Fast salts

Heavy metals are widely used as catalysts in the manufacture of anthraquinonoid dyes. Mercury is used when sulphonating anthraquinones and copper when reacting arylamines with bromoanthraquinones. Much effort has been devoted to minimising the trace metal content of such colorants and in effluents from dyemaking plants. Metal salts are used as reactants in dye synthesis, particularly in the ranges of premetallised acid, direct or reactive dyes, which usually contain copper, chromium, nickel or cobalt. These structures are described in detail in Chapter 5, where the implications in terms of environmental problems are also discussed. Certain basic dyes and stabilised azoic diazo components (Fast Salts) are marketed in the form of tetrachlorozincate complex salts. The environmental impact of the heavy metal salts used in dye application processes is dealt with in Volume 2. 

STABILISED DIAZONIUM SALTS AND AZOIC COMPOSITIONS 4.12.1 Fast Salts... 

As the range of components available for use in the azoic dyeing process expanded, research was simultaneously targeted on improvements designed to make the process more attractive to the commercial dyer. The necessity for the dyer to diazotise the Fast Base was removed with the introduction of stabilised diazonium salts [111], known as Fast Salts. Stabilisation was achieved by a judicious selection of the counter-ion to the diazonium cation various anions have found use in commercial Fast Salts and some examples are listed in Table 4-4. Particularly effective is the diazonium tetrachlorozincate, which can be readily prepared by adding an excess of zinc chloride solution to a solution of the diazonium salt. The precipitated complex diazonium salt is usually admixed with an inert diluent, which enhances its stability, and in use the dyer only needs to dissolve the powder in water to prepare the necessary diazonium salt solution. 

Fast salt A.D.C. Stabilising anion and parent base... 

Reactions of the respective chloro- and bromotris(trimethylsilyl)silanes with potassium /erf-butoxide did not give other P-halosilyl potassium compounds but a metalated cyclotetrasilane (Scheme 3) [7]. Most likely this can be explained by the assumption of chemistry similar to that discussed above, which, however, does not involve stable disilene precursors but exhibits fast salt elimination and dimerization steps so that part of the potassium alkoxide can react with the formed... 

Neolan Salt P, an anionic product. Palatine Fast Salt O, a fatty acid ethylene oxide condensate, and Dispersol A, an aliphatic ethylene oxide condensate, have been recommended as assistants capable of permitting... 

The diazotization of amines is somewhat troublesome and stock solutions cannot be stored for long because of their lack of stability. There was, therefore, a great demand for stabilized diazonium salts which, when dissolved in water, would immediately be ready for use. Such products are usually marketed under the name of Fast Salts such as Fast Red Salt RL, Fast Blue Salt BB, the Brentamine Fast Salts, etc. The earliest of these were the so-called anti-diazotates. 

In piece, yarn, or garment dyeing a two-stage method consisting of application of the Naphthol first followed by coupling with a Fast Salt is preferred. The Fast Salts are diazotized bases stabilized by formation of double salts with compounds such as zinc chloride, aluminium chloride, alkyl sulphates, benzene sulphonic acid, and 1 5 naphthalene disulphonic acid. 

There is considerable variation in the rate at which coupling takes place with different bases and Fast Salts, and the rate of reaction can be controlled by the pK (Huckel, J.S.D.C., 1958,74, 640). The diazo coupling components are divided into four groups according to their coupling energies, related to which are different pYi ranges at which the reaction will be most rapid. 

Palatine Fast Salt 0, 440 Blue GGN, 439 Para Red, 9, 444 Pararosaniline, 36, 369 Perlon Fast Orange RRS, 442 Phthalocyanine Blue, 121... 

Two dye components are needed for dyeing with azo dyes which are synthesised on the fibre a diazonium salt and the coupling compound, abbreviated as the naphthol . Diazonium components are aromatic amines, the fast bases, which must be previously diazotised or stabilised diazonium salts, the fast salts. Coupling components are arylamides of aromatic o-hydroxyacids and of acylacetic acids. Perkavec and Perpar [54] report the TLC-separation of these products. 

The fast salts are applied as solutions in 30% acetic acid to silica gel G and developed with n-butanol-acetic acid-water (10 + 10 + 50). A solution of naphthol AS-LR is sprayed on for detection (0.15 g dissolved in 0.3 ml 28 % sodium hydroxide, 2 ml 96 % ethanol added and the mixture diluted to 50 ml with water). Table 137 shows the hR/-values found. 

