Safranine Dyes

A zeolitised fly ash product was successfully used as a low-cost adsorbent for cationic and anionic dyes. Equilibrium and kinetic results obtained in this study may be useful for designing a treatment plant for dye removal from industrial coloured effluents. 

Applications of Dyes Dyes have a wide range of applications in several fields such as textile, food, medicine, electronics, etc. Some applications of the dye classes mentioned above are shown in Table 6.5. 

Acid dyes Reactive dyes Basic Direct dyes Mordant dyes Disperse dyes Vat dyes Solvent dyes Fluorescent brightners Other dye classes Nylon, sUk, wool, paper, inks and leather Cotton, wool, sUk and nylon Paper, polyacrylonitrile, modified nylon, polyester and inks Cotton, rayon, paper, leather and nylon Wool, leather and anodised altiminirun Polyester, polyamide, acetate, acrylic and plastics Cotton, rayon and wool Plastics, gasoline, varnishes, lacquers, stains, inks, fats, oils and waxes Soaps and detergents, aU fibres, oils, paints and plastics Food, drugs and cosmetics, electrography, direct and thermal transfer printing 

---

Saffron [138-55-6] Safimax Safi ex Safe an Safranin Safranine dyes Safranine T Safranine T [477-73-6] Safrole [94-59-7]... 

The addition of 2,2, 4,4, 6-pentanitro-6 -methyldiphenylamine [64653-47-0] to seawater precipitates potassium (38). Aromatic amines, especially aminotetrahydronaphthalenes and their A[-aryl derivatives, are efficient flotation agents for quartz. The use of DPA for image formation in films has been patented (39,40). Diarylamines are used as intermediates (41) for azo, sulfur, oxidative base, triaryhnethane, oxazine, nitro, and safranine dyes (see Dyes and DYE INTERLffiDIATES). 

Mauveine is in a group of azines termed safranine dyes ie, it is a A/-phenyl-phenazonium chloride. Although the stmctures of these dyes are often written to show a positive charge on a particular hetero atom, the charge is in fact distributed through resonance throughout the molecule, thus accounting for their deep color. 

Three methods for quantitative analysis of niclosamide at concentrations of 0.5-2.0 ppm were given. For in situ analysis, safranine dye solution was added to the sample and the extraction solution added which formed the upper phase. The niclosamide content was determined by the color intensity of the upper phase. The colors were compared with blanks of known concentration. When an accurate determination was required, niclosamide was extracted from the water sample with amylacetate, a methanol solution of sodium hydroxide was added to the extraction, and the resulting yellow color was measured at 385 mft in a spectrophotometer. Third method made use of a calibration curve [60],... 

Mauveine is a safranine dye safranine was discovered by Hofmann and A. Geyger, who determined its constitution. Witt obtained safranine by oxidising -diamines and monoamines. Perkin s later work on dyestuffs is considered on p. 791. 

Another dyestuff based on p-phenylenediamine is Safranine B Extra (C. 1.50200), an azine dye which is obtained by reaction with aniline, via an intermediate indamine stage the earlier importance of safranine dyes however has diminished. 

Bachurin, S. O. Dubova, L. G. Kireeva, E. G. Shevtsova, E. F. Screening assay using safranin dye for determining the effect of cjdoprotectants and cytostatics on mitochondrial permeabUity and... 

Azine dyes are relatively unimportant as a class of dyes but are used extensively as biological stains. Colors are mostly yellow to red. DurabiUty of some of these dyes is supported by the 1990 LATCC Buyers Guide pubflshed by the American Association of Textile Chemists and Colorists, which fists Basic Red 2, Safranine T [477-73-6] (13) and Basic Red 5, Neutral Red [553-24-2] (14), discovered in 1859 and 1879, respectively (1). Basic Red 2 is a safranine similar to mauveine (7). 

Historically the phenazine dyes have played an important part in the dyestuffs industry, although their use has largely been superseded by the more modern, color-fast dyes, in particular those dyes which become chemically bonded to the fibers of the materials being dyed. Amongst the earliest examples of phenazine dyes are those compounds known as the safranines. The discovery of the safranines has been attributed to Greville Williams in 1859 and they were apparently in commercial use shortly after that date, but it was not until 1886 that it was recognized that phenosafranine (138) was indeed a phenazine containing system. 

Numerous dyes structurally related to the safranines, such as the eurodines, e.g. (141), the indulines, e.g. (142), the nigrosines (143) and aniline black, a pigment of unknown structure used in the printing industry, are well known and a detailed account of their chemistry and applications has been presented (57HC(ll)l). 

In this work hybrid method is suggested to determine anionic surfactants in waters. It is based on preconcentration of anionic surfactants as their ion associates with cationic dyes on the membrane filter and measurement of colour intensity by solid-phase spectrophotometry method. Effect of different basic dyes, nature and hydrophobicity of anionic surfactants, size of membrane filter pores, filtration rate on sensitivity of their determination was studied. Various cationic dyes, such as Methylene Blue, Crystal Violet, Malachite Green, Rhodamine 6G, Safranin T, Acridine Yellow were used as counter ions. The difference in reflection between the blank and the sample was significant when Crystal Violet or Rhodamine 6G or Acridine Yellow were used. 

