Low-temperature hydrogen peroxide

Feldman L.A., and H.K. Hui. 1997. Compatibility of medical devices and materials with low-temperature hydrogen peroxide gas plasma. Med Dev Diag Indust 19 57-62. 

Kyi M.S., J. Holton, and G.L. Ridgway. 1995. Assessment of the efficacy of a low temperature hydrogen peroxide gas plasma sterilization system. / Hasp Infect 31 275-284. 

For medical devices a number of processes are available such as ethylene oxide and low-temperature hydrogen peroxide gas plasma sterilisation. 

Goldman M, Pruitt L. Comparison of the effects of gamma radiation and low temperature hydrogen peroxide gas plasma sterihzation on the molecular structure, fatigue resistance, and wear behavior of UHMWPE. J Biomed Mater Res 1998 June 5 40(3) 378-84. 

Another critical parameter for safe processing is the hydrogen peroxide addition rate, which in turn depends on the reaction temperature. Hydrogen peroxide should be added at such a rate that the latter equals the rate of its consumption, thus maintaining a low stationary concentration. The rate of hydrogen peroxide consumption via the molybdate catalysed disproportionation reaches its maximum when the predominant peroxomolybdate species in solution equals the triperoxo-molybdate Mo(02)3 Since the prevalent peroxomolybdate species that is... 

Very selective c/s-hydrogenations are also achieved by reduction with diiminc (N2H2, S. Hiinig, 1965 C.E. Miller, 1965 D.J. Pasto, 1991). The reagent can be used at low temperatures and has been employed in the selective reduction of C C double bonds, e.g. in the presence of a sensitive peroxidic function (W. Adam, 1978). 

Thiazole-N-oxides are prepared by the action at low temperature (-10°C) of hydrogen peroxide in acetic acid (474). 4-MethyIthiazole and 2,4-dimethylthiazole afforded the corresponding N-oxides with yields of 27 and 58%, respectively (Scheme 88). Thiazole-N-oxides without a methyl group in the 2-position are so unstable that they have a tendency to form 2-hydroxythiazoles and are decomposed by oxidation, whereas a 2-methyl group would prevent such rearrangement (474). 

TetrabromobisphenoIA. Tetrabromobisphenol A [79-94-7] (TBBPA) is the largest volume bromiaated flame retardant. TBBPA is prepared by bromination of bisphenol A under a variety of conditions. When the bromination is carried out ia methanol, methyl bromide [74-80-9] is produced as a coproduct (37). If hydrogen peroxide is used to oxidize the hydrogen bromide [10035-10-6] HBr, produced back to bromine, methyl bromide is not coproduced (38). TBBPA is used both as an additive and as a reactive flame retardant. It is used as an additive primarily ia ABS systems, la ABS, TBBPA is probably the largest volume flame retardant used, and because of its relatively low cost is the most cost-effective flame retardant. In ABS it provides high flow and good impact properties. These benefits come at the expense of distortion temperature under load (DTUL) (39). DTUL is a measure of the use temperature of a polymer. TBBPA is more uv stable than decabrom and uv stable ABS resias based oa TBBPA are produced commercially. 

The alkene is allowed to react at low temperatures with a mixture of aqueous hydrogen peroxide, base, and a co-solvent to give a low conversion of the alkene (29). These conditions permit reaction of the water-insoluble alkene and minimise the subsequent ionic reactions of the epoxide product. Phase-transfer techniques have been employed (30). A variation of this scheme using a peroxycarbimic acid has been reported (31). 

The stabihty of pure hydrogen peroxide solutions increases with increasing concentration and is maximum between pH 3.5—4.5. The decomposition rate of ultrapure hydrogen peroxide increases 2.2—2.3-fold for each 10 °C rise in temperature from ambient to about 100 °C. This approximates an Arrhenius-type response with activation energy of about 58 kJ/mol (13.9 kcal/mol). However, decomposition increases as low as 1.6-fold for each 10 °C rise have been noted for impure, unstabilized solutions. 

Classical chemiluminescence from lucigenin (20) is obtained from its reaction with hydrogen peroxide in water at a pH of about 10 Qc is reported to be about 0.5% based on lucigenin, but 1.6% based on the product A/-methylacridone which is formed in low yield (46). Lucigenin dioxetane (17) has been prepared by singlet oxygen addition to an electron-rich olefin (16) at low temperature (47). Thermal decomposition of (17) gives of 1.6% (47). 

Petoxycatboxyhc acids also have been prepared by the reaction of acid chlorides, anhydrides, or boric-catboxyhc anhydrides with hydrogen or sodium peroxide. These reactions ate carried out at low temperature and with excess peroxide to avoid the formation of diacyl peroxides (44,168,181,184). 

EDTA (ethylenediaminetetraacetic acid, [60-00-4]) chelates any trace metals that would otherwise decompose the hydrogen peroxide [7722-84-1]. The amine is preheated to 55—65°C and the hydrogen peroxide is added over one hour with agitation the temperature is maintained between 60 —70°C. The reaction is exothermic and cooling must be appHed to maintain the temperature below 70°C. After all the peroxide has been added, the temperature of the reaction mixture is raised to 75°C and held there from three to four hours until the unreacted amine is less than 2.0%. The solution is cooled and the unreacted hydrogen peroxide can be destroyed by addition of a stoichiometric amount of sodium bisulfite. This may not be desirable if a low colored product is desired, ia which case residual amounts of hydrogen peroxide enhance long-term color stabiUty. 

Isopropyl alcohol can be partially oxidized by a noncatalytic, liquid-phase process at low temperatures and pressure to produce hydrogen peroxide [7722-84-1] and acetone (24—26). 

Other Sterilants. Sterilization methods, developed in response to the requirements of a low temperature, noncorrosive stedlant and rapid turnaround time required by most hospitals, include use of hydrogen peroxide vapor, hydrogen peroxide plasma, and peroxy acetic acid. Acceptance of these methods was not universal as of this writing (ca 1996). 

The final solution should be checked for absence of free cyanide. The hypochlorite or CI2 + NaOH method is by far the most widely used commercially (45). However, other methods are oxidation to cyanate using hydrogen peroxide, o2one, permanganate, or chlorite electrolysis to CO2, NH, and cyanate hydrolysis at elevated temperatures to NH and salts of formic acid air or steam stripping at low pH biological decomposition to CO2 and N2 chromium... 

Free radicals are initially generated whenever polymer chains are broken and carbon radicals are formed. These effects occur during manufacture and in service life. Many elastomers are observed to oxidize at relatively low temperature (about 60°C), where carbon-hydrogen and carbon-carbon bond cleavages are highly unlikely. It has been demonstrated [52] that traces of peroxides impurities in the rubber cause low-temperature oxidation of rubber. These initiating peroxides are present in even the most carefully prepared raw rubber polymer [53]. 

At low temperature a 1 1 adduct of thioacetic acid and an enamine could be prepared (709). The previously described reaction of aminomethylene ketones with hydrogen peroxide was extended to bisaminomethylene compounds. However, acylated cyclohexenamines led to cyclopentane-carboxamides (770), Trichloromethyl adducts of enamines and the rearranged amine derivatives were described in a further study (777). 

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