Peroxide method

Polyethylene glycol [25322-68-3] various, from -200 to -35,000. May be contaminated with aldehydes and peroxides. Methods are available for removing interfering species. [Ray and Purathingal Anal Biochem 146 307 7955.]... 

The present procedure is substantially simpler and quicker than the best previous procedure,3 which requires 4 days instead of 4 hours. It is also safer, for no explosions have been encountered with the present procedure, even on a 1.2-mole scale,3 whereas care must be taken to prevent explosion of the intermediate hypobromite when the Hunsdiecker method is used,3 and one detonation has been reported. In comparison with the peroxide method,4 it is simpler and gives better yields. 

Antioxidant capacities of common individual curcuminoids were determined in vitro by phosphomolybdenum and linoleic acid peroxidation methods. Antioxidant capacities expressed as ascorbic acid equivalents (pmol/g) were 3099 for curcumin, 2833 for demethoxycurcumin, and 2677 for bisdemethoxycurcumin at concentrations of 50 ppm. The same order of antioxidant activity (curcumin > demethoxycurcumin > bisdemethoxycurcumin) was observed when compared with BHT (buty-lated hydroxyl toluene) in linoleic peroxidation tests. The antioxidant activity of curcumin in the presence of ethyl linoleate was demonstrated and six reaction products were identified and structurally characterized. The mechanism proposed for this activity consisted of an oxidative coupling reaction at the 3 position of the curcumin with the lipid and a subsequent intramolecular Diels-Alder reaction. ... 

Diatoms and the Scanning Electron Microscope Acid Treatment Method Hydrogen Peroxide Method Obtaining Diatom Specimens from Sediments Preparation of Attached Diatoms Preparing Cleaned Diatoms for Viewing on the Scanning Electron Microscope References... 

Fig. 2. Scanning electron micrographs of diatoms prepared using the hydrogen peroxide method. (A) A naviculoid diatom (bar = 10 pm). (B) Fragilaria sp. (bar= 13 pm).

Porter, N. A., 1984, Chemistry of hpid peroxidation. Methods Enzymol. 105 2Ti-2K2... 

Choudhury RB, Poddar MK. (1984) Andrographolide and Kahnegh (Andrographis paniculata) extract In vivo and in vitro effect on hepatic lipid peroxidation. Methods Find Exp Clin Pharmacol 6 481. 

A series of compds which contain both acetylene bonds and peroxide groups, was synthesized by Milas et al by using a modification of the sulfuric acid-hydrogen peroxide method originally described in Refs 1 ... 

Gaseous Hydrogen Peroxide. Methods for determination of gas-phase hydrogen peroxide have been reviewed (79-81). Hydrogen peroxide is determined by either scrubbing air with an aqueous solution and measuring the resultant liquid-phase peroxide or by measuring the peroxide directly with a spectroscopic technique. The method that has been most commonly... 

With adequate swelling vinyl monomers can be satisfactorily grafted to cellulose and its derivatives by the three main methods developed for other polymers (98). These are (1) the mutual or direct method where the polymer is irradiated in the presence of the monomer or monomer vapor, (2) the pre-irradiation (sometimes called post-irradiation grafting) method where the polymer is first irradiated and then brought into contact with the monomer, and (3) the peroxide method in which the polymer is irradiated in air and the resulting polymeric peroxide used to initiate graft polymerization. 

The peroxide method involves the precipitation of uranyl peroxide by addition of H202 to uranyl nitrate solutions according to equation (103). Below 50 °C, U04-4H20 precipitates, while... 

The third method involves the oxidative cyclization of S-benzylpropionic acid amides 145 by acetyl peroxide (method C) to afford tetrahydro-TAs 146 (Scheme 50). 

Soya bean Catalytic hydrogen peroxide Methods devised in the 1940s... 

Table V.24 Separation of Group IIIB cations with the hydrochloric acid-hydrogen peroxide method The ppt. may contain CoS, NiS, MnS, and ZnS. Wash well with lper cent NH4C1 solution to which 1 per cent by volume of (NH4)2S has been added reject the washings. Transfer the ppt. to a small beaker. Add 5 ml water and 5 ml 2m HC1, stir well, allow to stand for 2-3 minutes and filter (1).

Table V.25 Separation of Group IIIB cations with the hydrochloric acid-potassium chlorate-hydrogen peroxide method The ppt. may contain CoS, NiS, MnS, and ZnS. Wash well with 1 per cent NH4C1 solution to which 1 per cent by volume of yellow ammonium sulphide solution has been added reject the washings. Transfer the ppt. to a porcelain basin, add 5 ml water and 5 ml concentrated HC1 and stir for 2-3 minutes. If a black residue is obtained, the presence of NiS and CoS is indicated if complete dissolution takes place, only small amounts of Ni and Co are likely to be present. Evaporate the mixture to 2-3 ml in the FUME CUPBOARD, add 4 ml concentrated HN03 (1) and concentrate to 2-3 ml. If the solution is not clear, dilute with 8-10 ml water, filter off the sulphur and return the filtrate to the porcelain basin in the fume cupboard. Boil down to 1-2 ml, taking great care not to evaporate to dryness. Add 5 ml concentrated HN03 and evaporate again to 1-2 ml (2).

VI.14 SEPARATION AND IDENTIFICATION OF GROUP IIIB CATIONS ON THE SEMIMICRO SCALE The separation scheme outlined in Table VI. 16 commences with the sulphide precipitates obtained according to the prescriptions of the general separation table (Table VI. 11 in Section VI.9). It is a semimicro adaptation of the hydrochloric acid-hydrogen peroxide method, described in Table V.24 (Section V.15). 

It is important to pay attention to the potential role of peroxides created on the surface of plasma-treated, including plasma polymer-coated, TPOs in the formation of durable bonds between the substrate and primer. It has been known for decades that the peroxides formed on the irradiated polymers (by y-ray. X-ray, electron beams, etc.) can be utilized in graft copolymerization of various monomers. This method is known as the peroxide method of radiation copolymerization [27]. The trunk polymer is first irradiated by ionizing radiation in a vacuum or in an inert gas environment. The irradiated polymer is exposed to air or oxygen to convert free radicals to peroxides. Thus created peroxides-containing polymers were used as the initiator of the free radical polymerization of the second monomer. The polymer peroxides are decomposed by heat or by the use of reduction/oxidation accelerator, i.e., peroxides are converted to free radicals. 

Sodium Peroxide Method. This method consists in decomposing the chloropicrin with sodium peroxide and then volumetrically determining the chlorine liberated in the reaction. ... 

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