Bleaching production

Two sohd organic peracids have been utilized ia textile bleaching products. Diperoxydodecanedioic acid, (16), [66280-55-5] a hydrotropic peracid, and the magnesium salt [78948-87-5] of monoperoxyphthaUc acid, (17), [2311-91-3] a hydrophilic peracid, were contained in bleaching products for a short period of time (142). 

Bleaching products such as hydroquinone 4-8% are particularly useful in patients with dyschromias and in patients with Fitzpatrick skin types lll-VI... 

Mahe A, Ly F, Aymard G, Dangou JM (2003) Skin diseases associated with the cosmetic use of bleaching products in women from Dakar, Senegal. Br J Dermatol 148 493-500... 

Bleach products, fragrances in, 78 363 Bleed-and-feed process, 9 797 Blended cements, 5 492 493, 501 Blending, cotton, 8 17. See also Mixing and blending... 

If a liquefaction efficiency of 97% is assumed, the hypothetical 600 tpd plant will lose 18 tpd to tail gas. It is also assumed that the tail gas is diverted to production of sodium hypochlorite bleach with a sales value of US 50 per ton of chlorine equivalent, while the chlorine feeding the EDC unit has a value of US 180 per ton. The lost chlorine will cost the producer more than US 800 000 per year. Even this figure ignores the facts that an equivalent quantity of caustic soda is consumed and that there will be a marketing cost associated with the bleach product. 

Spiro-oxazine (NOSH) photo-induced ring closure reactions were first described by Bohne et al., who used two-laser two-color excitation in the UV and visible regions [71,72]. In this work, they found that photoexciting the merocyanine in cyclohexane leads to a bleached product which recovers quantitatively to the merocyanine form over 30 xsec. The transient bleach state had an absorbance... 

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... 

Wear safety glasses. Do not use bleach products because they will oxidize the pigment, rendering it insensitive to any changes in pH. You also do not want to run the risk of accidentally mixing a bleach solution with the toilet bowl cleaner because... 

The chemical tests include Determination of the moisture and ash detection and determination of the dressing, qualitative test of the nature of the fibre, quantitative determination of the different kinds of fibre in the sample, investigation of the nature of the dye and of its fastness, determination of the nature and extent of the waterproofing, detection and estimation of the weighting of silk, and distinction between certain crude and bleached products. The methods used are as follows. 

Distinction between Raw and Bleached Products.—In the raw state, many textile fibres, such as flax, hemp, jute, etc., exhibit a colour quite distinct from white and in these cases the distinction between raw and bleached products is simple and is made by the eye. Other fibres, however, such as those of cotton and wool, are often white in the unbleached state and in such cases the distinction between the raw and bleached products cannot be made by the eye but requires investigation. 

The fibres thus obtained, after removal of the knots and pieces not well defibred, are grouped so as to make a roughly circular tuft about 1 cm. in diameter and 1 mm. thick. This tuft is placed on the surface of distilled water contained in a weighing bottle and observed during a period of a few minutes. With raw products, the tuft of fibres does not become wetted and remains floating even when the liquid is agitated with a bleached product, on the other hand, the tuft is wetted more or less rapidly and, when the liquid is shaken, falls slowly to the bottom. 

Washed linen and hempen goods are also sold which have been subjected to intermediate treatment to the raw and the bleached products, and it may sometimes be necessary to distinguish such washed goods from the corresponding raw materials. A simple method of differentiation is based on comparison of... 

The hydrogen peroxide formed in situ can be used for bleaching22 of the textile fabric (wool, cotton), and its concentration is an important parameter concerning the quality of the bleached product. Cotton is mostly... 

TCDD were found in bleached coffee filters (5 ppt), unbleached coffee filters (2.0 ppt), bleached shopping bags (1.3 ppt), and cigarette paper (1.4 ppt) (Wiberg et al. 1989). Concentrations were found to be lower in the unbleached products than in the corresponding bleached products (Wiberg et al. 1989). 

Note If desired, the bleaching powder can be replaced with Clorox bleach or other Clorox like bleaches (that contain sodium hypochlorite only) however, because most bleach products only contain 5% or less of sodium hypochlorite it would take astronomical amounts of bleach to carryout the reaction, but nonetheless, if you would like to try this technique—by all means just remember to extract the entire huge reaction mixture with extra amounts of benzene, toluene, or xylene to properly recover all of the chloroform)... 

Did you know that many of the chemical products in your home are hazardous, too For example, common household bleach, when used as directed, is safe for disinfecting and whitening clothing. Hazard labels on bleaching products, however, warn against mixing bleach with acids, household ammonia, or products that contain these chemicals. Bleach, when combined with acids, produces toxic chlorine gas. The products of combining bleach with ammonia are explosive. 

In the textile industry, because of its intense, but nevertheless fiber protecting, bleaching effect. Sodium Chlorite HOECHST is used for bleaching nearly all natural and synthetic fibers. The effects on synthetic fibers, e.g., polyamide, polyester, and polyacrylonitrile are extremely good and cannot be obtained by other bleaching products which are used in the textile industry. 

Color and peroxide values (PV) have been compared for tallows bleached at atmospheric pressure and under vacuum at several temperatures (67). At 90°C, atmospheric bleaching gave better color than bleaching under vacuum, but peroxide values were lower for the vacuum bleached product (PVs of 2 versus 16, respectively). At higher temperatures, color was better and peroxide values were lower. A bleaching temperature of 90°C to 110°C was recommended for beef tallow. 

From a regulatory point, bleached products are traditionally grouped with the unbleached forms of cmde lecithin. No distinction is made between the bleached and unbleached forms as far as Generally Recognized as Safe (GRAS) status is concerned (136). 

Storage and handling. Liquid lecithin can be kept for years provided closed containers are used and the temperature does not exceed 20-25°C. Bleached products require more careful storage and handling. Color reversion will occur rapidly in bleached products, particularly at elevated temperatures. Decomposition of peroxide is thought to contribute to color reversion in bleached products. In order to prevent this phenomenon, low storage temperatures are recommended (115). 

The toxicity of hypochlorite arises from its corrosive activity on skin and mucous membranes. Corrosive burns may occur immediately upon exposure to concentrated bleach products. Most of this corrosiveness stems from the oxidizing potency of the hypochlorite itself, a capacity that is measured in terms of available chlorine . The alkalinity of some preparations may contribute substantially to the tissue injury and mucosal erosion. Sodium hypochlorite when combined with an acid or ammonia may produce chlorine or chloramine gas, respectively. An inhalation exposure to these gases may result in irritation to mucous membranes and the respiratory tract, which may manifest itself as a chemically induced pneumonitis. 

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