Hydrogen peroxide

“ Hydrogen peroxide behaves very frequently as a powerful oxidizing agent; thus lead sulphide is converted into lead sulphate in presence of a dilute aqueous solution of the peroxide, the hydroxides of the alkaline earth metals are converted into peroxides of the type MO2·8H2O, titanium dioxide is converted into the trioxide, iodine is liberated from potassium iodide, and nitrites (in alkaline solution) are converted into acid-amides (B. Radziszewski, Ber., 1884, 17, p. 355) . In many cases it is found that hydrogen peroxide will only act as an oxidant when in the presence of a catalyst ”

“ Similarly, hydrogen peroxide at once reduces a freshly prepared solution, forming colourless cerous salts, whilst if much hydrolysis has occurred, deeply coloured higher oxidation products are at first formed, and these lose their colour only slowly. ”

“ Hydrogen peroxide acts first chemically and then mechanically. When the decomposition takes place the oxygen is set free and escapes from a liquid to a gaseous form; this expansion of the gas distends the pus cavity, and as it escapes from the orifice, it carries much of the pus with it, and its application should be repeated till all purulent accumulations are evacuated. The liberated oxygen, being in a nascent or active condition, rapidly oxidizes the products of suppuration, and destroys many of the micro organisms of suppuration. ”

“ Addition of hydrogen peroxide to a neutral or acid solution of a titanium compound gives a yellow colour, due to the [236] formation of a peroxide, TiO3,aq. Such solutions have the same oxidising powers as hydrogen peroxide, but do not give the blue colouration with chromium salts. By treatment of the solution with dilute alkalies, an hydrated peroxide is thrown down, which, when dried over phosphoric anhydride, has the formula TiO3,3H2O, and forms a yellow, horny mass. The freshly precipitated peroxide dissolves in acids and alkalies ”

“ Hydrogen peroxide and ammonia throw down an hydrated peroxide, Th2O7; from neutral solutions hydrogen peroxide alone throws down peroxy-salts, which contain acid groups. This peroxide may also be obtained by the action of sodium hypochlorite or hydrogen peroxide on the hydroxide, as in the case of the zirconium compound. It readily gives up oxygen, passing into the more stable peroxide, ThO3. Since in neutral or faintly acid solutions zirconium and the rare earths give no precipitate with hydrogen peroxide, the reaction is extremely useful in the detection and estimation of thorium. ”

“ The fact that various surfaces, such as metals and fabrics, exert a marked effect upon the formation of benzoyl acetyl peroxide was established by the authors and served as a basis for the Adew that metals act upon bacteria by giving rise to energetic peroxides, which, of necessity, must be more active than ordinary peroxides. The action of sunlight has been ascribed by different workers to hydrogen peroxide, but the destructive action observed is greater than that which can be credited to this body. ”

“ Peroxide of hydrogen bleaches organic substances, dark or red hair being thereby changed to reddish-yellow or pale blonde. The coloration, or rather bleaching, does not appear at once, but is complete only after some time. The peroxide of hydrogen only exists in aqueous solution, which should be quite concentrated (15 to 20 per cent.) . Owing to the mode of preparation, the solution always contains some nitric acid and readily decomposes, when exposed to light and air, whereby it becomes useless. ”

“ Original footnotes ↑ According to Supervisory Special Agent J. Stephen Veyera, Chief of the FBI Bomb Data Center, hydrogen peroxide is a key component in homemade explosives because it is easy to obtain and very sensitive to heat, shock and friction. Specifically, hydrogen peroxide in combination with acetone and acid forms triacetone triperoxide ("TATP") , a very volatile explosive chemical. ”

“ When an acid of the strength H2SO4,6H2O is taken, at first the hydrate of the sulphuric peroxide, S2O7,H2O only is formed; but when the concentration about the positive pole reaches H2SO4,3H2O, a mixture of hydrogen peroxide and the hydrate of sulphuric peroxide begins to be formed. Dilute solutions of sulphuric peroxide can be kept better than more concentrated solutions, but the latter may be obtained containing as much as 123 grams of the peroxide to a litre. It is a very instructive fact that hydrogen peroxide is always formed when strong solutions of persulphuric acid break up on keeping. ”

