Wool, oxidation

At the end of the extraction the residual aluminum wool should be disposed of very carefully because it is in a highly reactive condition. As the ether evaporates, the aluminum wool oxidizes rapidly and becomes quite hot. In one run, 84% of the theoretical amoimt of metallic mercury was liberated during this oxidation. 

Wool oxidized with peracetic acid contains 14 % less histidine, 6 % less phenylalanine, and 1 % less tyrosine than the original wool (Corfield et al., 1958), and large amounts of dialyzable nitrogen have been detected in y-keratose (Alexander and Smith, 1956). Thompson and O Donnell (1959a) found that peracetic acid not only ruptures peptide bonds in the wool proteins, but also fails to oxidize all the disulfide bonds. Performic acid suffers neither of these disadvantages and is therefore preferable. 

Polyester/wool blends are very popular, the most common blend ratios are 55 45 and 70 30 polyester wool. Polyester rich blends are normally constructed from a texturised polyester fibre warp and 55 45 polyester wool weft yams. The 20 80 polyester/wool is woven from 55 45 warp and a pure weft yam. Worsted polyester/wool blend yams may contain 2.5 - 3% solvent extractable oil, compared with 3.5- 5% for similar all wool yams. The oils have much greater affinity for polyester fibre than wool and after normal piece scouring, the blends contain residual oil content of 0.6 - 1.2% compared with 0.3% for wool. Oxidation of combing oil is influenced by exposure to light which should be avoided before scouring. Addition of surfactant to combing oil improves the scourability of the blend fabric [75]. 

Hydrolysis with 6 M HCI in a sealed tube at 110°C for 24 h converts wool completely to its component amino acids for amino acid analysis. Tryptophan is destroyed by this procedure, and cystine, serine, and threonine are partially degraded. Peptide bonds on both sides of amino acid residues with acidic side-chains (aspartic and glutamic acid residues) are hydrolyzed faster than other peptide bonds [260]. Similarly, peptide bonds on both sides of cysteic acid residues hydrolyze rapidly therefore, wool oxidized during shrink-proofing is more susceptible to acid damage than untreated wool. 

The surface state of Fe appears to play a critical role in enhancing the rate of the CIO reduction reaction. Studies [58,62] performed with porous Fc203, Fe304, and FeO, and steel wool oxidized by washing with NaOCl showed that surface oxides of Fe participate in chlorate reduction (Figs. 4.2.16, 4.2.17). 

Cholestenone. Place a mixture of 1 0 g. of purified cholesterol and 0-2 g. of cupric oxide in a test-tube clamped securely at the top, add a fragment of Dry Ice in order to displace the air by carbon dioxide, and insert a plug of cotton wool in the mouth of the tube. Heat in a metal bath at 300-315° for 15 minutes and allow to cool rotate the test-tube occasionally in order to spread the melt on the sides. Warm with a few ml. of benzene and pour the black suspension directly into the top of a previously prepared chromatographic column (1) rinse the test-tube with a little more benzene and pour the rinsings into the column. With the aid of shght suction (> 3-4 cm. of mercury), draw the solution into the alumina column stir the top 0 -5 cm. or so with a stout copper wire to... 

The most abundant natural steroid is cholesterol. It can be obtained in large quantides from wool fat (15%) or from brain or spinal chord tissues of fat stock (2-4%) by extraction with chlorinated hydrocarbons. Its saturated side-chain can be removed by chromium trioxide oxidation, but the yield of such reactions could never be raised above 8% (see page 118f.). 

The purity of oxygen from chlorate candles before and after gas filtration is indicated in Table 2. A particulate filter is always used. Filter chemicals are HopcaUte, which oxidizes CO to CO2 molecular sieves (qv), which remove chlorine compounds and basic materials, eg, soda lime, which removes CO2 and chlorine compounds. Other than H2O and N2, impurity levels of <1 ppm can be attained. Moisture can be reduced by using a desiccant (see Desiccants). Gas purity is a function of candle packaging as well as composition. A hotter burning unit, eg, one in which steel wool is the binder, generates more impurities. 

Oxide Glass containers Flat for window and automotive Fiber glass Textile Wool Lighting... 

Fibrous materials may be naturally occurring or synthetically manufactured by thermal or chemical processes (Fig. 1) (see Fibers, survey). Refractory fibers are generally used in industrial appHcations at temperatures between 1000°C and 2800°C. These fibers may be oxides or nonoxides, vitreous or polycrystalline, and may be produced as whiskers, continuous filaments, or loose wool products. 

Oxide fibers are manufactured by thermal or chemical processes into a loose wool mat, which can then be fabricated into a flexible blanket combined with binders and formed into boards, felts, and rigid shapes or fabricated into ropes, textiles and papers. The excellent thermal properties of these products make them invaluable for high temperature industrial appHcations. 

Fabric preparation is often considered to be the most important stage to obtain good color yields, levelness, and brightness on wool fabric (104). This is done almost exclusively by an oxidative chlorination process, the most popular commercial methods using either a batch treatment with dichloroisocyanuric acid (DCCA), or a continuous fabric treatment with gaseous chlorine, called the Kroy process. 

This is apparentiy the reason for the high washfastness of these complexes as compared to their unmetallized precursors (48). The dichromate-acid after-treatment that is used technically oxidizes primarily cystine configurations ia the wool, which converts Cr(VI) to Cr(III). Alternatively, the fiber may be pretreated with dichromate whereby essentially the same final shade is obtained, although it is not known whether the same complexes are formed. 

Sodium dichromate and various chromic salts are employed in the textile industry (195,196). The former is used as an oxidant and as a source of chromium, for example, to dye wool and synthetics with mordant acid dyes, oxidi2e vat dyes and indigosol dyes on wool, aftertreat direct dyes and sulfur dyes on cotton to improve washfastness, and oxidi2e dyed wool. Premera11i2ed dyes are also employed. These are hydroxya2o or a2omethine dyes in which chromium or other metals are combined in the dye (see Azine dyes DYES Azo dyes). 

Calcium oxide. (Preheated to 700-900° before use.) Suitable for alcohols and amines (but does not dry them completely). Need not be removed before distillation, but in that case the head of the distillation column should be packed with glass wool to trap any calcium oxide powder that might be carried over. Unsuitable for acidic compounds and esters. Suitable for drying gaseous amines and ammonia. 

Bismuth [7440-69-9] M 209.0, m 271-273°. Melted in an atmosphere of dry helium and filtered through dry Pyrex wool to remove any bismuth oxide present [Mayer, Yosim and Topol J Phys Chem 64 238 7960]. 

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