Secondary bleaching

In the bleaching column, warm air strips the nitrogen tetroxide out of the red acid to give a product acid completely free of dissolved nitrogen oxides. The red acid enters the top of the column at 45°C and the secondary bleaching air enters the bottom of the column at 80°C. The final product leaves the bottom of the bleaching column at a concentration of 60% wt. nitric acid (40% water). The same type of... 

Fabric Softeners, Surfactants and Bleach Activators. Mono- and bisamidoamines and their imidazoline counterparts are formed by the condensation reaction of one or two moles of a monobasic fatty acid (typically stearic or oleic) or their methyl esters with one mole of a polyamine. Imidazoline formation requires that the ethyleneamine have at least one segment in which a secondary amine group Hes adjacent to a primary amine group. These amidoamines and imidazolines form the basis for a wide range of fabric softeners, surfactants, and emulsifiers. Commonly used amines are DETA, TETA, and DMAPA, although most of the polyethylene and polypropane polyamines can be used. 

One feature of this oxidation system is that it can selectively oxidize primary alcohols in preference to secondary alcohols, as illustrated by Entry 2 in Scheme 12.5. The reagent can also be used to oxidize primary alcohols to carboxylic acids by a subsequent oxidation with sodium chlorite.34 Entry 3 shows the selective oxidation of a primary alcohol in a carbohydrate to a carboxylic acid without affecting the secondary alcohol group. Entry 5 is a large-scale preparation that uses NaC102 in conjunction with bleach as the stoichiometric oxidant. 

Pulp mills. These separate the fibers of wood or other materials, such as rags, Enters, waste-paper, and straw, in order to create pulp. Mills may use chemical, semichemical, or mechanical processes, and may create coproducts such as turpentine and tall oil. Most pulp mills bleach the pulp they produce, and, when wastepaper is converted into secondary fiber, it is deinked. The output of some pulp mills is not used to make paper, but to produce cellulose acetate or to be dissolved and regenerated in the form of viscose fibers or cellophane. 

Deinked secondary fibers are usually bleached in a bleach tower, but may be bleached during the repulping process. Bleach chemicals may be added directly into the pulper. The following are examples of chemicals used to bleach deinked secondary fibers hypochlorite [HCIO, NaOCl, Ca(OCl)2], hydrogen peroxide (H202), and hydrosulphite (NaHS03). 

In an optimally controlled process free from transition-metal ions hydrogen peroxide bleaching is remarkably safe, there being no reported detrimental effects of bleaching at around 100 °C or for more than several hours [143]. Under such conditions, most of the peroxide appears to be consumed in the oxidation of chain end units of the cellulose macromolecule. The other major effect on the substrate is oxidation of secondary hydroxy to keto groups, accompanied by the formation of very few aldehyde or carboxyl groups [235]. 

In contrast to Ag, these emission profiles are insensitive to variations of the excitation wavelength within the threefold structure of the 2P 2S absorption band. Simultaneous with the photolysis of any of the three 2P - 2S components, one observes gradual bleaching of all lines with concurrent formation of Ci where n =2-5 (34,56). A further intriguing observation concerns the appearance of a weak structured emission near 420 nm for excitations centered on the secondary atomic site band of Cu in all three rare gas films (Figure 4), which has been found from independent studies of the absorption and emission spectra of matrix entrapped CU2 to arise from the A-state of CU2 (34). 

Secondary explosives, 10 722, 724 Secondary fibers, bleaching of, 21 51-52 Secondary fixed points, Tgo values for,... 

Furthermore, liquefaction efficiency will always be less than 100%. Some of the chlorine produced must remain with the non-condensable tail gas. The relevant factors were addressed in a paper presented at the 1997 SCI London International Chlorine Symposium [3]. In the processing of the tail gas, up to about 4% of the chlorine produced in the electrolysers is diverted to lower value products such as bleach or hydrochloric acid. Small quantities of secondary products such as these materials can also present a marketing problem. A further loss of chlorine product can occur in the storage system, particularly in systems where padding air is employed. 

In spin dyed secondary acetate threads, fibers, and films, P.B1.25 exhibits good textile fastness properties the only problem is a certain lack of fastness to bleaching with sodium hypochlorite (Sec. 1.6.2.4). Its fastness to light in 0.1% spin dyed specimens equals step 3-4 on the Blue Scale, while 1% samples equal step 5. 

Refined, bleached, and deodorized oils may contain some nutritionally objectionable compounds - secondary oxidation products, di- and tri-enoic... 

Kraft mill using 100% CIO2 Fish populations Changes in the reproductive development - reduction in gonad size, depression of sex hormones following exposure to bleach effluents subjected to secondary treatment Munkittricketal., 1997 [30]... 

Kovacs, T.G. Gibbons, J.S. Trembaly, L.A. O Connor, B.I. Martel, P.H. Vos, R.H. The effects of a secondary treated bleached Kraft mill effluent on aquatic organisms as assessed by short term and long term laboratory tests. Ecotox. Environ. Safe. 1995, 31, 7-22. 

Cardiovascular Effects. Infoimation regarding cardiovascular eiJects in humans following inhalation exposure to chlorine dioxide is limited to a single account of tachycardia that developed in a woman several hours after having been exposed to an unknown concentration of chlorine dioxide that had triggered respiratory effects severe enough to force her to leave the area where she had been bleaching dried flowers (Elkins 1959). The tachycardia was likely secondary to the primary respiratory effects. 

Potassium oxalate, along with calcium oxalate, is found in leaves and roots of certain plants. It is used for cleaning and bleaching straw and for removing stains. It also is used in photography, in clinical tests, as a secondary pH standard, and in wet chemical analysis. The analytical apphcation involves standardization of many oxidizing agents in titrimetric analysis. 

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