Table 137. h.Rf-values of the fast salts [54] details in text... 

This last solution should be prepared slowly as it is quite exothermic. Set all three aside in a freezer. Now prepare the mixing apparatus which will be a stainless steel "mixing bowl" suspended In the ice/salt bath made earlier. We use a stainless steel bowl here so that heat transfer will be maximal, while preventing any corrosive interaction. A glass bowl will not be sufficient for larger scale preparations as it will not conduct heat fast enough to prevent the reactants from going over IOC (at which point the Haloamide will decompose and you ll have to start over). Take the Sodium Hydroxide solution out of the freezer once it is cool, but not cold. 

These acid rhodamines are usually used for sHk and wool because they have level dyeing properties and show good fastness to alkaU however, they have poor lightfastness. An improved process for manufacturing 3,6-diaminosubstituted xanthenes is reaction of the inner salts of... 

High purity acetaldehyde is desirable for oxidation. The aldehyde is diluted with solvent to moderate oxidation and to permit safer operation. In the hquid take-off process, acetaldehyde is maintained at 30—40 wt % and when a vapor product is taken, no more than 6 wt % aldehyde is in the reactor solvent. A considerable recycle stream is returned to the oxidation reactor to increase selectivity. Recycle air, chiefly nitrogen, is added to the air introducted to the reactor at 4000—4500 times the reactor volume per hour. The customary catalyst is a mixture of three parts copper acetate to one part cobalt acetate by weight. Either salt alone is less effective than the mixture. Copper acetate may be as high as 2 wt % in the reaction solvent, but cobalt acetate ought not rise above 0.5 wt %. The reaction is carried out at 45—60°C under 100—300 kPa (15—44 psi). The reaction solvent is far above the boiling point of acetaldehyde, but the reaction is so fast that Httle escapes unoxidized. This temperature helps oxygen absorption, reduces acetaldehyde losses, and inhibits anhydride hydrolysis. 

A more recently developed pyrometaHurgical process is that of the proposed integral fast reactor, which would use metallic fuel (U—Pu—Zr alloy) and a molten salt electrorefiner as follows ... 

The condensation on the fabric of 1-amino-3-iminoisoindo1enines or 2-amino-5-iminopyrro1enines with phloroglucinol, preferably in the presence of metal salts and solvents, yields fast dyeings in brown shades (158). Metallized azo dyes derived from phloroglucinol yield fast dyeings on leather (qv) or silk (qv) (159). 

Xanthates. These compounds (12) are relatively fast accelerators which are used at low temperature because most examples decompose without cross-linking at higher temperature. Xanthates (qv) are produced by reaction of equimolar amounts of alcohol and carbon disulfide in the presence of caustic. The sodium salt is then converted to the 2inc compound or oxidized to the disulfide. 

The formation of amides can be accompHshed by dehydration of the ammonium salts of sahcyhc acid. The more common method for amines is the reaction of the ester, acyl hahde, or anhydride with an amine or ammonia. Each step is fast and essentially irreversible. 

J. J. Bartel, H. J. Rack, R. W. Mar, S. L. Robinson, E. P. Gersde, Jr., and K. B. Wischmann, 1. Molten Salt and Eiquid Metal, Sandia Eaboratories Materials Fast Group Keview of Advanced Central Eeceiver Preliminary Designs, Sept. 1979, SAND 79-8633, available from National Technical Information Service, Washington, D.C. 

The analysis of penicillins by mass spectrometry (qv) has developed with the advent of novel techniques such as fast atom bombardment. The use of soft ionization techniques has enabled the analysis of thermally labile nonvolatile compounds. These techniques have proven extremely valuable in providing abundant molecular weight information from underivatized penicillins, both as free acids and as metal salts (15). 

Mordant Dyes. MetaUizable azo dyes are appHed to wool by the method used for acid dyes and then treated with metal salts such as sodium chromate [7775-11-5] sodium dichromate [10588-01-9] and chromium fluoride [1488-42-5] to form the metal complex in situ. This treatment usually produces a bathochromic shift ia shade, decreases the solubUity of the coloring matter, and yields dyeiags with improved fastness properties. The chromium salts can be appHed to the substrate before dyeiag (chrome-mordant or chrome-bottom method), together with the dye ia a single bath procedure (metachrome process), or as a treatment after dyeiag (afterchrome process). 

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