Bleach-active materials

Thianthrene oxide, described in lit. [W.Adam, J.Am.Chem.Soc 113. 6202-6208 (1991)] as a mechanistic probe for oxidation processes, was applied under aqueous conditions to investigate the behaviour of several bleach active materials of detergent formulations. 

Modem detergent products are complex mixtures of many different ingredients. Typical formulations consist of surfactants, builders, and other additives designed to maximize performance for the consumer while maintaining reasonable raw material and manufacturing costs. Typical detergent formulations contain multiple surfactant types to optimize performance and product stability.21,22 Performance additives such as bleaches, bleach activators,... 

A process has been developed for bleaching textile materials containing cellulose activated by microwave radiation [65]. High degree of whiteness and capil-... 

With a total consumption of —90 kt in 2005, tetraacetyl ethylene diamine (TAED) [14] (Figure 16.5) is the most widely used bleach activator. The product fulfills the basic principles of green chemistry [15], as it has maximum atom efficiency both starting materials (ethylene diamine and acetic acid anhydride) are fully incorporated in the molecule. Its low toxicity profile and ready biodegradability reinforce the sustainability claim. The activator is weight-efQcient, as one molecule generates two molecules of peracetic acid. Under European washing conditions at SO-bO C, it has an excellent cost-performance ratio. The kinetic stability of peracetic acid at lower tanperatures, however, limits its use to warm wash applications. 

Once the appropriate treatment process has been selected to transform the bleach active into a suitable physical form, a manufacturing process has to be developed. Alternatively, sourcing from a supplier can be considered. In both cases, the product properties of sample material must be examined, and the fit to the defined requirements needs to be assessed. To characterize the product and powder properties of the finished (soUd) bleach components, a wide variety of test methods is... 

For pretreatment of stains, bleach activators in stick form are claimed [193], consisting of a water-soluble surfactant binder and TAED powders. The activator is applied directly on the stain before the wash process and activated by a persalt-containing detergent. A similar concept based on single-dosed laundry boosters was used some time ago in Europe. It comprised a nonsoluble sheet of nonwoven material, which contained a high amount of bleach activator but no peroxide source [194]. To work, the sheet had to be added to persalt-containing detergents. 

Sodium hypochlorite is a more convenient and efficient bleach than hydrogen peroxide. However chlorine-based bleach can suffer from the drawback that potentially biologically active materiaL i.e. sensitisers. may be generated when it is used for bleaching alcohol ethoxy sulphates and aipha-Qiefin. syipbonatss. 

Filter aids may be applied in one of two ways. The first method involves the use of a precoat filter aid, which can be applied as a thin layer over the filter before the suspension is pumped to the apparatus. A precoat prevents fine suspension particles from becoming so entangled in the filter medium that its resistance becomes exces-sive. In addition it facilitates the removal of filter cake at the end of the filtration cycle. The second application method involves incorporation of a certain amount of the material with the suspension before introducing it to the filter. The addition of filter aids increases the porosity of the sludge, decreases its compressibility, and reduces the resistance of the cake. In some cases the filter aid displays an adsorption action, which results in particle separation of sizes down to 0.1 /i. The adsorption ability of certain filter aids, such as bleached earth and activated charcoals, is manifest by a decoloring of the suspension s liquid phase. This practice is widely used for treating fats and oils. The properties of these additives are determined by the characteristics... 

The active paste has a typical composition of 40-50% AM (active matter), 5-9% sodium sulfate, and <1% unsulfonated organic material (free oil). Pastes from oleum sulfonation do not require bleaching. 

Azolides used as activators for sodium percarbonate/perborate in laundry bleaching,1261-1291 for decreasing the affinity of polyamide textile materials for acid dyes,1301 and as antiflammatory agents 1311... 

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