“ If it is obtained, water is easily formed from it; this reaction evolves heat, and the reverse action is not very probable. Direct determinations show that the reaction H2O2 = H2O + O evolves 22,000 heat units. From this it will be understood how easy is the decomposition of hydrogen peroxide, as well as the fact that a number of substances which are not directly oxidised by oxygen are oxidised by hydrogen peroxide and by ozone, which also evolves heat on decomposition. ”

“ Potassium permanganate, in the presence of dilute sulphuric acid, is rapidly reduced by hydrogen peroxide, oxygen being given off, 2KMnO4 + 3H2SO4 + 5H2O2 = K2SO4 + 2MnSO4 + 8H2O + 5O2. Lead peroxide is reduced to the monoxide. ”

“ Although the peroxide H2O2 is derived from hydrogen, and Na2O2 from sodium, yet there are no corresponding salts known, and if they are formed they are probably as unstable as hydrogen peroxide. Although carbon forms carbonic oxide, CO, still it has only one salt-forming oxide—carbonic anhydride, CO2. Nitrogen and chlorine both give several salt-forming oxides and types of salts. But of the oxides of nitrogen, NO and NO2 do not form salts, as do N2O3, N2O4, and N2O5, although N2O4 does not form special salts, and N2O5 corresponds with the highest form of the saline compounds of nitrogen. ”

“ It is volatile with steam, and, on exposure to air at ordinary temperatures, is slowly converted into anemonic acid; the oxidation proceeds more quickly if platinum black, hydrogen peroxide, or barium peroxide is employed. ”

“ Lead dioxide is often called lead peroxide, but this name leads to error, because PbO2 does not show the properties of true peroxides, like hydrogen or barium peroxides, but is endowed with acid properties—that is, it is able to form true salts with bases, which is not the case with true peroxides. Lead dioxide is a normal salt-forming compound of lead, as Bi2O5 is for bismuth, CeO2 for cerium, and TeO3 for tellurium, &c. They all evolve chlorine when treated with hydrochloric acid, whilst true peroxides form hydrogen peroxide. ”

“ The dilute aqueous solution is very unstable, giving up oxygen readily, and decomposing with explosive violence at 100° C. An aqueous solution containing more than 1.5% hydrogen peroxide reacts slightly acid. ”

“ The lower oxides of nitrogen and chlorine and the higher oxides of manganese are also formed with the absorption of heat, and therefore, like hydrogen peroxide, act in a powerfully oxidising manner, and are not formed by the same methods as the majority of other oxides. It is evident that, being endowed with a richer store of energy (acquired in combination or by absorption of heat) , such substances, compared with others poorer in energy, will exhibit a greater diversity of cases of chemical action with other substances. ”

“ Although the above-mentioned scientists have demonstrated by their experiments that peroxide of hydrogen is one of the most powerful destroyers of pathogenic microbes, its use in therapeutics has not been as extensive as it deserves to be. ”

“ The great disadvantage of peroxide of hydrogen is its great expense, which is enhanced by an increasing demand for it in other industries. A minor disadvantage is its instability, which leads to loss in transit and storage. ”

“ The majority of hydrocarbons do not combine with the oxygen of the air or oxidise at ordinary temperatures, but under the action of nitric acid and many other oxidising substances most of them undergo oxidation, in which either a portion of the hydrogen and carbon is separated, or the oxygen enters into combination, or else the elements of hydrogen peroxide enter into combination with the hydrocarbon. ”

“ The method of making hydrogen peroxide by cooling the acid solution, imparting thereto a continuous movement of rotation, as well in vertical as in horizontal planes,-such, for example as imparted by a revolving screw in a receptacle,-and adding to said acid solution the binoxide in small quantities, while maintaining the low temperature and the rotary or eddying movements, substantially as described.' The answer sets up, among other defenses, that the alleged invention and patent do not contain any paten table subject-matter. ”