Fig. 16. Retardation of the catalase activity of Fe-TAML activators by the dye Safranine O as an electron donor. Conditions [H202] 2.65 x 10-3 M [lk] 1.18 x 10 6M pH 10, 25°C. Inset shows that the rate of 02 evolution is inversely proportional to [Safranine O]. From Ref. (53).

Fig. 19. (A) Simulated bleaching of a hypothetical dye using Eq. (24) at different concentrations of Feni-TAML catalyst (in M) with the rate constants ki (in s-1) and ku (in M-1s-1). The numerical values are indicated on the graph. (B) Normalized experimental and simulated bleaching of Safranine O (4.3 x 10-5M) by H202 (0.012 M) catalyzed by la at pH 11 and 25°C. Experimental data are shown as a and. The simulations, shown as solid lines, were made as in (A). From Ref. (52).

Fig. 19B shows the la-catalyzed bleaching of Safranine O at different [la] for comparison. The experimental and calculated curves agree and prove that complete bleaching of the dye is achievable by just increasing the la concentration. The required amount is still very low, specifically, 10-6 M for the difficult-to-oxidize dye Safranine O. 

A different approach is the combination of a Pt-carbonyl-cluster with a special dye, Safranine O (Saf 3,7-diamino-2,8-dimethyl-5-phenylphenazinium) in an aqueous/organic two-phase system [48]. The dye is reduced in the organic phase and subsequently, in a type of phase-transfer catalysis, it reduced the cofactor in the aqueous phase. In this example l-LDH is used as a production enzyme, reducing pyruvate to L-lactate (Scheme 43.6). Complete conversion was obtained within 48 h, the mixture containing pyruvate, NAD+ and the Pt-cluster catalyst in a 600 10 1 molar ratio. The TOF for NAD+ was 15 h-1. 

Gram Stain A staining procedure used in classifying bacteria. A bacterial smear on a slide is stained with a purple basic triphenyl methane dye, usually crystal violet, in the presence of iodine/potassium iodide. The cells are then rinsed with alcohol or other solvent, and then counter-stained, usually with safranin. The bacteria then appear purple or red according to their ability to keep the purple stain when rinsed with alcohol. This property is related to the composition of the bacterial cell wall. 

When the stretched DNA-lipid film was soaked in an aqueous solution of ethidium bromide (itmax = 480 nm) for a day at room temperature, the transparent film turned red (itmax = 520 nm) and the aqueous solution became clear (Fig. 9a). Thus, the ethidium intercalated completely between base pairs of the DNA film. When the film was moved into the new aqueous buffer solution, the intercalated dye molecules were hardly removed from the film at least for a day. Similar intercalation behavior into the film was observed for other dyes such as proflavine, acridine orange, and safranine T [14-17]. 

Analysis. Colorimetry with proper reagents (such as nitrophenylfluo-ronone) permits analysis down to about 100 ppb. ETAAS detects Sn down to 1 ppb, and ICPMS is effective down to 0.1 ppb, as is anodic stripping voltammetry. Spot testing involves the use of cacotheline or diazine green (a dye made by reacting diazotized safranine with dimethylaniline). Sensitivity of these is about 50 ppm. 

Figure 6.2. A cross section of Lycopodium clavata (club moss) showing that different types of cells are selectively stained by specific coloured dyes (Safranin O and haematoxylin). (Courtesy of Jim Haseloff, http //www.plantsci.cam.ac.uk/ffaseloff)...

Exposure to ori/70-toluidine was reported to occur in an Italian plant producing fuchsin (magenta) and safranine T-based dyes (Rubino et al., 1982), in a German plant producing 4-chloro-ori/70-toluidine (Stasik, 1988) and in a plant producing rubber chemicals in the United Kingdom (Sorahan et al, 2000), but no data on exposure levels were provided. 

The first commercial synthetic dye, Mauveine (3), discovered by Perkin in 1856, was also a heterocycle, an azine of the Safranine class prepared by oxidation of aniline containing o- and p-toluidines. Since that time the contribution to colour chemistry from heterocyclic synthesis has been considerable and the present review can only hope to present some of the more salient features and at that only briefly. As an illustration it can be noted that since the late 1960s there have been in excess of 230 patents covering the use of azo dye couplers based on 2,6-dihydroxypyridine alone and the number of disclosures describing pyrazolones is probably greater than 1000. 

The more common and more important red lakes are those of cochineal, red wood, alizarin (or madder) and its derivatives, triphenylmethane dyes (fuchsine), safranine, eosin, developed and sulphonated azo-dyes the last give also orange lakes. 

Lakes of natural colours and those of alizarin are among the most stable and valuable. Eosin lakes and those of basic triphenylmethane dyes are very brilliant in appearance, but readily undergo alteration in the light those of safranine and those obtained from azo-dyes show more resistance. 

---