Oxidation, cleaning

NH4)2S208]. These are all examples of inorganic oxidizing clean-... 

The downside of the inorganic oxidizing cleaning method is that the oxidizers are very aggressive and heavy pitting may occur unless the corrosion inhibitor is particularly effective and is present at the right concentration. 

Enzymatic Oxidations Clean, Highly Selective and Catalytic 314... 

INORGANIC FILMS Oxide films Air oxidation Excessive heating O2 in deposition equipment Oxidative cleaning processes... 

For the liquid chromatographic detection of carbohydrates and alcohols, a pulsed waveform of the type illustrated in Figure 27.16A is employed the technique is called pulsed amperometric detection (PAD). In this case, the potential is stepped to El, where oxidation of the compound takes place. The current is sampled for a short time at the end of the pulse (16.7 ms), where charging current is at a minimum. The potential is then stepped to E2, where the electrode undergoes oxidative cleaning. Last, the oxide-free surface is regenerated at potential E3. 

Figure 27.16 Potential-time (E - t) waveforms. Processes Elt anodic detection E2, oxidative cleaning E3, cathodic reactivation. Waveforms are (A) pulsed amperometric detection (PAD) with a short current sampling period, (B) PAD with a long current integration period, and (C) integrated PAD with a long integration period. [Reproduced with permission from Ref. 31.]...

IOB alone can oxidize some alcohols, but catalysed oxidations are much more efficient. Thus, in the presence of RuCl2(PPh3)2 primary aliphatic alcohols were oxidized cleanly to aldehydes, at room temperature the use of m-iodosylbenzoic acid instead of IOB considerably increased the yields for example, hexanal was formed from hexanol quantitatively (by GC) [19], Another catalytic system involved the use of simple lanthanide salts such as ytterbium triacetate [20]. Cyclic y-stannyl alcohols, readily available from cyclic vinyl ketones and Bu3SnLi, underwent oxidation accompanied by carbon-carbon bond cleavage (Grab fragmentation), when treated with IOB.BF3 and DCC. The products were unsaturated aldehydes or ketones. 

The coulometer, or left-hand U-tube, should contain saturated copper sulphate solution, which is specially prepared for this experiment. The cathode is made of copper the anode is a spiral of heavy copper wire free of any coating of oxide. Clean and dry the anode and weigh it. 

Many authors pointed out that an oxidative pretreatment of the carbon surfaces is necessary to enhance the adsorptive accumulation of DNA [ 15,16,23]. The enhanced adsorptive accumulation is attributed to increased surface roughness and hydrophilicity following such treatment. This pre-treatment consists of the application of + 1.6 V/ + 1.8 V for a short period of time (1-3 min) in acidic media. The application of high potentials in acidic media (e.g. acetate buffer pH 4.7) seems to increase the hydrophilic properties of the electrode surface through the introduction of oxygenated functionalities accomplished with an oxidative cleaning [31]. 

A very different solution, and one suitable even for the selective production of HBr in the presence of chlorine, without any catalyst, is the treatment of the pyrolysis oils with molten polypropylene [13, 63, 56, 57, 59], Polypropylene acts within a temperature range of 310-350°C as a hydrogen donor. HBr is evolving from the brominated phenols and substituted phenols are formed in the case of the decomposition of flame retardants such as tetrabromobisphenol A (Figme 20.8). Together with HBr small brominated aliphatics are formed. Those can be converted to HBr together with all noncondensable compounds in a final oxidative cleaning. 

Not surprisingly, thiols can be oxidized cleanly to disulfides [138], as in the CdS-photocatalyzed conversion of cysteine to cystine, where the uptake of oxygen was pH dependent. The reaction rate was not increased in deuterium oxide nor decreased by added azide, suggesting that singlet oxygen is not involved. Superoxide dismutase did inhibit the conversion. Phosphines and phosphonic acids undergo similar oxidative transformations [139]. 

