Bleaching persulfate

If lighter colors than these are desired it is necessary to decolorize all the melanin in the hair in a preliminary step, and then add color back to the desired depth in a second treatment. This is known as a double-process treatment. The decolorization step consists of treating the hair with an alkaline mixture of persulfate salts and peroxide. The persulfate is added to the peroxide as a dry powder immediately before applying to the hair. Although the persulfate salts alone do not have any bleaching effect, the persulfate—peroxide mixture can remove all the melanin in the hair. Dark brown or darker hair can be lightened to a light blonde shade in about an hour. 

Bleaches of the simple ammoniacal peroxide type give limited lightening, which can be increased with bleach accelerators or boosters, including one or more per salts such as ammonium, potassium, or sodium persulfate or their combinations. These salts, which are susceptible to decomposition in aqueous solution, are packaged as dry powders and added just before use. In the absence of hydrogen peroxide, however, persulfates do not have any bleaching effect (41). 

Oxidation/bleaching Treatment with peracetic acid and/or hydrogen peroxide, or sodium hypochlorite or sodium chlorite, or sulfur dioxide, or potassium permanganate or ammonium persulfate... 

Bleached or oxidized starches are produeed by reaeting starch with a specified amount of reagent under eontrolled temperature and pH. The starehes treated with low levels of reagents, sueh as hydrogen peroxide, peracetic acid, ammonium persulfate and sodium hypoehlorite, in aqueous slurry are referred to as bleached starches. 

Oxidized Starches. Alkaline hypochlorite treatment introduces carboxyl and carbonyl groups, effects some depolymerization, and produces whiter (bleached) products that produce softer, clearer gels. Ammonium persulfate is used in some paper mills with continuous thermal cookers to prepare in situ bigb solids, low viscosity dispersions. Most of the hypochlorite-oxidized starch and all the ammonium persulfate-oxidized starch is used in the paper industry. The low solution viscosity and good binding and adhesive properties of these products make them especially effective in high solids, pigmented... 

Persulfate Ammonium persulfate [CAS 7727-54-0] (NH4)2S208, white solid, soluble, formed by electrolysis of ammonium sulfate under proper conditions. Used (l)as a bleaching and oxidizing agent, (2) in electroplating, (3) in photography. 

Oxidizer Ammonium persulfate Benzoyl peroxide Flour color improver Oxidizer for use in bleaching oils and flours... 

Sodium persulfate 4,400 3 Bleaching agent, analyzing reagent... 

Potassium persulfate 3,200 3 Catalyst, bleaching agent, reagent... 

Ammonium persulfate 4,500 Polymerizing agent, oxidizing bleaching agent... 

As can be seen by inspection, there are only a few oxidising agents that are likely to be suitable for making a solvent bleach dichromate, permanganate, persulfate and hydrogen peroxide. The last two in the list are very poor bleaching agents as their oxidation appears to be kinetically hindered. They can only be used in the presence of a suitable catalyst, which will be described later. 

Persulfate bleaches can be used efficiently, provided a catalyst is present. The catalyst might either be expected to disrupt any layer formation on the surface of the silver or be an electron transfer agent that can act as intermediary for electrons between the silver and persulfate ions. 

Figure 41. Effect of onium catalysts I-IV on bleaching rate in persulfate.

Willems also showed, in the same article, that some compounds that formed stable radicals would also catalyze silver bleaching by persulfate. He suggested that these compounds acted as electron transfer agents, performing as a shuttle for electrons from the silver to the persulfate thus a superadditive mechanism, similar to that seen in development, could operate. Kobayashi et al. [141] observed a similar effect with Af,7V,Af, 7V -tetramethyl-/j-phenylenediamine but also showed that this compound was destroyed by the action of persulfate, and benzoquinone was formed. It was this quinone that acted as the electron transfer agent in aged solutions. 

Hairdressers have higher rates of asthma than the general public. They are constantly exposed to persulfates in hair bleaches (hydrophiles) and hair sprays (mixtures of lipophiles and hydrophiles) J55 ... 

Potassium permanganate (KMn04) is a purple substance that is used as a disinfectant and to kill bacteria. Potassium persulfate (K2S2Og) is a bleaching agent and an antiseptic. 

Disodium peroxodisulphate EINECS 231-892-1 Peroxy-disulfuric acid, disodium sail Persulfate de sodium Sodium peroxydisulfate Sodium persulfate UN1505. Bleaching agent (fats, oils, fabrics, soaps), battery depolarizers, emulsion polymerization. Soluble In H2O (549 g/l MLD (rbt iv) = 178 mg/kg. Degussa AG FMC Corp. ... 

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