“ On the other hand, solutions of diacetyl, benzoyl acetyl, and of benzoyl hydrogen peroxides, and of phthalmonoperacid, exert pronounced and even remarkable germicidal properties. With reference to diacetyl peroxides and benzoyl acetyl peroxide, it was shown that the bodies themselves are chemically and bacterially inert, but on contact with water they undergo hydrolysis and give rise to the extremely energetic acetyl hydrogen and benzoyl hydrogen peroxides. A solution of these peroxides (1:3,000) is capable of destroying all pathogenic bacteria. ”

“ It is found, more especially in the case of organic compounds, that if a substance which oxidizes readily at ordinary temperature be mixed with another which is not capable of such oxidation, then both are oxidized simultaneously, the amount of oxygen used being shared equally between them; or in some cases when the substance is spontaneously oxidized an equivalent amount of oxygen is converted into ozone or hydrogen peroxide. ”

“ The suggestions which have been made are speculative, rather than based on experiment. The existence of many peroxidized substances, such as percarbonates, perborates, persulphates and of crystalline compounds of salts with hydrogen peroxide, makes it difficult to draw any indisputable conclusions as regards valency from a consideration of oxygen compounds. ”

“ It is a dark yellow powder, which fuses at a high temperature, the liquid on cooling depositing shining tabular crystals; at a white heat it loses oxygen and yields the monoxide. Exposed to moist air it loses oxygen, possibly giving the dioxide, K2O2; water reacts with it, evolving much heat and giving caustic potash, hydrogen peroxide and oxygen; whilst carbon monoxide gives potassium carbonate and oxygen at temperatures below 100°. A violent reaction ensues with phosphorus and sulphur, and many metals are oxidized by it, some with incandescence. ”

“ These haem catalases are not detectable by BLAST in Thermus, which seems only to have manganese catalases, so it is likely that they were lost or altered beyond recognition by Thermus when it became a thermophile.
One might expect catalases and other hydroperoxidases to be absent or less diverse before the atmosphere became oxygenic. Hydroperoxidases, of five major types, destroy the poison hydrogen peroxide generated by active oxygen. ”

“ Browne seems to have worked before hydrogen peroxide became generally available, or possibly before its bleachng powers were recognised. For bleaching most biological specimens, especially bones and the like, hydrogen peroxide is in every way better, less offensive, less corrosive, and less damaging to tissues, than hypochlorite. Soaking even badly yellowed teeth in say, a "five volumes" concentration (about 1 to 2%) of peroxide for a few days or weeks, whitens them beautifully without damage or rotting of tissues. ”

“ The germicidal activity of oxidising agents has been shown by Novey and others to be somewhat proportional to the energy liberated during the reaction but even when this factor is taken into consideration chlorine compounds are more active than other oxidising agents. Hypochlorous acid is far superior to hydrogen peroxide as a germicidal agent and is as active as ozone, which liberates a greater amount of energy. ”

“ The destruction of bacteria in the mouth and saliva takes place with extraordinary rapidity and the reagents have shown themselves useful in diseases of the mouth. The powerful effects of the organic peroxides is not explainable as due to nascent oxygen, since a solution of hydrogen peroxide, which will produce equal germicidal action, contains one or even two hundred times as much nascent oxygen. The authors incline to the belief that the acetyl and benzoyl ions are the active agents. ”

“ Concentrated nitric acid is an irritant and may burn skin. Perform all acid digestions in a fume hood. Hydrogen peroxide is a strong oxidizing agent, a strong irritant, and corrosive to the skin. Wear gloves and eye protection.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Sample at an accurately known flow rate between 1 and 4 L/min for up to 8 h for a total sample size of 1 to 1500 L for TWA measurements. ”

“ A peroxide of that metal is formed by the action of the currents, and may be readily reduced for use over and over again after working for from one to three months. The peroxide of lead, as is well known, is a conductor of electricity, and this fact constitutes an important advantage in the working of the process. The thin layer of sand is saturated with an electrolyte, such as dilute sulphuric acid (H2SO4 + 20H2O) to give a simple hydrogen amalgam; (Na2SO4 + xH2O) to give a hydrogen sodium amalgam; or (K2SO4 + xH2O) to give a hydrogen potassium amalgam. ”