and the urea is removed by filtration through cotton and celite. Concentration of the filtrate affords 10.3 g (97%) of the nitrone as a yellow solid (Note 11). 

Immediately upon addition of the urea-hydrogen peroxide adduct to the solution containing methyltrioxorhenium, a yellow color develops due to formation of the catalytically active rhenium peroxo complexes.3... 

Urea hydrogen peroxide adduct (UHP) was employed in metal-catalysed asymmetric epoxidation [98] and Baeyer-Villiger oxidation [99,100]. Since the presence of urea does not change the course of the reaction, this will not be described here. Conversion of epoxides to halohydrins with elemental... 

UHP = urea-hydrogen peroxide adduct Balicki. R. Kaczmarek, L. Synth. Commun., 1993, 23, 3149... 

Anhydrous peroxytrifluoroacetic acid is not easy to handle, but the procedure has recently been revised.121 Namely, reaction of urea-hydrogen peroxide complex (UHP) with tri-fluoroacetic anhydride in acetonitrile at 0 °C gives solutions of peroxytrifluoroacetic acid, which oxidize aldoximes to nitroalkanes in good yields (Eqs. 2.58 and 2.59). Ketoximes fail to react under these conditions, the parent ketone being recovered. 

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]. 

Scheme 22 Reagents and conditions i) poly-L-leucine, urea-hydrogen peroxide, THF, diazabicycloundecene.

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. 

In a lOmL round-bottomed flask equipped with a magnetic stirrer bar were placed tetrahydrofuran (0.8 mL) and immobilized poly-D-leucine (100 mg). (7 )-Benzylidene acetophenone (50 mg), l,8-diazabicyclo[5.4.0] undec-7-ene (90 mg), and urea-hydrogen peroxide (27 mg) were added to the mixture. The thick white reaction mixture was stirred vigorously for 30 minutes. 

Urea hydrogen peroxide Zinc bromate Zinc chlorate Zinc permanganate Zinc peroxide... 

Methods A Immobilised poly-(L)-leucine, urea hydrogen peroxide, DBU, THE B Immobilised poly-(D)-leucine, urea hydrogen peroxide, DBU, THE... 

Scheme 18. Reagents and Conditions (i) Immobilised poly-(L)-leucine, urea hydrogen peroxide, DBU, THF, 12 h, 76%, 94% e.e. (ii) mCPBA, CH2CI2, 94%. (iii) HCl (g), CH2CI2, 66%. (iv) Amberlite IRA-420 ( OH), THF, 80%. (v) NaNj, MeOH, H20,94%. (vi) H2, Pd/C, EtOAc. (vii) NH3,MeOH. (viii) benzoyl chloride, (ix) trifluoroacetic acid, CH2CI2,74%...

The oxidant (e.g. urea hydrogen peroxide) and the base (various) used in the reactions are readily available and cheap. 

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