Carboxymethylmercaptosuccinic acid and thiodiglycolic acid were oxidized cleanly to their respective sulfoxides, but thiodiglycolic acid could not be oxidized to its sulfone at room temperature in chloroform, acetic acid, acetonitrile, or water containing molybdate ion. This is no doubt due to the slow rate of oxidation of the sulfoxide to the sulfone, which can readily be explained on the basis of electronic theory. This is apparently the first successful preparation of carboxymethylthionylsuccinic acid by any method (5). 

Oxidations. Clean products are generally obtained by using alumina-supported reagents. For the oxidative dimerization of thiols by OMSO or NalOj, the conversion of hydroquinones to quinones and 2-naphthols to BINOLs in the presence of CuSO, the formation of lactones from a,co-diols under the influence of NaBrOj, and the hydrolytic defluorination of certain perfluoroalkylarenes, alumina has unique or positive effects. 

In subsequent work, the effect of the sizes of the cation and the associated [(M+)(SiVWnO405-)]4- (M+=Fi+, Na+, K+) ion pairs—the same ion pairs in Equation (9) above—on both the rate of oxidation of an organic substrate and the energy of electron transfer to these ion pairs was addressed.93 The organic substrate used was a diphenol (DPH2) because it is oxidized cleanly by these ion pairs to the corresponding diphenoquinone (DPQ) (Equation (12))... 

G. Langhendries, D. E. De Vos, B. F. Sels, 1. Vankelecom, P. A. Jacobs, G. V. Baron, Clean catalytic technology for liquid phase hydrocarbon oxidation. Clean Prod. Proc. 1 (1998) 21. 

Butylene Oxide Clean protective clothing rubber gloves chemical worker s goggles self-contained breathing apparatus. If any ill effects occur, immediately remove person to fresh air and get medical help if breathing stops, start artificial respiration. Promptly flush with plenty of water remove all contaminated clothing and wash before reuse. Promptly flush with plenty of water for 15 minutes and get medical help. 

TMDO inserts an oxygen atom into C-H bonds, with high selectivity in the order 3° > 2° > 1° bonds. The reaction is stereospecific with retention of configuration, and apparently occurs concertedly. ° As an example, c/5,c/i-l,3,5-trimethylcyclo-hexane (65) is oxidized cleanly to triaxial triol 66, and adamantane (67) is transformed to a mixture of bridgehead tetrol (68) and triol (69). The reaction with adamantane is accompanied by chemiluminescence, with triplet trifiuoroacetone El 75 kcal/mol) the apparent emitter. This observation constitutes further evidence that the oxygen atom transfer takes place concertedly. 

The cyathane diterpenoids have a characteristic 5-6-7 membered tricyclic skeleton. Piers et al. reported the synthesis of one of the cyathane diterpenoids, ( )-sarcodonin G (198) [58]. In this synthesis, a mixture of 196 and 197 (30 1) obtained from selenide 195 by oxidation, cleanly isomerized to give thermodynamically favoured 197 in the reaction with DBN in refluxing benzene (Scheme 7.45). 

Routine scheduled maintenance activities at Poelkapelle include the removal of condensate water from the cold plasma oxidizer, cleaning of piping, and removal of filter dust. These and other activities take about 30 minutes per day, an additional 3 hours per week, and yet another 3 hours per month. 

The main objective of this phase is to convert plutonium feed materials into plutonium oxide for immobilization in Phase 2. The feed materials include clean and impure oxides, clean and impure metals and alloys, and various fresh fuels. The basic steps include ... 

The clean coke process (Figure 19.6) involves feeding oxidized clean coal into a fluidized bed reactor at temperatures up to 800°C (1470°F) whereupon the coal reacts to produce tar, gas, and low-sulfur char. Alternatively, the coal may be processed by noncatalytic hydrogenation at455°C-480°C (850°F-900°F) and pressures of up to 5000 psi hydrogen. 

Tertiary amines can be oxidized cleanly to tertiary amine oxides. This transformation can be brought about by using hydrogen peroxide or a peroxy acid ... 

---